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Post by kmcrane9578 on Nov 30, 2009 18:13:49 GMT -5
Hi my name is Kevin, I am new to this forum. I have had a problem with my 2000 montero sport. It has the 3.0l engine. I t has 160,000 miles. I started a few months back having idle problems in the mornings. I didn't think much of it as i just figured it needed a tune up. It would run around 1100 rpms then just dip and almost die! I could get in and rev it up and drive a block or 2 and it would run fine. But one day it started and the check engine light came on. I have a friend who owns a auto repair shop, so i took it to him. He scanned it and it read "multiple misfires" So he kept my car to work on it. What he did was.... 1: cleaned the injectors (twice), new spark plugs & wires, cleaned the throttle body, and intake with a special machine, changed the phlem gasket also (sp).. he said there was oil on the spark plugs from that gasket leaking. But no change on the idle. There is no check engine light, but it will idle VERY rough for 2-3 mins if it has sat more than a couple hours. My friend is lost on what to do next. I have to let the car idle for a couple mins now because it is really bad. I may die if i try to drive it too soon. My exhaust smells very rich (like pure gas) until it warms up, and my gas mileage is down about 2 miles per gallon from normal. Any input would be greatly appreciated. Thank You Kevin
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Post by kmcrane9578 on Dec 12, 2009 16:14:58 GMT -5
under some more reserch, a different mech says it could be a fuel pump module..? My mech says if he unplugs the MAF sensor the car instantly smooths out and runs better. but yet he says it is NOT a bad MAF sensor. If that helps.... i haven't had any reply's here...
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Post by mctweety on Dec 12, 2009 18:06:32 GMT -5
You said you cleaned the throttle body with a machine? How does that work? The best way is typically just a rag and some carb cleaner spray. Did you check/clean the EGR valve?
Did you replace your spark plugs with the correct type (NGK PFR6J-11)?
I doubt it's the fuel pump. If the exhaust smells rich, it could be the MAF sensor. I assume you have tried a computer "reset" by disconnecting the battery for a while?
Once the engine is warmed up, does it run fine or still a little rough? When was the last time you replaced the timing-belt?Maybe it has slipped 1 tooth on one of the camshafts.
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Post by Joel_CA on Dec 12, 2009 22:56:41 GMT -5
I have seen many issues where the fuel pump control module has failed causing very rough running issues that smooths out when the airflow sensor is disconnected. In every case- prior to this problem occurring, the vehicle required a jump start and was accidentally jumped in reverse polarity. Has this happened to you? The fuel pump control module varies the amount of voltage being sent to the fuel pump depending on fuel needs. Disconnecting the airflow sensor will default this varying voltage to full power.
If you want to verify this is your problem- you can measure voltage at the fuel pump or even check your fuel pressure at idle with the airflow sensor connected and disconnected.
JJ
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Post by kmcrane9578 on Dec 13, 2009 21:00:28 GMT -5
I was wrong on how he cleaned the MAF Sensor, it was by hand. Also i am running a huge car audio system in my car with dual batteries. I will disconnect the batteries for a while tonight and do that, i have not tried that yet. He said the fuel pump was fine and he thought it was the fuel pump control module.... I will relay that trouble shooting techniques to him. Thank you for the help so far.
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Post by marketmagoo on May 29, 2011 9:20:17 GMT -5
joel_CA I know this thread is old, and I'm a newbie here, but you describe my problem exactly. Hope you can help me a little more here! A very kind guy helped my wife jump our 2000 Sport after lights were left on. She thinks he first put cables on backwards, then quickly changed them. We did end up replacing battery and alternator, but our Sport has never regained idle memory. Our mechanic said that the mass airflow sensor is reading bad, but still read bad after replacing, so he put the old one back in. He couldn't get the idle to relearn, so he disconnected MAS entirely to achieve a functional idle. He directed us to the dealer. Now our exhaust smells VERY rich, and fuel economy has dropped thru the floor, which seems to jive with your description. We live about 200 miles from a dealer, so I'm hoping someone here can help me out. I'd rather solve this locally or by myself. So, my questions are these: 1. Is this a test/part replacement I might be able to do? (No specialty tools or equipment - no high pressure lines - no complicated or in depth procedure.) Or should I go back to my mechanic with these recommendations? 2. If it is the fuel-pump control module, how expensive is this part/repair? Ballpark is fine. 3. How sure can one be based on the troubleshooting tip you give that that will fix it? Or is there possibly something else going on too? Thanks a ton for your help on this! We really love our Sport, and I'm glad to have found this forum!
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Post by buggzyy on May 30, 2011 20:20:17 GMT -5
Joel is correct in testing the fuel pressure system. easiest way to check is to use a volt meter at the fuel pump control module back probe pin. 3 Black/White check the voltage output with connector still connected while the engine is running then disconnect the MAF sensor and recheck the voltage it should be pretty close to the same if not your fuel pump control module has failed this is about 239 dollars. easy to replace. You can also check fuel pressure but this will require a special adapter to tap into the fuel line. curb idle pressure is 39psi. This is a 99% for sure test for this component. Also check the big fuses at the battery. This will not guarantee there are no other problem its just one for sure known failure when its been jumped backwards. We had one in last week where it fried the ECU but it still ran. The fuel pump control module is located behind the RH kick panel if you have 4WD it will be up near the glove box above another module. should be a 5 pin connector going to it. Hope this helps.
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Post by marketmagoo on Jun 1, 2011 11:02:50 GMT -5
buggzyyThanks for the detailed instructions! I will give this a try and report back.
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Post by marketmagoo on Jun 1, 2011 15:49:19 GMT -5
Your directions for testing were perfect - I was able to find and test the module. The result was that the voltage read the same both times (roughly 13VDC) - with MAF connected and disconnected.
However, if I read your post right you seem to say that the readings should be the same both ways, whereas based on Joel's post it sounds like the reading should vary - that the voltage to the fuel pump is variable to vary the flow rate.
So am I misunderstanding one of you? Which way does a good module read?
If my test results indicate a good module, then where do I look next?
Thanks for your help on this!
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Post by buggzyy on Jun 5, 2011 21:49:39 GMT -5
Joel is correct but when cold the fuel pump should have full power to keep the mixture rich. and may back off some as it warms up. I have never hooked a voltmeter to the pump to see when the voltage changes so I cannot accurately describe its function.
It is possible that your PCM has been damaged.
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