Yeah, but we did that:-?

He does, i will ask him to send me the magic file.

How could you tune for the new MAF size if you can't get it to run properly?

Not tuned, calibrated rather.

Same thing, how could you do it without the engine running?

Maybe try disconnecting the MAF as long as your IAT isn't in it

Try uncalibrating it and I'll bring my MAF over after work one of these days.

It is, the maf is a 5 pin so the IAT is built in to it. I did unplug the MAF and give it a go, but that would mean unplugged IAT as well.

I can toss this thing back together and try it with the MAF unplugged but IAT plug plugged into the IAT thats in the lid.

Just to rule out the 85mm MAF I would revert back to original MAF and IAT and give that a shot. Also relearn the TSP if you haven't done that already. I ran my car on stock 78mm MAF and IAT plugged in the lid with my PRC heads and Cam on original start up before converting to LS3 card style. Ran a little lean but it was good enough for startup.

Im gunna grab a stock maf from Mike, and im picking up a IAT sensor from chevy tmmr (one in the lid has been knocked around and painted over lol)

Really hung up on if the low compression numbers are related to the firing issue, or if thats a completely separate issue Ive just bought to light. Maybe there coming up so low bc the engine has only ran for 10 seconds in the past 6 or so months. Who knows.

Uh, good to know I guess :lol: Obviously, you're welcome to it. You can take my SLP lid with IAT sensor too. Also, if you're feeling frisky there's a truck MAF & breakout harness installed on the car that you can borrow as well. You should know the garage code, but if not, text me. Just to rule out valves, grab my assembled 243s and springs off the shelf too, because at this point, it'll only cost you a Friday night & a set of head gaskets--fuggit.


Question for the pros: There's a correlation between MAF and those low compression numbers??


Beggers, jog my memory:

• You pulled the valve covers and verified rockers are going choo-choo?
• You double checked that you didn't butcher anything during your snipping-spree or the re-looming of the harness?
• Did you move coil packs around? You can grab LS1 coil packs & plug wires for testing/Racewars purposes as well.
• Swapping to stock injectors helped, correct? How did you ascertain that there were no fueling issues in the system you plumbed?

4 days. Buckle in for some long nights.

At this point, the easiest test to run would be:

Rocker bolts snug down, then back off two turns. Run compression test. If the numbers jump up significantly, points to too-long pushrods.

The low compression test numbers are clue we shouldn't ignore. Also, crank the motor until the gauge stops climbing, that'll give the lifters a chance to pump up with a little oil.

I agree. I just wonder if the gauge is bad or slow cranking speed since they were all low. After kirk told me how you measured for pushrods, I would do like the bishop says and see if the numbers improve.

Nothing at all

No Relation between MAF and compression, like we were talking in text, im starting to think low compression doesnt have to do with the firing issues.

I had the rockers down snug with the pushords in for the leakdown and nothing got by the valves, it all came past the rings. You can clearly hear the air coming out of the crankcase(still had timing cover off) No hissing out of exhaust or top end. Wouldnt this verify pushrods are not holding valves open?

I can grab the gauge from work and try it with that one. Mine is SnapOn, not sure of the work brand. Its audi supplied.

Low compression will definitely give you firing issues. Snapon should be good. Wanna buy my car?

no way lmao this is my last fbody hurrah

don't blame the car for the loose nut in the toolbox. :)

Haha what i mean is Id like to graduate to a C5 or C6

Just give me a call when you're ready for that diploma

No, not really because when the lifters sit, they bleed down which will let the valves close. If you crank it with all the plugs out, it should turn over pretty quick, which will build oil pressure, which will get the lifters to do what they'd be doing when running. If the pushrods are slightly too long in a hydraulic lifter setup, it'll show in a compression test but not necessarily in a leakdown test.

At this rate i think graduation is less likely than being left back. :lol:

If the pushrods are too long and hanging the valves open while the engine's trying to run, it'll bleed off cylinder pressure which will make it run like ca-ca, and the back pressure will force a combustible amount of fuel/air into the intake, which will occasionally ignite when some burning gasses leak into it, hence the backfires.

That's my theory, anyway.

Ok ok......I'll sell you my 10 second lt1. Had compression last time I used it :rofl:

Knock Knock...


whos there?

Endless pit.

https://farm5.staticflickr.com/4583/...ae753aec_z.jpgUntitled by mickey beggs, on Flickr

https://farm5.staticflickr.com/4581/...e4125857_z.jpgUntitled by mickey beggs, on Flickr