REALLY bad gas miliage - REFERENCE
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Post by jkdv8 on Sept 27, 2014 14:17:43 GMT -5
Good info Ed. Much appreciated. One question I have is the tank "spray" when you undo the cap to fill up. I noticed it did the first few years, as well as getting the stated fuel economy or better, then, the past few years it doesn't spray any more and fuel economy for one reason or the other hasn't been all that great. Always assumed it was the tires, extra weight, then the most recent the alt (think I calculated 15 this past tank was 16) although I was running the a/c more than usual. Also wondered how sensitive the diagnostics are on these trucks cause I've had issues with the egr solenoid that didn't throw a code. So now you got me wondering. Guess I need to run through the check list. Keeping logs as you mentioned with the scan tools is a great idea. Ill have to go back and check the few I have recorded over the years.
Edit: I did change the gas cap a few years ago and it made no difference.
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Post by jay4x4 on Sept 27, 2014 23:01:15 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 Funny I just got one of those too lol. Right on the lip of the flex pipe. Sounds terrible.
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Post by ES_97Sport on Sept 30, 2014 20:05:44 GMT -5
... Funny I just got one of those too lol. Right on the lip of the flex pipe. Sounds terrible. Dang! Must be that time of year. Get that fixed soon. Once you have a pin hole, it doesn't take long to get really bad and it'll REALLY mess with the ECM/PCM. The last thing you want is a persistent rich condition in the CAT. Literally, the CAT burns itself up. Edward
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Post by ES_97Sport on Sept 30, 2014 20:21:06 GMT -5
... One question I have is the tank "spray" when you undo the cap to fill up. I noticed it did the first few years, as well as getting the stated fuel economy or better, then, the past few years it doesn't spray any more and fuel economy for one reason or the other hasn't been all that great. Always assumed it was the tires, extra weight, then the most recent the alt (think I calculated 15 this past tank was 16) although I was running the a/c more than usual. Also wondered how sensitive the diagnostics are on these trucks cause I've had issues with the egr solenoid that didn't throw a code. So now you got me wondering. Guess I need to run through the check list. Keeping logs as you mentioned with the scan tools is a great idea. Ill have to go back and check the few I have recorded over the years. Edit: I did change the gas cap a few years ago and it made no difference. No worries. "is the tank "spray" when you undo the cap to fill up" I'm not sure what you mean. Uh, 'sensitive' is open to interpretation. I've had things that the service manuals swear will pop a code but don't. EGR, evap are two off the top of my head. I've had things are are supposed to pop a specific code that actually trigger some other code. It gets better on the '00-'05 Sports, but the '97-'99 Sports are interesting. They all still have some strange OBD behavior, though. This I can say with assurance. If you're relying on the vehicle OBD to alert you, you're heading down the dark path. Yep, that seems to be the most reliable way. There's just too much slop programmed in. Long before a code comes up you almost certainly notice something wrong if you're keeping a log and paying attention. Ironically, I noticed this before I left for UT last week. I pulled up the fuel trims and noticed that I was running +3.5 LTFT. What the hell??? I had everything zeroed out with the F/IC. Then I blew a hole through the flex joint in the exhaust RIGHT in front of the primary O2 sensor. No way it was fine before leaving - there had to be a leak there for a while. Explains my trims, though. Fresh air getting into the exhaust in front of the O2 sensor so the sensors telling the engine, 'Hey!!! You're running lean! Need more fuel!!!' The point is that I checked the flex joint Friday before leaving and it APPEARED fine. I didn't hear anything, didn't feel any leaks when I ran my hand around it and I didn't see any black spots but obviously there was a leak. Confirmation of this was when I slapped the band clamp on and it actually ran BETTER than when I was driving out before I blew a 50 cent size hole in it. That flex joint is a PITA. I wish I could pull it out but it is needed. The problem is its corrugated pipe and its wrapped in a woven mesh so you can't see how bad a shape its in within the mesh. Pretty much you wait for it to leak and then replace it. The shop rag in the tail pipe technique is a good way to test this, BTW. Similar to the potato in the tail pipe technique, but not quite the same. Edward
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Post by jkdv8 on Oct 1, 2014 12:48:45 GMT -5
Yep that finicky behavior just about drove me crazy . It took taking the egr solenoid off to test it before figuring out that was it. Tested it while it was on there 2 or 3 times and everything seemed fine. However I believe it was an intermittent issue. As far as the fuel spray thing it's more or less I guess the tank releasing pressure when undoing the cap. Noticed on some cars it says on the cap to be careful of fuel spray when undoing the cap. However I was having an issue with the fuel temperature sensor around the same time so it could be attributed to that. Doesn't do it anymore and it doesn't sound like y'all have a problem with it either.
