Fuel pump & ECU startup question after winter battery out
Discussion
HELP needed from an ECU / wiring "expert" / knowledgeable mechanic on a 1994 Pre-Serp Griff or Chimera 500 owner !
Background: I completed an engine out rebuild & reinstall over the Winter but now no fuel pump initial prime when the ignition is on.
I have had the ignition switched "on" numerous times after the re-build for various electrical checks etc, but never had the starter engaged to turn the engine over since the rebuild.
The fuel pump runs if I feed it 12v power directly at the pump, so I know the pump works, so it's not getting power with the keyed ignition on.
I have not tried starting / turning the engine with the starter since the install, and have primed the oil system with the "drill " method.
Both the Bosch relays in the loose wiring in the LH footwell for fuel pump and the ECU ignition were new last year.
After doing TVR Griffith / Chim /Pistonhead searching, with the key / ignition switched "on", the fuel pump relay terminal 30 should be live (it is), and if I feed a 12v jumper wire direct from 30 to 87 on the relay base (fuel pump power source), the Fuel pump should switch on ( but it does not)......... so there's a 12v loss/break somewhere after the fuel pump Relay then on to the Inertia cut-off and then finally on to the Fuel pump.
HERE"S MY QUESTIONS:
1. Where the battery has been out for months, and now in & out for wiring checks, now if I try using the starter to start the car for the 1st time since the re-build does the ECU do some sort of internal various engine / sensor "checking" before feeding 12v through the Fuel Pump relay and on to the inertia cut-off and then on to the fuel pump??
2. Should I simply feed external 12v direct to the fuel pump to force it to run to try to start the engine for it's first time after re-build?
3. I don't want to crank the engine alot using the starter if it's not getting any fuel supplied by the electric pump....and not starting.
4. Or should I go ahead & feed 12v direct at the pump and then try to start the engine?
5. Does the ECU power the fuel pump every time the ignition is switched on, or does it do other internal tests for crank speed or electrical test from the Dizzy signal (shared with the rev counter)?
Sorry for all the questions, but I'm sure someone's been down this road before me.... and can help!
Thxs!
Doug
Background: I completed an engine out rebuild & reinstall over the Winter but now no fuel pump initial prime when the ignition is on.
I have had the ignition switched "on" numerous times after the re-build for various electrical checks etc, but never had the starter engaged to turn the engine over since the rebuild.
The fuel pump runs if I feed it 12v power directly at the pump, so I know the pump works, so it's not getting power with the keyed ignition on.
I have not tried starting / turning the engine with the starter since the install, and have primed the oil system with the "drill " method.
Both the Bosch relays in the loose wiring in the LH footwell for fuel pump and the ECU ignition were new last year.
After doing TVR Griffith / Chim /Pistonhead searching, with the key / ignition switched "on", the fuel pump relay terminal 30 should be live (it is), and if I feed a 12v jumper wire direct from 30 to 87 on the relay base (fuel pump power source), the Fuel pump should switch on ( but it does not)......... so there's a 12v loss/break somewhere after the fuel pump Relay then on to the Inertia cut-off and then finally on to the Fuel pump.
HERE"S MY QUESTIONS:
1. Where the battery has been out for months, and now in & out for wiring checks, now if I try using the starter to start the car for the 1st time since the re-build does the ECU do some sort of internal various engine / sensor "checking" before feeding 12v through the Fuel Pump relay and on to the inertia cut-off and then on to the fuel pump??
2. Should I simply feed external 12v direct to the fuel pump to force it to run to try to start the engine for it's first time after re-build?
3. I don't want to crank the engine alot using the starter if it's not getting any fuel supplied by the electric pump....and not starting.
4. Or should I go ahead & feed 12v direct at the pump and then try to start the engine?
5. Does the ECU power the fuel pump every time the ignition is switched on, or does it do other internal tests for crank speed or electrical test from the Dizzy signal (shared with the rev counter)?
Sorry for all the questions, but I'm sure someone's been down this road before me.... and can help!
Thxs!
Doug
Not sure, did the earlier cars have the kill switch/roll over switch fitted up behind the glovebox? If it’s activated doesn’t it kill the fuel pump. Maybe worth a quick check and reset if activated. May have disturbed it ??
Immobiliser is another potential culprit?
I can’t answer the ECU questions. But, are you on standard ECU or aftermarket?
When I did have standard, every time you turn the ignition on it primed the pump, later car, but same system.
Immobiliser is another potential culprit?
I can’t answer the ECU questions. But, are you on standard ECU or aftermarket?
When I did have standard, every time you turn the ignition on it primed the pump, later car, but same system.
Edited by Johno on Monday 29th April 22:37
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