Thread: More flapper EFI drama - help needed urgently!

Before I started troubleshooting again today, I tried to start the car and it was a no-go but did cough and almost ran when you let the ignition off but would then just turn over with nothing happening if you cranked again straight away. For some reason I decided to check the coil and ignition module connections (which were all fine) and while I was doing that, decided to change the fuel overrun relay under the AFM as it looked quite, old? Well after I did that, the thing then started straight away and has been running exactly like it was last Saturday when it decided to work again. However, it is now blowing black smoke and fouling plugs. I've checked the vacuum hose coming off the pressure regulator and it doesn't have any fuel in there so that apparently means the regulator is not leaking.

But, could a faulty fuel pressure regulator cause the no-start, hard start, stalling and now over-fuelling problems?

A update on this, it is now starting and idling but idle is very low, any throttle movement at all stalls it unless I start it with the AFM flap wide open, then if I give it a short burst of throttle it blows black smoke and then stalls.

Spark is good with a new Bosch 024 module, known to work dizzy and Bosch MEC717 coil, all off a running car and fuel is reaching the rail, I don't know the pressure in the rail but I have at least come full circle now to be back exactly where I was before but know that I have good spark and I think that the only things left to look at are the ECU, resistor pack, AFM and relays.

I'm trying to find a straightforward procedure to test the resistor pack, any help there? I have 2 spares to use also.

Check the EFI/water temp sensor. Should be about 300ohms at operating temp.


Had problems with this twice. 1st time plug failed (high resistance), 2nd time sensor failed. Both resulted in overfueling (except when very cold). The sensors are quite cheap.

Rick, the temp sensor is still on the list and I will look at it if I can actually get the car to start again!

Another update though, it won't even run now, it turns over and nothing happens. There is still spark but I am not sure about fuel, I pulled a plug when it would not start (after it had been idling low and stalling) and the plug was wet but I did the same today after cranking with no luck and the plug was dry. I have also now tried both a working ECU and working AFM and it did not make a difference, so it has to be a wiring and/or relay problem?!

If I cannot find a electrical cause, well...

have you short circuited the vacuum fuel cutoff?

it's the thing on the drivers side bank beside the last fuel injector.

has a vacuum hose and two wires on it, disconnect the wires and use a bit a wire to link the two spade fittings on the loom.

To test for fuel problems it helps to have a pressure gauge connected to the fuel rail. Undo the hose to the cold start injector and put a pressure gauge into the hose instead. Observe if the pressure comes up during cranking and if the pressure stays up after cranking. An air pressure gauge capable of reading 20 - 40 psi is fine.

If the pressure doesn't come up quickly your pump may be dying. If it drops quickly after cranking it may be flooding the engine via the fuel pressure regulator vacuum hose or failed injectors.

The fuel cut-off valve is something I am going to check yes, I'm not 100% certain but in my patience-wearing-thin daze I may have got the terminals connected the wrong way around!

Getting a pressure gauge onto the rail is also on my short list to do but because I replaced the fuel pump with a brand new unit (Goss, supposedly for a Range Rover) I have not tested pressure yet only checked there is fuel at the rail by undoing the CSI hose and there is plenty of fuel there.

Does the information in this document about the 4CU injection on the USDM TR8s apply to the Range Rover 4CU? It's a very well put together document so I hope so! http://www.vintagemodelairplane.com/...cal/ECU01.html

I'm doing the test procedures that start on page 27 in this document from step one http://www.aulro.com/afvb/local_link...catid=7&id=117

It's a hot day to be out working on the car!

Edit: This might be a very stupid question but which side of the ECU multiplug starts with the #1 pin? Where the clip is or where the loom is? I could be going blind but I cannot see anything clearly stating WHICH pin is #1?

To cut another long-ish post short(er), I've done basically everything I can think of and that has been suggested and there is now no power getting to the injectors. A noid light doesn't give any results, plugging a spare (known to work) injector in doesn't give any result, there is 36 PSI of fuel pressure at the CSI hose, there is spark, the ECU is picking up the pulse signal while cranking. ECU, AFM, EAV, Throttle Potentiometer, overrun shutoff valve, resistor pack and coil are all ok.

I've tried a few different relays (including a brand new one) in place of the main power relay and get no change. I may be stuffing up the procedure for testing the injector ohms at the ECU multiplug but with the ECU connected, cover removed off the multi-plug, multimeter set to 2k ohms, probe between the 87 pin on the main power relay and other probe on each injector wire in the ECU multiplug I get a reading of 10 ohms, not 7-10k. Doing a resistance check at the injectors themselves shows them to be within a working range, slightly higher than what the documentation says they should be but they are all within 1-2 ohms.

I've checked the relays in the engine bay between the firewall and washer bottle on the passenger side and none seem to be for the injection. There is (of course) no sticker or anything to show which relay is for what. I can see the ignition and starter relays from the wires going into them, though do not know what the other 5 are for.

Is there a main 12v feed wire for the injectors? Is it brown with a orange stripe, or brown and red?

I think I now need to pull the injector harness out, get the tubing off to check the whole loom, check the injector plug ends that are under the rubber boots and HOPE that there is a broken wire or something in there. If there isn't I am genuinely out of ideas and completely out of motivation!