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Post by ES_97Sport on Oct 1, 2014 15:01:06 GMT -5
Yep that finicky behavior just about drove me crazy . It took taking the egr solenoid off to test it before figuring out that was it. Tested it while it was on there 2 or 3 times and everything seemed fine. However I believe it was an intermittent issue. Yep, sounds like the P0125 code I've been chasing for years. I still don't know if it was the evap or EGR solenoid but after replacing both I haven't had any problems. This is one of the codes that will come up for things that don't even tangentially relate to what this code is actually supposed to relate to. :rolleyes: OH! Ok. Duh. Sorry, I'm a little slow this week. Need a vacation from my vacation. Lets see if I remember this right. The tank evap stuff is different than the evap solenoid next to the egr solenoid. That stuff is all attached to the evaporative emissions canister in the driver side rear corner and the fuel tank itself. Haven't had to mess with that much. I had to replace the entire fuel tank about 2006 which is sold as a complete unit - pump, sensors and all - after having gravel wedged between the skid plate and tank eventually wear through the bottom of the tank. So, that's all relatively new. And, I replaced the entire evap system two or three months ago because my evap canister was saturated after 500K+ miles and it was cheaper to buy everything then just the canister. '99 3.5L and '00-'05 are the only ones with the fuel temp sensor. '97-'99 (excluding the 3.5L) don't have that. Thank God. So, no, I haven't had to get involved in that system much. Edward
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Post by jkdv8 on Oct 2, 2014 17:28:55 GMT -5
No worries Edward. That sucks about the fuel tank. That job looks like a pita. Part of the reason I put off replacing the fuel temp sensor. Two dealers told me it was integrated in the fuel pump. Looked in the service manual and someone on here confirmed it was on the floater assembly. Took like 10 min to change.
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Post by ES_97Sport on Oct 2, 2014 17:52:48 GMT -5
No worries Edward. That sucks about the fuel tank. That job looks like a pita. Part of the reason I put off replacing the fuel temp sensor. Two dealers told me it was integrated in the fuel pump. Looked in the service manual and someone on here confirmed it was on the floater assembly. Took like 10 min to change. Oh, no. The tank was cake. I know it looks bad and sound like a miserable job, but the hardest part was draining the fuel. Which wasn't that bad because the tanks have a drain plug on the bottom. Very, very handy! Like I said, the tank comes with everything - literally - so all you do is disconnect everything you can get to, drain the tank, then take out the four bolts on the bracket (two front/two rear) that holds it in. Support the entire thing with a hydraulic floor jack with a 2/2.5' long 1"x4" or 1"x6", take out the four bolts, lower it down until you can finish disconnecting everything and then drop it out. Reverse the process. I think it took about an hour. I hate that the tank is a unit from a cost perspective, but it makes replacement extremely easy. I think the entire assembly is about $500 new. Not cheap, but I got spare parts like a fuel pump (which I needed) off the old tank, so it wasn't too bad a deal. Never paid too much attention. I thought it was on the tank itself. That's interesting to know. Edward
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Post by jkdv8 on Oct 2, 2014 18:55:40 GMT -5
Good to know. Hopefully I'll never have to replace it. It is odd you have to buy the whole thing. $500 isn't bad though. Seemed when I was browsing (thinking the sensor was in the pump) they were pretty pricey for the oem one and it was just for the pump. No strainer, assembly etc. seems I came across a walbro and a Bosch which were way up there. Some other big name to but don't remember. It appeared that I and or the previous owner filled it up a little too much, too many times. The circuit board was all corroded at the portion where the wire for the sensor connects to it. So word to the wise don't fill it up to the gas cap. really bad idea but usually only did it when going off road. Usually by the time I got to where I was going it would be back down to the "normal" full level.
