REALLY bad gas miliage - REFERENCE
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Post by ES_97Sport on Apr 21, 2014 15:56:50 GMT -5
I wanted to get some documentation down since people have been mentioning this a few times in various posts over the last six months or so. This is not an "OMG, I'm getting 17 instead of 18.5 MPG!" thread. This is a "OMG, I was getting 20 and now I'm get 14 MPG, but it seems to run 'ok'." thread.
Stuff to check that may not change driveability enough for most to really notice a change and may or may not trigger a code or CEL. This is the relevant stuff to a vehicle getting on in years that no one pays any attention to and then never thinks to check.
In no particular order:
#1 Evaporative canister - saturated
#2 Evaporative canister purge valve - dead, inconsistent operation, stuck open/closed/halfway
#3 EGR valve - stuck open/closed/halfway, inconsistent operation
#4 EGR solenoid - dead, inconsistent operation, stuck open/closed/halfway
#5 Manifold Absolute Pressure sensor (MAP) - dead, inconsistent operation
#6 Mass Airflow Sensor (MAF) (unit also includes IAT and barometric pressure sensors) - dead, inconsistent operation
#7 O2 sensors - inconsistent operation
#8 Catalytic converter(s)
#9 EGR valve feed line restrictor bee-bee. Partially or completely plugged.
I want to reiterate - any of these could be in need of replacement but MAY NOT trigger a code or CEL. Any or all of these together should negatively affect emissions if nothing else obvious so a sudden change between two tests is a good sign you have a problem.
Edit:
Added #8. Long term fuel trim (LTFT) is generated using both the pre and post CAT O2 sensors. Therefore, if the CAT isn't operating correctly, this will have negative affects on fuel delivery.
Added #9. Restrictor 'bee-bee' in the EGR valve line. If I remember correctly, this is in the vacuum line with the white line (on factory original lines).
Edit:
#10 Exhaust leak before the forward O2 sensor(s). An exhaust leak before the forward O2 sensor(s) will allow air into the exhaust stream BEFORE the forward O2 sensor creating a bogus lean fuel mixture reading. This will cause the ECM/PCM to richen the fuel mixture unnecessarily. Depending on how bad this leak is, issues can range from poor fuel economy, lack of power, and/or uneven idle to burning out the CAT (literally, in very short order).
This primarily is of concern to owners of '97-'99 Sports where there is a 'flex joint' just inches forward of the primary O2 sensor which has a tendency to crack and leak over time. On '00-'05 Sports the forward O2 sensors sit between the bank manifolds and the catalytic converters positioned in the manifold down pipes.
Edward
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Post by dclambertt on Apr 23, 2014 18:25:42 GMT -5
Thanks Ed
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Post by ES_97Sport on Apr 25, 2014 14:59:55 GMT -5
No worries. Stuff is getting on in years and these things are starting to wear out. Worse, they're parts that no one thinks of and don't generally cause massive issues that scream 'OMG, there's something broke! Fix me!!!' I just went through 1, 2, 4, and 5 on my big Sport. All of them were misbehaving and needed replaced - not one of them triggered a code. The EGR solenoid was working about 30% of the time and drawing a ton of juice. The evap solenoid was just flat shorted out and wasn't working at all. :rolleyes: Evap canister was just 550K miles old. I'm still not sure what the MAP's problem was. Had a weird driveability problem like it was working correclty about 1/2 the time. Replaced it with my spare and that was the end of that. Runs like new now! Also, after replacing these, I can stop with the windows down. Prior to these replacements the exhaust fumes were so bad it'd make your eyes water. Nice to not smell like a 40 year old out of tune muscle car again. Edward
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Post by jay4x4 on Apr 27, 2014 3:34:56 GMT -5
In the fsm does it show the correct readings for the sensors if I wanted to check it with a multimeter? I know I was able to find out my IAC was in acceptable range and just needed to be cleaned..have since misplaced mine, plan to get a new one but wondering how to go about checking.
