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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Cowboy_Customs on November 05, 2008, 07:45:04 pm
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My SES light does some odd things, I was sittin in my truck listenen to the satellite radio drinkin a beer (in my driveway!) after runnin the truck long enough for my code 32 to come up (still no clue why, no prob with EGR system) and after about 10-15 min the SES light blinks off, then back on. About 5 minutes later it begins flashing at me, no rythem, not in code, just steady flashing, some quick like its going to flash a code, then slow, ON......... Off....... ON.....
off....... Just no steady pace or rythem. I have been wondering if the ECM is going brain dead for a while now, lots of new sensors from the O2 to the knock sensor, all brand new ignition system, yadda yadda yadda, good running condition. Or outta be anyway.
But the truck in general does weird things, starts perfect, 1-2 cranks when cold, but have to start it like a cold carbed motor when its up to heat.
A quick throttle stab and it spits black smoke, spits black smoke when ya start it when its up to heat.......
Any idea guys? I havent tryed the Stealer to find out what a new puter is going to cost, and I have one of those rare one a kind trucks, 454 TBI with a 4L80E. Only year in this body style to recieve the combo.
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What's your fuel pressure look like? Have you replaced the regulator?
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The light shouldn't be doing that. Either you have an intermittent grounded circuit or the ECM is on the fritz. Did you check for dtc's?
As far as your hot start with black smoke, take a look at the map sensor and it's vacuum hose.
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I had one do that and the cluster light was grounded...
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I have just a code 32 right now. But I still dont know why, the EGR itself works just fine, and I just put on a new EGR control unit. My MAP test out fine, Vacuum line is good to it as well.
When I was working the bugs out of it, the SES light did have some kind of ground issue (I think) I never got far enough to pull the dash apart to find out why, I was more conserned with getting whatever code was in the ECU. Got the code put everything back together.
Took the truck for a 1200 mile ride to Columbus OH in the beginning of Oct. and during that drive the ground or whatever fixed itself. The SES light used to fade in and out. Not just ON, then OFF, but like I said faded in and out. No prob with that now.
All the wiring looks good, all the grounds are clean, brand new Alt. 120 Amp too. Thought maybe that was giving me issues, lots of bearing dust, truck would run poorly upon startup and the volt meter would be under 13 on the guage, then it would pick up over 13 and run just fine, so replaced alt and cleaned grounds. Didnt fix the prob. still does it. Thats one more reason im thinking the puter is dying. When it is in its poor running deal my voltage on the gauge is under 13, no matter what, giving it throttle makes no difference, then it'll pick up and truck idles fine. Now a cold start, like I said, runs great, instant voltage. I know the alternator is good. Battery might need replacing, a lil under rated for a truck like mine.
Now how do I acctually check the puter? Im assuming probly a laptop and WinALDL program? Do I need the WHOLE thing, OR can I just get a new PROM like from TBIchips? I did find some computers for around 115 bucks.
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Download WinALDL spend about $15 and built yourself a cable. if you want to check the ECM...
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aight, thanks Capt. I'll get to work with that.
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This is my setup:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=7711.msg47384#msg47384