Formula383

iTrader: (8)

As some of you guys know, my opti went out earlier this summer and after doing some more investigation also found out I had some bad head gaskets. I ended up getting a Dynaspark and some Cometic .040 thisckness gaskets and after getting everything installed, I have a problem with the car that I just can't figure out.

The car will start fairly easy but will have a tough time idling for about the first 30 seconds or so. Then the idle will clean up and sit around 930. After about 3-5 minutes the idle will break up and the car will die if I don't keep the throttle open. Now during this time, the number 8 primary is getting exterely hot (300+ deg) while the other primaries are around 160 - 180 deg.

Nothing is showing in Datamaster. No SES, no codes. IAC counts are little high, long term trims are in range. I thought maybe the #8 injector was going bad, so I swapped #1 and #8 but that didn't change anything. #8 plug looks clean and oddly enough I pulled the #3 plug to compare and it looked completely black.

At this point I am thinking it's either a bad injector wire in the harness or a vacuum leak somewhere. Any help or suggestions would be great!

Thanks!
Kyle

fleetmgr

I'd think a vacuum leak would show up all the time, not just initially and again some time later. The one cylider getting really hot like that sounds like a lean problem.

Turnin20s

iTrader: (12)

Hmmmm, that doesn't sound very nice. My car has trouble finding idle when I slow down for a stop or am just driving and push in the clutch, it will idle down to about 300 rpms and stumble a little bit and then come back.

Thats strange why the #8 primary would be 2x as hot as the rest of them though. Mabye try pulling the injectors and see if they all spray when the car is turning over, or when the ignition is cycled. What kind of injectors are they?

Sorry man, that sucks hopefully someone can chime in and help you more than I can

Formula383

iTrader: (8)

Ford SVO 42 lb/hr injectors. They only have about 4K miles on them and were bought new. I haven't any issues with them at all.

I'm going to get a noid light and test the injector drivers & harness.

Turnin20s

iTrader: (12)

Yeah that would be alot easier. Me and my brother tried that on his truck but something didn't work.

But its just really strange that the primary would be so hot. Mabye your valves are messed up or something. Thats just strange, be sure to post up if you figure anything out

Formula383

iTrader: (8)

If it was something with the valves, what would you think it could be? The only reason I ask is that when the heads were resurfaced, there were two valve seats that were re-cut because the valves weren't sealing.

Tony Shepherd

iTrader: (4)

A compression test and or leak down is a must at this point.

Formula383

iTrader: (8)

Yeah, I just want to understand what kind of valve issue would cause a lean condition.

Tony Shepherd

iTrader: (4)

I think the hipnovalve is stuck open causing the injection case to stick open.

On a serious note. I still think it is an injector issue more than likely a short in the injector wire. Noid light should tell us that.

Formula383

iTrader: (8)

Turnin20s

iTrader: (12)

What I meant was the valve preload may be off. Leaving the exhaust valve open when the #8 cylinder is firing making the primary tube hotter than the rest of them.

Reason I say that is my buddy was having problems with the center primarys of his headers glowing red when the car was just idling and his valves were off. After they were adjusted the problem went away. But his car was carbed. It could be an injector too, but its strange that it would get hotter if the injector wasn't working correctly

Formula383

iTrader: (8)

Ah, ok. Thanks for the info.

Turnin20s

iTrader: (12)

Not a problem man, just let us know if you figure anything out

Formula383

iTrader: (8)

Did a vacuum test at the intake manifold and was pulling 14" at normal idle. Also sprayed carb cleaner around the intake and there was no increase in RPM. Coolant level is steady and has not dropped any.

The noid light showed some interesting things. When the car was first started, the noid light was working fine. However, after the car warmed up a few minutes, the noid light quit blinking on almost every cylinder, #8 had no light whatsoever, but the car was running. Thinking the PCM injector drivers might be failing, we swapped PCMs and loaded my tune into the new PCM. Same problem. PCM also threw a DTC - 44 which is Left bank O2 sensor error (lean condition indicated). This is clearly visible on the AFR guage which is reading 16-16.5 at idle.

Everything is pointing to the Dynaspark. I guess it's possible I could have gotten a bad one. We're going to put a factory opti back on and see if the problem disappears. If so, I guess I'll be calling the Dynaspark guys for a replacement.

myltwon

iTrader: (1)

did you get the heads milled or checked for proper surface? I've heard that cometic gaskests are VERY picky about mating surfaces

Formula383

iTrader: (8)

Heads were checked and resurfaced. I think the heads are sealed good.

Formula383

iTrader: (8)

2 more weeks, no more progress.

I've changed out the opti and PCM. I also changed the O2 sensors over the weekend thinking that would help the code 44. I guess a compression test is next.

Turnin20s

iTrader: (12)

Still no fix man? That sucks, I hope you get that thing figured out.

Formula383

iTrader: (8)

Compression test has yielded good results and a little relief for now.

#1 - 195
#3 - 200
#5 - 204
#7 - 186
#2 - 195
#4 - 204
#6 - 202
#8 - 194

This has to be something electrical. I just can't find it!

fergymoto

iTrader: (129)

I feel your pain man. I was going through the LT1 blues too for the last 3 years. Just all kinds of little problems and electrical gremlins. I never had any problems that were because of the LT1 motor itself, just its EFI system. Fix one problem and shortly another comes up. I got tired of it and there is no longer a LT1 in my engine bay.