GN dies on freeway at 70mph

[SS_Sean]

ESC stands for Electronic Spark Control....but where is it located?

 

[kenny]

Passenger side fender. I can go take a pic if you want.

 

[TURBOPOWERED68]

86-87 Turbo 3.8 Liter Engine Sensors

 

[SS_Sean]

Naw...thanks. There are only a couple things over there...map sensor, esc and some kind of relay. Thank you very much, though. Good idea.....apparently 87's didn't have ESC?

 

[kenny]

Both 86 and 87 had them, one was a 4 pole and one was a 2 pole if I remember correctly.

They are interchangeable as they function the same.

I wish I had the part number off hand but I don't.

 

[MSDGN]

I had my car pop/backfire then die on the freeway...but it wouldn't start...ended up being the cam sensor...the screw for the interruptor ring had come loose...probably not that but easy to check...remove the cam sensor cap and check the screw/ring...

 

[SS_Sean]

msdgn...good thought, i have had this happen, as well. the cam sensor is a new a/c delco unit and is good.

 

[bmackinnon]

It was a NAPA unit. I don't remember who they use. Do you suggest AC Delco for the module/coil?

As I understand it, the AC Delco is the only one that will work properly. None of the aftermarket units have proven to be reliable, if they work at all. Alot like the the maf sensors....

 

[quick 6 racing]

Did it again to me. This time I was watching the fuel pressure as the car was cutting out. I'm tending to believe this is some sort of electrical issue. The fuel pressure was rock solid on 40 psi, and the car died on me. I pulled off the side of the road and tried to start the car. It fired, but wouldn't stay running. This happened twice. Then the starter would just go click, click, click.

I called for a tow and had it towed to a shop here in town. This morning it fired up no problem and ran like a champ.

I'm going to order up a coil pack and module today and try and reseat the chip in the ECM.

Sean...if your car starter goes click,click,click either the starter is bad or more likely your alternator or charging system is not working correctly...if your loosing battery voltage due to the alternator not keeping up...the car will eventully die due to lack of minimum required voltage to keep the car running (like 9 volts) ...just like you descibe after driving for many miles (is it worse at night?) If your battery is very good the voltage will come back after sitting overnight, but running the car will again drain it back down. A voltmeter would verify that or when the car doesn't start turn on the headlights while starting and see if they dim out big time. If your around a garage have them test with an AVR tester for alternator voltage under load and amperage output. Easy and fairly cheap to do and would eliminate what I have descibed above that may be causing your problems.

So far your symtoms recently described don't resemble a coil pack or module problem otherwise your car would just turn over and over without starting.
And BTW I have run a Napa module & Coil pack for many years without problems and so have many of my local GN guys.

Are you on the coast...if so we'll be there in two weeks

Wayne - Quick 6 Racing

 

[SloGN]

Sean...if your car starter goes click,click,click either the starter is bad or more likely your alternator or charging system is not working correctly...if your loosing battery voltage due to the alternator not keeping up...the car will eventully die due to lack of minimum required voltage to keep the car running (like 9 volts) ...just like you descibe after driving for many miles (is it worse at night?) If your battery is very good the voltage will come back after sitting overnight, but running the car will again drain it back down. A voltmeter would verify that or when the car doesn't start turn on the headlights while starting and see if they dim out big time. If your around a garage have them test with an AVR tester for alternator voltage under load and amperage output. Easy and fairly cheap to do and would eliminate what I have descibed above that may be causing your problems.

So far your symtoms recently described don't resemble a coil pack or module problem otherwise your car would just turn over and over without starting.
And BTW I have run a Napa module & Coil pack for many years without problems and so have many of my local GN guys.

Are you on the coast...if so we'll be there in two weeks

Wayne - Quick 6 Racing

sounds to me like the positive cable is arcing against the hot exhaust causing the entire system to lose power for a instant and that why the pop out the exhaust. i have had this happen to me when i had a broke driver side motor mount and it burnt my battery cable pretty bad. plase check that cable!

