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Showing results for tags 'jeep 2.5l tbi'.
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On the passenger side engine compartment on my 89 yj 2.5 liter there is some diagnostic plug in connectors. which one is the connector for the isa motor control? Which one is D-1 and D-2? How are each individual holes in connectors numbered ( 1-2-3-4-5-6 etc>)?
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I've read that drilling out the upper mounting hole will get my cps a hair closer to the flex plate BUT that is just close enough to improve the voltage to a much more respectable reading. My problem is, I haven't read anything that clarifies which hole. Am I drilling the mount hole on the bell housing or the one on the cps bracket. And this is my first post so I'll let y'all get the flaming out of your systems now with a second question. What in the wide wide world of sports are us early 2.5 (1987) TBI remix guys supposed to do when we need a MAT (NOT MAP) Sensor? NLA -
Hello to All.... I wish to thank all the members and especially you Mr. Ludell for all the time spent on our endless problems.... I have reviewed all the posts that might pertain to my problem and do not wish to ask a question that can be easily answered by simple review... My YJ has had an.. "on again / off again" problem that may not be related to this exact problem but it just seems to have never been 100 % or maybe even 80%... The current problem started on an outing in the woods ..drove fine climbing, downhill and 4wd.. coming back the engine began to act like it was starving for fuel..the harder you press on the gas the more it chocked out...would idle fine..no power.. So... I took it to mean a faulty pump and ordered same...pulled tank ..found sock off the pump..Problem solved ??..decided since I have a new one might as well drop it in.. "nice to have a trail spare anyway".. replaced tank with new filter... went to fire it up ...no start..no apparent fuel at the TBI....Now it wont run at all... So... check electrical to pump ..fine..check lines..fine.. Ordered a Pressure gauge...slap it on the TBI access port ..No pressure.....Check pressure before the TBI... jumps to 50 psi...way to much..?? checked inline with " T " Key on 25 psi.. Start..jumps to 50 psi..no apparent fuel returning to tank.. SO.... rebuild the TBI... bad regulator..Maybe...clean, replace TPS , new injector, and filters while its apart... " Nice to have trail spares anyway" reassemble...try to start ...no fuel.... So....Back to ZERO.... No fuel getting past the Regulator... Remove TBI..reinspect , reassemble..try to start...no fuel Also the CPS..MAT sensors replaced during the last session...Of unknown problems..."Nice to have trail spares anyway" When fuel is manually poured in the carb. she fires right up and I can keep it running if i drizzle it in.. So... it runs if i can figure out how to get my wife under the hood with a squeeze bottle while I drive....Could work...Maybe.. Make a great hood ornament...Should switch that around encase she reads this..She Drives....ya sounds better... The questions are.....will the pressure spike to 50 psi if there is no return to tank..? Is 50 psi just way to much ..? Will to much pressure cause the regulator to shut down so to speak..? Is it possible the spring in the regulator is bad ,The kit did not have a new spring...Seems a weak spring would allow to much fuel...did try to adjust with set screw...no Fuel...? The TBI is clean no blockage in ports...so what could be stopping the flow... Other than the regulator... ? "Did I just answer my own question..Maybe" Why are my troubles worse now after the repairs..At least it ran at idle before? Your Attention , Patience and experience with this matter will earn you my admiration and a box of Girl Scout cookies...of your choice Jamie -
