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VFR750 VFR750 is offline
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Join Date: Mar 2004
Location: Windsor, CT
Posts: 2,119
CIS Injector Sleeve w/Backfire Damage??

Pulled CIS a couple of weeks ago. 121,000 miles, no issues. Looked at the system today, and I was surprised to see this damage. Car had issues with occasional backfire. Pop-off valve always saved the day. I had sealed the injector sleeves with RTV to prevent vacuum leaks.

Ever see this before? #2 cylinder sleeve is melted. All others look fantastic.


Close up


I think it must be due to backfires. #2 must have been the frequent source of the backfires. Looked down at the valve after the CIS was removed and saw no visible damage to the valve. So it's a little mystery.

I bet air was leaking past the o-ring on the injector, but was the backfire blowing past the o-ring?
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Mike

'82 911SC, SSI, 22/29 tbars, 22F/22R Adj swaybars, Bilstein Sport, Elephant polybronze & monoballs, Cambermeister bar, turbo tierods, Carrera oil cooler, front brake cooling ducts, Sparco Sprint 5 & Recaro SRD PAX seat, Teamtech harness, DAS Sport rollbar.

Last edited by VFR750; 09-06-2010 at 04:37 PM..
Old 09-06-2010, 04:34 PM
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