Thanks
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Post by ES_97Sport on Apr 28, 2014 17:09:35 GMT -5
In the fsm does it show the correct readings for the sensors if I wanted to check it with a multimeter? I know I was able to find out my IAC was in acceptable range and just needed to be cleaned..have since misplaced mine, plan to get a new one but wondering how to go about checking. .... Yes. Mostly. A problem to be aware of is that not everything checks bad when it's bad. Sorry. I know that's probably not what anyone wants to hear. But, its something to keep in the back of your mind. My EGR valve and solenoid were tested a dozen times over the last couple years - and I'm almost certain now the solenoid was the cause of my spurious P0128 code that has since disappeared - and they came up within spec every time. Then about two weeks ago when we were testing the injector stuff for the AEM F/IC install, the tech happened to noticed weird sporadic behavior on his MUT. After fiddling with it for half an hour he finally decided there must be something wrong with the EGR solenoid - even though we couldn't get it to behave consistently the entire time. About 70% of the time it checked out fine, but 30% of the time it obviously wasn't working quite right. He was correct, because when I changed it out there was a VERY obvious - huge - behavior change in the vehicle (for the better). Another issue is that there are Technical Service Bulletins (TSB) that are not included with or in the FSMs. The '90s Sport IAC (ISC) is a good example. The original part was superseded years ago. The FSM specs are incorrect for the new IAC. The IAC is problematic. Just because the coils check out doesn't mean its working correctly. DSMIAC Automotive This is a good FAQ on the IAC. This is an issue with any electrical/mechanical device - make sure and check both halves. And don't forget to replace the o-ring. Besides a good multimeter, you will need a good automotive hand vacuum tester setup. One that will hold specific psi for a good period of time and is accurate. An inaccurate tester will make testing things like the MAP impossible. I didn't put this in the original post but probably should have. Besides the standard FSM diagnostics there are other ways to tell something is wrong. Given the discussed pieces and parts, an emissions test is one. Another is by monitoring fuel trims at the ECM/PCM. Long Term Fuel Trim (LTFT) and Short Term Fuel Trim (STFT) are the measurements of how much fuel is being added/subtracted to/from your engine from the level specified by the base fuel map in the ECM/PCM. These can be monitored via OBD-II/CAN with appropriate monitoring hardware and software. There are four 'levels' of both the LT and ST fuel trims. Each of the four 'levels' corresponds with an RPM range. Sorry, I don't have the exact ranges yet - still waiting on Mitsu. Roughly, zero to max-RPM (about 6K) are divided into four chunks. Idle, low, mid and high (this isn't Mitsu terminology - this is just what everyone typically visualizes). The top two always look 'abnormal' to me, because they're rarely used for real. By the time you're at 5K the vehicle is usually in open-loop drive mode and isn't using the O2 sensors. The bottom two, however, are very useful. Fuel trims have a negative to positive range of about +/-25% either way of zero - +n% means add fuel and -n% means subtract fuel. Beyond this the ECM/PCM will most certainly trigger a code and CEL - probably the vehicle won't run at all at this point. Fuel trims NORMALLY swing back and forth of zero - both LT and ST trims. ST fuel trims cycle quickly - sub-second-ish - while LT trims have a much wider window - upwards of 15 minutes per cycle. ST fuel trims deviate from zero much more than LT trims do. According to Mitsu within +/-5% of zero for LT trims is acceptable and normal. ST trims can fluctuate up to +/-15% from zero while driving. The ECM/PCM itself may (will most likely) begin to have issues when LT fuel trims approach or exceed +/-10% of zero. LT is the average correction to the base map over a period of time. ST trims are the running correction to the base fuel map with the LT trims applied. Total fuel trim is LT + ST. Deriving useful information from ST fuel trims - while possible - is more difficult than with LT trims. While virtually any OBD-II/CAN scanner hardware can be used, usefully using fuel trims really require something that can log for review latter. Fuel trims are great for looking at behavior over time - just a snapshot of 'right now' isn't terribly useful for diagnosing what's being discussed here. Same goes if its a PC/iStupid/Droid application. The other thing that is necessary is hardware or an application that actually reads all the trim levels separately and doesn't just display them as 'LT fuel trim' and 'ST fuel trim'. First, its easier if you can see them separately, and second, there's no way to tell for sure which trim level you're viewing or if its some average of all four (which is not just totally useless, its inaccurate) The simplest example of a problem and using fuel trims to diagnose it is a manifold vacuum leak. If the vehicle appears to be sound and behaving consistently, but LT trims are +8% say (adding fuel), then its a fairly good assumption that there's a vacuum leak. The engine is getting unmetered air from the leak and the O2 sensors are telling the engine to add fuel to compensate for a lean condition. I use this method to double check after having plugs and wires replaced since that requires that the manifold be removed and if the torque sequence and specs are not followed exactly its very easy to end up with a problem. Another slightly more difficult and opposite problem is leaking injector(s) supplying unmetered fuel. Consistently negative LT trims of -8% say, indicates that the fuel system is supplying too much fuel. The O2 sensors are seeing a rich condition and are telling the ECM/PCM to subtract fuel. Computer controlled vehicles are a lot like steering stabilizers. They're really nice to have but they can cover up things you really should know about. That's why its important to keep track of things somehow and to have more visibility into your vehicle than just a dash light. Having a log of how your vehicle is running three months ago when everything was fine, compared to a log of now when it just doesn't seem to be behaving right is a huge help in troubleshooting. Edward
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Post by jay4x4 on Apr 29, 2014 0:04:21 GMT -5
Haha I love the istupid reference.
