Need help......Can't figure this thing out.

[TURBOTIMMER]

Ok, I tried just about everything I could think of. So here it goes.

Start my car. I let it sit and idle for about 5-10 minutes. I get in it to go. It seems to run okay for the next 3 minutes. Once I'm driving at a steady speed, the car just dies. It gives me a couple of backfires and my boost gauge goes nuts, and finally quits. It does not restart. I think I've checked everything. The only thing I now for sure is I'm not getting spark. These are the parts I've tried with no cure. All are off of my GN, with the exception of the crank sensor. I bought it new at advanced auto.
coilpacks
module
ecm
chip
crank sensor
cam sensor
maf sensor
Here's another thing. On my OTC4000, the BLM# is right at 128 up to the point where it gets to about 150 degrees. For some reason, when the car warms up, the BLM# slowley climbs to 146-150. I've tried adjusting the fuel pressure, and it doesn't seem to bring the numbers down.
My opinion is that something is telling the computer to shut the spark off, but it's driving me nuts. I just don't know where else to look.
Could someone please clue me in as to what to look for.
Thanks in advance
Tim

 

[MeanBuicks]

Could very well be a wiring harness problem.

 

[Jimn8or]

Sounds to me like you possibly have a Positive battery cable that has the casing burned off in some spot. When the car drives it bumps just enough to make contact on this same area, thus putting positive to a negatively grounded car/frame creating an electrical sh!t hemmorage and it quits running Physically check every inch of the cable from battery to starter solenoid and be certain the cable isn't run accross the neg terminal of the solenoid...like someone elses once was
HTH
Jim

 

[Black1986Beast]

Originally posted by Jimn8or
Sounds to me like you possibly have a Positive battery cable that has the casing burned off in some spot. When the car drives it bumps just enough to make contact on this same area, thus putting positive to a negatively grounded car/frame creating an electrical sh!t hemmorage and it quits running Physically check every inch of the cable from battery to starter solenoid and be certain the cable isn't run accross the neg terminal of the solenoid...like someone elses once was
HTH
Jim

That makes alotta sense to me--Check this out

 

[TURBOTIMMER]

Thanks for all your input, guys. I have all day Thursday to look this thing over. However, do you think that would have an effect on the BLM numbers?

Anyways, thanks for the ideas. Please keep them coming.
I'm pulling my &^%$in hair out.

 

[Chuck Leeper]

Dies?

If the BLM'S are going up, the ecm is adding fuel.. I'd be looking at what could cause this to happen. Sensor readings gone fubar?

Electrical problems causing loss of power, thus the ECM is adding fuel, as the inj's are lazy.??
No spark would lead me to look at the 'ADvance Aurter parz" crank sensor.
Does the engine start after it cools off??
Mean Buicks mentioned harness. Look at the grounds and the fuseable links near the starter.

 

[TURBOTIMMER]

Chuck, to answer your question, yes, the car starts up after it cools off. However, it has to sit for at least 3-4 hours before doing so.
Looks like I'll be taking the crank sensor off the GN, too.

Thanks for your input Chuck.

 

[Steve Wood]

my money is on the module. Swap coil packs and see if the problem does not go away.

 

[Chuck Leeper]

Module vs HEAT soak

Steve W. wrote:
my money is on the module. Swap coil packs and see if the problem does not go away.

__________________

I'm w/ Steve on this... I've seen a module actually melt the potting material and it ran out whan I opened it up.

 

[TURBOTIMMER]

The car did the same thing with the original module and the one off of my 50k mile GN.

If this keeps up, I'll never get the GN back on the road when I get the tranny back.

Oh, here's smomething else I thought of:
When this problem first started happening, I was able to get the car running again. When it would start back up and run, the belt would squeel kinda bad.

Now does that make this all the more confusing or what.

 

[Chuck Leeper]

Squeelin??

Sounds like there could be a problem w/ the alternator. Low volts could cause poor pump output, thus the BLM problem, thus the backfire and ???
Start it and check alt output at the alt and at the batt.

 

[TURBOTIMMER]

Man, I never even thought of that. I assumed it was ok since I never had a problem with it cranking after it would stall. That does make a hell of a lot of sense.

I'll be lookin at it tonight.
Thanks again, Chuck.

 

[V6 Beast]

Make sure the bolt holding the balancer on didn't work it's way loose. It can cause backfires and such because it will skip the crank sensor.


Sully

 

[TURBOTIMMER]

Sully, I just checked that tonight. It seems to be real tight. Chuck, I checked the voltage at the battery. At idle, my voltmeter reads 14.02v, but it doesn't go up when I rev it up. Does that sound a little low?

