1989 245 b230f with new 398 head and k cam.

just wondering i am getting my car back normal specs and im gonna test the oxy sensor now i just changed the head and had a horrible start issue, got that fixed and then the idle was horrid with a vacuum pull of only 12. i did put a k cam in, so i expect some idle jiggles...but i am still getting a idle variation of anout 50-100 rpm and its blowing gas, amm has been replaced wiht a good working one. so thats good....

the iac was hissing all the time, but now its doing ots normal routine again, might have been my vacuum leaks i had..and timing has been checked over and over and over agian so its ok. i was just wondering if wih a super rich condition it may cause backfiring in the intake?

ROBERT
--
Gauvain the Brickster Uses "Volvo" Brand Station-Wagons!!!

Backfiring in the intake is usually a result of severely advanced or retarded ignition timing.

damn, its all lining up p[erfect thgouh...

should i retard the ignition then? move the disty gear ahead of the #1 position?

it is almost dea don right now
--
Gauvain the Brickster Uses "Volvo" Brand Station-Wagons!!!

Hmm, hard to say at a distance. Check the basic timing as a guide: With #1 cylinder at TDC on the firing stroke (both valves closed), the distributor rotor should be pointing at the distributor lead for #1. If it's off by much (tough to eyeball), then the intermediate shaft is off, relative to the cam and crank.

Do you have a timing light? I think the basic ignition timing is 12 degrees BTDC at idle with the vacuum to the ignition unit plugged. Try 2-4 degree timing changes either way to see if it improves, but if you still get backfiring in the intake manifold then there's a valve that's staying open when it shouldn't.

Seat of my pants says either ignition timing or valve timing (i.e., t-belt) are off.