My 305 started to run rich last week and I can not find the problem. I have checked fuel pressure (47 psi) and also checked it with my OTC scanner. The O2 was switching between rich and lean with it staying on rich for a longer time. While it was in open loop it was rich. Is this normal? Is there anything else that I should check? I'm also having a problem with my timing jumping around. It goes between 9-16 degrees at idle. I can disconect the timing wire and it is steady at 8 degrees. Could I have an ECM problem? This has been going on since I have owned the car. Any help would be greatly appreciated.
My list of mods are...
gutted air box
K&N filters
Relocated air temp sensor
TB coolant bypass
air foil
adjustable fuel regulator
Air pump removal
Thats about it far as the motor goes. It does have 180,000 miles on it.

Thanks,

------------------
Billy
92 B4C 305TPI T5
Texas Spokes Sports Car Club #63 ESP
73 Z28

 

When was the last time you changed the 02 sensor? If it's more than 15-20K now would be a good time to go ahead and put in a new one.

The jumping timing at idle is normal. The computer uses the timing to help adjust the idle rpm.

------------------
87 IROC-Z, 5.7, auto, 3.27, leather, !cat, Holley fpr, K&N'S, SLP 1-3/4" Jet-Hot coated headers, SLP .218/.224 .495/.502 cam, Comp 1.5 roller tip rockers, $uperPITAram, Edelbrock lower intake, Holley 52mm tb, Dynomax\Flowmaster catback. Coming Soon(?)- Fasttrack/Accell DFI

1989 Pontiac 20th Anniversary Turbo Trans Am - 161,000 miles, !cat, 9" K&N

[This message has been edited by irocz (edited December 09, 2000).]