V8 Flapper system - stopped starting!!

V8 Flapper system - stopped starting!!

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heavy squad

Original Poster:

38 posts

152 months

Saturday 16th November 2013
quotequote all
Hoping to pick the brains of some of the good folk on here!

Have a 3.5 RV8 with flapper type efi fitted in a mk1 Granada by a previous owner. First sign of trouble was a couple of months back when she wouldn't fire up. Couldn't hear the fuel pump priming when turning on the ignition. Had a bit of a poke around with the hidden cut out switch and got her going so put it down to that being a bit iffy.

All was well until yesterday when trying to start her up after two weeks of being parked up in the garage. Again no fuel pump priming so started investigating....hidden cut out switch working ok, main relay coming on with ignition ok, tested fuel pump relay and is functioning, pump operates by bridging white and white/pink high current wires but no current coming in on the white/green.

From what I have now read it seems in this system the fuel pump isn't actually supposed to prime when the ignition is on but only when the engine starts cranking....I was certain it had been priming before but am now beginning to question my sanity!

Anyway, give the flap in the AFM a prod and fuel pump operates. Insert trusty bit of wood to hold it open a little, try the key and she runs for about one second and dies. Try again, same thing. Bridge relay again just for the sake of it, same thing. What has really confused me is that after removing the trusty bit of wood the engine will still fire and run for a second although nothing has actually been altered from the previous state of affairs where there were no signs of life!

Do you think I'm on the right train of thought with the idea that the engine is running briefly from the fuel supplied by the cold start injector but the main injectors aren't operating?

Should I be able to hear the injectors 'clicking' over the sound of the starter motor?

Have done a continuity test on the black/white wire going from the coil negative to pin 1 on the ECU, think this is ok, cheapo budget multimeter gives a reading but decays to zero after a couple of seconds...also does this on a short piece of test wire and when touching the probes together, is this normal?

Connectors in the power resistor multiplug are quite oily, going to clean this up tomorrow when the battery is recharged...coil was new about 150 miles ago, terminals are clean and seem tight.

Apologies for the long post and further grovelling apologies for not owning a TVR (yet) but hopefully someone here will know whats at the bottom of all this....have looked through loads of old threads on here and on the excellent vintage model aeroplane site but couldn't find anything similar.

Cheers!

V8 Fettler

7,019 posts

133 months

Sunday 17th November 2013
quotequote all
Sounds interesting, link to photos of the car please!

For fault finding only, run a temporary 12v supply to the positive side of the fuel pump, make sure the earth (return) is good. Ensure that you can remove the temporary supply quickly if required (all at your own risk etc). This should create constant fuel rail pressure. If the car then starts and runs then it's unlikely to be anything else than the control circuit for the fuel pump.

My understanding is that the fuel pump on a flapper is signalled to run when cranking the starter motor and when the flap is off the closed position (air flowing or wood-assisted). Someone on here did say that their pump ran when the ignition was switched on but before cranking.

wild rover

447 posts

182 months

Sunday 17th November 2013
quotequote all
Seems to be in the fuel side, pump works with the flapper. If the direct feed to the pump makes no diffirence check the contacts at the Ecu and rectifier unit next.

heavy squad

Original Poster:

38 posts

152 months

Sunday 17th November 2013
quotequote all
Here you go V8 Fettler:





Needs the proper mk1 alloys on it really but still gets a lot of admiration...will be going up for sale as soon as she's running again due to me being laid off recently and having to sell off some toys just to pay the bills. Gutted!!

Didn't get the early start I hoped for today due to getting a puncture on the way home from the workshop last night...and finding the spare flat as well! Then having to find a tyre place open on a Sunday with the right size in stock and having to lug the wheel across town on the bus....what with that and the Granada not starting and the botched haircut I got yesterday things aren't going too well at all! Must be due some good luck soon?

Pretty sure the pump kept running yesterday when it was firing briefly but will try the direct feed in a bit when I've cleaned up the power resistor multiplug - nothing to lose!

Wild Rover - whereabouts in the system is the rectifier you mentioned? Don't think I've seen that on any circuit diagrams?

Many thanks for the replies - much appreciated!

Wedg1e

26,806 posts

266 months

Sunday 17th November 2013
quotequote all
heavy squad said:
1. Do you think I'm on the right train of thought with the idea that the engine is running briefly from the fuel supplied by the cold start injector but the main injectors aren't operating?

