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Showing results for tags 'jeep tbi'.
Found 5 results
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I'm at my wits end troubleshooting my lil 2.5L engine. I googled and found your page from about a year ago. 1990 jeep wrangle 25l engine timing. Today I thought about timing. It misses, like running on only 2 cylinders when at low speed and and only pulling slightly. As I move into mid and upper rpm range it stops missing. I still do not have much acceleration but at least it stops missing. I've check and/or changed every sensor it has. TPS is only rough since I have not gotten my laser tach to work yet. In checking fuel I have only 10 psi so I know that's a problem. This started about a month after the SMOG guy changed the O2 sensor to pass smog. I've check the voltage when hot and it's within spec. I also had massive exhaust gasket leak so I cleaned the surfaces and replace the gasket. I'm a machine mechanic from way back in the Navy so I'm not just a new mechanic. I just can't quite figure this one out. I'll check timing tomorrow. Lowell -
I hate to bring this up again, but I need help. I have a 1990 2.5 TBI wrangler that is killing me! I say I've been throwing parts at it, but given it's age everything I've done was either bad or well on its way. Now that almost everything has been replaced including the IAC I need help adjusting it. I assumed the IAC was in the correct position when I replaced it, but I'm suspect the PO had adjusted it when some of these parts I replaced went bad or possibly when they plated off the EGR (I replaced the egr and cleaned the egr tube) and now I find myself trying to adjust the IAC. I've adjusted it twice. The first time I was very close, but was not perfect so I adjusted it a turn more and it's acting up again. I've ready your very helpful advice, but call me slow I could use a bit more help or even pictures on how to do it the way you describe. The adjustments I made were before I found this page and I was told to just unplug it adjust it to 3500 rpm turn it off, plug it in, start it up for a minute then reset the ECU and I'd be good to go. Which is "close" to what I read here but miles away too. It did make it much better, but one more turn and it's back stalling out again. Can anyone give me pictures or better yet a video? I've hardly been able to drive the jeep since I purchased it. -
Thanks for the engine information. Ok .... update for today. I'm really not finding a vacuum leak and before I build a smoke machine there's been this gnawing in the back of my mind to check the valve timing. I found this pdf manual http://oljeep.com/JeepEngines.pdf and on page 63 it tell how to check valve timing. So I removed all the plug, it was easier to rotate by removing all the rocker bridges, set up a dial indicator on the #1 intake push rod and checked .... Hmmm the dial moved .010 but I don't see the index mark anywhere (????) ... oh, there it is 3 inches to the left, or 3 inches BTDC ... really???? Guess I'll pull the timing cover and check it out.
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Moses, I made a video of the Snap-on MT2500 scan tool readings maybe this will help in the RPM issue. Here is some history of the 89 Jeep Wrangler YJ 2.5L. I have what i call a hiccup when idling or driving every once in awhile. The engine is usually warm to operation temp and will hesitate or act like it dies ( rpm drop at an idle to 200 rpm or so) while idling in the drive way. Sometimes will die but will start right back up and there is days when it dose this hiccup while i am going 25 or 45 mph or what ever speed and has no rhyme or reason. Here is what I have replace or trouble shoot with a multi-meter (analog and digital meters), i check and replace vacuum hoses where needed and replace 4 small hoses on the TBI. Clean the crank sensor, replace MAT sensor, installed MAP sensor but ended up not using so replace with original. I compression check each cylinder and had 95 to 100 psi per cylinder. I put Seafoam in each cylinder and let sit overnight. Did this twice to get rid of the blow-by and it hasn't consumed any oil in 1000 miles spark plugs look good too, light colored. The Plastic valve cover was replace with an new oil cap as well because of oil being push out thru the oil cap. After the Seafoam treatment I check compression and found it went up to 110 in each cylinder. The engine has no leaks and no noise of any kind that would point towards replacing it. Also put Seafoam in the gas and poured some into the TBI. This seem to work quite will for smoothing out the idle and performance. I have real good acceleration. Previous owner replace the spark plugs, wires, rotor and cap, O2 sensor, belts, and change all drive train fluids to synthetic and oil change with Valvoline 10-30. I Check grounds under hood and they look great. The engine idles about 800 rpm. I borrowed a Snap-on MT2500 and scan it but really nothing stands out. When the jeep is running I wrote down the readings from the MT2500 and notice the ST Fuel trim 126 and LT Fuel trim 133 steady. I listen to the TBI with the air horn off and sounds like a hissing noise when the engine starts to hesitate or stall, but will start right up. Kind of out of answers other than the TBI needs replace and I have plenty of power on the highway and thru the whole power band from start to 80 mph. I removed the gas tank because the sending unit was showing incorrect gas level so I tested the gauge and the sending unit and found the baffle in the tank was the issue, so I removed it and check all the fuel lines and the vents and all is good and not plugged up. Gas gauge reads correct now and it seems to run pretty good today as I drove it for about 10 miles. What is your thoughts, thanks. VID_20161029_134408091.mp4 VID_20161029_134128876.mp4 -
My 88 Comanche 2.5 liter doesn't have a wot sensor did some of them not come with them or maybe some one took it off when I wasn't looking