This is very interesting didn't expect to deal with this on this vehicle as much, but sadly it's a bit familiar to me. It reminds me back when I had my audi turbo, tuning it by checking fuel trims and with a turbo a vac/boost leak was pretty noticeable and a big no no since between what the maf and o2 sensors, the readings differed and put you rich or lean. On top of all that I ended up having to go with colder plugs....anyways before going too subject, I think I may slowly replace all the items. I have about 240k and the PO hasn't taken very good care of it. As for mpg, I know this ain't a feather weight 4cyl but I think I should be getting numbers(15mpg), this is how I got it so don't really have much to compare on. I totally relate to the whole computer thing, reminds me of tuning my motorcycle vs my audi.......carbs lol....jets and needle took care of must things... I noticed on your website you got up to 24-25 in the mild stage..hope to achieve that. Best I got was 18mpg on a Vegas trip...
Thanks!
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Post by ES_97Sport on May 5, 2014 14:54:42 GMT -5
Haha I love the istupid reference. This is very interesting didn't expect to deal with this on this vehicle as much, but sadly it's a bit familiar to me. Never changes. Just the tools available change. What I would have given for this kind of visibility 30 years ago when building my 'Bird. First, KIM that I run 5-speed M/Ts. The 4-speed auto isn't that efficient. I've side-by-sided the M/T and A/T - the A/T just doesn't get as good of gas mileage as the M/T. Second, I bought my '97 with 67 miles on it and immediately switched to full synthetic in everything - including the transmission, which you can't do. It can make a big difference if you can do this from square one, rather than 100K miles and three nit-wits latter. Third, I had/have manual locking hubs on the front. That means I'm not driving all that rotating mass up front (if you can find hubs, at least you can fix that) and that makes a HUGE difference. I'd be looking at closer to 20 if I were you. That's more realistic. Even with my little '97 having issues with something (don't know what yet) - I can still get 20 back and forth from Denver and Moab. That's with 180K miles. The best out of my '03 Limited AWD - with the Montero 5-speed A/T - is high 18s to 19 (if I'm lucky), and that's on a vehicle that's in perfect condition. The '03 is bone stock. The little '97 has a ARB bull bar and Warn XD9500. Mmmm. 18 is a little low for straight highway, but not much, unless you're doing 85-90 Mph all the time. Unless you take two steps backwards every time you take a step forward, even with wear and tear, you should be able to get 20. But, that means EVERYTHING needs to be working correctly. Solenoids, valves, sensors, CATs, filters, etc., and compression has to be normal, no worn out valve stem seals, and a good evap canister. Edward
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Post by jay4x4 on May 8, 2014 20:43:54 GMT -5
Haha I love the istupid reference. This is very interesting didn't expect to deal with this on this vehicle as much, but sadly it's a bit familiar to me. Never changes. Just the tools available change. What I would have given for this kind of visibility 30 years ago when building my 'Bird. First, KIM that I run 5-speed M/Ts. The 4-speed auto isn't that efficient. I've side-by-sided the M/T and A/T - the A/T just doesn't get as good of gas mileage as the M/T. Second, I bought my '97 with 67 miles on it and immediately switched to full synthetic in everything - including the transmission, which you can't do. It can make a big difference if you can do this from square one, rather than 100K miles and three nit-wits latter. Third, I had/have manual locking hubs on the front. That means I'm not driving all that rotating mass up front (if you can find hubs, at least you can fix that) and that makes a HUGE difference. I'd be looking at closer to 20 if I were you. That's more realistic. Even with my little '97 having issues with something (don't know what yet) - I can still get 20 back and forth from Denver and Moab. That's with 180K miles. The best out of my '03 Limited AWD - with the Montero 5-speed A/T - is high 18s to 19 (if I'm lucky), and that's on a vehicle that's in perfect condition. The '03 is bone stock. The little '97 has a ARB bull bar and Warn XD9500. Mmmm. 18 is a little low for straight highway, but not much, unless you're doing 85-90 Mph all the time. Unless you take two steps backwards every time you take a step forward, even with wear and tear, you should be able to get 20. But, that means EVERYTHING needs to be working correctly. Solenoids, valves, sensors, CATs, filters, etc., and compression has to be normal, no worn out valve stem seals, and a good evap canister. Edward ahh yes this is one second auto vehicle, first 5 were stick shift, and although I love it on California traffic. still miss being more in control of the vehicle... I plan to look for manual hubs, whenever that'll happen lol, I think I may just check those items out and hope for 20mpg. yes I am getting average 15mpg with 18 on long highways. the trip to vegas was done at 65mph with cruise control because any faster and steering would be dangerously loose lol (fixed btw will post about it in my other thread).