2. Should I be able to hear the injectors 'clicking' over the sound of the starter motor?

3. Have done a continuity test on the black/white wire going from the coil negative to pin 1 on the ECU, think this is ok, cheapo budget multimeter gives a reading but decays to zero after a couple of seconds...also does this on a short piece of test wire and when touching the probes together, is this normal?

4. Connectors in the power resistor multiplug are quite oily, going to clean this up tomorrow when the battery is recharged...coil was new about 150 miles ago, terminals are clean and seem tight.
1. Yes.

2. Probably not, but if you switch the ignition on and then snap the throttle open quickly you should hear a definite click from the fuel rail area as all the injectors fire together; it's analogous to the accelerator pump on a carburettor, it fires all the injectors at once for an enrichment burst. It's just a happy glitch in the 4CU system whereby it does this regardless of whether the engine's running.
This tends to prove (a) that the ECU is doing 'something' and (b) it can detect the throttle potentiomenter is connected.
No injector click tends to suggest either the injectors aren't getting any power, the throttle pot's not connected or the ECU is disconnected or faulty or has no 12v supply biggrin

3. Idealy you should see zero - Ohms, that is. Watch out for hanging your meter on this wire whilst the engine is running as the back-EMF of the coil is present on it... at several hundred volts.

4. The oiliness could be down to someone having tried to weatherproof it with grease, WD40 or silicon grease.
You should be able to measure 12v on the two brown/ orange wires with ignition on... and you should also see 12v-ish on all the other wires as well (feeding the injectors) since the impedance of the multimeter is so high it presents no load to the dropping resistors - people make the mistake of expecting to see 3V or so here but that's not the case.
If there's 12v going in (on the brown/oranges) but nothing on the other wires then you can assume corroded terminals. I wouldn't expect the resistor network itself to be faulty - let's just say that in a dozen or so years I've never seen a faulty resistor pack and the circumstances that would cause all 8 'resistors' to fail would probably result in a fire.
If the 12v is missing then check the 'Main' relay for the injection.

Easiest was to cheat the fuel pump is to unplug it and make up a short (but thick, say 2.5mm wire minimum) link wire with two male Lucar terminals. Plug the terminals into the 'top' and 'bottom' receptacles on the relay base (the 'sides' would be the two parallel receptacles that are the relay coil connections). Fuel pump should run as long as the ignition is on. If you have access to a DC clamp ammeter, hang it on this link and it'll tell you how much current the fuel pump is taking - don't be surprised to see 8-10A.


heavy squad

Original Poster:

38 posts

152 months

Sunday 17th November 2013
quotequote all
Cheers Wedg1e, very much appreciated mate.

Got the ECU connected back up, cleaned up power resistor and AFM multiplugs but now it seems we're back to square one where it's not even firing up for a second as it was yesterday.

Can't hear the injectors clicking when snapping the throttle open...there is some kind of sound coming from under the bonnet but I think it's coming from the throttle linkage.

Have 12v on the two brown/orange wires at the power resistor multiplug but virtually nothing on the others - around 0.05-0.1v (doesn't help that my cheapo multimeter has now decided to sit at 0.13v when not connected to anything).

Thinking then this may point to a break between the ECU and the injectors...or an ECU fault?

V8 Fettler

7,019 posts

133 months

Sunday 17th November 2013
quotequote all
Does the pump now run constantly with the temporary wiring mods (either direct to pump or wedgie's fiddly method)?

The "click" of the injectors when you operate the throttle position device is not particularly loud, but you can hear it if your head is in the engine bay

Edit: interesting car, I've been looking for a Mk2 Granada with a V8 of some description for a couple of years, is it a manual gearbox?

Edited by V8 Fettler on Sunday 17th November 17:21

Wedg1e

26,806 posts

266 months

Sunday 17th November 2013
quotequote all
Hmmm, you should have something coming out on the injector feed wires.
One thing though, do you definitely have nice fat sparks at the plugs? The ignition system has to be 100% as the ECU looks at the coil (-) trigger wire (from the ignition amplifier) so it knows when to start firing fuel.

heavy squad

Original Poster:

38 posts

152 months

Sunday 17th November 2013
quotequote all
Yes have bridged the high current terminals on the fuel pump relay as this was easier than taking the battery off my daily driver and rigging it up that way.

Love the mk2's as well, tough call on which is better looking I think. Not a manual sadly, has a ZF 4 speed auto out of a BMW on a Sherpa (I think) bellhousing...was planning to do the manual conversion but now need to sell her on...would make quite a weapon with a proper cog swapper!