 

[SS_Sean]

Alternator is new and is operating flawlessly. The battery cable is new and is not arcing against the header. The battery is nearly new and is holding a charge. I will doublecheck these things, however.

 

[pgoffner]

Alternator is new and is operating flawlessly. The battery cable is new and is not arcing against the header. The battery is nearly new and is holding a charge. I will doublecheck these things, however.

Are you getting any codes? I'm having very simular issues with my car right now but my scanmaster keeps throwing code 42 . Let me know if you figure your issue out and I will be sure to let you know If I figure my issue out as well.

Seems all the other similar threads I've searched never post about how they solved the problems

 

[TURBOPOWERED68]

Are you getting any codes? I'm having very simular issues with my car right now but my scanmaster keeps throwing code 42 . Let me know if you figure your issue out and I will be sure to let you know If I figure my issue out as well.

Seems all the other similar threads I've searched never post about how they solved the problems

i don't get any codes either. and for now the car is running great again.

 

[Jerryl]

A good way to resolve is to start "logging" right before she quits.
It can tell you quite a bit.

Edit:
Guessing here ...... Did you verify ECM connections?

 

[Blazer406]

I think it could be the flux capacitor....... have you checked it?

 

[SS_Sean]

I think it could be the flux capacitor....... have you checked it?

I called Mr. Fusion and they said they won't warranty a flux capacitor on a Grand National, since it was not originally designed to haul ass and eat mustangs and vets.

After consulting some local experts I'm going to say I have a heat soak situation . The 3.5" downpipe is probably heat soaking the starter, solenoid and wires down there. The problem goes away once the car cools down. I am going to wrap everything down there and see if I can't get the problem to repeat. If this doesn't work I will probably next replace the coil/module. I'll report back.

 

[SloGN]

do you know of someone that could loan you their known good coilpack and module to try for a few days to see if thats the problem.


does how about checking the ecm to se if it's getting hot and crapping out try driving the car witht he ecm out of the kick panel to see if the ecm is getting hot and messing up.

 

[SS_Sean]

Good ideas, but I don't know of anyone in town who has a spare ecm. I'll get to that next. The last ecm I bought turned out to be junk and it cost me hours of work to figure out the supposed good, rebuild, ecm was bad and the old one was good.

 

[bison]

If there are no obvious shorts id look at the crank sensor. Bring a can of brake parts cleaner with you. Next time it shuts off, spray the crank sensor with the brake cleaner to cool it off. If it restarts immediately the sensor is shot. It usually wont throw codes. The ecm just loses the signal and the spark is gone. You should have tested for spark when it first crapped out. Any blue spark at all and it should still fire even if its random misfires. That is unless its fuel related. To test that just un plug your fuel pump and crank the engine. The fp will drop as the injectors pulse. If the fp doesnt drop id look at the cam sensor. Do you have a service engine soon with key on engine off? If not the power to the ecm is interrupted. You will have nothing then spark or fuel.

 

[bigmac_ns]

I was fighting the same problem

I'm having the exact same issue when I run my car on a hot (for Canada) day. Once I run it up a few times, I can't find the problem. But after a hard dash and some fooling around on the highway, I've had to coast into gas stations after a few nasty backfires (scary) and towed it home and it starts up the next morning. (note: this was last summer and there were posts on here about it)

I have replaced a lot of stuff, but I'm leaning towards the timing chain now. I'm wondering if the cam and crank sensors can get somewhat out of phase after too much slack. I've replaced the cam and crank sensor. I've replaced the coilpacks and the ignition module a few years ago and it just started doing this last summer.

Since last summer I've kept the boost under 15 and if I don't run it really hard, I haven't seen the issue since. I'm planning to change the timing chain and get on it again to find the faults.

Best of luck, I'll be watching your post to see what happens.