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Post by ES_97Sport on May 9, 2014 13:35:08 GMT -5
... yes I am getting average 15mpg with 18 on long highways. the trip to vegas was done at 65mph with cruise control because any faster and steering would be dangerously loose lol (fixed btw will post about it in my other thread). Hear that! Mine was getting a little sloppy before I replaced the steering box and shaft. Its really nice, now. Like driving a new vehicle. 15 in town is way low. Something's not right. Even my '03 AWD doesn't do that. I get real close to 18 and that's AWD with big tires. In fact, even with my big '97 not running right, I still get 15.5-15.8 in town on that. If everything on your Sport is still original under the hood, I'd start looking at the list and going through things. None of this stuff lasts forever, especially #7, #8 and #1. Usually, O2 sensors should be changed every 80-100K. I know they'll 'work' much longer in most cases, but like CATs they wear out over time and become less efficient. O2 sensors basically tell the ECM/PCM how much fuel to inject into the engine. If the CAT isn't working efficiently, the rear O2 will send a skewed reading to the ECM/PCM which will throw off fuel delivery. If the vehicle is burning oil, that'll seriously decrease the life span of O2 sensors and the CAT. If I were to suggest an order, I go through the emissions stuff first. Start with EGR. On stock Sports (I don't know how many years, but I know more than the '97 had it), there is a little restrictor in the EGR line. I believe it's the line with the white line. That tends to plug up over time and then your EGR quits working or doesn't work consistently. The techs take that out if they find it still there. The solenoid and valve have to be working correctly or you'll spend a lot of time chasing 'issues' elsewhere that don't actually exist. Next would be the evap stuff. The MAP (or MDP as Mitsu calls it) sends data to the ECM/PCM that is used for a LOT of things - all of which are directly fuel delivery related. I've replaced two over the live of my big '97 that just over time kinda stopped reading correctly. O2 sensors would be next. If they're both old, you can't replace just one. You have to replace both and I strongly suggest using the Mitsu sensors. Yes, I know they're God awful expensive, but there's a reason after market sensors are $40. While they may technically function the same - which is actually untrue in a lot of cases - they will not last as long as the factory sensors. Which leads to the CAT. The ECM/PCMs use the O2 sensors to check CAT efficiency which in theory will trigger a code and CEL if its not within the required range. How well this works and how reliable it is is open to debate. IMHO, it's not a way to tell if the CAT needs replaced. Anyhow, CATs wear out over time, even the factory ones which are REALLY good. CATs prices are pretty much tied to material costs - the more platinum inside, the more they cost. And the better they work and the longer they last. Last would be the MAF unit. Barometric pressure isn't as important as MAP, maybe, but its important. If the IAT isn't reading the temperature of the incoming airflow correctly, this can seriously skew fuel delivery. Anyway, that's kind of the order I look at things. Probably it will not be just one thing, but a combination of things. An unfortunate drawback of things getting old. Edward
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Post by jay4x4 on May 13, 2014 1:49:38 GMT -5
Hear that! Mine was getting a little sloppy before I replaced the steering box and shaft. Its really nice, now. Like driving a new vehicle. 