Have been through the test procedure on the vintage model aeroplane site for checking the injection circuitry - Voltage between injector ECU connector pins and ground with ignition on is 12.15v...resistance between pins and terminal 87 on main relay is 8.6ohms...resistance of power resistor is 5.6ohms...all uniform and bang on where they should be it seems? Not tested the injectors themselves but think the above would show up any problem with them or with a bad connection somewhere?

Have even just put another gallon of fuel in just in case I was being really stupid but still not going.

Was just about to check for the spark, although it was obviously working for a bit yesterday.

Also wondering about a possible fuel pressure regulator problem or maybe a collapsed fuel hose? Shame I don't have a pressure gauge....

Or still maybe duff ECU?

V8 Fettler

7,019 posts

133 months

Sunday 17th November 2013
quotequote all
Does the fuel pump run all the time now when the ignition is switched on? Should be a noticeable hum when you stand beside the car. Sufficient fuel?

Pressure gauges are available from ebay at a reasonable price. You can WITH CARE break into the fuel line, point the fuel line into a container and run the pump. Pressure gauge is easier and safer though.

Modern fuel eats old fuel lines http://www.pistonheads.com/gassing/topic.asp?h=...

You can temporarily bridge a couple of the wires for the throttle position sensor to "blip" the injectors (in case the TPS is faulty), I can't recall the colours though.

I have a trailing lead with a croc clip to clip onto a battery terminal (I also use it to run temporary earths), this can be clamped onto the +ve battery terminal on the car (doesn't need another battery from another car), then attach to the pump positive. Need to be careful though.

As per wedgie, do you have a good spark?

heavy squad

Original Poster:

38 posts

152 months

Sunday 17th November 2013
quotequote all
Yes pump running constantly with ignition on, put another gallon of fuel in today, is still in the red though to be fair although it did drive into the garage under it's own steam two weeks ago.

Tried working the throttle linkage by hand with my head under the bonnet but can't hear any click, will try to find out which wires to bridge on the TPS.

Struggled for about 15 minutes trying to check the spark but no joy with only one pair of hands, just reading up on how to check out the components with a meter until I can get someone to give me a hand with this.

Breaking into the fuel line could be next on the cards, think I read something about depressurising it beforehand?

One other thing is that I can't seem to see the inline resistor that should be in the wire between the coil -ve and ECU pin 1?


Wedg1e

26,806 posts

266 months

Sunday 17th November 2013
quotequote all
heavy squad said:
Breaking into the fuel line could be next on the cards, think I read something about depressurising it beforehand?

One other thing is that I can't seem to see the inline resistor that should be in the wire between the coil -ve and ECU pin 1?
Wrap a rag around whichever hose end you disconnect, that'll suffice to catch spare fuel.

Don't worry about the resistor, most don't use it.

Ref. your earlier question, yes it could be an ECU fault but you should rule out everything else first.

adam quantrill

11,538 posts

243 months

Sunday 17th November 2013
quotequote all
Mine cut out today and would not start - I thought for a minute I was going to be stuck in Peterborough...

Had spark and fuel but no firing. The exhaust didn't stink of fuel though.

Turned out the ECU multiplug had got dislodged and semi-disconnected - so no drive to the injectors. An easy fix, that one.

Found a quick roadside check for fuel pressure is to loosen the clip on the cold start injector a little bit - a little fuel will start spraying out of the join - then screw it back up again quick!

heavy squad

Original Poster:

38 posts

152 months

Sunday 17th November 2013
quotequote all
^^^^If only it was always that quick a fix!

Slight faux pas on my part seems I left the coil +ve connection to the ignition amplifier disconnected last night and failed to spot it due to the coil being hidden under the AFM. Whoops!!

Nice bright blue spark at the plug and we're back to the engine running for a second then dying. Still can't hear injectors clicking with ignition on so thinking test the TPS next? Engine will rev up before dying if you start it with the accelerator pedal down but I suppose this could be down to the throttle butterfly being open even if the TPS is faulty? Engine does hunt/surge a little sometimes if that's an indicator? Had initially suspected an air leak somewhere in the inlet.

Out of time now for today but thanks again to everyone for the input!

