I have a stored Code 32. Only time the SES comes on is after about several minutes of highway driving, then goes off later. The big problem with the flow charts is that the SES code isn't on at startup. It takes about 15 mins of highway driving to set code.

--I pulled the EGR solenoid wire and jumped both terminals w/a test light--it doesn't light. --Grounded test light and probed each wire (39 & 435) and it lights when 39 is probed.
--Checked resistance across both terminals of the solenoid wire; 200 ohms
--To test for a bad connection, I ran a jumper wire from 435 to the interior and checked resistance to the ECM connector and it shows continuity.
--Disconnected EGR temp switch and checked voltage at connector (the dreaded Dark Green 935) with ign. on--13 volts

I couldn't get at the EGR with my finger to check the diaphragm and didn't check vacuum pressure. I have a gauge but can't seem to find a pressure tester locally

Stuff I do/don't know:
-Late 1986 C4
-NOx was slightly higher than inspection limit (don't know the value)
-I believe ECM, EGR valve & sol. have been replaced before.
-Don't have ECM #
-Don't know if intake gasket's been replaced or if EGR/Head passage is open.

Any input is appreciated!

 

Code 32 does point to the EGR and Code 42 points to the EST wire. If you have set timing lately check the EST wire for connection (tan with black stripe located between the distubitor and brake booster and right above the steering shaft). Do you have a FSM? It has troubleshooting diagrams for both codes.

 

Still looking for some input on this one and I just updated a couple things in my original post.

This is a stored code and the SES only comes on during highway driving and it eventually turns off. I don't really want to be pulling the plenum off and on as this is a DD and don't want to tie it up at the moment. Can anyone offer any input on where to turn next? Or does anyone know if I'll be able to diagnose this problem (specifically) easier if I get some scanning software and an ALDL cable? A lot of the test procedures seem to be pointing towards a faulty ECM.

thanks again.

 

I doubt the ECM is at fault...it's usually the last thing to fail and will probably show more things wrong. It next step is to invest in a FSM for your year car. Code 32 is either the switch, solenoid, EGR, connection, vacuum's, or wiring. Contact Agent86 for a scan of the Code 32 troubleshooting info. That will lead you to the culprit.

 

I have a Haynes manual and Alldata software, pretty much the same flow chart as Helms. I've been going through all the EGR items as mentioned above.

 

After installing high flow cats, I occasionally get the same code during highway cruise.. I'm guessing not enough back pressure. Are you running cats or high flow cats?

 

Yes, I do have cats and I'm sure they're tired as the NOx was high on inspection. The car is stock though, no mods.

 

when I experienced an intermittent 32....it was the EGR switch, mines an 87.

 

The ECM will check EGR operation when:
Vehicle speed is above 30mph
Manifold absolute pressure is between 15kpa and 70kpa.
TPS is between 8% and 30%
No more than 4% change in TPS

The ECM monitors integrator during a Code test and must detect a change to pass the test. If the integrator is at a fixed value when a code 32 is ran a code 32 may set.

The EGR circuti can be inoperative if the park switch is faulty or not adjusted correctly.

All that being said, mine started throwing codes as soon as I cut the air filter lid and installed a K&N filter. I also had a gutted cat and aftermarket mufflers. Good luck. If you want me to send you a troubleshooting flow tree, let me know...

 

I have had the same problem with at least 5 other tpi cars that would only code after a highway drive,I think that switch is only about 10-15 bucks.

 

Thanks for the additional input. Yes, the temp sensor is cheap and I would have just changed it had I known what a PITA it would be just to get at the connector!! Only reason I didn't r&r it was because I didn't want to start a chain of part swapping. I may throw one in anyway.

I just ordered an ALDL cable and I'll get some software. I'd like to see if I can tell what it's doing while I'm driving on the highway, as well as work on the fuel economy.

 

ive got an 86 with the same problem,doesnt bother driveabilty but that ses light is embarrissing.mine has a new egr installed.still code 32.i noticed yesterday the air return line from the cat was disconnected. maybe the problem. gonna check it out later today.