Hi, I have been restoring an XJS motor v12 6.0 liter which is in a car that originally had a 6 cylinder. The car is a 1985 Vanden Plas and I have been stumped why the fuel injectors aren't firing, at least during cranking. I should point out that the car ran with this motor before I got it, just had a blown head gasket. Unfortunately I didn't take it apart, it was abandoned before the heads were off because the guy working on it couldn't figure out how. I made up a pull plate and did the head gaskets and have been reassembling ever since. I did find a wire at the firewall that receives a high signal on crank but I used it for the starter signal and perhaps that should have fed something to get injection during crank? If anyone knows, please shed some light on this.

 

Not knowing the system in use in that car makes it guess work for starters.

The HE 5,3 had a 2nd wire from the starter relay "start" terminal that was LIVE when in crank mode.

The heavier wired at that terminal is the White/Red solenoid wire, and a 2nd smaller wire went to the ECU, and then a combination of that power and the ignition pulse from thw ign amp to pin 18 of the ECU via the infamous shielded wire, activated the ECU injector pulse circuits.

The 6ltr are all Marelli system engines, and some similarities carried over.

 

Thank you so much for your helpful reply. I have finally figured out the problem and got her fired up! .
Cheers

 

AND







You found what??????