Also, I had the car running tonight. I was to afraid of taking it out for fear it would leave me stranded again. The BLMs stayed around 142-145 with the temp at about 170. Then, I sat in the driveway and did a couple of high boost brake stands to bring the temp up, and the BLMs crept up at the same time. Its almost like they go up only when the temperature goes up. Could my coolant sensor be giving my computer bogus information, even though I'm getting what appears to be an accurate temp reading on my scan tool? Also, I put a 160 thermostat in the car. I'm not so sure it should be getting to 190-200 at idle.

 

[Joe 1320]

It is possible for the coolant temp sensor to affect what the computer does to the fuel. I had a car once that would run great until I got out on the road a mile or two from the dealership and it would quit and not restart. Did that 4 times before I had it towed to another dealership who fixed it the very first time. I'm with the other guys on the module. I had one do the exact same thing. Ran great until it got enough heat in it and it would start sputtering and die until it cooled off. You really should look at any device that could potentialy be prone to heat soak. The coil,module,alternator,cam sensor, crank sensor, coolant temp sensor, even the TPS and 02 sensor!

 

[Chuck Leeper]

TEMPS??

The BLM constantly creeping up is a signal that the ECM is being told "more fuel".
Is the ECM showing closed loop? If so, then the 145 @170* is too high right off the bat.
The Batt volts at 14.02 at idle is ALOT!! Somewhere over about 13.2 is good and 14.02 is PLENTY! I'm wondering why the regulator is asking for that much at an idle w/ low demands on the batt, IE: such as low plug firing volts,fuel pump demand,power master cycling,etc. You had all the accessories off?? You said "last nite".. were the headlites on? Have you had the batt. load tested?? Try the test w/ the "voltbooster" off the alt and see what happens.. That thing is not supposed to be active until the engine sees boost.. Is it on all the time????[I'm NOT a VB fan!]..

As for the temps... A system in GOOD condition should hold the temp within 5* of the stat value. This does not appear to be happening. Is the car using water? Does the fan come on like it should? [according to the settings on the chip]
Here's a little trik to see if the temps are being displayed accurately. Get a food thermometer, take the cap off when cold, start it and watch the therm. Compare to the scan tool and the ga. Also, have the system pressure checked.
Where is the FP set? Does it vary alot when driving at a steady speed?? IF it does, that could be a sign of ALOT of voltage variation to the pump.

Bout out of iders! Let us know what else you find...

JUSt thot of another "what if" ider!!
How bout the VB is on all the time.. thus the 14.02 at idle. THEN going down the road, the volts go up some more and the module overheats???
I'd run that sucker til it quit if I had to run back and forth on the driveway!! When it quits, I'd take a sandwich bag of crushed ice and put it ALL over that coil pak and module.. If it then took only that fast cool down to allow it to start, instead of 3-4 hours to cool off, then WALA!!, all we have to do now is figger out why it's getting hot!!

Damn, I'm almost as CLEVER as Cairns!!! [Some day I'll be as famous as Steve W.], I HOPE!!!

 

[GNVenom]

When the car's engine dies, turn the key off, then remove the PROM chip. Try another attempt to start the car (give it some throttle). Your engine should start in default mode and by removing the PROM chip, you are forcing calculated table values to all of the closed-loop sensors (O2, MAF, CTS, IAC, TPS) so this should eliminate the potential of sensors causing your problem. If the car runs, that is. Also, when the engine is cold, start it up, then unplug the cam sensor - forcing the engine into multiport mode - which will eliminate the potential of the CAM sensor being the culprit. Next, start the cold engine, and wiggle the battery positive cable wiring at the terminal (three connections here). I've seen problems like this happen because of acid "leaching" into the cable terminal, causing heat-related high resistance, particularly with the ECM MEM feed (orange wire). Food for thought here...
-John Spina
http://www.casperselectronics.com

 

[TURBOTIMMER]

Chuck, yes my scan tool shows the car going into closed loop. When the voltmeter was showing 14.02v, that was with the lights off. When I turned them on they went down to 13.2-13.3v.

You guys are great. I very much appreciate all of your input. I don't have a printer, so I'm writing everything down. Tomorrow's the day it'll be fixed (Not leaving the garage until it is).

I'll let everyone know what I find.

Thanks again everyone............Tim

 

[TURBOTIMMER]

Chuck, I didn't run a compression test on it, but I don't see or know of any leaks in the coolant system. When I did the timing chain and gears, I put the 160 stat in it. That was about a month ago. It hasn't lost coolant since then.

 

[TURBOTIMMER]

FIXED AT LAST

Well Chuck, you hit the nail on the head. Turns out the alternator was the culprit. I drove the car for about 10 miles with the alternator unpluged, and the battery still held a good charge. Not to mention, no problem with the car.

Just took the alternator off my GN, and she runs great again, for more than three minutes.

Thanks to all who replied.

thanks Chuck Leeper.