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Please Help guys with Where to start. Please help interpret these codes. 🙁 I am a student and still learning. :blink:
1994 Ford Escort. l.9L, Auto, with the following codes pulled. OBD 1
This is with key on, engine off (KOEO)
Code 181..fuel system at rich adaptive limit at partial throttle/system lean.
Code 186..Fault in injector pulse width, circuit/high.Key On Engine Running (KOER) following codes.
Code 412..cannot control RPM, koer high RPM check.
Code 538..Insufficient RPM change during KOER dynamic response test.
So, here’s what the car is doing. Cold, engine runs great. No check engine light. Shifts fine and transmission kicks down fine on acceleration.
Only issue is when its cold, it starts great but the idle kicks up high around 2500 and then drops to 1500 for couple of minutes at idle. Still no check engine light.
Warm, while driving, if I accelerate firmly, the check engine light comes on. Also the transmission doesnt kick down into the lower gear unless I accelerate hard, then it kicks down and the car accelerates but the check engine light comes on. On a roll, the trani doesnt kick down to the lower gear and i have to push the pedal down firmly to get the transmission to shift to the lower gear for acceleration, otherwise sluggish. Check engine light comes on and stays on. Stays running with this problem.
When I turn the engine off, and restart, check engine light is off.
Please help guys! Any suggestions would be greatly appreciated. With these codes, what sensors should I be checking? Im thinking IAC and TPS but I need help to interpet precisely what the codes are telling me. Sorry for my ignorance 😳
I did not mess with the idle screw but will make sure no one has moved it. Am I looking in the right spots with those codes pulled?
I only have a hand held innova 3120 scan tool. No live data. This is what i pulled the codes from.
PS….I pulled the IAC and cleaned it and unpluged it while running. Its working but not sure if in specs. Thottle body and MAF are spotless clean.
Thank you for any help!!!
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You’re on the right track. The car is OBD1 so I wouldn’t put too much stock in those codes. Check the out voltage (with a multimeter) on the TPS through it’s entire range. You not only need to make sure these components are working, but working correctly. Also check the MAF, IAC, EGR, and fuel pressure regulator. You also might want to spray some carb cleaner around on the engine hoses and injectors. If the engine idle drops you have a vacuum leak.
Let us know what you find.OK….
So Im on the right track then. I will check IAC, TPS, MAF and EGR. Fuel pressure regulator as well. I was also told it sounds like a vacuum leak, so I will go hunting with carb cleaner as well. Unfortunately the Shop Manual doesn’t give me the specs on the IAC, TPS, MAF. Im assuming its universal on these, so I will go by that and see what I can come up with. Now I wish I had a scope to check the TPS sweep….What a pain!!! :angry:
Thanks for the great advice and I will post my results if and when I find it either way. I just wasn’t sure how to interpret the codes given. Its more like the codes given are what the sensor is causing other things to do but not pointing to which sensor it is…….frustrating. :pinch:
Let the fun begin. :unsure:
Yeah. The specs for those are usually pretty universal (give or take a bit). I don’t think I’ve ever run across a TPS that isn’t .5 to 4.5. Make sure there’s no fuel leaking around the fuel pressure regulator. Some people push in the Schrader valve with a screw driver to check for fuel pressure. This only tells you there is pressure. It doesn’t indicate if it’s correct pressure. Hook a pressure gauge up to the fuel rail Schrader valve and fluctuate the engine rpms. The fuel pressure should stay steady around 40-50 psi.
Coming to conclusions soon.
Will report back this week.
I think I found the fix and the issue. :woohoo:Sorry for the Delay…..
The Main Issue was with the MAF.
This caused codes 181 and 186. Replaced MAF. Codes gone!
Power came back considerably on acceleration and gas mileage improved.The other issue was with the IAC. Replaced and code 412 was gone.
Only code remaining is 538, so I will probe further but for now , car runs great! NO check engine light.
Thats it! Passed smog with flying colors and runs great.
Amazing how the MAF caused fuel system rich and fuel injector pulse width/high, not to mention a great loss of power and gas mileage.
Cause and effect here. Its just too bad the codes don’t give you the cause but just the effects. :angry:
As Ive learned codes are back door guides, but you have to get to the front door which is now back probing and testing the sensors suspected. :sick:Hope this helps someone in the future when you get a code like or similar to these.
ON to the next car problem.
91 Nissan D21 truck with very bad idle. Runs great past idle.
I will post in new thread, problem and issue and fixes for this one soon.Thanks for the help on this one thisisbuod! 😛
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