I am having a problem with my car and spark retard. The computer is pulling out timing, up to 20*, in a certain RPM range and then it returns to normal. The RPM range in question is about 1400-1900. After the engine gets passed 1800 RPM the retard stops pulling out timing. By 1900 it is gone, and the engine begins to have power once again. It is very annoying to say the least.

I disconnected the knock sensor and turned off the diagnostic in the PROM. On a test drive I got no spark retard. This tells me it has something to do with the knock sensor and or the ESC.

Help me out. What does anyone think? Thanks...

BTW, I have a similar question posted in the DIY PROM...

Ryan

Do you have any means of collecting data while running? If so, monitoring knock counts might be a good idea.

Yeah, with Datamaster they were about 100 or so in a few minute drive around my area of town. Maybe 4-5 miles total...

Just checked the file, 113 Knock counts in a 760 second record run...

Thanks

What's you initial timing set at?

Jake

15*. I know, too much, but the engine runs better with it higher. I set the base timing in the PROM to match...

I remember reading in Jacobs Ignition book that higher ignition timing "feels" better SOP, but the engine actually lays down higher up the band.

So since you are into the PROM, can't you just modify the area that's causing the problem by taking out a few degrees of timing in just those areas?

I'm in over my head in the PROM burning thing, but I know there are guys on the forum that can advise you better than me on that.

I was going to suggest the MSD Timing Control unit that I'm running that allows me to take out as much as 15 degrees of timing by turning the **** on the dash mounted control unit. But since you have the burning equipment, modifying the PROM would be a much better way.

Keep us posted.

Jake

My spark retard problem is weird. It only has spark retard at low RPMs. It also seems to have something to do with the CCP duty cycle. One of the DIY PROM guys, Grumpy, was helping me figure it out and he noticed that when the CCP was trying to purge, the Spark Retard would activate. I don't know if that is why I get spark retard, but it only shows the spark retard when the CCP is activated. I think that is pretty strange. I did lots of searches and found many people just plan don't have the CC in the car anymore. However, I was not able to find out how people were eliminating the CCP from trying to activate. For now, I just unhooked the knock sensor and turned off the diagnostic, and I get no spark retard and no knock counts. That makes me think there is something else going on. Cause I would think that if the CCP was doing something to make the spark retard, it would still do it.

I don't know...

When I get some free time, I am going to try to sort it out. I am just too busy with school and work to be able to devote some quality time to the car...

Well, since you hanve GRUMPY on your case, you're like ALLSTATE, In Good Hands.

Could it be vacuum related? When CCP activates a vacuum leak is created causing A/F ratio to go lean resulting in knock; then retard kicks in?

Wish I could help you more; I know how frustrating these problems can be.

Be sure to post when you solve it.

Jake

The most troubling part of the equation to me is that the CCP is not even hooked up to the engine. And I even unplugged the connector on top of it. The hose that should connect to the throttle body has been pointed down away from the engine compartment for a long time.

I guess that could led to another area of questions, oh well, one thing at a time I guess..

Yes, if and when I ever get this thing figured out, I will add to this post. Thanks...

Sounds to me you might have a lean A-F ratio problem. The knock sensor will pick up on this and retard your timing 20* the the EST system will take over and some performance will return after a few seconds. Can you check fuel pressure through the RPM range while driving? That will confirm or eliminate that question.

Just so we're on the same page, by CCP are you referring to the Charcoal Canister Purge system for the gas tank?

Jake

Yes.

sqzbox

My fuel pressure is set to 42. It is about 38 with the vacuum hooked up. I have noticed it stays pretty steady at 38 while in the light throttle area of my RPM range where the spark retard occurs. I have not ruled out a lean condition, but I highly doubt it based on the INT and BLMs. They show a mildly rich condition during my datalogging tests...

Thanks for suggestions...

Pressure looks very normal.

Spark Retard? Is that anything like an Ignition Idiot? Detonation Dunce?

Sure, why not!!

What heat range spark plugs are you running?

Yes, the CCP is the same as the EVAP canister purge (not some remnant republic of the former Soviet Union).

I've looked over some rudimentary ECM schematics and a few program hacks that I have, and can find no correlation between the EVAP purge (CCP) solenoid control and the EST or KS. That doesn't mean there isn't any, but I can't find one.

There are some common items that may be related, however. The EVAP solenoid, EST, KS, and ECM share some common power links and grounds. You might want to check the ECM and engine grounding connections.

Your fuel pressure readings seem factory perfect.

Sounds good. I will look into checking the grounds. Now, if you don't mind, tell me what I am looking for while checking the grounds. Should I just make sure the connections are tight, or should I use a DVOM and measure the resistance between the grounds and the battery. Thanks for the info...