Monte SS ECM threw a code 51....UPDATE !!!

[V]

well if you arent sure what code 51 refers to..

"Code 51: Defective PROM; PROM not properly installed; incorrect PROM installed; Defective ECM"

so now i'm not sure what to do, i guess i have to swap out the ecm and prom and now spend big bucks to get one custom done AGAIN. i wish i knew how to burn memcals right about now... plus i gotta find a good 730 ecm, not hard but who can i trust....ugh. i'm not happy at all, i was going to try to set timing tonight on the monte and now this.... piece of ****. Â*im just surprised it did/does run how it does with that ecm/prom issue...oh well, its just my luck. Â*Can anyone help me? please....i got parts to trade Â*:roll: ok...and yes cash....just help ASAP...

[j0n]

fasterthanyou aka jon prevost

[NJSPEEDER]

you could ask foff667, he does some tunign work for the newer cars. he can prolly find the problem or turn the code off if that is all it is.

later
tim

[j0n]

its (one of) his monte ss's thats havin the problem...prevost knows those 80's ****...i highly doubt bill does

[V]

im just afraid the ecm or prom itself is fried of just plain bad. Â*i have another 730 ecm in a car out back so tomorrow im gonna try that, if its still bad, i'll have to look into gettting the prom reburned if possible or buy a new one thats programmed for 350 SD tpi, 5spd manual, LT1 injectors, no vats and no A.I.R.

oh yeah i'll just clearify...its an 87 monte ss but with a 350 tpi setup, 87 350 block, 88 TB and plenum, 92 base, runners, and fuel rail. SD retrofit harness for stand alone. 730 ecm.

[The Fixer]

Hey Paul,
Check all of your ECM grounds as well (back of the heads, and possibly the frame or fender, wherever you mounted the other one). I'm sure if they're loose it'll screw some things up.

[V]

well today i bought i timing light to try to get this thing running. since the code 51(or so ive been told) is more specific to ecm or prom failure, if it was bad connections it should be a different code. but anyway, i took the "730" comp from the 90 RS i have(6cyl and v8 SD comps are same whoohoo) and i installed my custom PROM into that. i plugged that in, then set the timing with the est connecter unplugged. one main thing i did notice was that the ses light was on when i turn the ignition on the went off when the car started. after i set the timing, i checked again and the ses light was back on. However thats all good, thats how it should be, the ses should have been set by the est unhooked. other times the SES light would stay on from when i turned the igniton on , started the engine and then shut it off. i set base timing right at 6*(pretty close to where it was all along) So now i reconnected the est, and disconnected the + terminal to clear the code which i assume was a code 42(est problem). now i'm just gonna have lunch then hook up the battery again and go from there.

[The Fixer]

So, what's the update? Is it running alright now?

[V]

ill know tomorrow, i'm still not back from lunch, haha, other stuff came up. tomorrow i have to finish xmas shopping and get a tree, then ill try it again.

[V]

ok well i finally got time to get back to the car today, i reconnected the + battery teminal, got in turned the key, "vrooommm" started right up, idling very nice at like 1200, it was ice cold and i think i turned the idle up last week, but smooth. It didnt even smoke really like it did last week. i let it run a few seconds, its still not full with cooloant(since i was maybe pulling the timing cover) after like 10 seconds, i gave the gas pedal a little stab, it easily shot the tach up to 4500-4700 rpms solidly. And the SES lights is off and stayed off. so all in all i think i figured out the issue it had. apparently the ECM was bad and messed everything up since thats all i changed(other than correctly setting the base timing :lol: ) but the SES light now is fine and i dont think bad timing would have set a code 51. Tomorrow the car is getting registered and insured, then i can test it on the road and fine tune it from there..... :drive: