OK, guys... I need some help, please. I converted my 870 to a 165 a while back, and I'm having a few problems...hope you can help. Something is just not quite right here. I have back-probed the connectors, and all the voltages seem to be correct, according to the FSM. I ran new wires to the ALDL connector, because the old ones were in such bad shape....20 yr old wiring!! The car has taken to not starting, recently....I've checked everything: has spark (Nearly knocked me to the floor when I accidently grabbed the coil), has fuel (38#'s at the rail), new maf....but just cranks, and cranks, but won't ever catch....tries to, but won't. Timing is set to 10*, and is right on the money. Does this for a few days or weeks, and then wham! starts up??? don't know why?? I've tried to scan, but I CANNOT get it to connect at 8192, with any software. Tried Tunerpro RT, datamaster, turbolink, freescan....no sync. They all find the cable, and say it is ok. The TTS ALDL tester passes ALL the tests, both fast, and extended....I can however, connect @ 160 with WinALDL, or Tunerpro RT. Datamaster says it finds a GM 160 PCM (never been able to get a good answer on what that means, but I would guess it finds a 160 baud PCM)...Freescan says it get invalid header information...Turbolink just says it can't communicate....been chasing this for about 6 weeks, so I'm hoping I can get some help here on the Forum...BTW, I have an 85 vette, L98....
Checked the ignition module...it checks good, as does the coil.....ANY help would be most appreciated....

Cheers,
Michael

 

You say you have good spark and good fuel pressure, but is the ECM firing the injectors ? Does vats come into play when converting ECM's ?

 

Yes, I've checked the injector harness with a noid light...they all flash as expected...ohm'ed the injectors, all at or very near 16ohms.....VATS is disconnected in the PROM....using a $6E ARAP code.....spark at all the plugs...plugs just changed...brand new, and gapped correctly...

 

do the spark plugs get a little ''damp'' with gas when it cranks for10-15 seconds ??

 

not really...they get damp, but not soaked...

 

''damp'' is good, ''soaked'' is not...the fuel system is ok (i assum that you found gas on the spark plug, not water or beer--the nose knows, stick a screwdriver into the gas tank fill and get a sample sniff if you are not sure)

beacuse the engine runs on occassion, we can rule out major mechanical trouble.

just leaves spark gremblims...since you got bit by the distrib, sounds like spark is being made, not dispensed properly ( i routinely grab the top of hei distribs to turn em to set timing with the engine running and never get zapped)...throw in a known good distrib rotor, look at the little ''nipple'' that carries juice from the coil to the rotor while you're in there

 

Just changed the rotor...got a small cap,external coil...no difference...I'm thinkin I must have some electrical gremlins of some sort, but everything I check, checks out with the FSM.....

 

at this point, i would grab a small dizzy and the matching coil from an early 90's chev v-8 pik-up at the j-y....problem is one of three places; the ecm/prom, the dizzy/coil, or the wiring...we have had so many probs with the small dizzys around here that you need to expend effort to give one away, and its the easy change, i'd start there