PDA

View Full Version : Exhaust Too Rich


garysbgn
10-04-2004, 10:42 AM
Got new MAF, 42#, new O2 sensor, adjustable Fuel Regulator, correct pressure for injuectors, etc. but when car is idling or movign under 25 mph, the smell of gas inside car is very strong. Driving over 25 mph, smell is gone, but could be due to moving fast enough to clear. Just rebuilt engine and everyone is befuddled by this. With SCANMASTER, readings of 795 and about 3.0 knock retard, so it's not picking up the richness during WOT. TPS is right on. Anybody got any ideas on how to get rid of the rich gas at idel or slow rpm's?

bmackinnon
10-11-2004, 02:24 PM
What kind of "new" MAF? What is Scanmaster reporting for idle gps? I've 'heard' that many replacement Maf's are questionable at best. Also, you state 'correct fuel pressure for injectors'. Maybe you could elaborate a bit? I'm assuming the 42# you mentioned is inj. size? What pressure are you running?

Turbo2nr
10-11-2004, 07:41 PM
I guess if you smell raw fuel, you have a leak. Start motor, and pull off the fuel regulator vac. line to raise pressure, and look for leaks, I had an "O" ring cut on my Fuel regulator from when i installed it, new one fxd it. Only leaked over idle (higher fuel press) Also check the inj. seals on the manifold and fuel rail. You should NEVER smell raw fuel! :nono:

garysbgn
11-10-2004, 12:15 AM
What kind of "new" MAF? What is Scanmaster reporting for idle gps? I've 'heard' that many replacement Maf's are questionable at best. Also, you state 'correct fuel pressure for injectors'. Maybe you could elaborate a bit? I'm assuming the 42# you mentioned is inj. size? What pressure are you running?

OK - thanks for your reply, sorry it took so long to get back. MY "new" MAF is a reman DELCO, recommended to be the best. Heard about the "repalcements and made sure I didn't get one of those. Fuel pressure has beens set by two different GN engine rebuilders to match my injectors 42.5lb and boost 18-19 with non-race gas. Pretty sure they have it set right, but what do you suggest?

We've tried reducing the tps down to 36 and there still is rich smelling exhaust even though it seems I get detonation with tps set that low. No detonation at 42.

Got any ideas?

garysbgn
11-10-2004, 12:18 AM
What kind of "new" MAF? What is Scanmaster reporting for idle gps? I've 'heard' that many replacement Maf's are questionable at best. Also, you state 'correct fuel pressure for injectors'. Maybe you could elaborate a bit? I'm assuming the 42# you mentioned is inj. size? What pressure are you running?

What is "idle gps"? AF at idle registers 6, I believe allother readings are where they are supposed to be.

Keller
11-10-2004, 12:54 AM
Fuel pressure has beens set by two different GN engine rebuilders to match my injectors 42.5lb and boost 18-19 with non-race gas. Pretty sure they have it set right, but what do you suggest?

Not running that much boost on pump gas, for one. For 93 octane, 15 or 16 is all you will likely get without knock.

Base TPS can not be down at .36 and run right. Try .42-.44.

We still have no numerical idea on your fuel pressure. The idea to check for leaks sounds like a good one. Maybe something is just leaking?

garysbgn
11-11-2004, 01:11 AM
Thanks for your thoughts - fuel pressure is 43 / 36 at idle. Moved tps back to 42, little or no knock. Seems more suggestions are to check for bad injector(s). Running test on each in the AM with mechanic. Block learn seems to indicate it could be the injectors since all else seems to be in line.

Any other thoughts are much appreciated.