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Discussion Starter #1
PLEASE HELP! My car was runnin

PLEASE HELP! My car was running perfect a couple of months ago. 6 months ago I replaced my plug wires and plugs along with cleaning my distributer; water pump, air filter, oil, etc.. Then just several weeks back I heard a popping sound which got worse to backfiring. I then checked out my extenders and replaced all of them along with new plugs once again. The problem seemed to have gone away. It ran great when it was cold, then after I drove it for a while, it began to pop a bit at idle or a real slow speeds. I then double check my gaps and connections thinking this must be an ignition problem. The car still did the slight backfiring when hot. So my next thought it my be the fuel pump or perhaps my injectors. I don't know? Well just recently as of a few days ago, the popping has evolved to major backfiring, and it feels like it is running on 4-6 cylinders, even when cold now. I am thinking now this could be one of my coils gone bad or perhaps both. Please Help, I am stupid Ferrari 101. I appreciate all or any responses. Thanks!!! Aris
 
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Discussion Starter #2
Hi Aris,

Welcome to Ferrari


Hi Aris,

Welcome to Ferrari-Talk.

Certianly more than one thing can cause the symptoms you describe, but there are quie a few basics that should be covered first.

Have you checked the wiring harness connections to the Digiplex units, and upgraded their ground wire connections? Loose wires & bad, corroded grounds to the Digiplexs are a well known source of erratic ignition problems.

Regards, JRV
 
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Discussion Starter #3
Have you verified that the plu

Have you verified that the plug wires are installed in the correct firing order? Next, if the problem occurs at idle too, using plastic plug wire pliers, pull the plug wires off one cylinder at a time to locate which one is causing the problem. As each wire is removed, a noticeable loss of engine rpm should occur. If pulling a wire off one cylinder does not affect engine speed, that's the problem cylinder.
 
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Discussion Starter #4
Thanks JRV and Bill... I check

Thanks JRV and Bill... I checked the wiring harness and grounds near the Digiplex and there is very little corrosion, perhaps just a slight at the connectors. As for the firing order Bill, it's all right. Since the car as of now is missing spiratically, I did not bother pulling each wire off, in fact, I am almost afraid to start it with the increased backfiring. So today, since I live in FL, nice day, I took my dist. cap off and noticed my points were burned and worn down badly. It looks as though I need some new caps for sure. I slightly sanded them down a bit but they still look bad. I am going to place them back on and give the car a turn to see if it helps a little. I will get back soon, doing it now, please get back with a post. Do you know where I can get some inexpensive new caps in the meantime? This still might not be the problem. Thanks!!! Aris
 
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Discussion Starter #5
Hi Aris,

I'm not aware


Hi Aris,

I'm not aware of quality aftermarket caps.

How did the cleaning work out?

Regards, JRV
 
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Discussion Starter #6
Hey JRV, cleaning was what I e

Hey JRV, cleaning was what I expected, clean but still burn marks.. is this normal? Started it up and I had low pressure, like 4-6 cyls. I ran it until the high rev kicked off. It started backfiring. Didn't help the problem. I noticed the sound was very weak while also noticing the tach reading high rpms, but no strong sound or power like usual. At start up it was showing 5000 then kicked down to the 2500-2800, but the high rev sound was absolutely not there. The choke then went off, I steped on the throttle to give it a little gas, then the tach would shoot straight up fast to 5000-6000 rpm but had no type of power. I shut it off, A long day, but not too much progress. I cleaned around the harness also and the ground like you were talking about, but that part was relatively clean. I was to hope it was something simple, but I am getting a bit aggrivated. Probably still the distributer caps for sure plus who knows. I'd hate to take the car in for service at this point, normally I fix all of the problems because I like to do it for one, and it saves me thousands. What do ya think???????? A Coil? What's Next? Oh, by the way where are those 3 electrmagnetic sensors on this car? Could that be part of the problem?
 
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Discussion Starter #7
Hi Aris,

The 3 pick-up sens


Hi Aris,

The 3 pick-up sensors are around the bell housing in relation to the flywheel, 1 by the starter, 2 on the back portion of the bellhousing.

The way to isolate the problem is to first determine if one or both banks are missfiring. This can be done by pulling each coil wire in turn while the engine is running to see what effect it has. The problem with the early systems from a diagnostic point of view, is that there are no tests for the Digiplexs themselves, so testing is done by a careful, methodical process of elimination. If the problem is isolated to one bank, that must be determined first. If both banks are erratic that needs to be known.

Regards, JRV
 
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Discussion Starter #8
Hi JRV, Ok, I tried to keep th

Hi JRV, Ok, I tried to keep the car running as much as I could I had it about 4500rpm. Took off the 1 coil cable and the car died. I did the same with the other and the car just shut off also. The car would not run either way with only one coil connected. So we are getting somewhere right?HA! PLease Help, you seem to know this car better than me. Next? Thanks for the locations on the 3 sensors! Aris
 
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Discussion Starter #9
Oh, when the car died at both

Oh, when the car died at both trys it left a major backfire on each time. Aris
 
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Discussion Starter #10
Factory Marellis dist. caps ar

Factory Marellis dist. caps are available from the Ferrari Owner's Site (Ferrari UK) for around $225(!) which is the same as the currently available reproductions, which I have heard some have had problems with last summer.
 
