I just installed my new Accel intake the other day along with a brand new EGR and MAP sensor. Drove great on my way to work but coming home the check engine light came on and stayed on. I ran my codes and I get 12 and 32. 12 of course is normal when you pull codes right? But 32 is listed as either a bad MAP, EGR, or electronic vacuum regulator valve.

How do I determine which it is? I mean if it were MAP, the car would run and idle like crap right? It doesn't it still runs great. The EGR, it's brand new and hooked up to the correct vacuum line. The electronic vacuum regulator valve, what the heck is that anyway?

On a side note, how do you check for codes using TunerPro RT?

 

Mark Mansur would be best suited to address that last question. I may be able to help with the others.

Incidentally, the '32' on your engine is for an EGR fault. The electronic vacuum regulator valve is used on other EFI (and some diesel) engines to modulate vacuum, much like what the IAC stepper motor does for idle air on TPI and TBI engines.

First, what EGR valve replacement did you install? The generic replacement EGRs that require the installation of a calibrated orifice washer are frequently problematic on TPI engines. The calibrations tables provided by the manufacturer are suspect, at the least. The valves themselves are frequently no better.

Your '92 has several means of monitoring EGR function.

First, the ECM will cycle the EGR vacuum solenoid as necessary, and if no electrical load is detected (voltage drop across an output sensing resistor) an error code will set. This is helpful, since the generation of a code shortly after startup and at low RPM can indicate a solenoid or wiring problem, whereas a code that is set only during a part throttle cruise EPM typically indicates a different problem.

The ECM also monitors the diagnostic temperature switch mounted in the base of the EGR valve. If the sensor does not indicate an increase in EGR temperature when the valve is supposed to open, the ECM will set a code. This can indicate a failed or disconnected switch, or a failure of the EGR valve to open when commanded by the ECM. If the EGR fault code is set shortly after teh engine is started, that could also indicate that this switch is shorted, or the switch wiring is grounded.

On later speed-density TPI engines (like yours), the ECM can also monitor MAP to indicate whether the EGR valve opens. The MAP should increase (vacuum decrease) when the valve opens, and a failure of that can indicate an inoperative EGR valve or clogged EGR passages. This is the only method that other speed density schemes have to monitor EGR, such as the TBI and MPFI V-6 engines.

Since you have a new EGR valve and new intake base, I would suspect that the EGR passages are not clogged, unless there is some casting flaw in the EGR passages or blockage of the distribution passages under the plenum.

There are a few other and more obscure potential causes of EGR system failure, such as the PARK/NEUTRAL switch failing to open. The EGR is only supposed to be operable when the transmission is in a range other than PARK or NEUTRAL, so this switch must report that to the ECM. If the ECM detects vehicle speed and engine load, but no indication of the transmission being in gear, the error code may also set.

This flow chart may be helpful in your diagnosis:

 

I used a brand new AC Delco EGR from the dealership, all I use are dealer parts, no chain store crap.

My EGR has no temp sensor on it, nor did my old one, nor does my harness have this provision.

I made sure the passages were clear and cleaned before install.

I was driving at like 40mph @ 3K RPM or so when it went off, just barely had my foot on the gas.

How the heck can you get your hand in there with the engine warm and not burn yourself to hell? Gloves I guess. I'll give it a try and then maybe I'll be replacing my EGR solenoid and flushing out it's vaccum lines....

Thanks!

 

What is the part no. on your EGR valve?
Also read through this: http://www.champion-auto.com/Documents/52_EGR.pdf

 

GM P/N 17113456, AC Delco P/N 2145535 IIRC...

 

No temperature switch? Then your ECM uses the MAP change to monitor EGR operation - just like the TBI and other S/D applications. Is the vacuum solenoid active?

 

I think because in my data logs I can see my EGR duty cycle change. Do you know what the normal EGR duty cycle should be at full temp in 4th gear at like 3K RPMs?

 

Should be close to this:

 

Oh yeah then somthing is wrong because the highest I've seen in the last 2 days was like 1.20 and it was mostly 0.01 or 0.02.

I'll try replacing my EGR solenoid and flushing my vacuum lines....