Rough idle engine seems to hunt after it warms up. New fuel pump 3.5 bar pressure at rail no drop in fuel pressure with ignition off. If I block fuel return line instantly fixes problem. Please advise.
regards terry
Tuesday, March 17th, 2015 AT 8:07 AM
3 Replies
HMAC300
MECHANIC
48,601 POSTS
We have no info on these as they are not in US. Try cleaning throttle plate first with choke cleaner then check for spec on fuel pressure if it' s not dropping I doubt it's the regulator but could be.
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Tuesday, March 17th, 2015 AT 8:17 AM
TERRYSHERE
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Thanks for your reply, I believe this motor is also called ecotec l61 as in your l300 and others. Have cleaned throttle body swapped with known good one from running motor, no change.
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Tuesday, March 17th, 2015 AT 3:55 PM
HMAC300
MECHANIC
48,601 POSTS
On a chevy cavalier with the 2.2L the fuel pressure should be 53-59 psi or 3.87-4.2 so it may be low pressure then. If fuel pressure remains constant when blocking off return pipe then the regulator may be at fault. Fuel pressure should not drop more than.3kg after 10 minutes of stopping engine. Do not let fuel pump go over 75psi if blocking return line