350 problem

[dickymint]

Just had a call from my mechanic. I got him to pick up the 350 to sort out the non starting (no fuel pressure) after a long lay up and it had to be taken off the road as the tax ran out. Also i wanted my new starter motor fitted. The no fuel pressure was due to perrished pipes and is now sorted.
However he rang to tell me it will start but cuts out after a couple of seconds. I'ts comeing back for me to sort it out. I am told the fuel pressure is holding and thers good spark. Any ideas guys before i get my ten thumbs into its innards?

[shpub]

Check that the ECU plug is not loose.

[dickymint]

shpub said:

Check that the ECU plug is not loose.

Cheers Steve, it has been dangling in the footwell for ages
First job will be to try the SEAC's ecu.

[wedg1e]

Dodgy kill switch in the airflow meter. Pump gets a feed whilst cranking, pressurises the fuel rail and car starts. Once the AFM flap moves, the kill switch should take over the job of telling the diode pack to run the pump. If it's oxidised etc then the pump stops and the fuel rail runs dry so she dies... unless the rail is staying pressurised OK, in which case...er...

[dickymint]

wedg1e said:

Dodgy kill switch in the airflow meter. Pump gets a feed whilst cranking, pressurises the fuel rail and car starts. Once the AFM flap moves, the kill switch should take over the job of telling the diode pack to run the pump. If it's oxidised etc then the pump stops and the fuel rail runs dry so she dies... unless the rail is staying pressurised OK, in which case...er...

The tech did say that he hard wired the pump to keep it running but it still cuts out.
There is an immobilser on her but its always switched off, however it needs a constant supply so am hoping that the negative battery terminal is loose. But doubt if its that simple

[tallbloke]

Reboot the immobiliser in accordance with mfrs instructions. The mechanic prolly put it into some kind of maintainance mode or otherwise befuddled it by disconnecting/reconnecting the battery a lot.

[SADBLOKE]

I had the same ??? problem on ford injection system a few years ago. After substituting every sensor,ecu, checking every cable and voltage, all injectors etc it ended up being the fuel pump at fault. At start up the pressure in the fuel rail was OK, fuel was expelled from the outlet of the regulator indicating that that part of the system was functioning, however, once the injectors started to supply fuel, the pump could not maintain sufficient flow to keep the constant pressure required to maintain the air/fuel ratio within limits for the engine to run. The engine would die after a few seconds, it could be started again almost straight away with the same result. The standard check for the pump (measuring the volume of petrol flowing into a can in one minute- as directed by ford main dealer!) indicated the fuel pump was fine. Changed the pump and the car ran fine for years.

[dickymint]

SADBLOKE said:

I had the same ??? problem on ford injection system a few years ago. After substituting every sensor,ecu, checking every cable and voltage, all injectors etc it ended up being the fuel pump at fault. At start up the pressure in the fuel rail was OK, fuel was expelled from the outlet of the regulator indicating that that part of the system was functioning, however, once the injectors started to supply fuel, the pump could not maintain sufficient flow to keep the constant pressure required to maintain the air/fuel ratio within limits for the engine to run. The engine would die after a few seconds, it could be started again almost straight away with the same result. The standard check for the pump (measuring the volume of petrol flowing into a can in one minute- as directed by ford main dealer!) indicated the fuel pump was fine. Changed the pump and the car ran fine for years.

So could I check this by running on 4 or 6 cylinders?

[badredwedge]

I had this problem with my 350 a small wire had come of the starter motor, turned over fired up ran a second then cut out. Wire back on no problems. I dont know what the wire is (someone on here will) but as you have replaced the starter it may be a good place to begin.

[tasmania]

Dicky,
Glad to hear you're thinking of using the 350. Sorted the Rad?

I had a similar problem with the SEAC. Started ran initially then died - if I gave it a few revs. Turned out to be a loose earth connection on the main earth at the rear of the engine.

If the pump is working but not delivering enough fuel trying it on 4 cylinders should, in theory, work as a diagnosos!