V8 Fettler

7,019 posts

133 months

Sunday 17th November 2013
quotequote all
Engine should run OK if the TPS is disconnected, although a bit flat. Operating the TPS is a useful way to check that injectors do something. As mentioned earlier, with ignition on but the engine not running the clicks from the injectors should be clearly audible with your head in the engine bay when you operate the throttle linkage (assuming TPS is OK). As I recall, there are 3 wires to the TPS, bridging 2 of them pulses the injectors.

Wedg1e

26,806 posts

266 months

Sunday 17th November 2013
quotequote all
V8 Fettler said:
Engine should run OK if the TPS is disconnected, although a bit flat. Operating the TPS is a useful way to check that injectors do something. As mentioned earlier, with ignition on but the engine not running the clicks from the injectors should be clearly audible with your head in the engine bay when you operate the throttle linkage (assuming TPS is OK). As I recall, there are 3 wires to the TPS, bridging 2 of them pulses the injectors.
If the TPS is working OK, simply unplugging it and plugging it back in again with the ignition on often has the same result.
However, the wires to the TPS do become brittle with age and heat so it's as well to avoid yanking them around unnecessarily.


RCK974X

2,521 posts

150 months

Monday 18th November 2013
quotequote all
Just reading this thread.....my expertise is 2.8 V6, but I thought of a possible cause from Ford setup.

Q. Do Rovers have a coil resistor ? Could the resistor have blown ?

I had similar symptoms with a 2.8V6, it would run with key held at 'Cranking' position, but as soon as released, engine dies, as no power to coil....

I might be completely wrong, just suggesting in case it helps...


wild rover

447 posts

182 months

Monday 18th November 2013
quotequote all
Power resistor pack oops I call it a rectifier pack, Sorry about that just a thought are the relays powering the system operating properly.

V8 Fettler

7,019 posts

133 months

Monday 18th November 2013
quotequote all
For TPS fitted to 1985 flapper 350i, 3 wires (red, yellow and green), bridge red and yellow to trigger injectors (ignition on, engine not running). I disconnected the LT side of coil and ignition amp, injectors still triggered (so probably not dependant on signal from coil or ignition amp). Also, injector click (probably) when ignition is switched on but engine not started, disconnected cold start injector and click still audible. All clicks stop when power resistor pack disconnected (really!?).

It is possible that the "click" when the ignition is switched on is a relay, although it does sound as if it's from the engine bay.

Need to bear in mind that it is possible that the TPS fitted to the Granada has never been "live", the car will still run with no TPS signal. It will run very poorly with a corrupt TPS signal.

As I recall, my car had a similar fault a couple of years ago, good spark but no start, it was the wiring to the power resistor pack, the harness was too tight. This also lead to running on 4 cylinders until resolved by removing previous owner's tape from harness. Also worth checking all wiring running across the front of the engine, gets crispy and brittle with heat.


heavy squad

Original Poster:

38 posts

152 months

Monday 18th November 2013
quotequote all
RCK - Think the original rover setup had a resistor inline from the coil negative to the ECU but can't see it on mine (unless it's taped up inside the loom), general consensus seems to be that it's not required. Engine won't fire at all with this wire disconnected and continuity test seems ok so it must be doing something....had wondered about running another wire in parallel just in case though?

Wild Rover - Have tested the power resistor and seems within spec, has power to it but have a conspicuous lack of volts coming from the injectors. Relays are powered up so at least that's something!

Definitely no injector clicks either from unplugging and reconnecting TPS or even from bridging the red and yellow wires so I guess this ties in with the lack of volts at the power resistor? I assume there's no way of testing voltage at the injector without the engine running? Thinking there must be a break between injectors and ECU or between injectors and power resistor as per V8 Fettler's experience?

Does anyone know if there's normally a multiplug between ECU/injectors and injectors/power resistor that might be taped up inside the loom or are they all run directly?

Slightly confusing though as the tests carried out on the injector circuitry as per the vintage model aeroplane site all checked out ok?

Also, the engine will still fire briefly with the CSI disconnected whereas it won't with the power resistor unplugged so the injectors must be doing something?

Cobbled the pressure gauge from my compressor into the CSI fuel feed....registers 30 psi (a bit low but could be cheap and inaccurate) and holds it. After the engine dies and with the pump still running there is a sloshing/liquid flowing sort of noise which my handy length of hosepipe tells me is coming from the FPR so I think that means it works? Or is it that the spring is weak and it's not working?

Thought I had it sussed earlier when I noticed a split in the vacuum hose from the plenum to the FPR - but no!

Really overwhelmed by all the help received on here - thanks!!