Here is 1987-90 Jeep YJ Wrangler and Jeep XJ Cherokee/MJ Comanche 2.5L TBI diagnostics information in PDF form. The first document includes all sensor and switch tests plus adjustments that affect engine tune, idle and reliability. Wiring schematics and ECU pin locations, test plugs and diagnostics included. Jeep 2.5L TBI Complete Diagnostics-Sensors-Switches.pdf Jeep 2.5L TBI ECU Inputs and Outputs.pdf Jeep 2.5L TBI MAP Sensor Test.pdf Jeep 2.5L Timing Chain and Tensioner.pdf Jeep 2.5L Valve Timing Check.pdf Jeep YJ 2.5L TBI Sensors and Pinout.pdf YJ Wrangler 2.5L TBI Wiring of WOT to ECU.pdf Jeep YJ 2.5L ISA Wiring Diagram.pdf 1987-90 2.5L TBI Intake Manifold and Sensors.pdf 1987-90 YJ Wrangler 2.5L TBI Emissions System Parts.pdf YJ Wrangler Fuel Filter and Guard.pdf 2.5L TBI ISA Motor Adjustment.pdf Used in conjunction with the many forum exchanges (search under "All Content" and "2.5L TBI" in the search box), plus the Jeep 2.5L TBI troubleshooting article at the magazine website, this information will help solve your Jeep YJ Wrangler or XJ Cherokee 2.5L TBI troubles. In references, the Model 81 is the Jeep YJ Wrangler. The Model 60/70 is the XJ Cherokee and MJ Comanche Pickup. Moses -
Here is 1987-90 Jeep YJ Wrangler and Jeep XJ Cherokee/MJ Comanche 2.5L TBI diagnostics information in PDF form. The first document includes all sensor and switch tests plus adjustments that affect engine tune, idle and reliability. Wiring schematics and ECU pin locations, test plugs and diagnostics included. Jeep 2.5L TBI Complete Diagnostics-Sensors-Switches.pdf Jeep 2.5L TBI ECU Inputs and Outputs.pdf Jeep 2.5L TBI MAP Sensor Test.pdf Jeep 2.5L Timing Chain and Tensioner.pdf Jeep 2.5L Valve Timing Check.pdf Jeep YJ 2.5L TBI Sensors and Pinout.pdf YJ Wrangler 2.5L TBI Wiring of WOT to ECU.pdf Jeep YJ 2.5L ISA Wiring Diagram.pdf 1987-90 2.5L TBI Intake Manifold and Sensors.pdf 1987-90 YJ Wrangler 2.5L TBI Emissions System Parts.pdf YJ Wrangler Fuel Filter and Guard.pdf 2.5L TBI ISA Motor Adjustment.pdf Used in conjunction with the many forum exchanges (search under "All Content" and "2.5L TBI" in the search box), plus the Jeep 2.5L TBI troubleshooting article at the magazine website, this information will help solve your Jeep YJ Wrangler or XJ Cherokee 2.5L TBI troubles. In references, the Model 81 is the Jeep YJ Wrangler. The Model 60/70 is the XJ Cherokee and MJ Comanche Pickup. Moses
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Ok I have seen talk on here about there 2.5 yj skipping but no answers, mine is skipping and can't find a answer about what's causing it, plz help -
How may I test the idle speed actuator in my 88s 2.5L4 MJ is still ok? got the feeling there's no activity from it! maybe the wiring, or the isa is broken? Changed the isa though!! thanks from Germany!! kalle -
My son just purchased a 1990 Wrangler with a 2.5 4 cylinder. We noticed that it had oil leaks and coolant leaks that needed to be addressed. So we replaced the radiator hoses, heater hoses, heater core, thermostat, and thermostat housing. As we were bringing the Jeep up to temperature to ensure there were no leaks from the hoses we had just replaced, the engine died, as if it had ran out of fuel. The gauge read 1/2, but to be safe, we added fuel and tried to start it. No start. I checked for spark, and we had spark. I pulled the spark plugs out of the engine and cranked the engine over. I noticed a large amount of fuel pouring out of the back cylinder. I checked this site for values on different sensors so that I could check them one by one. I tested the MAP sensor, voltage read 5 volts in, 4.85 volts out. I tested the TPS, seemed to test OK. I unplugged the fuel injector that rests on top of the throttle body. I ohm'd it, got a reading of 2.5 ohms. I purchased a remanufactured injector from the parts store and ohm'd it, which I received the same 2.5 ohm reading. I replaced the injector with the remanufactured one, no start. I unplugged the injector and the engine started for a few seconds, presumably from the fuel that was left in the throttle body. I could repeat this by keeping the injector unplugged and using starting fluid to run the engine. Seemed to run fine. Being absolutely stumped, I read about the MAT sensor acting similarly to a Mass Air Flow sensor. I replaced the MAT sensor with one that Car Quest cross referenced as being the right one. The sensor itself looked right, but the connector was different. I purchased a new pigtail and wired it in. After doing so, the Jeep started right up and ran. I drove it for about 5 miles before it died. Same symptoms: seemed to be over fueling. I read more information about the Coolant Temperature