TaS

[dickymint]

Well She's back on my drive. He didn't get around to changeing the starter motor but it cranks fine. Like he told me it fires up then dies straight away. However for the second it does fire its as rough as a badgers are Looks like i'm stripping the SEAC to bits tommorrow

[dickymint]

Had a brief look for the problem:
It appears that the engine fires for a second but only if the cold start injector is plugged in. Injectors don't seem to be operating at all.

Swapped ECU

fuel pressure is fine however operation of AFM flap does not start the pump!

resistor pack - diodes all read 6 Ohm (not checked voltages)

So i think theres no power to injectors.

Does this sound like a dodgy ignition amplifier?

Edited to add - just checked the throttle pot and could not find 4.5 Volts
beginning to wonder if my immobilser (never used) has stirred into life!!!



>> Edited by dickymint on Sunday 8th January 13:57

[wedg1e]

If you have sparks it's unlikely to be ithe ignition amp, but it could be the white/black that takes the trigger signal from there to the ECU has a poor connection. Usually there's a bullet connector somewhere in that wire, under the AFM. If it pulls apart or corrodes then the ECU gets no info to tell it when to fire.
The cold start injector is simply fed as long as the engine is cranked, so the ECU plays no part.
You should have 12v on the brown/orange wires going into the power resistor module (ign. on): if you don't it's highly likely the whole injection system is not getting any supply.
Now you've arrived at the EFI 'main' relay and the red diode module
You can swap the relay for another one (as long as you can identify which it is): as for the diode module, it's substitution time unless you are OK with component-level diagnostics... which I think you are, so get on with it!

Email me your mobile no. if you want and I'll give you a bell, might be quicker...

[350zwelgje]

dickymint said:

Edited to add - just checked the throttle pot and could not find 4.5 Volts

Should it not be something like 325 mV (=.0325 V), instead of 4.5 V? If we talk about the same throttle pot (std 350i one), that is.

Rob

[wedg1e]

350zwelgje said:

dickymint said: Edited to add - just checked the throttle pot and could not find 4.5 Volts Should it not be something like 325 mV (=.0325 V), instead of 4.5 V? If we talk about the same throttle pot (std 350i one), that is. Rob

Yes, 325mV output, but it gets 4.5v supply rom the ECU.

[devoniain]

This is probably of no help at all, but my wedge has just spent the whole summer off the road due to the fact that it only ever ran until the moment you tried moving it. Turned out to be nothing more than a loose wire at the back of the fuse box.

Fingers crossed it might get driven in 2006...

[D1 MAD]

Hope you have got the problem sorted by now, but if not I had a very similar problem with my 350i a couple of years ago. The car would start up no problem but after about 2 seconds would cut out. After hours of investigation, trying a new ECU, thinking the worst etc, it turned out to be a simple relay problem. Mine is an 87 model and has about 18 relays fitted, about 10 of them are the same and have pins marked.

....30
85 87a 86
....87


However the ECU relay is marked.

....30
85 87 86
....87

Numpty me had fitted the wrong relay! Doh!! My only excuse is that it was very dark down in the footwell and the 'a' suffix on the centre pin was very difficult to see.
Anyway enough of my confessions. My point is that a simple relay problem caused the exact same problem as you describe. Could be worth a double check?
Best of luck!

[dickymint]

Thanks all. Yet again this forum rallies around the needy

As its my birthday today (blatant plug). I've booked a day off tomorrow and will be on the case to get it sorted.

Wedg1e just about to mail you my number. Give us till say mid day tomorrow! would be good for the ego if i can find it

[devoniain]

Happy Birthday Dicky

[dickymint]

Another Welsh Wedge breathes fire and lives

Checked out the diodes in the "steering Module" and all measured 0.56V one way and 0V the other. There is also a 2.9 ohm resistor in there and that was ok.
Turned ignition on and measured 12V at the back of the Main relay (Bosch type). 'bugger nothing wrong here' I thought.......but whilst checking this with a firmer prod of me probes......click click clickety click of the relay made me jump and smack my head on the glove box. Eureka, wire not making contact with relay pin Jumped into the drivers seat, first turn of the key and the sound of that eight cylinder symphony was pure

Now I can either spend the rest of the day labelling the relays and tucking them and the ECU where they belong .............................Nah i'm off for a

Cheers guys thanks for being there