OK so I'm fairly new to GN's and have an 87 I'm trying to get running right before adding any uprades. I've read on here you need a scanmaster before you do anything, so got a scanmaster 2.1 and here are my readings. Also some numbers kept jumping around. 02 milivolts started at 450 on a cold start up and dropped to 260-350 after warm up. I know I have the famous cracked header and guess that could lead to this #?? AF - 04 LB 34-39 BAT - 13.4 IN- 128 BL - 150 CLT - 190 - my fan comes on right a 190 still ATS - 120 R - 650 - 700 IAC - .42 idle and 4.44 wot IAC - 73 CC - 192 I started off trying to adjust the IAC to then set my TPS, I could get my IAC down to 39 but no lower the number starts to rise even turning the screw the same direction. Also everytime the fan kicked on the IAC number jumber up 20 or more. Lastly no matter what I adjust it on a restart its back to 73. Could I have a bad IAC? I thought I check for vacuum leaks and havn't found any, I even but a vacuum gauge on and pull good vacuum. Any help would be great! Thanks
Check for vacuum leaks too. A BL of 150 is numerically high, and may indicate a vacuum leak. Ideal should be 128, give or take a few.
Please read the following link, to help you understand your new scanmaster readings. http://turbotweak.com/scanmasterinstructions.pdf Baty 3.4 ? Assuming that was meant to read 13.4 Agree with quickv6 bl should be in the 118 to 138 range, 128 is dead on. I see you tried to bring the IAC back in line with no success, I would pull the Idle Air Control Valve and clean or replace it. Chuck
The vortex link in post #3 should be in everyone's favorites (bookmark). I refer to that site all the time, Steve Wood is a great person to talk/type to. Chuck
First thing I'd do is get the header cracks fixed, so your not chasing your tail. It'll spool much faster too. Also, double check for vacume leaks. Check where the vacume lines hook to the vacume block on top of the throttle body. They like to crack on the bottom, where you can't see it. Make sure that the little one way check valves arn't blown out. Start with the simple stuff first. Happy spooling. Mike Barnard
thanks for all the info, dumb question but one way check valves in the vacuum block or somewhere else?
