Anybody Know what fuel pressure LT1's are supposed to run? My 95's been acting strange like she's lean and when I checked the fuel press. it was around 20psi. Seems way too low to me, I thought SFI motors ran a lot higher. Have any of you guys experienced low pressure? I'm thinking regulator issues as the filter was just changed 15,000 mi ago.
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The LT1 should be around 42psi with the vacuum line off.
KnightFire -
Could just be a weak pump. 20psi is way too low. As noted in the post above.... 41 to 47psi with the vacuum line off is the factory spec. Reattach the vacuum line and the fuel pressure will drop proportional to manifold vacuum... a 6 to 8psi drop is normal. The pump should hold within 1 or 2psi of the "no vacuum" value at WOT, all the way to redline.
You can check the fuel pressure regulator by looking at the vacuum line. If the regulator diaphragm is bad, fuel will get into the vacuum line.Fred
381ci all-forged stroker - 10.8:1 - CNC LT4 heads/intake - CC solid roller - MoTeC engine management - 8 LS1 coils - 58mm TB - 78# injectors - 300-shot dry nitrous - TH400 - Gear Vendor O/D - Strange 12-bolt - 4.11's - AS&M headers - duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP/800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117MPH straight motorComment
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Thanks guys- for some reason I couldn't find the spec on the net anywhere. Injuneer had it right- fuel pump crapped out late last night after replacing the regulator and the filter (I didn't see Fred's test for a bad regulator till this morning) Thanks again guys-
SteveComment
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