15 in town is way low. Something's not right. Even my '03 AWD doesn't do that. I get real close to 18 and that's AWD with big tires. In fact, even with my big '97 not running right, I still get 15.5-15.8 in town on that. If everything on your Sport is still original under the hood, I'd start looking at the list and going through things. None of this stuff lasts forever, especially #7, #8 and #1. Usually, O2 sensors should be changed every 80-100K. I know they'll 'work' much longer in most cases, but like CATs they wear out over time and become less efficient. O2 sensors basically tell the ECM/PCM how much fuel to inject into the engine. If the CAT isn't working efficiently, the rear O2 will send a skewed reading to the ECM/PCM which will throw off fuel delivery. If the vehicle is burning oil, that'll seriously decrease the life span of O2 sensors and the CAT. If I were to suggest an order, I go through the emissions stuff first. Start with EGR. On stock Sports (I don't know how many years, but I know more than the '97 had it), there is a little restrictor in the EGR line. I believe it's the line with the white line. That tends to plug up over time and then your EGR quits working or doesn't work consistently. The techs take that out if they find it still there. The solenoid and valve have to be working correctly or you'll spend a lot of time chasing 'issues' elsewhere that don't actually exist. Next would be the evap stuff. The MAP (or MDP as Mitsu calls it) sends data to the ECM/PCM that is used for a LOT of things - all of which are directly fuel delivery related. I've replaced two over the live of my big '97 that just over time kinda stopped reading correctly. O2 sensors would be next. If they're both old, you can't replace just one. You have to replace both and I strongly suggest using the Mitsu sensors. Yes, I know they're God awful expensive, but there's a reason after market sensors are $40. While they may technically function the same - which is actually untrue in a lot of cases - they will not last as long as the factory sensors. Which leads to the CAT. The ECM/PCMs use the O2 sensors to check CAT efficiency which in theory will trigger a code and CEL if its not within the required range. How well this works and how reliable it is is open to debate. IMHO, it's not a way to tell if the CAT needs replaced. Anyhow, CATs wear out over time, even the factory ones which are REALLY good. CATs prices are pretty much tied to material costs - the more platinum inside, the more they cost. And the better they work and the longer they last. Last would be the MAF unit. Barometric pressure isn't as important as MAP, maybe, but its important. If the IAT isn't reading the temperature of the incoming airflow correctly, this can seriously skew fuel delivery. Anyway, that's kind of the order I look at things. Probably it will not be just one thing, but a combination of things. An unfortunate drawback of things getting old. Edward Yes, their seems to be a combination of things wrong lol. I think I may go in that order as well, seeing as the O2 sensors will murder me. I just hate replacing all this expensive stuff lol but seems to be the only way...funny though on this vehicle, maybe other NA vehicles as well, that when parts aren't working 100% you still don't notice them. Gosh I remember my MAF going bad on my audi and let me just say wow soon as you got into the boost it would buck like hell, and spark plugs would create really noticeable misfires. Oh I also forgot I think I may have a exhaust leak too so that'll be another thing to check since I am pretty sure they are going to be pre O2s....long mission ahead lol
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Post by monty98 on May 15, 2014 13:51:05 GMT -5
Ugh, haven't been on this forum in a long time and I came around to join back up and now reading through your post Edward, I realize I am nearing my 200K milestone with my 5speed and I have been seeing HORRIBLE MPGs the last few months, to the point where I'm lucky if I can get 250 miles a tank, hovering right around 16-17 mpg combined city/highway driving.
So it looks like in addition to doing the timing belt next year I will be working down this list you provided for us. Come to think of it I haven't had any red flags EVER with the monty *knock on wood* mostly due to my preventative maintenance, but also because the PO was very gentle and good with the truck. Now me? I've been to hell and back through the Colorado mountains last year, 3000+ mile trips and it the issues are starting to pop up. I'll diving in head first to this one!
Thanks for the write up too Edward, it really helps!
