93 Trans Sport SE 3800. No.5 Injector dead.

[Paul Taylor]

Hi all,

Got a Problem with my Pontiac Trans Sport SE with the 3800 Series 1 V6.

Fuel Injector No.5 is completely Dead. Its not the Injector itself, its the fact no Pulse is being sent to No.5 Injector.

Oviously i know i need to check the Main Harness plugs under the bonnet, and check back to the ECU connector. But is there anything else that could cause this ??

Please dont say dead ECU...

PS: When running on LPG ( Propane to Americnas ) she runs great. Its just on Petrol ( Gas ) that you notice the engine is missing.

Regards,
Paul Taylor ( UK )
93 Trans Sport SE 3800 TPI. 87 Camaro Z28 IROC-Z 5.7 TPI.

[LMP]

Originally Posted by Paul Taylor

When running on LPG ( Propane to Americnas ) she runs great. Its just on Petrol ( Gas ) that you notice the engine is missing.
.

Questions only....I think LPG conversion on this model is not very well documented in America....but does it use the same ECU as the fuel only version? or Is there a "mode change " signal of some sort that is sent to the ECU....and, do you have the electric pulse to the #5 injector when it runs on LPG?

[Paul Taylor]

The LPG system is a "Off the Shelf" LPG system for a V6 or V8.
Lots of cars are converted to LPG in the UK as LPG is not subject to government taxes and hence it is much cheaper.

Its actually a very simple system that has a T adapter that goes on each Fuel Injector Plug. This is so the LPG ECU can shut of the Petrol Injectors when running on LPG.

But my problem is i am not getting any Voltage Pulse to the No.5 Injector plug itself even after pulling off the T adpater.

Help....................

[Paul Taylor]

Well today i have traced the wiring back from Injector No.5 to the 34pin ECU plug. All the wiring is fine.
So i removed the ECU and opened it up. It looks like Line Driver No.5 is dead ( Transistor ). Does not look to difficult so should be an easy fix.

Regards,
Paul Taylor. UK.

[LMP]

Glad to know it is not submerged in epoxy.......take a picture of that if you can

[Paul Taylor]

I replaced the dead Transistor in the ECU today. Its a 3 pin MosFet.
Put the ECU back in the Trans Sport and she fired up great, and runs real smooth on all 6 cylinders.

So there you go. Next time your 3800 seems to be running lumpy check to make sure the injectors are all firing. If you have a dead injector chances are its a dead Transistor in the ECU.

Paul Taylor.
UK.

[Paul Taylor]

For future Reference the MosFet Transisitors used in the 3800 ECU are

IRF530

This is the appropriate replacement to be used in the event of Injector firing failiure.

Regards,
Paul Taylor.