New Injectors - The Bleeding Edge

Tim just a thought, from the video, it sounds like not all cylinders are firing, I say tist because two weeks ago my car was miss firing and coughing a lot during idle, during acceleration, and on steady speed, it was really bad, anyway to make the long story short, it turns out that my Digiplex were both bad and when I swapped it for another set of Digiplex boxes, the car ran like new and smooth in all action, idle, acceleration, and at steady speed. So, you may want to check your Digiplex by unplugging the harness, check it, then plug it back in and see if that makes a difference. This Digiplex also commonly to go bad, just saying.

 

"You do realize that Stabil is 95% heating oil."

Ah, but what about the other 5% which turns heating oil into stabilizer?

 

Bourbon.

 

It definitely sounds to me like you have a cylinder or two not firing... Is it possible that you now have a fowled plug or two? I've found that I've fixed the primary concern only to have it overshadowed by the secondayry issues it caused... I had a loose plug connection on the 3.2 Carrera and when I pulled the plug it was a mess. So, even getting the cap seated didn't really help. After I pulled the plug and cleaned it all was better. Just a thought... F

 

"Is it possible that you now have a fowled plug or two?"

Yeah, chickens in the system would definitely clog it!

Sorry..couldn't resist...

 

I think things are getting way ahead of themselves. I can't say much about the backfire or miss, but from the video it doesn't seem to be doing it at the higher idle after the throttle is blipped. At least I don't hear it. As for the higher idle, all I can say is my car has done that since new. In fact, on a cold start, if I don't blip the throttle it will often stall on a cold start. Once the throttle is blipped the RPM settles in somewhere between 2 and 3k RPM until the coolant temp comes up, then it drops down to around 1k and hunts a little. I can't say if that is normal, but all majors on my car have been done by the dealer or by a highly regarded indi who worked for the dealer when I bought my car back in '85, and for the first 5 years everything was done at the dealer.

I won't make this a suggestion as Tim already commented on it, but if it's only popping at the 1k idle speed, if it were my car I'd definitely get it out on the road and see what happens. But that's just me.

 

Tim, disconnecting the vacuum hose to the Digiplex should increase the RPM as it advances the ignition timing by around 4-5 deg. but jumping from 1000 to 2500 RPM is quite a bit. This shouldn’t have nothing to do with not allowing the idle to return unless something is binding between the throttle cable and the linkage which it did happen to me but that’s another story. If there’s only a way you could borrow a pair of the Digiplex, would help us a lot as far as where to go next.

Just FYI, Ferrari service of Bedford in NH do repair them and/or make new ones for you.

 

Certainly suggests that something different is going on with combustion between the two banks. Process of elimination: air, fuel, or spark. Uneven air delivery to the front vs rear bank seems the least likely given the single throttle body and shared intake plenum. As we discussed separately, it certainly could be uneven fuel delivery from the fuel distributor, however, given that each cylinder has its own dedicated fuel line from the distributor it would be odd for the distributor to be out of balance in a pattern that clearly discriminated the front from rear bank. Since the 308 has separate digiplex boxes for each bank I'm suspicious that one may be functioning differently from the other. Tim have you put a timing light on the primary wires from the coils to the distributors as well as each of the plug wires and confirmed even signal?

 

Tim, this is what they said when I told them my Digiplex are bad and if I could send it to them and here’s their email address: [email protected] (603) 493-1696

“Hi Mike,

Yes, you can send us the boxes.
The testing fee is $300 for the pair, plus return shipping
However, If the boxes test bad, we’ll waive the testing fee.
A pair of remanufactured boxes is currently $2,460/pair, including return shipping to you.
As I might have mentioned, the only component we reuse is the case. All of the electronics, including the connector, are new!
We’re out of town until Monday...

Thank you.
Best,
David”

 

The best way to clean plugs is with a propane torch. The only thing better would be new plugs.

An easy way to find a misfiring cylinder is to run the engine from cold for 1 minute. Then touch the exhaust manifolds at each cylinder close to the ports on the head. If you can hold your finger there, then that cylinder is misfiring.

 

Probably pointless to post this but as I said before, I don't think you can conclude anything about the fast idle unless you let the engine come up to temperature and it continues to run fast. From your video it appears the engine is cold and from the manual,

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I think by blipping the throttle you are just engaging the fast idle device, or have I missed something?

 

Why do you believe it was "running right" before? Without knowledge of how these cars behaved when new, how do you know what "right" is?

DYing is great but there comes a time when throwing parts at a car that don't achieve the desired result becomes the wrong path to follow. I don't blame you for not following my advice. I don't follow advice from FChat without independently verifying its validity, so I can hardly expect anyone to follow mine.

 

Fast idle is likely the plunger getting stuck at a slightly higher than the correct idle position. Get the fault to show up then see if there is play in the air vane movement. Play meaning that the air vane moves slightly without touching the plunger. In correct operation, the plunger should follow the air vane all the way to the closed position.

 

Has the cold start valve been disconnected or disabled?