couple more questions

[rubydist]

Here's the situation - my 'new' 92 has a 3.2 w/ 122k that I pulled running fine from a 95 atx w/ a bad trans. I did a full 60k service, put the 3.0 (KOA) intake cams in, a fidenza flywheel and a highflow Y-pipe and put it in the 92 w/ the single accessory belt system and a custom front motor mount.

It has 2 issues that I could use some insight with:

1. it returns the koeo code 564 (EDF circuit failure) but the cooling fan kicks on just fine when needed. what does that code mean?

2. the idle is erratic - once warm, it will surge from 800 to 1500 and slowly drop to 800 again, this will repeat every 8 seconds. the engine has the 3.2 intake, and it did not do this when in the 95 atx. I cannot hear any vacuum leaks, but it doesn't act like a vacuum leak to me, it acts like the pcm is doing that. any ideas?

 

[jmpSHO2nd]

Only two things that would cause that code, damaged CCRM or PCM.

 

[shomethe$$$]

block off the IAC for the surge issue, see if it goes away, check to make sure your thermostat is open and no air in the system. Possibly some tuning with the 3.0l cams

 

[jmpSHO2nd]

block off the IAC for the surge issue, see if it goes away, check to make sure your thermostat is open and no air in the system. Possibly some tuning with the 3.0l cams

I don't think the 3.0l cams require a tune.

 

[jonheese]

For the surging idle, it's probably worth the time to clean your MAF element.

 

[jmpSHO2nd]

If rubydist is asking us for help I'm sure he has tried all the obvious stuff.

 

[jonheese]

Yeah, I hear that, but I figured if it hasn't been said yet, we'd better say it. Even the most experienced among us (and I know rubydist certainly qualifies for that title) can forget the obvious stuff every now and then.

 

[zblackbeast]

vacuum leaks?

 

[VortecGT]

3.2 intake, what did you do with the egr?

 

[pitaSHO]

I had the engine surge issue with my 89 and it turned out to be a dirty throttle body. All those little holes in the TB were all gunked up. Instead of cleaning it all out I just ended up replacing the TB; problem solved. A 280k mile 3.0 sounded healthy again.

My .02.

Chris K

 

[rubydist]

3.2 intake, what did you do with the egr?

The egr valve is on there, and I capped the inlet where the tube normally comes from the exhaust manifold. It turns out that a regular pipe plug and a little gasket sealer take care of that.

The mafs has been cleaned, but I can do it again.

The throttle body is from a 3.0, and I never heard that one run, so its possible that the tb has issues - I'll look at that tonight or tomorrow.

 

[jonheese]

Have you done anything else in chasing this issue? It may save us the time of suggesting something you've already tried.

 

[rubydist]

I just got home from work, and its freezing and dark, so I will wait until tomorrow to do any more investigating. I'll let you know what I find when I:
1. unplug the iac
2. clean the mafs again
3. check out the throttle body

 

[rubydist]

Here is what I learned today, after putting at least 50 miles on the car. Still only shows the 564 code and a code for the vss not providing enough signal, which is obviously due to the fact that the speedo gear in the trans is dead (still waiting for the part).

1. unplugging the iac makes no difference! it still surges or runs fast. changing the iac made no difference.
2. changing to a known good mafs made no difference.
3. cleaning the throttle body made no difference.
4. the 564 code is curious - the cooling fan will run as needed when the car is warm enough, but when I jumper the connector to pull the codes, the fan will not run when the key is turned on, which it normally does.

sometimes it will surge on a 6-8 second cycle, sometimes it will stay at 1500 rpm for a long time (several minutes) before slowing back down.

Any more thoughts?

 

[boat]

Sounds like something funny is going on with the PCM. Did the PCM in this 92 work fine before?

 

[rubydist]

The pcm was pulled from another 92 that was running badly, but had the same symptoms after a different pcm was installed. that car turned out to have a valve timing problem. I expected the pcm to be okay, but am starting to have my doubts.....

 

[jonheese]

It's certainly an odd/rare symptom for a bad PCM to cause, but at the same time, if you've got a spare to swap in (and I'm sure you do), it's easy enough to cross off the list.

 

[SVOFANATIC]

Do you have a wideband? I would check your AFR see what it tells you. I'm also wondering was your car a 3.2 to begin with or did you swap one in? If it was a 3.0 before and you didn't swap the ECU's not saying you didn't this would be your issue. I've seen something like this happen before. Other than this the only thing I can think of is vac leak. If the IAC has no affect then it is all the way closed as it is and is still getting too much air at this point.

 

[rubydist]

no wideband, so no way to check afr.

I put in the 3.2 and have a X2J pcm, which has been done about a hundred times already with no ill effects, so unless the pcm is bad it should work properly. plus, since I'm at 5000' elevation, the 3.2 flows no more air than a 3.0 at sea level.

I have never seen a vacuum leak that came and went (especially on a regular cycle of 8 seconds) - where would a vacuum line go that could leak sometimes but not others?

 

[shomethe$$$]

I'm assuming valve timing has already been checked again? sure those cam's were stock and not aftermarket, did you blow through the IAC holes, if I remember correctly you shouldn't be able to blow through it, sometimes the plunger unthreads itself, so even disconnecting would have no affect if the plunger is partly stuck open, I know you switched it out but check it.

also how does it run passed 2000 rpm, smooth?