What are you *hi-psi* guys setting plug gap at? When the boost needle swings past16-17 psi, I get a bad misfire, like the spark is being blown out of the plug. I'm gapped at .035 right now, and I'm gonna try .030 tonight. Should I go lower than that? How low is too low?

I am not a high psi guy just yet. the injectors go in this weekend though. But I gap mine to about .30. I think you should try a littel lower than .35.

>When the boost needle swings past16-17 psi,
>I get a bad misfire, like the spark is
>being blown out of the plug

I am having the same problem. I ran for a 1/2 day on Saturday at 20-21 psi on 110 octane and it ran VERY strong no misfires or anything. Sunday was another story, I had the same problem as you are having. I had my plugs gapped at .30 and I was still getting a misfire above 16 psi. I gaped them to .26 and they seem to be ok right now. I am only runnig 17psi so I havent tried it at 20 lbs yet. I also think the 110 was a little over kill, 104 would have been fine.

Try .30 and see how it runs. Like I said above I was running at .30 and I was getting misfire above 16lbs so I went down to .26 and the car runs fine.

Try .028-.030 for higher psi boost. I had mine set at .035 before and the car felt like it was misfiring also. The car seems to run better when the plugs are gapped at .028.

Kon Chittavong
HRC: Stage IV | http://laoracer.homestead.com/mainpage.html

yeah, just make the gap a little smaller, the bigger the gap, the more detonation you will get I believe?

I was wrong, they were already at .030 so I closed them up to .028. And now on the way home today it started doing it at less than 15psi. It's not throwing any codes either (at not any new ones). ARRGGHH!

buy new plugs.

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............

I think (hope) all my problems are related.

1- misfire above 8-9psi
2- erractic timing at idle (-1.5 degrees to 14 degrees)
3- lean condition while cruising. o2 will just go to zero for a few seconds, and go back to cycling like normal. Does this constantly on the freeway. Engine feels like it would if timing was being pulled.

Where do I look?

No codes, no lights, no unusal gauge readings (except the o2). I'm going to datalog on the way home, hopefully that will shed some light on things.

Ok, your starting to scare me. How did or do you get your map to cycle w/ the DFI. A stock car would cycle because the stock ecu is constantly making adjustments but how did you get the DFI to cycle??? Do you have the O2 for the DFI hooked up???

I see way lean at cruising speeds in vac. but as soon as it sees positive manifold pressure it goes over to the rich side. I don’t see any kind of cycling at cruising or idling. At idle it stays on the rich side, if I adjust my power control box it will lean out to about .94v but after that it goes to the lean side.

Anyway...

I have no clue what would be causing your problems, especially w/ you not changing or adding anything new. I was getting a weird hesitation or misfire at higher boost 20ish. I had my stock injector harness hooked up w/ the injectors on it to get rid of the cel I had. It was the culprit in my case. I was getting a backfire, misfire and it spit out a too rich code at me. I took off my injector harness (stock) and it fixed the problem. All I have now is the "no injector harness" code. I have no idea why it would do this?

Sorry I couldn't be more help.
Let me know about the cycling thing.

Brian

Yes I have the o2 hooked up for the DFI. What I learned yesterday about my idle problem:

Not the plugs or wires

Couldn't swap out the coil pack - Did anyone know that a 95 cp has a different connector that a 99 cp? I do now. Anyone have 99 model they want to trade for a 95?

Not the tach adapters

Take the HI-6 out, and it's all better. Until I step on the brakes?!?!

So I drive to work without the HI-6 in-line and it seems better. Of course I can't boost past 10psi (no boost retard). Even stepping on the brakes today seemed to have no effect.

My theory: The DFI needs to see a minimum voltage to run properly (can't remember what it is, but it's high - like 12.9 or something). There is a small voltage drop when applying the brakes, which combined with the UDP takes alt voltage to 12.9-13v. Car runs like crap. Foot off the brake, voltage is 13.2-13.3 and no problem. Disconnecting the HI-6 just gave me some more *voltage* to play with.

I am going to try raising idle (and subsequently the alt voltage) and putting the HI-6 back in and see what happens.

The o2's still bottom out on the freeway though. Datalogging shed no light on that.

It's true that the Accel DFI needs a minimum voltage to effectively control idle. I've read this on Accel's site and I've also noticed this with my own car. Accel's online manual states that "voltage drop due to underdrive pulleys affect idle quality and can even induce stalling and surging..." "...this condition usually shows itself during an extended idle condition." The DFI needs a minimum of 12.2 volts at engine idle.

When I have my headlights and the radio on, I noticed that my engine vibrates harder, and not as smooth. This is also true during acceleration. If I turn off the headlights, the problem goes away. This is why I'm going to get rid of my UDP soon.

Kon Chittavong
HRC: Stage IV | http://laoracer.homestead.com/mainpage.html

Rule #1 If your car is running goofy, check for vac/boost leaks. Even though you checked everything 2 weeks ago when it ran fine, check again.

I'm going to have this tattooed on my hand. I found three vac/boost leaks on my car tonight. Two of them that I could fix, I did and my idle problem went away. Simple as that. I feel sooo stoopid. The 3rd leak is the throttle shaft seal. It leaks at 10psi. Has anyone had luck fixing this?

Thanks for all the ideas and help. Tomorrow I will see if my cruising o2 problem has disappeared as well.

The last time i took it apart i learned that the center shaft doesn't actually rotate in the seal - the (two piece, possibly bearing'd) seal rotates with the shaft. Take it apart and you'll see what i mean. Just silicone the mother into the bearing/seal. Also try siliconing the TPS and IAC into the TB - they aren't sealed all that well from the factory.

looks like a leak under ur car greg!


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Thanks Dino, I'll give that a try. Now I'm back to the original topic of this post. The engine breaks up bad past 12psi or so. Fiddling with the power tuner and the boost retard makes it a little better, but not good enough for me to bother taking it to the track.