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Post by ES_97Sport on Oct 3, 2014 13:05:09 GMT -5
Good to know. Hopefully I'll never have to replace it. It is odd you have to buy the whole thing. $500 isn't bad though. Seemed when I was browsing (thinking the sensor was in the pump) they were pretty pricey for the oem one and it was just for the pump. No strainer, assembly etc. seems I came across a walbro and a Bosch which were way up there. Some other big name to but don't remember. It appeared that I and or the previous owner filled it up a little too much, too many times. The circuit board was all corroded at the portion where the wire for the sensor connects to it. So word to the wise don't fill it up to the gas cap. really bad idea but usually only did it when going off road. Usually by the time I got to where I was going it would be back down to the "normal" full level. Yea, considering what you get. I think if you add all the parts together separately you'd end up spending a lot more. Tanks usually last for a LONG time. I finally replaced the tank on my '68 'Bird four years ago. Original tank. It didn't leak - yet - but it was a rusty mess inside. Far as I know I'm the only on that's ever had to replace a tank because the the tank leaking. THAT I could have avoided by pulling the skid plate after wheeling and getting rid of all the crud wedged between the plate and tank. Something I stupidly never thought of doing. That's the problem with having a low slung vehicle for wheeling - the gas tank takes a beating. Those little holes tend to scrape up whatever you drag it across and wedge it between the plate and tank. Add a little vibration, and .... I never got an answer from Mitsu on why that is. I guess they figure if you have to replace the tank, you should be replacing everything else, too. I mean if something gets in the tank, its probably going to destroy all the sensors, pump, etc. anyway, so .... I couldn't find a pump that was a direct replacement. Everyone had 'generic' pumps that were supposed to fit but they didn't look like the stock one which made me a little paranoid. I'd hate to get on the trail, have a pump go out and then realize my spare couldn't be installed because I didn't have some other part. That's not the only thing doing that will screw up. It'll also saturate the evap canister. Not a cheap part to replace. When I did mine a couple months ago, I got an entire assembly off of eBay. Found a really low mileage vehicle and kept my fingers crossed someone wasn't in the habit of overfilling the tank. So far, so good. Edward
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Post by jkdv8 on Oct 3, 2014 16:23:46 GMT -5
Good to know. Hopefully I'll never have to replace it. It is odd you have to buy the whole thing. $500 isn't bad though. Seemed when I was browsing (thinking the sensor was in the pump) they were pretty pricey for the oem one and it was just for the pump. No strainer, assembly etc. seems I came across a walbro and a Bosch which were way up there. Some other big name to but don't remember. It appeared that I and or the previous owner filled it up a little too much, too many times. The circuit board was all corroded at the portion where the wire for the sensor connects to it. So word to the wise don't fill it up to the gas cap. really bad idea but usually only did it when going off road. Usually by the time I got to where I was going it would be back down to the "normal" full level. Yea, considering what you get. I think if you add all the parts together separately you'd end up spending a lot more. Tanks usually last for a LONG time. I finally replaced the tank on my '68 'Bird four years ago. Original tank. It didn't leak - yet - but it was a rusty mess inside. Far as I know I'm the only on that's ever had to replace a tank because the the tank leaking. THAT I could have avoided by pulling the skid plate after wheeling and getting rid of all the crud wedged between the plate and tank. Something I stupidly never thought of doing. That's the problem with having a low slung vehicle for wheeling - the gas tank takes a beating. Those little holes tend to scrape up whatever you drag it across and wedge it between the plate and tank. Add a little vibration, and .... I never got an answer from Mitsu on why that is. I guess they figure if you have to replace the tank, you should be replacing everything else, too. I mean if something gets in the tank, its probably going to destroy all the sensors, pump, etc. anyway, so .... I couldn't find a pump that was a direct replacement. Everyone had 'generic' pumps that were supposed to fit but they didn't look like the stock one which made me a little paranoid. I'd hate to get on the trail, have a pump go out and then realize my spare couldn't be installed because I didn't have some other part. That's not the only thing doing that will screw up. It'll also saturate the evap canister. Not a cheap part to replace. When I did mine a couple months ago, I got an entire assembly off of eBay. Found a really low mileage vehicle and kept my fingers crossed someone wasn't in the habit of overfilling the tank. So far, so good. Edward Hmm. Seems I heard that before. Guess I should start by checking that *fingers crossed*. Isn't that also called a charcoal canister.
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Post by ES_97Sport on Oct 6, 2014 12:32:48 GMT -5
... Hmm. Seems I heard that before. Guess I should start by checking that *fingers crossed*. Isn't that also called a charcoal canister. Yep. The big rectangular box right in the driver side corner up against the firewall. Edward
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Post by jkdv8 on Oct 6, 2014 16:09:41 GMT -5
... Hmm. Seems I heard that before. Guess I should start by checking that *fingers crossed*. Isn't that also called a charcoal canister. Yep. The big rectangular box right in the driver side corner up against the firewall. Edward I suppose it is easy to tell even if it's lightly saturated. I'm thinking it would smell like gas regardless. thanks again Edward.
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Post by ES_97Sport on Oct 7, 2014 15:13:39 GMT -5
Yep. The big rectangular box right in the driver side corner up against the firewall. Edward I suppose it is easy to tell even if it's lightly saturated. I'm thinking it would smell like gas regardless. thanks again Edward. No worries! Unfortunately, no, it isn't. I don't know HOW to tell really. Allegedly tailpipe emissions goes up. Nowhere can I find or find anyone who can tell me how much 'up' is. There's nothing in OBD either. The techs told me that if you weigh a new one and an old saturated one, the old one weighs more. Sounds like voodoo logic to me. :rolleyes: But, that was the only thing they could come up with. I mean, I KNEW mine was almost certainly shot because I had 500,000+ miles on it, but I never had empirical evidence. This might be one of those 'change after n number of miles, no matter what you think' parts. I know almost no one actually changes this part out ever, but they're not designed to last indefinitely. I also have no idea what 'n' would be. They were right, though, my old one did weigh more than the new one I got off eBay. Noticeably more. Edward
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Post by jkdv8 on Oct 7, 2014 18:32:14 GMT -5
Ahh emission control systems. Good times. Guess I'll see about taking it off to try that. Do you still have the weight for the old one and is there is a size weight difference from the 97-99 and 00 and up.
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