I have a 1997 Jaguar Vanden Plas 4.0L straight 6. The car was having high idle issues, so I found out the IACV motor was stuck open causing the idle issue. After removing the throttle body and cleaning the IACV I reinstalled it. My issue now is the vehicle will not start. I have checked all fuses, spark, fuel pressure and it all checks out. When I check pulse on the injectors, the noid will pulse once while cranking and then stops. I am at my wits end with this vehicle and could use some professional help. Thank you

 

Gotta be something you missed...? Have you checked all of your plugs?
The TPS is plugged back in; likewise for the MAF and air temp sensor?
How complete is your tool box?

 

I have triple checked everything on the throttle body, all sensor have been plugged back in... I was suspecting bore wash as the vehicle sat around for a while and was only started to drive in the shop... Did the suggested process and still nothing... I have a fairly complete tool box and access to all the special tests tools...

I am curious as to why when I test the injector pulse I only get a single pulse and the nothing.. could the IACV be no good after cleaning it? what would cause the injector to only have a single pulse? Thank you

 

Single pulse on all injectors at the same time or one at a time?
I'd suggest the crankshaft position sensor but that's ignition?
What about the throttle position sensor on the bottom of the throttle body?
If you have a DVOM you can test the TPS.
Do you have the service CD?

 

Can you back probe the TPS and ensure you are getting a valid signal from it as the throttle moves?

I suggest this as the only thing that I'm aware of that would turn off the injectors during cranking (apart from obvious wiring issues) is to have the throttle wide open (this is what you would have done I think to clear your suspected bore wash). It could be that either the throttle plate or the TPS is stuck in a wide open position.

(I'm assuming the ECM takes the reading for WOT from the TPS as there is no Pedal position sensor on the car AFAIK).

I assume there are no codes stored?

 

All the injectors pulse once for a single revolution and then stops, I will run the tests suggested and post the results, thank you.

 

Ok, I did the back probe on the TPS... I have power and ground to the plug but get nothing when I plug it in and back probe it. No codes are stored.

 

The power is on and you open and closed the throttle plate to change the voltage coming out of the TPS?

 

Yes power is present but no voltage change while moving the throttle

 

Just to be clear, what voltages are you seeing at the TPS.

You're saying you have power and ground with the TPS plugged in. What voltage power do you have. More importantly what voltage is on the signal wire.

According to the manual you should see 0.6V at idle and 4.9v at Full Throttle on the signal.