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hesitating and spluttering at 1.4 bar

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Old 02 April 2006, 04:29 PM
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S3TH
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Default hesitating and spluttering at 1.4 bar

Some of you will probably know this car, I bought it from paul a couple of weeks ago, a 96 WRX putting at 340bhp @ 1.4 bar.

Basically it as an apexi ecu with commander and has 4 different boost/map settings. 0.6 up to 1.4 bar. The car runs perfect on the first 3 settings, up to 1.2 bar. but when set to 1.4 bar, turbo spools and it begins to pull but then the car hesitates and hangs back, at the same time i can hear what sounds like spluttering from the exhaust and the exhaust note also gets very raspy. But like i said on all the other boost settings the car is fine.

My thoughts are it could be over fuelling but im no mechanic!

for those that dont know engine spec is, walbro 255, sx FPR, FMIC, 550cc, apexi ecu, Headers & decat exhaust.

Will probably take it up to local specialist and let them road test or put on rollers to see whats happening. just wanted to check that its not something simple and obvious that i might be missing!

Previous owner said that it might be the apexi adjusting and autolearning the turbo gain and do to a few runs. Well over the last week have been out and done a few runs at 1.4 bar but its not getting any better.
Old 02 April 2006, 05:15 PM
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coilpacks are failing, causing ignition related misfire. You could try reducing the gap on the spart plugs, but you may need to replace the coil packs for a proper fix
Old 02 April 2006, 06:51 PM
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S3TH
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Hi m8, I believe it was yourself that looked after this car when paul was the owner

Im sure paul said new coilpacks went in with the new engine, thus they have only done around 6000 miles. Can they fail that early?

If they are can you supply coil packs?

thanks.
Old 08 April 2006, 11:20 AM
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right confirmed with previous owner that coil packs have only done 6k miles and the car had new plugs a couple of months ago. Does not seem feasible that these items could have failed so quickly?

Took her out yesterday and the red led is lighting up on the AFR gauge occasionaly on part throttle, but constant on full throttle. so looks like she is running lean now as well?

Anymore ideas anyone?
Old 08 April 2006, 11:43 AM
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I think I know the car now. It was fine just a month ago, running sweet. I wouldn't put much faith in the Dawes AFR meter, but it would be a good idea to get it over to us and I can check the map is as it was left and it's running okay.

Paul
Old 08 April 2006, 11:52 AM
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Yes paul said he didnt have any problems, and when i went on the test drive it held 1.45 bar and was fine. I drover her slowly on the way home, next day went out for a run and it felt chocked was hanging back so we thought it was the bung in the exhaust, removed it still the same.

regarding the dawes AFR guess im just paranoid, i once ignored a knocklink to great expense so just crawling around on part throttle at the moment.

Guess it makes sense to travel to yourself as you know the car, Im in norwich though so about a 2.5 hour drive. LOL if i leave now could be there by 3.
Old 08 April 2006, 10:47 PM
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Andy.F
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Unlikely to be new coilpacks giving issue. Check the vac line to the SX FPR, a leak here would cause lean running.

Andy

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Old 14 May 2006, 06:25 PM
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still got this problem and it has worsened, runs like a dream on 0.6 and 1 bar, anything above that hesitating and spluttering.

took it to local specialist and they could not get the fault to replicate on the rolling road, but when they actually road tested it the fault happened twice.

They checked the coilpacks and found a hairline fracture on one so replaced it. Said if problem was still there it would need more diagnostic time on the RR. picked her up and yep problem is no better.

Any ideas anyone? not been running right since day one
Old 14 May 2006, 08:20 PM
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Best bet is to have the mapping looked at again. Surely any problem this major will show up fairly quickly once you're on the road and the laptop is hooked up?
Old 14 May 2006, 08:28 PM
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yeah, think that could be the way to go. will have to get over to Zen.
Old 14 May 2006, 09:00 PM
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Likewise. I've got a couple of things need looking at, and it's easiest to get it all done in one go with the right equipment and expertise than keep speculating at home...
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