Help still needed. Fuelling issue.

[jaybee747]

Hi Guys

Car came to a halt as if it had ran out of fuel.
Spark at coil. Spark at plugs.
Plugs/leads can be eliminated as it would be unlikely that 8x of each would fail.
Fuel at the fuel rail, shraeder valve emitting fuel, however, pressure not known.
Fuel pump works as should, ie. Operates for approx. 1 sec priming.
Just seems that injectors are not opening, ie grounding.
Have ordered fuel pump relays but think this could be a ECU problem.

Any guidance would be greatly appreciated.

John

[Belle427]

I would change the main relay first as its responsible for power to the injectors.
Its one of the two you speak of, its worth changing both together and making sure they are the correct type.

[Steve_D]

Do you have RoverGauge? (If not why not).
If you do check to see if it shows revs whilst cranking.
The ECU will do a pump prime when the ignition comes on but then does nothing until it sees a signal that the engine is cranking or running.
This signal is from the negative side of the coil (white/blue wire) and goes to the ECU. On some cars this wire goes across the front of the engine ending up at a single connector underneath the inlet air pipe by the throttle body.

Steve

[blitzracing]

It would be odd to loose both banks of injectors as they are switched in blocks of 4, but they wont fire if the ECU does not get a pulse from the ignition coil. This is via a nasty little resistor burred in the loom and if this disconnects or fails the injectors wont fire.





You can look for 12v on one side if the injector connector when the ignition is on to check they are getting supply from the main relay

[jaybee747]

Thanks Guys

Belle427.
I have a main relay on order as well. is there any outputs I can check beforehand as I`m still waiting on postage?

SteveD
Never needed a Roverguage before so never bothered. "2 Chim owner since 2005 and only had immobiliser issues in all that time. Not on this car though."
Will check Blue/White wire for condition, but what should it read in what state?

Blitzracing
Is this a common problem that they fail? What is the availability on this part, come to think of it, where is it located on the loom?
What`s the part description/name, is that a part number on the photo?

Sorry for all the questions. it`s just frustrating that I can`t get the parts quick enough, nevermind finding the time to fit and diagnose.
Again thanks in advance.

John

[Belle427]

Pins 87 x 2 on the main relay should have 12 volts with ignition on and cranking.
wire colours should be brown/orange.

[blitzracing]

Resistor failure is not common, but Lucas wiring looms are not known for there reliability, so it would be corrosion on the contacts if anything. Now its position, from memory its where the 14CUX loom splits off to its coil feed- but the resistor may be taped in the loom so not obvious. As it is now its not easy to see if the ECU is getting the RPM feed without RoverGauge, but you can create a spark by unplugging the king lead from the dizzy and taping it away on the chassis Then remove the top of the dizzy, then the rotor arm, followed by the plastic shield below that to expose the pick up head. Then rotate the engine until one of the lobes aligns with the trigger pickup (small air gap). Now get a screwdriver and put a stick a magnet on the shaft near the bottom, and tap the screwdriver tip across the air gap with the ignition on. You should a crack from the coil as it arcs, just stay away from the end of the king lead. This should cause the fuel pump to kick in for a couple of seconds if alls well. A lot of faffing about however for a simple test.

The resistor can be replaced with a standard 6.8k 1 watt resistor if needs be (you dont need a watt, they are just larger and stronger), but I doubt the resistor itself would have failed anyway.

[jaybee747]

Right guys.
Roverguage on order, received relays and swapped both. No difference.
As a process of elimination, could I attach a 4.0 ECU to the 4.5 to see if it is an ECU failure?
Also, what can I measure at the -ve side of the coil to eliminate that?

thanks

John

Also, just tested the injector electrical plug. I have 12.6v at both sides. This can`t be right can it?

Edited by jaybee747 on Friday 24th July 13:37

[blitzracing]

12 v on both sides of the injector is correct if the engine is not running. Like wise 12 v on the negative side of the coil is correct if the engine is not running. You can try another ECU to see if it will run.

[jaybee747]

Just to let you guys know. I pushed my owd 4.0L out of it`s resting place and borrowed it`s ECU. Low and Behold, runs like it`s never had anything wrong with it. (Should have kept the old one on the road.)

Anyhow thanks to you guys for guidance, it`s given me a bit better understanding of the ECU fuelling, and diagnosing a problem there.

Don`t suppose anyones got a 4.5L ECU going for sale anywhere before approaching the Wallet Breakers?

Once again thanks

[Belle427]

blitz maybe your man here, isnt it just the chip inside them that’s different meaning you could just change them over if you have the removable type?

[blitzracing]

Unfortunately the days of £40 14CUX's seem to be long gone, which is odd as there cant be a big market for them but you could try a Range Rover breaker. The stock Range Rover units from the early 1990's had the fuel chip soldered in, but at some point they changed to a plugable chip socket that makes life easier but unfortunately I dont know the date the change took place. You need to avoid the really early ECUs pre 1991 as they wont support the current TVR chips. On the early units you can cut the Range Rover chip out and careful use of a solder sucker remove the legs and solder a chip socket in, but its not advisable unless you familiar with circuit boards. There should be a number of "TVR" ECUs floating around by now that all have plug-able sockets.

[jaybee747]

Would the problem be the ECU and not the chip?
I won`t use the 4.0 ECU as there`s nothing wrong with the car, just the outriggers, and its quite an original example.
The 4.5 is Cat C and not bothered what is in or on it.
Just don`t see £300 worth of kit to replace at the breakers. they wern`t that dear some years ago.

john

[Belle427]

I was thinking you could use the 400 ecu if it’s not being used and you could change the chips over.

[O mage]

Some of the capacitors used are the usual suspect and are not expected to last as long as the newer tech used in the controller sometimes you can see when a cap has blown.

[Steve_D]

A new chip from Blitz or stevesprint would be well worth having on your car whichever ECU it ends up with so getting one and fitting it to your 'Dead' ECU will prove if it is the ECU or the chip.
All good if it was the chip as you are back on the road.
If it is the ecu that is dead then the new chip will be ideal in the replacement ECU you will need to find.

Do a separate post on here asking for an ECU. There are a growing number of owners who are converting to newer after-market systems.

Don't go near TVR breakers use a Land Rover breakers such as Martin Toole 01794 884305. Nice guy I trust.

Steve

[Belle427]

I have a spare 4.6 chip that was burnt for me but I didn't use.
pm me if you want it, no charge for it just pay the postage.