It's bugging the crap out of me!!! I installed an Accel base, brand new egr, reman TB, new EGR solenoid, and cleaned/checked all of the vacuum lines and physically tested the egr. It all checks out. For some reason though when I'm cruising with hardly any throttle at like 40mph or whatever in 4th the SES light trips giving me the EGR code. It only happens like once a week but still. I'm in CA and I want it working right, no unchecking the flag in the bin.

Now my question, I see in the $8D there are several variables which have to do with the EGR, I'm wondering if you guys can suggest any changes to any of them to try and cure this problem? I wish I could give you an exact mph, temp, RPM, and TPS % but it never seems to happen when I'm logging. Murphy's law I guess...

Thanks!

Do they actually check the function of it when you take it in for emissions?

Unless they put a multimeter on the solenoid to see if it activates I would turn it off. If you have the tune dialed in close with a cat it'll pass fine.

I've had 2 different vans with a total of 5 different engine combinations, all with the EGR turned off or removed altogether. We have the dyno test where I live. I can post a pic of my last e-test results. The NOx barely registered.

Did you replace the MAP sensor also? If it can't "see" the change in vacuum when EGR is requested, it will set the code.

I have to have it working because they physically push on it to see a change in RPM and is the SES light were to go off it would be an automatic fail.

Yes I replaced the MAP sensor too. All of my sensors are all within 2 years old. It wouldn't be smart to start adjusting VE tables without an engine in good running condition with lal new sensors.

What would cause the vacuum not to change when it enabled though? So your're saying it has to be something in the vacuum lines going to it from the TB or the solenoid?

I figured PROM related because it only seemed to start happening after I installed my 180 thermostat...

You could always move ;^).

You don't mention this, but are reprogramming a "Flash Prom" or just an eprom? The reason I ask, when I was first playing with eprom tuning, I would every now and then get the "EGR" SES code also after about 30 minutes of driving.

I did a lot of checking and investigating, including reburning my original bin back onto my original memcal to see if it occurred. Occasionally it did.

The problem turned out that I wasn't erasing my "eprom" just quite long enough. It was erased long enough to "appear" like it was fully erased, but it wasn't. So I increased the erase time longer and the problem went away.

Later, I went to a Flash Prom (AT29C256) and I have never had the problem again. Try a different prom (if it's Flash) or increase the erase time if it's an eprom (or a different eprom too - they don't last forever).

Great thought but I've always used the AT29C256's. I burn with TunerPro and it starts at 000000 and ends at 007FFF. I've tried different AT29C256's and a couple different MEM-CAL's. I've also restarted again with the stock virgin bin a few times.

Come to think of it though, I started burning PROM's exactly when this started happening! I also happened to have installed the new intake parts at the same time. Here are still a few things I can think it may be:

Not enough vacuum at the enable TPS and MPH it tries to enguage due to different intake and TB.

Maybe my Virgin bin isn't so virgin? I got from DIY-EFI though...

Maybe something in the TPiS TB or gaskets that limiting vacuum to that line?

I have no multimeter so I can't check the new EGR solenoid but I'm sure it works, it's brand new and with my old one the same thing was happening?

Maybe something in the Accel intake? I know I cleaned it throughly though...

I guess all I can due is rip off my plenum and triple check everything again

There may be some sort of mismatch between the TB, plenum, and runners. Over the years the IAC passages and maybe some others have changed. I know the older TB's do not operate on the newer plenum/runners, or such.

As for why the code is popping up I would tackle it from the MALF 32 side. IOW, what is the ECM looking for to run the EGR test. And what is it looking for to say the test passed.

There are a handful of qualifiers before the test will be run: min MPH, TPS% range, min EGR DC%, manifold vacuum range, steady state TPS.

The actual test is looking for a change in the INTegrator value over a period of time. With the engine changes that have been made it is possible that a parameter needs to be tweaked.

BobR.

That's exactly what I was figuring I just don't know what paremter to tweak

It happened again tonight driving home from work, 50mph, 1700-1800RPM, 4th gear, hardly any TPS. My engien temp was about 175.

Looking at the variables for the EGR I can see none of them seem to have anything near the conditions I just listed above. Here is a list of what my bin shows:

EGR Diagnostic Min. Vehicle Speed: 30mph
EGR Enable Min. MAT Temp.: -5.50 Deg C
EGR % TPS Disable Threshold: 1.17 %TPS
EGR % TPS Enable Threshold: 1.95 %TPS

All of those are still stock settings, all of my EGR settings are.

Any ideas?

Oh and I have the correct year SLP runners and I checked my TPiS invoice and have the correct year TB. The Accel base is generic for all years and I still have thre stock plenum...

Actually I was referring to these settings:
One thing you have mentioned in each post is that it only happens when you are barely on the throttle. It may be that the test is being run while there is not enough throttle opening. Changing the size of the TB will change the ratio of airflow vs. TPS%.

RBob.

You could just turn off the diagnostic and leave the EGR functional by changing the minimum speed for EGR diag to 255. Works like a charm.

That's the very first thing I thought about but I didn't know if it would still leave the EGR working as it should. I might have to do that because looking at what RBob posted I still have no clue what I would chnage and in what direction.

Maybe I'll just try that an see....

What RBob is saying, is you need to change one of the parameters in the list he provided. Example instead of having the test done while the TPS > 7 and < 30, try narrowing > 10 and < 20. Or change the number of "fails" from "3" to maybe "30". But you need to "broaden" the parameters so it doesn't fail as quickly.

All you are doing is altering the conditions that causes the SES code to display, you are not actually altering how the EGR functions (or, at least, you shouldn't be).

I had a very similiar problem on a van that I did no PROM mods to. It was right after an engine swap. The EGR code would pop up erratically at conditions similiar to yours. I checked & rechecked my vacuum lines etc. I even vacuum checked the EGR solenoid. It held. However, if I put the vacuum pump on and tapped on the EGR solenoid, it lost vacuum.....solution: changed the EGR solenoid for real cheap& problem went away.
Good Luck
Mike

Did you ever get this problem fixed?

Nope, I just set the EGR test speed to 255mph IIRC...

IIRC, 8D looks at the O2 sensor also to check the egr. function.

looks for a change or something.
I could be thinking of something else though.