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Ruben
Junior Member
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Monday, April 14, 2003 3:46 PM
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My mechanic told me one of the coils was week and I should replace it so I did the unthinkable and through research on Ferrari tech tip sites(not this one)I discovered that the Accell 8140 coils work fine so I purchased two of them and installed them. The car ran fine with much better pick-up etc.. but it started to make a terribly loud popping noise during idle, acceleration, and deceleration. The carbs were worked on previously so while doing this I fully believe I fouled them and need to clean them or replace them (have not checked yet). Did I destroy the vehicle by using this non Ferrari part ?. Most importantly Why did a coil change create such a horrible condition. What can I do to keep the new coils and get the car to run without the gun shot sounds ? Will stock Ferrari coils improve running without the horrible popping ? I tried to readjust the carb's air/fuel mix with limitted success. Please help!! I love my car and can't believe this is happening, forgive me Enzo!
One clarification; what I fully believe I fouled was the sparkplugs not the carbs. Could fouled plugs with two new coils cause such a popping noise ? Thank you all in advance for your help.
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Ruben
Message edited by: Ruben on 04/14/2003 15:52:43
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BillBadurski
FCA Technical Chairman
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Monday, April 14, 2003 7:52 PM
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It's a little difficult to diagnose these things from afar, but here are a few comments. First, fouled plugs will cause a rough idle and "popping" at higher rpm. Why not check the plug condition and gap and replace as required. Next, make sure you have not mixed up the plug wires/firing order. Make sure all wires including the coil wires are intact and fully seated. Don't have experience with Accel coils, but I have used standard AC Delco without problem. I believe the Ferrari coils had external resistors to prolong point life, but if the points were good and you haven't put many miles on this configuration the points are probably still OK. Something to think about down the road though.
As for the carbs, if the car ran well before, the carbs probably are not at fault. I would retrace all steps taken during the coil change to see if something else was incorrectly assembled.
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William V. Badurski
FCA Technical Chairman
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Ruben
Junior Member
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Monday, April 14, 2003 8:32 PM
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Thank you. I will check the plugs. As far as that goes I have changed plugs on other vehicles but not on my 308. Is there any precautions I need to take given that the plugs are deep "inside", specialy on the rear bank ?. What size plug socket do I need ? Also I did not make any changes to the plug wires at all just the coil swap. One thing I did not mention before was that at one point while poping I stopped and looked at the tail pipes and I could see small puffs of flames when it popped?. Does this mean anything ?. It all started with the
new coils ??
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Ruben
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BillBadurski
FCA Technical Chairman
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Thursday, April 17, 2003 10:44 PM
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The forward plugs aren't too bad actually. I use a flex-head ratchet and a combination of a 1" and 3" extension on a 13/16" plug socket. It's all done by feel. Reinstall the plugs using a length of 3/8" fuel hose over the ends. This allows you to start them in the unseen holes with insufficient force to cross-thread.
One other thing that crossed my mind regarding coils involves voltage developed. Ferraris are notorious for bundling plug wires close together as opposed to domestics which not only separate them well, but in some cases even specify keeping consecutive firing cylinder wires at opposite ends of the separator. If these Accel coils are "too hot", maybe you're getting crossfire. If spark plugs don't resolve this problem, I'd go back to original type coils.
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William V. Badurski
FCA Technical Chairman
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HankTheCrank
Junior Member
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Tuesday, May 13, 2003 6:38 PM
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Here's my two cents,
I've worked as an exotic car mecanic for over twenty-five years, and poping (at idle) isn't related to the coils, or their replacement, but if you take an old mirror (a rear view mirror works for me) and look down the throttle bodies 80% of the time you'll see the accelerator jet dripping into the center of the carb! It means if you've adjusted the mixture it's too lean. The bench mark to start is screw them in till they stop "DON'T OVER TIGHTEN!!!" Then back them out 2 and a half turns, and start to adjust them from there. If you don't have one now I strongly recomend a "Carb Sync. Tool," This procedure is caried out by first poping off the linkage from each carb (so each is sucking gas & air uniformly), then adjust each carb slowly (once in a while give them a manual rev, and wait a few seconds before continuing, I beleive that one of the carb's is adjusted a bit lean, and this prosedure will remidy it! It's not fast, but you don't have to do this but once every year or so...
Good Luck,
HTC
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I've worked on almost all Italian cars, and can "Spin a wrench with the best of them!"
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