OBD1 code 32

g00se

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Hi Guys! I'm trying to figure out a random appearing code 32 on my 94 5.7L.

I've pulled out the EGR valve and it looks pretty clean --it holds open with vacuum. How do I test the EGR solenoid? Should I be able to get an ohm reading between pnk/blk and blk/wht to test the coil? I was unable to get anything --not sure if I'm using the meter correctly.

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Also, I wasn't able to get vacuum from the TBI's 'S' Port shown below at idle (I did not check at open throttle) --and I also was unable pull vacuum through the EGR solenoid to the EGR valve. Does the coil need to be energized before vacuum can flow to the EGR valve? I'm guessing vacuum was probably bleeding off through the vent filter end cap and it needs to be powered up for that to be checked.

Thanks in advance for any advice you have to give.

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Nick_R_23

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You mentioned in another post that you had a CTS code. That needs to be taken care of before anything, otherwise, the truck is running rich.

The typical reason the Code 32 sets is because the ECM is commanding a solenoid function to cycle the EGR valve, then watching the O2 sensor to see if the change occurred. If nothing happens, the EGR valve may not be the correct unit or the exhaust gas passageways may be plugged in the intake manifold. It’s pretty uncommon to have a solenoid fail. Modified exhaust or aftermarket camshafts that operate outside the ECU’s parameters can be known to set this code also.
 

1997

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Code 32, according to GM - Wiring open circuit/short circuit to ground, EGR valve, ECM.
Random issue, guess would be wiring issue/bad ground.
you should get close to zero ohms between A and B if solinoid is good.
Ifinitity ohms would be open circiut, don't think that would be random.
 

Schurkey

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I've pulled out the EGR valve and it looks pretty clean --it holds open with vacuum.
The diaphragm is still good. If the valve actually passes exhaust gas, and seals when vacuum is released, the valve should be OK.

How do I test the EGR solenoid? Should I be able to get an ohm reading between pnk/blk and blk/wht to test the coil? I was unable to get anything --not sure if I'm using the meter correctly.

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Test from pnk/blk (439) to gry (435). Those are the two ends of the solenoid coil according to your diagram.

Also, I wasn't able to get vacuum from the TBI's 'S' Port shown below at idle (I did not check at open throttle) --and I also was unable pull vacuum through the EGR solenoid to the EGR valve. Does the coil need to be energized before vacuum can flow to the EGR valve?
EGR is not used on gasoline engines at idle. Vacuum is shut off at the throttle body by placing the vacuum port passage ABOVE the throttle plates when the throttle is closed. No vacuum "bleeds off" at idle because there is no vacuum supplied.

Your test results are perfectly normal. You have to open the throttle to get EGR vacuum to the solenoid, then energize the solenoid to get vacuum through the solenoid to the EGR valve.

And the hoses have to be connected properly at the solenoid. There's three nipples, one is supposed to have a crappy foam filter on it. The foam disintegrates, then the hose from the EGR valve gets mistakenly crammed onto that vent nipple instead of the correct nipple during some service procedure. At least, the solenoid on my '88 has three nipples, one of which "used" to have a foam filter.
 

g00se

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Hi Guys! Thanks for all the help so far --I appreciate your responses.
Quick update --I took it in for a third emissions test and it still failed --but it is much closer now. I'll post up the results. It is still failing for HC. I should point out that this is all stock, no upgrades. The grounds look good, I cleaned the one by the thermostat but it didn't seem to have anything bad --just surface grime.

The question I have now is that I tested between pnk/blk (439) to gry (435) and am getting 2k ohms. Not sure I am doing that right but it is something that I had thought was zero before. I probably did not have the probes plugged in all the way (doh!).
 

Schurkey

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I took it in for a third emissions test and it still failed --but it is much closer now. I'll post up the results. It is still failing for HC. I should point out that this is all stock, no upgrades.
Wish you'd mentioned that in your opening post. "I" would be in there with a REAL scan tool, looking at the outputs of every sensor (O2, coolant temp, MAP, knock, and all the rest) and then all the computer outputs (IAC, EGR, spark advance, etc.)

It will not hurt to verify fuel pressure.

High HC indicates misfire, and/or a faulty catalytic converter. High HC WITHOUT high CO is probably misfire, high HC WITH high CO is probably a really-rich mixture. CO is a better indicator of rich mixture than HC. Misfire on the side of the engine that has the O2 sensor can drive the O2 sensor to report a FALSE lean condition. Then the mixture gets even more rich.

How old is the catalyst? Is the rear of the catalyst hotter than the inlet? Measure temp with an infra-red "non-contact" temp gun. If the rear isn't hotter than the inlet, the catalyst has likely failed. (Maybe the exhaust coming out of the engine is so screwed-up that the catalyst isn't effective, but not so damaged it can't recover. NOT likely, but possible.)

Just for giggles, how old is the O2 sensor? Anything beyond 50K miles is suspect. I don't really suspect the O2 sensor as part of the misfire problem; but I've had trouble with them in the past--anything is possible.

I tested between pnk/blk (439) to gry (435) and am getting 2k ohms. Not sure I am doing that right but it is something that I had thought was zero before. I probably did not have the probes plugged in all the way (doh!).
I don't know what the spec is, but I bet it's in the service manual.

Did you have your meter set on the proper scale? (i.e., not a decimal error--2 ohms, 20 ohms, 200 ohms, 2000 ohms can be displayed similarly, if you're not paying attention you can get them confused.)
 

g00se

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I don't have an OBD1 scan tool --just an old OBD2 that doesn't appear to give live data --only freeze frame. I will keep an eye out for a deal though. It seems like a good thing to have since I like my truck. The cat is probably original --I did change the O2 sensor recently and put a three wire heated one, the one wire I took out seemed cleaner than I would have expected.

I'll check my meter for the setting I used --and verify the reading. The manual says to replace the EGR solenoid if less than 20 ohms. So my 2k reading was probably misread --but I'll double check.

I have a laser temp gun --somewhere, I'll dig it up and check the cat for temp from inlet to the exit too.

Thanks for the help!
 

Erik the Awful

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The EGR system is responsible for lowering NOx emissions, which occur during lean mixtures. It's not the cause of your high HC count.

Make sure your air filter is reasonably clean.

Check your O2 sensor cross-counts - it should switch from rich to lean and back at least seven times in ten seconds.
 
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