uig & lig ?

[thecotas69]

i have a 93 se 3.4l with 130k. i think my problem started about 6 months ago, my low coolant light started flashing. i periodically check coolant,no loss.this week it began hard starting, i have to give it gas to get it to start.then when it starts it runs really rough. if i dont have my foot in the gas pedal, it will stall. i borrowed a code reader and counted 3 codes 12,23,45, 12 is test working,23 is mat sensor voltage +- or tps error or m/c selonoid open, 45 is rich exhaust indication left o2 sensor. upon further inspection ,oil and oil cap seem to be normal (no chocolate milk) and resivoir tank has no visable sludge. im thinking uim/lim leak. does this sound correct? if so do i need to do both gaskets? can a shadetree mechanic like me do this job successfully?

[tblake]

you mean UIM and LIM gaskets? I think a "shade tree" mechanic (much like myself) could handle this job, however, a leaky intake manifold gaskit will usually cause a lean condition and your getting a rich code. I would focus initially on code 23, then if after fixing 23 if 45 hasn't cleared up, then worry about 45.

What motor? 3.1mpfi or 3.4DOHC? I didnt know they put 3.4DOHC's in GP SE's. (shows how much I know)

[thecotas69]

its 3.4l dohc. any easy ways to ck mat,tps?

[CrazyHorst]

There could be a bad ground or a sensor in the circuit that's pulling down the voltage.

For example, the O2 sensor "rich" means that the signal is pegged rather than "toggling". Also your MAT sensor voltage (or the others) could also hint at that.

A good inspection of all the split black conduits in that area of the engine harness is a very good idea.

[tblake]

Stupid question guys.... what is a MAT sensor?

You can ohm sweep the TPS with a multi-meter. Set it to ohms, and move the tps armature while observing the dvom screen. The ohms should gradually go from low to high or high to low and have no sudden drop offs. If you have a drop off, you have a bad TPS.

[richtazz]

Here's the correct code definitions I have for your year/make/engine combo.

code 12- no spark reference signal.

This is normal for a key on/engine off test and nothing to concern yourself with. Many people mistakenly call it the "test code".

code 23- Inlet air temperature sensor signal showed an air temperature of -31� F for 10 seconds after the engine has been running for 4 minutes.

This code indicates a bad IAT sensor or a bad wire/connction to it.

code 45- Oxygen sensor rich, voltage was over 0.7 volts for 50 seconds of closed loop operation. Engine had been running for at least 1 minute with the throttle angle between 3% and 45%.

This indicates a rich fuel trim condition which could be caused by the IAT sensor showing the air is colder than it actually is.

Tim's (Tblake) suggestions are spot on (as normal, ). Bad intake gaskets on these cars cause it to lean out especially when cold due to vacuum leaks around the intake ports. I agree that you need to concentrate on the cause of the code 23 first, as it could cause the code 45 to also pop up.

[tblake]

Originally Posted by richtazz

Tim's (Tblake) suggestions are spot on (as normal, ). Bad intake gaskets on these cars cause it to lean out especially when cold due to vacuum leaks around the intake ports. I agree that you need to concentrate on the cause of the code 23 first, as it could cause the code 45 to also pop up.

Thanks Rich!