NEED help...car stay running.

[Blacktop87]

Well the car wont' stay running after I changed the Radiator (to F-body Rad) and to a 160* T-stat. The funny thing is that I had it running right after I did the swap for about 15 mins and the temps never got about 175* when it was sitting idle. I checked the coolant, rad and overflow tank is filled properly. No Air is in the lines that I can see or feel. I squeezed the lines to try and push the air to the Rad. Now after a couple days later the car wont even stay running. I thought it was getting hot or something. I get no symptoms that it starving for fuel. It just cuts off (no bucking or stuttering, nothing) after about 5 mins every time IF I get it running, then I can't get it started unless I wait for about 30 - 40 mins. These are the things that I checked:

Battery is good, constant 13.6v
Alt is good, Its charging good also.
Plugs are good, I'm getting spark (I can get it running, when its first started)
Wires are brand new stock version,
Coil pack is good,
Ignition Module is good, no grounding inside where the wires are at.
I check the ground and their right (near the battery) none are broken (both on the side of the vehicle and behind the engine)
No Vac leak as I replaced most of them.
Check Fuel pressure and the regulator (41 with line on. 38 line off) both good.
I thought it was fuel but the pump is still pushing good fuel.
Replace LT1 maf with stock maf and TT chip back to stock chip, then resetting the ecm. ECM was getting warm tho.
Checked wires ( starter, grounds...)
Fan comes on like it should.

I haven't changed the ECM to another one yet...still looking for one.
I doubt its the crank sensor (since I can get it running) but how do I tell its bad or not. Guess I'll keep looking.

Could I have knocked or moved (cam sensor) something, just wanted to get some info on where to look or if someone has similar problems where I could look to get more info at before I send it to a shop to have it checked out. I know I'm missing something to check but I can't think of it for the past 2 days.

 

[bmackinnon]

It just cuts off (no bucking or stuttering, nothing) after about 5 mins every time IF I get it running, then I can't get it started unless I wait for about 30 - 40 mins.

Coil pack is good,

Ignition Module is good, no grounding inside where the wires are at.

Check Fuel pressure and the regulator (41 with line on. 38 line off) both good.
I thought it was fuel but the pump is still pushing good fuel.

ECM was getting warm tho.

I haven't changed the ECM to another one yet...still looking for one.

Those are classic signs of a coil pack/ign. module problem. There's no way to positively verify the module good without Casper's tester, and even then, bad ones have passed. Problems usually occurs when the module warms up. If you can, I would swap the module/coil pack with a KNOWN good set, and if that doesn't do the trick, then swap the ecm. You can easily get a 7148 ecm from the junkyard for $35-$40... they are used in several cars that are plentiful at the yard. GNTTYPE.org has the list of donor cars in the technical articles.

Also, are you SURE the fuel pressure is maintaining when it goes dead? Big problems with the pumps these days.... dying out for apparently no reason.

 

[Blacktop87]

Thanks for the info...I'll check on the yard and see if there's more ECM's just to be safe. Well I did put a FP gauge on it and it held for about 30 mins before starting to go down very slowly. Guess I'll look to see if I can borrow a IGN mod (I have a new Coil pack) from someone.

Thanks for the help.

 

[Blacktop87]

Well I got my car up and running again. I believe it was the grounds again, so I just made a nice ground straight from the bottom of the ign module in between the 3 studs and to the firewall. Fixed it and she can roll but now i have to check why the lights are on all the time now before it drains my batter...ugh. One things leads to another. Thanks for the help everyone.