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Discussion Starter #11
Thanks Dave, I want to stick w

Thanks Dave, I want to stick with the Marellis. I'll look into that, that is one of my first steps to this problem I suppose. Aris
 
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Discussion Starter #12
>So we are getting somewhe

>So we are getting somewhere right?HA! <

actually maybe we are, you just found out that if it was that easy, everyone would be Ferrari experts.


Without being there and with very limited info in this medium we always have to fall back on standard testing procedures. I hope you realize that not every test one performs on a Ferrari is a lotto winner, but they must be done none the less.

We just had a case where an owner was asked repeatedly about the engines fuel pressure, he insisted it was within spec several times, then proceeded to playing pin the tail on the donkey, only to find out that Fuel Pressure that he insisted was fine was the problem all along. The point is, tests have to be performed in a methodical process of elimination otherwise it's simply an exercise in wasting time and chasing shadows.

Why won't the car idle?

What condition are the plugs in?

The mre info we are armed with the less flying blind we are.
 
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Discussion Starter #13
another quick question...Is it

another quick question...Is it back firing through the intake or exhaust?
 
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Discussion Starter #14
Have you done a compression te

Have you done a compression test to verify cylinder pressure? I would definatly start with that first. You have to make sure your starting with a healthy engine before you go and start throwing parts at it. Just like a house. You must have a good foundation to build on, otherwise your throwing good money out the window.
 
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Discussion Starter #15
My '82 GTSi did the identi

My '82 GTSi did the identical thing, popping and back-firing, turned out to be a combo of bad thermo-time switch giving faulty info to WUR/cold start valve, thus altering the fuel delivery, and bad fuse block also causing poor electrical delivery to engine compartment.

I too had new wires, plugs and Stabilant-22'd all electrical connections including the Digiplexes in the trunk, all to no avail (except quicker windows, brighter lights thx to Stabilant).
 
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Discussion Starter #16
Hi Mark,

Welcome to Ferrari


Hi Mark,

Welcome to Ferrari-Talk.

Excellent suggestions for things to check!

Regards, JRV
 
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Discussion Starter #17
HI JRV, yesterday when I start

HI JRV, yesterday when I started it, it kept idle only until the choke kicked off, then I had to give it gas to keep it going, perhaps it being cold??? Not enough fuel? When I ran it several days ago the car kept idle also, but it was lagging. The last day I drove the car which was on Christmas, the car ran great and had full compression. I drove it until the car got to 190 temp., then it started to putter and pop, seemed missing a bit. That was the best it ran in a while... I had placed a new check valve on where the air injection system is, which I thought that perhaps helped it some. Later that night I drove it about 15 minutes and then the popping and backfiring started again, but this time it was the worse ever. It would kick in all 8 cylinders then down to maybe 4-6 then back up to 8 again.. By this time I was back at my house and time to shut it down. So I don't think there is something seriously wrong with my engine. The NEWS. Today I just yanked my plugs. They are only about 5-6 weeks old. The all looked carboned, very black. No oil on any. The 4 in the one bank towards the rear looked worse, darker. The 4 in the inside were not as bad. I thought they all looked very black considering they were less than 2 months old. The 4 that were slightly cleaner seemed like a lot of carbon, but looked more towards normal. Thanks Tom for your posts.. I have not done a compression test, several days ago the car had full compression and was running fine. After the car got warm like I said before it would pop, I guess on the intake, when I would lay off the gas. But later it would backfire and pop out the exhaust. So the answer would be both. When I took a coil check test and disconnect, the car backfired super loud each test after it died. I did not start the car today, didn't want it too hot to yank the plugs. The plugs are out now. Any suggestions? Mark-very logical! Thanks!
 
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Discussion Starter #18
Aris,

put in a NEW set of p


Aris,

put in a NEW set of plugs...I realze they are a symtom not the problem, but it will be helpful to have the engine running as well as it can considering it has some unresolved issues. NGK BP6ES plugs are a good choice.

It will be helpful to try and eliminate some ignition components if possible, for that it is best to have at least some sort of decent idle. If we can eliminate ignition, then we can move on to fuel. If not we are trapped not knowing which system is at fault or at east worse than another. I like to split everything up/down to their simplist forms, and derive some important info rather than jumping back & forth. Generally ignition is fastest & easiest to diagnois with a minimun of tools and minmun of professional knowledge or experience.

Regards, JRV
 
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Discussion Starter #19
Ok JRV, sounds like the right

Ok JRV, sounds like the right plan. I am almost tempted to get new caps too and include in our diagnois at this point. But the plugs can be obtained a little simpler. Cheaper too! When I changed the plugs over a month ago, the car ran about 95 percent. I will get new as of Now! Will Napa or Discount have them?? I hope THANKS! Aris
 
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Discussion Starter #20
Aris,

yes NAPA or simular s


Aris,

yes NAPA or simular store should have the plugs as they fit alot of different engines.

Regards, JRV
 
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