95 850 HORRIBLE knocking after tranny swap - not solved Topic is solved

850TurboTurtle · Post by **850TurboTurtle** » 10 Sep 2015, 01:19

Got a code off it: 1-2-1, which is apparently MAF sensor signal. I swapped out the MAF from my donor car and nothing changed. Pulled apart all the air hoses, turbo hoses, vac hoses and reconnected, and no change.

I'm stumped. It runs terrible, won't idle, knocks like a hammer is whanging the turbo. Anything else I can try? Turbo to intake hoses are new 1 year ago from the head gasket job.

850TurboTurtle · Post by **850TurboTurtle** » 10 Sep 2015, 01:23

abscate wrote:This sounds a lot like my 1999 did with loose induction. The metering is completely screwed up at idle but kind of works at mid Rpm range ..followed by backfiring and WONK ! Detonation

Was your backfiring really sharp and hard, like a hard hammer blow from a big wooden mallet on the engine? That's how mine sounds. Not the long 'firework bang' you hear from a tailpipe backfire. I'm afraid to run it much for fear of detonation harming something.

I wonder if the intercooler could be cracked and leaking air? I didn't remove it for the job, and it was fine before, but who knows.

850TurboTurtle · Post by **850TurboTurtle** » 10 Sep 2015, 01:26

dosbricks wrote:Did you remove the knock sensors?

Thanks dosbricks. I only unplugged them from the wiring harness but left them on the engine. The harness length made it so i could only reconnect the right way. So I think that's not it. Still stumped though.

850TurboTurtle · Post by **850TurboTurtle** » 10 Sep 2015, 21:35

So, I've listened to the hoses for leaks, checked hoses and electrical connectors, vac lines. Swapped out MAF. Checked injector spray patterns. What else can it be?

Bad ECM?
Timing belt slipped? (Put on new last year during head gasket).
Bad fuel or clogged filter/pump/?
I can't think of anything else to check given the symptoms.

Help!

850TurboTurtle · Post by **850TurboTurtle** » 11 Sep 2015, 00:19

All 5 look the same, a short puff of fuel in a cone, apparently. I'm guessing this is working normally.

Post by **abscate** » 11 Sep 2015, 01:13

Check fuel pressure at rail to rule out fuel

Check for timing belt slip by turning engine over by hand and confirming marks

We have learned the hard way that you have to remove induction parts to check for leaks, Inspection is not enough

Post by **dosbricks** » 11 Sep 2015, 10:39

Most likely an intake leak somewhere as the consensus suggests (assuming you used a new manifold gasket and that is not the source). But (and this is a long shot) since you got a MAF code--certain models had problems with the plug/wireing where it connects to the the MAF.

Some electrical contact cleaner sprayed into the connection and making sure the engine side wiring is secured and can't flex around with engine torque might be worth trying. I have been concerned with the way all the aged wiring must get wooled around to get it all out of the way for my own in progress engine removal. So I'm watching this thread closely and pulling for you to solve this problem.

dos

1ezliving4ume · Post by **1ezliving4ume** » 11 Sep 2015, 10:54

In your video it looks like a small puff of smoke comes out of the turbo cold air discharge. The side going to the intercooler. Its around the 12 second mark on your video. Do you see it?

Post by **abscate** » 12 Sep 2015, 05:20

When these engines wonky-run, codes are meaningless. You will get all kinds of spurious stuff popping up if there is a lot of misfiring.

850TurboTurtle · Post by **850TurboTurtle** » 13 Sep 2015, 01:04

1ezliving4ume wrote:In your video it looks like a small puff of smoke comes out of the turbo cold air discharge. The side going to the intercooler. Its around the 12 second mark on your video. Do you see it?

You're right. In fact, I think maybe there are smaller puffs after each knock. Hmmmmmmmm..... I'll have to take a closer look into that. thanks. Good eyes!

95 850 HORRIBLE knocking after tranny swap - not solved Topic is solved

Code 1-2-1, MAF, still no progress