Sensor, which I was able to finally locate it on the under side of the intake manifold. I noticed the CTS had bare wires near the sensor. I ohm'd the CTS which ohm'd out at 8,000 ohms. I ohm'd the new part which ohm'd at 6,200. I replaced the CTS along with the MAT sensor (which I had warrantied out at Car Quest). The Jeep started right up. I drove the Jeep for approximately 5 miles with no issues. I started it up the next morning. I thought everything was fixed until I went to start it up later in the day. It failed to start again. Same symptoms: over fueling. I thought the CTS with the bare wires was the smoking gun. Now, i'm not sure. It seems like both times that I have replaced the MAT sensor, it ran great for 5 miles or so then back to the same problem. I ohm'd the second MAT sensor after the no start. It ohm'd out at 18,500 ohms. I'm at a loss at what to do from here. Maybe an ECU issue? Any help would be greatly appreciated! Shawn -
At random times I start my 1990 jeep wrangler tbi. It starts fine but its idle will go up to 3500 and stay there until I shut it off. But I go to restart it and it starts normal -
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 -
Hello, first off let me begin by saying thank you to Moses for your site. It has helped me fix a lot of issues with my jeep. I have a 1988 jeep yj with the renix 2.5 tbi setup. The problem is that the jeep starts and runs but consistently spit, sputters and stalls. I can be driving down the road doing 55 mph and then it is like somebody turns the key off and back on again. it does this at idle as well. Things I have already done/replaced: new cap, rotor, plugs, wires, coil, ign. Module, ign. Switch, and the cps. I have gone through and tested the coolant temp sensor (for the ecu), intake temp sensor, map sensor. Also pulled the wiring harness from the engine compartment and went through each individual wire with my multimeter to ensure that they were good. I did this under the dash as well and cleaned all grounds. The throttle body i rebuilt about 6k miles ago. New fuel filter and pump. I am at a loss at this point and i hope for some guidance. The only thing i can think of is the ecm is going out but not positive. Thank you for your help, and i look forward to your reply Thomas -
I've got a very stubborn jeep that just won't stay running. I've been fighting it for a year now. And since has improved. But I've been just uses sing and I need a way to solidly diagnose what's going on with it. It has a 2.5l 4cyl Tbi. The issues I'm having is most defiantly effected by the weather and climate and time of day. But the issue seems to mostly fluctuate with time of day. 1. So in the morning at like 5:25am I start it to warm up before I leave for work and it'll start and run just fine till it got to be about 100 degrees then it'll idle down to like 300 rpm and stall ( unless i floor it and hold the gas then it would run fine and do it again. 2. some days it floods so I have to give it gas to get it to start and it'll be fine for the rest of the day. 3. some days (seemingly more humid) it'll start fine or it'll do the first problem mentioned but as I give it gas ( like to go up a hill or some thing) I lose power and then it kicks in again till l let off the gas then give it gas it'll repeat. 4. It kind of goes along with issue 3 it hesitates or "fish biting" effect with acceleration I've replaced fuel pressure regulator, ignition coil and module, spark plugs and wires, distributer cap and roter, timing chain. Last year i did have issues with the injector but since has been fixed. And in the fall the map sensor went bad and almost left me stranded. I did some digging in the Internet and tested the egr and it wont hold vacuum so that's going to be replaced here soon but I don't think that's the issue but it could be playing a part in it
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1990 jeep wrangler with the 2.5l 4cyl engine. it was rebuilt about 10 years ago its got 100,000 ish on the engine. About 4 years ago it started making this noise. Some people thought it was a diesel engine. oil pressure test confirms somethings up. The needle was some what jumpy. It only does it when the engine is warmed up. I suspect its a lifter issue or a spark knock. Any ideas?
