When flooring it I will get a lot of backfiring (after around 4k rpm). My suspicion points to the ignition system.
Dizzy cap + rotor less look good,
HT leads good,
Spark plugs good,
Coil is cracked slightly (now filled with silicone)
Ignitor (original, yet to test)
No Fault codes (Not knock sensor or fuel cut)
The car has a high idle now (1500 rpm). Could it be possible it's slipped a tooth on timing or would the coil and ignitor be a good items to replace first?
Cheers in advance, I am going to have a proper look later.
(3s-gte) Massive machine gun backfiring after 4k RPM
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Re: (3s-gte) Massive machine gun backfiring after 4k RPM
Was it running okay before? when did it start? did you do anything to the car that might have caused the problem? has water got into the engine bay?
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Re: (3s-gte) Massive machine gun backfiring after 4k RPM
Rev1/2/3/4/5 ? are you running higher boost? What fuel are you running?
Re: (3s-gte) Massive machine gun backfiring after 4k RPM
My guess is either an air leak somewhere or your AFM is playing up.
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Re: (3s-gte) Massive machine gun backfiring after 4k RPM
It has been rather wet lately. I have been driving in a lot of rain.
Rev 1 converted to Rev 3 Map sensor.
Rev 1 converted to Rev 3 Map sensor.
Re: (3s-gte) Massive machine gun backfiring after 4k RPM
I'd bet on it being an air leak from somewhere also.
96 Rev 3 Turbo, Done!
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Re: (3s-gte) Massive machine gun backfiring after 4k RPM
I have a new coil on the way. The spark plugs look tired (after 6 months) as well.
All vac piping is good, I have had boost leaks before and never got backfiring, let alone backfiring like this.
Fingers crossed anyway, I will update the thread with the result.
All vac piping is good, I have had boost leaks before and never got backfiring, let alone backfiring like this.
Fingers crossed anyway, I will update the thread with the result.
Re: (3s-gte) Massive machine gun backfiring after 4k RPM
Although you say you have had boost leaks before, my boost gauge (aftermarket) vac hose split where it was "T-pieced" into the system and I had the same outcome as you are getting.
Just a thought
Just a thought
Re: (3s-gte) Massive machine gun backfiring after 4k RPM
Ive got exactly the same issue on a Rev2. Its been going on for about 9 months so the car has been wet / cold / dry / hot and it doesnt seem to make a difference. My first thoughts was the cold and damp last November, but Ive since ruled out the damp as the car hasnt been wet expect for washing . Also, Ive tried it on a variety of fuels.
If a search engine brought you here, I have solved mine, heres what I did........
The car has had a full service including plugs, HT & King leads , cambelt and pump changed. This made no difference what so ever.
As far as I can tell there are no leaks, but did replace all the jubilee clips / clamps just incase. No difference.
New AFM and inlet piping replace. No difference.
Changed coil / igniter pack - woohoo! Back to normal
If a search engine brought you here, I have solved mine, heres what I did........
The car has had a full service including plugs, HT & King leads , cambelt and pump changed. This made no difference what so ever.
As far as I can tell there are no leaks, but did replace all the jubilee clips / clamps just incase. No difference.
New AFM and inlet piping replace. No difference.
Changed coil / igniter pack - woohoo! Back to normal
Last edited by Matt on Thu Aug 09, 2012 2:49 pm, edited 1 time in total.
Re: (3s-gte) Massive machine gun backfiring after 4k RPM
My guess would be the coil or faulty wiring to the coil causing the misfiring. This is how my 2 step rev limiter works. Destabilizing the coil by grounding the negative signal wire.
Kev.
Kev.
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Re: (3s-gte) Massive machine gun backfiring after 4k RPM
All is well and the car is driving properly now.
The fault could have been one of a number of things, so I will list what I found today:
1 ht lead may not have been making a good connection on the spark plug,
Intercooler piping removed and reinstalled (in case of boost leak),
MAF Sensor cleaned (slight coating of oil),
The coil has also had 48 hours to dry (If it was indeed damp inside).
As a new coil is in the post I will install that anyway. The old one is 22 years old and could do with changing. It could have got damp and caused the issue (as it has a crack).
Thanks for all ideas. Matt, good luck with the fault. I would double check all of the wiring to each sensor, earthing points etc.
The fault could have been one of a number of things, so I will list what I found today:
1 ht lead may not have been making a good connection on the spark plug,
Intercooler piping removed and reinstalled (in case of boost leak),
MAF Sensor cleaned (slight coating of oil),
The coil has also had 48 hours to dry (If it was indeed damp inside).
As a new coil is in the post I will install that anyway. The old one is 22 years old and could do with changing. It could have got damp and caused the issue (as it has a crack).
Thanks for all ideas. Matt, good luck with the fault. I would double check all of the wiring to each sensor, earthing points etc.