virtuetovice Posted December 29, 2012 Report Share Posted December 29, 2012 89 Cutty, 2.8, 240k miles. So here's what I've got so far with this damn thing. Replaced the crank sensor, coils and ICM. Coils and ICM came from a 3100 so I'm certain they're not heat damaged. That was the first step and the car still showed the same symptoms. It would start most of the time and idle perfectly but as soon as I give it gas it cuts out. Other times it had trouble starting. Replaced the crank sensor[never break it for the love of the car gods!!!] and nothing changed. The fuel pressure is over 40psi at the rails and doesnt go down when the car is idling. I've taken the PCM apart and checked all the solder connections, there are no cold solder joints. The whole board looks perfect, no corrosion anywhere either. The PCM itself seems to be a dealership replacement. No idea what to do at this point. Save the bullshit and swap it?? Is there something retarded simple I'm missing?? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted December 29, 2012 Report Share Posted December 29, 2012 TPS? MAP? got an ALDL cable? Quote Link to comment Share on other sites More sharing options...
virtuetovice Posted December 29, 2012 Author Report Share Posted December 29, 2012 An ALDL cable would be awesomesauce, but no monies. I did find a pile of MAP sensors in the garage when I went home for the holidays. Worth a shot.... AS for the TPS....isn't there a way to test it with a multimeter? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted December 29, 2012 Report Share Posted December 29, 2012 more or less. should be a grey wire giving it 5V, a black wire for ground, then the other color of wire is the voltage reference for the ECM. should be ~.5 volts at idle, ~4.5 volts at WOT, linear progression between the two points. obviously, you'll need to give it power to check it, so you'll either have to have it plugged in and pierce the wires or figure out another way to give it 5V and ground. actually, while you're at it, make sure the 5V reference is actually 5 volts.... i've seen an instance where the reference voltage was messed up and that caused all kinds of havoc, since the reference voltage circuit is also what powers the ICs inside the ECM. i do think i need to make an ALDL cable "rental" service... Quote Link to comment Share on other sites More sharing options...
virtuetovice Posted December 29, 2012 Author Report Share Posted December 29, 2012 And I've already devised a way to make a 5v power source. Cig lighter USB plug! Looks like I have a project tomorrow... What all is involved in a ghetto manufacturing of an ALDL cable? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted December 29, 2012 Report Share Posted December 29, 2012 depends on how ghetto you want to get. just need a TTL to USB adapter that uses a FTDI chip(they're the only ones that work reliably at 8192 baud). http://www.gearhead-efi.com/Fuel-Injection/showthread.php?719-Uber-easy-DIY-USB-ALDL-Cable Quote Link to comment Share on other sites More sharing options...
Hairdo12 Posted December 29, 2012 Report Share Posted December 29, 2012 Will it stay running if you press the accelerator and hold the motor at 1000 rpm and then put the car in gear? Check the IAC if that works. Quote Link to comment Share on other sites More sharing options...
virtuetovice Posted January 3, 2013 Author Report Share Posted January 3, 2013 Nope, when it decides to idle it shuts down as soon as the throttle is touched. Right now all it wants to do is act like it will start and then shut down as soon as i let go of the ignition. If I keep holding it it runs for a second and then fires random cylinders with no intent of starting back up. If I shut the car off and try again it does the same thing. I just went off and paperclipped codes 22, 33, and 43. 22 is TPS signal low, but I disconnected it to see if it would start disconnected. 33 is MAP sensor indicating low vacuum. last is 43 knock sensor error. Quote Link to comment Share on other sites More sharing options...
Night Fury Posted January 3, 2013 Report Share Posted January 3, 2013 My 88 was doing a similar thing, I took it to a shop. They said 'the PROM ends were fucked' And did something to them, also itemized on the bill as 'PROM END REPAIR KITS', of which they used 2, at $10.94 each. I have no idea what they did, how they did it, what they are, but it fixed the problem and it has been fine since. Just something to ponder/discuss Quote Link to comment Share on other sites More sharing options...
virtuetovice Posted January 3, 2013 Author Report Share Posted January 3, 2013 Trade PCMs??? Quote Link to comment Share on other sites More sharing options...
