Well Cory and I spent the whole day trying to get this motor to run properly. We have finally concluded that the number 1 and number 8 cylinders are "dead". What we mean is that they are not firing. Or at least they are not getting hot whereas the other 6 cylinders all are.

We HAVE spark, we know that. We have fuel, we pulled the plugs and they are wet whereas the others are sooty from the rich tune. We checked the number 1 cylinder for compression - we got 100 lbs. We checked the rockers. The valves seem to be going up and down, we even backed the rocker arms off 1/4 turn.

We changed the plugs between 1 and 3. I replaced the number 1 spark wire. I changed fuel injectors between 8 and 6. None of these had any affect.

Meantime, until I can get the harware working, the FAST is useless. It is reading super lean because the oxygen is going through without being burnt. In reality the tune is quite rich.

Any way, tired and burnt out and we have run out of ideas.

Anyone got something we could try?

 

Try switching coils with someone? I'd say your problem MUST be spark to those cylinders. I'm sure you've checked for burned-shorted or non-conductive leads? I'm tired too after a fuel pump/tank removal on my Caprice tonight. I'll give it some more thought in the A.M. when I'm awake...
Larry

 

Remember it can only be opti(which I doubt) or wire related, check the wires once again, since you have no coils opti either fires or does there is none in between unless something inside is really messed which in this case of have given you many warnings. Do you mean 100PSI? It should be in the 170+ range I belive for a good motor even with 8.5:1 compression, don't quote me on that though, also the cylinders won't all have the same temp, primaries 4&6 will be the hottest, primary 2 will be hotter than primary 8, get the drift? 4&6 heat eachother up, #2 gets more air so it burns leaner than cylinder 8, but 4&6 are hottest cuz they heat eachother up.

Did I do rockers on your car? If so than don't worry, otherwise maybe you have a problem there, I would remove those rockers for those cylinders, remove spark plug, put finger in spark plug, turn the engine over by hand, you have blow/suck? If so, good. Try disconnecting fuel injector wires for those cylinders, makes a difference? If so call me or something, can't say good or bad, both bad Injectors all the way in? no leaks of fuel anywhere?

Just food for thought from Matt

 

Ps. He doesn't have coil(s) he has coil

I on the other hand, have coil(s) now

 

HeyLlarry.

New plug wires and now go over the top. I'm leading to think it is a compression issue.

As I say, we DO seem to have spark at the plugs.

 

Like I said, I was tired! Thought you had an LS1, DUH! With more thought, I still believe you've got an ignition problem, although only 100 PSI does sound low. The washing of your rings in those cylinders by fuel that didn't get burned could lower any compression readings though... Can you put an inductive timing light on each plug lead while it runs? No flash, no spark...
Sorry, that's all I can suggest with the info you stated so far

 

Thanks Larry.

i going to check some other cylinders for compression next.

 

Hey Matt,

How much did it cost you to swithc over to Coil Packs? and what was involved in the switch? Thanks

 

Ussually costs about $1,000 to switch, I got it on a group purchase & got the coils for doing some work

Also, Try doing that thing with the injectors I suggested, put 24lb's in those cylinders having trouble see what you get.

 

Important Update.

Ok we tested the injectors with a special light thngy.

INJECTORS 1 AND 8 are NOT working, suggesting that there is a wiring problem for those injectors.

When we took the PCM out, we saw three pins - one in the red, blue and white that are "hot" and have had some melting happening.

Getting closer to a diagnosis although still lots to be done.

 

Did you upgrade the wire size to the injectors?

Steven

 

since you had lots of fuel on the plugs, prolly melted wires are shorting causing those injectors to constintally fire at all times?

 

Steve: No i did not upgrade

matt: We have to RETRACT our observations about the plugs haveing fuel.

Further review suggests they are not "wet".

 

OMG you guys are useless than rewire that $hit

 

We checked the wires going to the injectors. Everything is fine.

At this pioint we are speculating the ECU is at fault OR the stock PCM.