308QV Ignition Problem--I'm Stumped

Thats what I was thinking.

With the motror hot and idling put your hand on the frequency valve. Is it vibrating? Can you hear it. If you unplug it does the running change?

 

They are the electronic ignition boxes and are under a panel on the left side of the trunk under the carpet.

 

I know of electronic boxes under the right side where the Catlytic temp box is, there is stuff under the left side too?

 

Right side is the injection stuff. Left side is ignition.

 

Brian, Are you going to Rutlands open house in April?

 

No.

 

Darn, I was hoping you would be there. I am considering trailering the car up, and was going to have you look it over.

 

Post #10

 

Thanks to everyone who responded! Turns out I had two spark plug extenders that weren't fully connecting to the plug and arcing under load. There was a wire under the expansion tank that had come loose. I had two small vacuum leaks and one bad one. One hose I replaced two years ago was too short and had split at one end....very hard to see without blowing smoke through the system. It took my mechanic from Modena 4 hours to find everything with scopes and smoke machines, so I don't feel too bad about giving up on fixing it myself. Again, thanks for all of your help!

 

Actually, on a Mondial, they are mounted just ahead of the left rear wheel.

 

My 2 cents; some already mentioned.

If it's fuel, I can't imagine how. Fuel issues appear at high RPMs, not low. That being said, a loud fuel pump is a sign it's about to die, but this isn't your problem.

It sounds electrical; have you changed the spark plugs? I would do that first as it's easy and cheap, and may solve the problem. Once they're fouled, they don't always return to normal even if they're working.

I'm not familliar with your ignition system but it sure seems to me that's where the problem lies. The only other thing I can suggest is a vacuum leak, which was also mentioned before. On my carb car at least, vacuum leaks make for crappy idle which vanishes at higher RPMs. I'd recheck those hoses, especially at the clamps.

Ken

 

You are correct but during the hijack I was referring to my brothers 308.

 

You contradict yourself. Vacuum leaks are without doubt a carburation problem so even in your scenario it can be a problem rev range wide.

Also you are applying carburetor theory to fuel injection.

And for what it is worth fuel delivery systems have far more low speed running problems than high speed. At high RPM as long as there is fuel delivery, nothing, even proportions dont matter as much. It is much like flushing the toilet.

 

Someone else mentioned vacuum; I repeated it because as you state, some problems disappear at high RPMs like unbalanced fuel/air delivery....which can be a result of a vacuum leak somewhere. When I said I doubted fuel delivery, I was thinking of too little fuel due to a bad pump (or blockage); I wasn't clear on that as you point out. I still say the fuel pump may be going bad but it's not the issue.

Ken

 

In the final analysis, you were both right....which is why it was over my head to diagnose. It was ignition and a vacuum leak and a fuel delivery problem due to the wire that was disconnected. I was trying to figure out how all three problems came to be at the same time. Obviously, they didn't. I suspect that the ignition wires shaking loose were the straw the broke the camel's back and it was just too much for the ignition and fuel systems to compensate for. It's hard to detect a subtle decline in performance when your heart starts to beat faster every time you sit in the driver's seat