Pre-Serp Fuel Pump / ECU question....HELP!
Discussion
HELP needed from an ECU / wiring "expert" / knowledgeable mechanic on a 1994 Pre-Serp Griff or Chimera 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
The fuel pump should prime for a few seconds when you initially turn on the ignition. You need to check the fuel pump wiring as it looks very much like a poor connection in the path. This may help:
http://www.bertram-hill.com/fuel-pump-schematic.ht...
The connectors behind the passenger B post are very prone to getting corroded connections so worth checking first. If these are OK then you need to logically check the circuit through to the pump.
I would advise against hard wiring your fuel pump it could be dangerous.
http://www.bertram-hill.com/fuel-pump-schematic.ht...
The connectors behind the passenger B post are very prone to getting corroded connections so worth checking first. If these are OK then you need to logically check the circuit through to the pump.
I would advise against hard wiring your fuel pump it could be dangerous.
The sequence is:-
Ignition on the ECU signal the pump to prime.
When the ECU detects an ignition pulse from the coil (white/blue wire) it turns on the pump and injectors.
You said you jumped pins 30 & 87 at the fuel pump relay but did not say which pin 87 as there are 2. One has 2 wires Black for the pump, white/purple for the purge canister. The other 87 has 2 white/orange wires for the lambda sensors.
The black wire to fuel pump goes via immobiliser & inertia switch so both of these could be your issue.
Steve
Ignition on the ECU signal the pump to prime.
When the ECU detects an ignition pulse from the coil (white/blue wire) it turns on the pump and injectors.
You said you jumped pins 30 & 87 at the fuel pump relay but did not say which pin 87 as there are 2. One has 2 wires Black for the pump, white/purple for the purge canister. The other 87 has 2 white/orange wires for the lambda sensors.
The black wire to fuel pump goes via immobiliser & inertia switch so both of these could be your issue.
Steve
I’d always start with any advice from Steve_D.
I’d also try a direct 12V feed to the pump to see if it runs
Then I’d look at bypassing the immobiliser to isolate that, especially if it’s a Meta. Though as a ‘94 car it’s probably the Foxguard, which is also in my 95 Chim.
The info for Meta is out there, on here in fact. That’s where I got it.
Dave at HF Solutions is a handy person to talk to on immobiliser/alarm topics - he advised me on my Foxguard.
Dash top off to do it - which I suspect you might have done already with a rebuild?
I’d offer to help, but looks like you’re a long way from Blighty
I’d also try a direct 12V feed to the pump to see if it runs
Then I’d look at bypassing the immobiliser to isolate that, especially if it’s a Meta. Though as a ‘94 car it’s probably the Foxguard, which is also in my 95 Chim.
The info for Meta is out there, on here in fact. That’s where I got it.
Dave at HF Solutions is a handy person to talk to on immobiliser/alarm topics - he advised me on my Foxguard.
Dash top off to do it - which I suspect you might have done already with a rebuild?
I’d offer to help, but looks like you’re a long way from Blighty
Edited by PabloGee on Tuesday 30th April 20:53
To all that replied: Thxs for the advice! fuel pump now live after resetting the inertia switch behind the glove box.
Is there a way to verify TDC ( other than timing mark) without pulling off the pass side valve cover & verifying both valves closed? The oil pump drive is difficult to get aligned while the rotor is aligned to #1 plug wire. Seems like I can’t get the rotor, oil pump drive, and TDC mark all aligned to start….
Is there a way to verify TDC ( other than timing mark) without pulling off the pass side valve cover & verifying both valves closed? The oil pump drive is difficult to get aligned while the rotor is aligned to #1 plug wire. Seems like I can’t get the rotor, oil pump drive, and TDC mark all aligned to start….
I'm planning on check TDC on mine (after I got two different readings from two different timing guns) by removing spark plug 1, and using a measure thing.
I got one on ebay using the search "top dead centre tool for 14mm spark plugs", which I checked against the spark plug thread specs.
Now I just need to get the car over a pit to get enough leverage on the crank pulley bolt to turn it (don't fancy lying under it on axle stands doing that)
I got one on ebay using the search "top dead centre tool for 14mm spark plugs", which I checked against the spark plug thread specs.
Now I just need to get the car over a pit to get enough leverage on the crank pulley bolt to turn it (don't fancy lying under it on axle stands doing that)
My distributor approach to getting initial timing "close":
1. turn crank to get to 10 degrees before TDC
2. align ign rotor slightly ahead of #1 plug contact in distributor cap (bevel gear when installed will get closer to #1 contact in dist cap)
3.make sure the oil pump shaft aligns with slotted end of dist shaft.
4.install distributor with elec connection on front side facing forward ( so I have room & can rotate the dist to correct timing once installed.)
if it doesn't fire up, mark where the rotor is currently pointing, and lift the dist out 1/2 way & rotate and turning the Ign rotor 180 degrees from your initial mark on the distributor body, and fully reinstall.
( the dist will only fully reinstall one of 2 ways: either at TDC or be 180 degrees out as the oil shaft drive is :slotted: so the dist shaft can only install one of 2 ways.)
That should get timing very close to correct, so then use your timing light & mark to get it to spec.
1. turn crank to get to 10 degrees before TDC
2. align ign rotor slightly ahead of #1 plug contact in distributor cap (bevel gear when installed will get closer to #1 contact in dist cap)
3.make sure the oil pump shaft aligns with slotted end of dist shaft.
4.install distributor with elec connection on front side facing forward ( so I have room & can rotate the dist to correct timing once installed.)
if it doesn't fire up, mark where the rotor is currently pointing, and lift the dist out 1/2 way & rotate and turning the Ign rotor 180 degrees from your initial mark on the distributor body, and fully reinstall.
( the dist will only fully reinstall one of 2 ways: either at TDC or be 180 degrees out as the oil shaft drive is :slotted: so the dist shaft can only install one of 2 ways.)
That should get timing very close to correct, so then use your timing light & mark to get it to spec.
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