3800sc new swap only starts with starting fluid (Page 1/2)
Riddick85 OCT 03, 02:03 PM
So me and my dad are working on our second 3800sc swap. First one went fine with no issues but his car will only start with starting fluid. Getting spark but it seems we are not getting injector pulses while cranking. Once it kicks with the starting fluid, the fuel injectors take over and all is well and runs like a champ. I have tried researching if maybe the ECM gets a different signal to fire the injectors during crank but I cannot find anything.
Everything else seems to work flawlessly and we are hoping to get some miles on it before the weather turns cold. Please Help!
Gall757 OCT 03, 03:33 PM
You need some advice from Darth Fiero, but until he finds your question, here is a thread that covers potential issues.

Dennis LaGrua OCT 03, 04:54 PM
Unless you try to diagnose your problem with a quality scanner or scanning software, you are working in the blind. No fuel at the injectors can mean any one of a dozen or more things could be wrong..

" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H

Riddick85 OCT 08, 04:51 PM
Did a little work on the he car. I used an app on my phone with one of those bluetooth obd2 scanners, not the best but it gives me data. Seems like everything is working the way it should once we get it running but it still doesn't get any injector pulse while cranking. Also, there are no codes when I checked.

Another thing I tried since I have my working 3800 fiero to try to diagnose my dads is we swapped my ICM into his car and there is no change and also put my PCM into his car and there is no change. Tried putting his into my working car too and mine starts and runs fine. So doesnt seem there is a ICM or PCM that is bad.

It actually seems to work really well once its started with starting fluid. Gets up to 185 or so and coolant fan kicks on, car moves around the driveway fine.

Biggest question is what controls the injectors only during cranking though?
OntarioKev OCT 08, 09:55 PM
Have you used a light on the injector circuit to diagnose that the injectors aren't firing?

Checked fuel pressure during key on before start, and during cranking?
Riddick85 OCT 08, 10:56 PM
I dont have a light but I did have a spare fuel injector that I plugged in to the harness when cranking. I did put 12v to it before to make sure it worked. It did nothing plugged into harness. I also checked ohms across each injector and all were right around 12. Fuel pressure is 40 key on not running and there is no leak down. It is also around 40 when running.
OntarioKev OCT 09, 10:51 AM
I am assuming you would be able to tell if the spare injector was firing during crank, so another thought has VATS been disabled on the PCM you are using?
Riddick85 OCT 09, 01:03 PM
I read about VATS being a problem that could cause something like this. That's the biggest reason I put the PCM from my running swap into my dads car. Same no start with a known correct PCM. Just for good measure I put his in my car and it started and ran fine also.

Only difference between the 2 cars is my is manual and his is auto using the 4t65 that came with the engine.

[This message has been edited by Riddick85 (edited 10-09-2019).]

OntarioKev OCT 09, 07:20 PM
Ok that helps rule out VATS. There are several codes that need to be disables for it to run well on the manual but none of them should prevent startup.

How did you test with the spare injector to know it was firing when cranking?
olejoedad OCT 09, 08:00 PM
Have you had the PCM set up for the swap?