Jefferson
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Post by ES_97Sport on May 16, 2014 13:37:12 GMT -5
Yes, their seems to be a combination of things wrong lol. I think I may go in that order as well, seeing as the O2 sensors will murder me. I just hate replacing all this expensive stuff lol but seems to be the only way...funny though on this vehicle, maybe other NA vehicles as well, that when parts aren't working 100% you still don't notice them. Gosh I remember my MAF going bad on my audi and let me just say wow soon as you got into the boost it would buck like hell, and spark plugs would create really noticeable misfires. Oh I also forgot I think I may have a exhaust leak too so that'll be another thing to check since I am pretty sure they are going to be pre O2s....long mission ahead lol Unfortunately, that seems to be how it goes. On the plus side, after replacing most of what's in my list my big Sport runs like a top and idles like glass. Runs like it was new. What I've gathered over the decades of building and working on vehicles - and this isn't my experience since I only run NA vehicles - is turbo and super charged vehicles are a lot more sensitive to things just not being quite right than NA vehicles. And sensitivity changes depending on brand, make, and even model and sometimes even between exactly the same vehicle but different years when you start throwing computer controls into the mix. All depends on how much 'slop' is programed into the ranges - so what is considered 'bad' and 'not bad'. And, it also depends on how 'smart' and ECM/PCM is - so how good the algorithms are. Nice having a hardware programming background - helps to understand some of this. Yea. I noticed I have a leak today on the way into work. Sigh. Depending on where the leak is, that'll really hork up fuel delivery, too. After the last O2 sensor is irrelevant, but before the first O2 sensor or between the O2 sensors can make a huge mess. Edward
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Post by ES_97Sport on May 16, 2014 13:47:31 GMT -5
Ugh, haven't been on this forum in a long time and I came around to join back up and now reading through your post Edward, I realize I am nearing my 200K milestone with my 5speed and I have been seeing HORRIBLE MPGs the last few months, to the point where I'm lucky if I can get 250 miles a tank, hovering right around 16-17 mpg combined city/highway driving. So it looks like in addition to doing the timing belt next year I will be working down this list you provided for us. Come to think of it I haven't had any red flags EVER with the monty *knock on wood* mostly due to my preventative maintenance, but also because the PO was very gentle and good with the truck. Now me? I've been to hell and back through the Colorado mountains last year, 3000+ mile trips and it the issues are starting to pop up. I'll diving in head first to this one! Thanks for the write up too Edward, it really helps! Jefferson No worries! Hope it helps! Trying to get some stuff out there since people have started mentioning it. Problem with most of this is it creeps up on people. Nothing on my big Sport was glaringly obvious. Seemed to run pretty much ok. Power seemed a little off, but not really bad. Mileage, though, just started going down hill and it wasn't consistent. Sometimes it would seem fine but then it'd go back to being really bad. Sometimes even in the same drive cycle. But, over the course of months it just steadily degraded. But, because it kinda creeps up, most people don't notice the steady degrading. Especially if it takes months or a year or more to get bad enough to actually notice. It's like they say, "If you dump a frog in a boiling pot of water, it'll jump right out. If you dump a frog in a pot of cold water and heat it up gradually, it'll just boil to death." Edward
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Post by jay4x4 on May 17, 2014 0:01:40 GMT -5
Yes, their seems to be a combination of things wrong lol. I think I may go in that order as well, seeing as the O2 sensors will murder me. I just hate replacing all this expensive stuff lol but seems to be the only way...funny though on this vehicle, maybe other NA vehicles as well, that when parts aren't working 100% you still don't notice them. Gosh I remember my MAF going bad on my audi and let me just say wow soon as you got into the boost it would buck like hell, and spark plugs would create really noticeable misfires. Oh I also forgot I think I may have a exhaust leak too so that'll be another thing to check since I am pretty sure they are going to be pre O2s....long mission ahead lol Unfortunately, that seems to be how it goes. On the plus side, after replacing most of what's in my list my big Sport runs like a top and idles like glass. Runs like it was new. What I've gathered over the decades of building and working on vehicles - and this isn't my experience since I only run NA vehicles - is turbo and super charged vehicles are a lot more sensitive to things just not being quite right than NA vehicles. And sensitivity changes depending on brand, make, and even model and sometimes even between exactly the same vehicle but different years when you start throwing computer controls into the mix. All depends on how much 'slop' is programed into the ranges - so what is considered 'bad' and 'not bad'. And, it also depends on how 'smart' and ECM/PCM is - so how good the algorithms are. Nice having a hardware programming background - helps to understand some of this. Yea. I noticed I have a leak today on the way into work. Sigh. Depending on where the leak is, that'll really hork up fuel delivery, too. After the last O2 sensor is irrelevant, but before the first O2 sensor or between the O2 sensors can make a huge mess. Edward lol this will be interesting seeing as this is how I pretty much got the vehicle so I have no basis for comparison but looking forward to having it running better
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Post by ES_97Sport on Sept 27, 2014 0:43:37 GMT -5
Post #1 updated Sep, 26th 2014.
Added #10 to the list.
I had forgotten this little issue until my '97 decided to give me a little refresher. Blew a hole through the flex joint somewhere between Rifle, CO and Green River, UT in 90 degree weather doing 70 MPH. Leak started getting noticeable about Cisco and got REALLY bad about 10 miles from Green River. Started running really rich and power went straight to hell. Of course, by this time I could tell I had the granddaddy of all exhaust leaks. Managed to limp into town without doing any permanent damage.
Quick temporary fix? Napa and a 3" wide x 3" diameter stainless exhaust band clamp. Can't wheel this way, but good enough to get back to Denver.
Edward
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