Night Fury Posted January 3, 2013 Report Share Posted January 3, 2013 Perhaps if it weren't my ONLY car Quote Link to comment Share on other sites More sharing options...
virtuetovice Posted January 3, 2013 Author Report Share Posted January 3, 2013 I know. The only thing is, I've already taken apart and inspected the PCM and I see no problems whatsoever... Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted January 4, 2013 Report Share Posted January 4, 2013 What number is your PCM? I think I have a spare 9396 and couple spare MEMCAL's laying around. Not really sure how I collected them but I did Quote Link to comment Share on other sites More sharing options...
virtuetovice Posted January 7, 2013 Author Report Share Posted January 7, 2013 So I guess now the question is....will the low vacuum or knock sensor error cause the problem I'm having? Just doesn't make sense, I've had a vacuum leak before and the car just idled high. The knock sensor error shouldn't keep it from starting either. Maybe I'll get a video of the problem and see if someone can shed some more light on this. So confused! Quote Link to comment Share on other sites More sharing options...
virtuetovice Posted January 7, 2013 Author Report Share Posted January 7, 2013 If it helps anyone my PCM is 7727. Still fighting this but the more I read around, the more I believe my PCM decided to an hero. I read somewhere that the cooling fan is supposed to kick on when I try to pull a code? This hasn't happened once and I've pulled codes twice. I did notice that when I hold the ignition trying to start the car, the SES light flashes constantly. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted January 8, 2013 Report Share Posted January 8, 2013 yes, fan 1 should turn on when in field service mode (blink codes on the SES). could be a bad relay, bad fan or the ECM itself. SES light flashing while cranking..... i've never seen it before? Quote Link to comment Share on other sites More sharing options...
virtuetovice Posted January 8, 2013 Author Report Share Posted January 8, 2013 Nope, as far as I know the fans and relays are fine. Last time the car ran they worked. I guess the hunt for the PCM begins. Will I be looking for any 89 2.8/3.1, or is it more/less specific than that? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted January 8, 2013 Report Share Posted January 8, 2013 a 1227727 or 16149396 will work for you. basically, any 2.8/3.1/3.4 W-body from 88-93 will have what you need. the 94 3.1 lumina also has a 16149396. the 90-91 L98 corvettes also used a 1227727. other platforms didn't use underhood PCMs, so the case and connectors are wrong. if you were really in a bind, you could adapt a 1227730 in place of a 1227727 and have it work perfectly. Quote Link to comment Share on other sites More sharing options...
Garrett Powered Posted January 8, 2013 Report Share Posted January 8, 2013 Just get a couple of those ECM's. I have a bunch of them. If the junk yard tries to sell you one for $60 or something outrageous tell them to fuck off. But then get a ATMEL chip intalled on it and if you can't tune someone can email you a tune. that is if you can't get a stock BIN on a chip that will run it. Or burn the stock BIN and start datalogging. if you get a cable. Quote Link to comment Share on other sites More sharing options...
virtuetovice Posted January 8, 2013 Author Report Share Posted January 8, 2013 Some more info on an ATMEL chip would be great, I'm always open to trying new things. I'm sure if I got my hands on a chip I could install it myself. All I'd really need is the chip itself and some info. I know the first thing on my list is acquiring a PCM. Quote Link to comment Share on other sites More sharing options...
Garrett Powered Posted January 8, 2013 Report Share Posted January 8, 2013 the chip itself is very inexpensive. I got someone else to solder all of mine. If I were you, I would have a few MEMCAL's with the atmel chip installed, then you can just quickly swap them and it's easier. Quote Link to comment Share on other sites More sharing options...
Garrett Powered Posted January 8, 2013 Report Share Posted January 8, 2013 how much will you give me for a couple ECM's out of my pile in the garage? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted January 8, 2013 Report Share Posted January 8, 2013 27SF512 is also a really good EEPROM that will basically drop in place of the 27C256 used in the MEMCALs from GM. Quote Link to comment Share on other sites More sharing options...
skitchin Posted January 8, 2013 Report Share Posted January 8, 2013 Bit behind on the thread, but you're probably looking for a chip from the Atmel ATmega line, perhaps the ATmega328(Saar where you are)? Solder in a DIP socket and you can just swap pre-programmed chips. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted January 8, 2013 Report Share Posted January 8, 2013 no, nothing like that... these are just PROMs, i believe Rick is referring to the 29C256. Quote Link to comment Share on other sites More sharing options...
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