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1990 Jeep Wrangler 2.5 tbi system. I checked the oil and it sort of smells like gas. The jeep has been running real rich lately and I have a thread trying to fix that but I’m investing in a old code reader for it. I suspect that the pcv system is clogged. Can the pcv cause this? Any ideas will help greatly!
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The pcv should not cause the over fueling.
http://www.ericthecarguy.com/faq/solving-automotive-performance-issues
On those old jeeps you can get the codes manually without a scan tool.
There is a pattern of turning the key on without starting it the vehicle.On, off, on, off on and then count the flaskes of the check engine light.
For example a code 25 would be flash, flash, pause flash, flash, flash, flash, flash.
Code 55 will be flashed at the end of the sequence so you will know when you are doneunfortunately its old enough to not have a check engine light dispute its fuel injected. Its got a “emissions maintenance” light. I’m currently trying to track down a old snap on mt 2500 scanner so i can figure out whats wrong with it. but with a rich condition can that contaminate the oil with gas?
[quote=”sisterwillys1940″ post=157251]unfortunately its old enough to not have a check engine light dispute its fuel injected. Its got a “emissions maintenance” light. I’m currently trying to track down a old snap on mt 2500 scanner so i can figure out whats wrong with it. but with a rich condition can that contaminate the oil with gas?[/quote]
Oh bummer that is a very primitive system.As far as the emission light on that is on timer that illuminates to remind you to change the oxygen sensor. To turn the light out you can unplug the module and toss it in the trash. Iirc the module is under the dash by the steering column and it does say emission timer on the box. When those came in for service we replaced the module along with the oxygen sensor. I doubt you will be able to get a new module at the very least unplug it from the harness. It won’t hurt anything.
As far as using the 2500 to scan for codes that system doesn’t store codes so the 2500 will only let you see real time data
If I were a betting man I would change the oxygen sensor and toss the module and that should take care of the over fueling. I would also check and make sure you don’t have a leaking injector as well.It’s easier than you think.
The SBEC II or PCM can detect certain faults in the fuel injection system. A fault code indicates that the engine controller has recognized an abnormal signal in the system. Fault codes indicate the result of a failure cannot identify the failed component directly. Any part of the component’s circuit could be the cause of a fault and diagnosis must be approached with that in mind.
Fault codes can be obtained by cycling the ignition switch ON-OFF-ON-OFF-ONwithin 3-5 seconds. Upon activation of the trouble code read-out, fault codes will be flashed by the check engine light. Each of the flash represents a digit in the fault code. Please refer to the fault code description charts followed by the corresponding diagnostic tests, later in this section to help troubleshoot fault codes.
A Diagnostic Readout Box (DRB) may be necessary for diagnosis of certain engine malfunctions
Also check these
1. Check the Manifold Absolute Pressure (MAP) sensor. MAP voltage should drop to 1.3-2.0 volts with vacuum applied. The signal wire is the Violet wire.
2. Check the Engine Coolant Temperature (ECT) sensor voltage on the Tan wire. The voltage should be less than 1.0 volt at temperatures greater than 90 degrees Fahrenheit. A 150-1500 ohm resistor could be used in place of the ECT sensor to simulate a warm engine.
Good luck and keep us posted.
I haven’t had to to look at over the few days but I finally got around to tinkering on it. But to answer and keep you guys posted the i tested the map sensor and its good. The injector doesn’t leak I put in like 3 before I got it right, and I haven’t checked the temp sensors (there’s 2 for some reason). Is there a way I can check the o2 sensor?
is possible that gas could be mixing with the oil. Probably not in huge amounts but if the engine is running rich, some of the fuel is probably not getting completely burned. Since oil and gas both work inside the combustion chambers and the rings are probably not perfectly sealing on this old Jeep, there could be a bit of mix. Gasoline has a very strong smell that doesn’t dissipate very well so even tiny amounts will leave a scent.
The main thing is to find out WHY it is burning rich. That seems to be the root of your problems.
It’s a newish engine rebuilt by napa over 10 years ago so the rest has a ton of miles on its been a daily driver since day one. Would a tps that’s out of adjustment cause it to run rich?
I would suggest doing a compression check. Worn rings and cylinders can result in compression/combustion pressure and fuel contaminating the oil.
A coolant temp sensor is more likely to cause a rich condition over a TPS. I would agree that verifying the engines mechanical health is a great idea.
Were you able to pull any codes with the method I gave you?
Ill be able to check the compression and the temp sensor tomorrow. I wasn’t able to pull codes it doesn’t have a check engine light despite the fact it has the old school single port fuel injection or tbi renix system. I did manage to track down a scanner for it but I don’t have it yet its being shipped.
I checked the ect and in this wrangler there’s 2 but I don’t know which one does what. I think the one on the end of the engine is the one for the gage and the one on the intake manifold is for the ecu. I used his chart to see what was normal. It was from a 1987 jeep factory repair Manuel I found online. The readings I got from the sensor on the manifold was some where around 450 ohms or according to the chart 160 but the gage on the dash said its 210. I don’t know what temp it’s supposed to run at can anyone tell me what spec temp it’s supposed to be? Thank you all for you input!!!
The CEL may be labeled “Service Engine Soon”, or something like that. The key check should work. I would try it just for the heck of it and look for the flashing lights.
Coolant temp sensors don’t come on at a given temp. They actually measure the temperature and send the information back to the computer so that it can calculate a fuel mixture. They normally list a specific resistance at a given temperature. If you check the resistance at that temperature and it matches up, the sensor is most likely good. Not a bad idea to check it at a couple of different temperatures just to make sure it can function within a range of temps.
I would see if I could pull codes first before going further. They can be your most important clue to solve the problem.
I did the 3 clicks and it didn’t do anything. Either the bulb is burnt out or it just isn’t capable of storing dtcs. I did some research on the “renix” system ill include the link about it but it was advanced for its time but it doesn’t say if it stores dtcs. I’ll put in a new bulb and try it again just to make sure. I’ll also test the temp sensors more thoroughly to see what’s up
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