High rpm hesitation - is this detonation?

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08-31-08, 02:24 AM

#26

walken

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Quote:

Originally Posted by kevino

88 TII

This is problem that suddenly started to occur. The car pulls hard as normal until I get to around 5500 to 6000 rpms and then the engine starts to hesitate. It is actually sort of a smooth hesitation (certainly not fuel cut). The only thing I can relate this hesitation to is clutch slipage, because that is kind of what it feels like. But there is no way it could be slipping because I installed all new clutch components 2 years ago (including new pressure plate and flywheel) and I hardly ever let the clutch fly.

So what could be causing this? From searching, I've seen some situations which could be the same, in which grounding problems were suggested. Also vacuum leaks could be a problem or something happening with the turbo.

Any suggestions? thanks

everytime I've had this happen with my sevens (and sometimes it would go away) I changed the fuel filter and pump strainer. everytime it's solved the problem.

on my 88 t2 I've had major backfiring at 6k, but I had a F-Con and when I removed it that went away... that also blew my engine in a 5th gear pull on the freeway.

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04-07-10, 03:32 PM

#27

oregano

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I had the same problem on my 89 s5 n/a up until 2 hours ago. At first i thought it was plugs or plug wires but replacing those items made no difference. So next I suspected AFR being too rich or too lean. Turns out it was too lean as richening it up with the SAFC seems to have fixed the problem (I dont have a wideband. I bought the car like this 2 weeks ago. Im getting a wideband soon). I will change fuel filter now and also inspect the fuel tank sock.

I read somewhere someone saying that the s5's do not use the MAF sensor at WOT... is this true or was this person mistaken? I have not had time to research this yet.