87 RRC EFI Flapper 4cu trouble shooting wiring / ecu / AFM / regulator /

[RRC James]

G'day, still working away at my EFI system to get the car running properly

I've made plenty of progress after a mobile auto electrician/automotive engineer made a bunch of mistakes in front of me including ignoring the dealer diagnostic manuals I kept trying to hand him and the dealer workshop manuals. He also pulled out the distributor with out finding TDC on the harmonic balancer first or marking anything and was confused with the 30 degree change when sliding the dizzy onto the oil pump shaft. Yes he was that bad.

Car is starting and running at idle now when AFM is unplugged. It will rev quite a bit but will cut out if I don't do it a particular way.

As soon as I plug in the AFM it dies.

When the car originally died - if you were sitting at the lights idling it would just cut out after about 30 seconds. Even if you caught it cutting out and gave it some gas it still cut out. To keep it running at the lights it just required revving but sometime that wouldn't stop it. Eventually it just wouldn't start again. This happened over the space of 2 weeks.

I have swapped the AFM over for an apparently reconditioned one, however off a Jag V6. Can't be a reconditioned one as once the fuel pump circuit is closed it won't open again unless unplugged.

Tried swapping out the ECU for another unit, untested but, seller said it was good. No change.

I will be working through the diagnostic manuals with the multimeter and going over the relays and wiring tomorrow. Can anyone give advice on what to look out for?

BTW - new plugs, all HT leads in spec for resistance, new pickup coil magnet with air gap in spec. I've been over the ECU with the microscope and found a cold joint at one of the transistors as it was intermittently firing on one bank before eventually becoming a permanent fault. Thats been fixed. Negative air valve switch has been pinned out and the relay attached to that circuit next to the AFM and attached to the negative on the coil is working.

I may have done some damage to electrical system during all my poking around trying to learn and fix the EFI system making mistakes as I went, sometimes reversing polarity in coils or putting down a spanner in the wrong spot causing a few sparks and a tiny bit of smoke. It there anything I should look for?

A couple of other things are happening electrically that seem odd or broken. Could anyone please shed some light on them please?

There is AUX digital battery gauge, its all over the place some times, anywhere from 7V up to 26 volts. Rest of the time the readings are as they should be.

The fuel gauge is showing over full whenever the ignition circuit has power. I have pulled the two connections out to the sender in petrol tank. No change. Any suggestions or experiences with the same issue?

Otherwise mechanically engine is great and even though its not finished its sounding better than ever as that old pickup coil had been gradually going open circuit over the last few years and that cylinder bank fault was dogging the thing.

Any advice welcome thanks for your time

[PhilipA]

When the car originally died - if you were sitting at the lights idling it would just cut out after about 30 seconds. Even if you caught it cutting out and gave it some gas it still cut out. To keep it running at the lights it just required revving but sometime that wouldn't stop it. Eventually it just wouldn't start again. This happened over the space of 2 weeks.

My experience is with the earlier "Federal" system which I fitted to a 77RRC.

In that system the fuel pump is controlled firstly by a time delay relay which energises the fuel pump for about 20? seconds when starting.

The fuel pump is then energized by the flapper lifting a bit as air flows through.You can check by lifting the flapper a little with the ignition on.
I think that yours has the same system.

I would look at the flapper to see if the contact inside for the fuel pump activation is OK, and that the wiring to the fuel pump relay is OK, and that the time delay relay is working.
Regards PhilipA

[RRC James]

My experience is with the earlier "Federal" system which I fitted to a 77RRC.

In that system the fuel pump is controlled firstly by a time delay relay which energises the fuel pump for about 20? seconds when starting.

The fuel pump is then energized by the flapper lifting a bit as air flows through.You can check by lifting the flapper a little with the ignition on.
I think that yours has the same system.

I would look at the flapper to see if the contact inside for the fuel pump activation is OK, and that the wiring to the fuel pump relay is OK, and that the time delay relay is working.
Regards PhilipA


Hi Phillip,

Yes this has the fuel pump switch inside the flapper afm which is operating correctly when plugged in with ignition on. I am right now trying to work out which of the relays is responsible for switching the circuitry over to the next system once its started, I'm guessing it cooked. Looks like its happy to sit there idling on the starting circuit with the AFM unplugged indefinitely. I've got all the books just trying to put it together. Thanks for your input the time delay relay makes whats happening make a bit more sense.

Cheers J

[Konradical]

Under the drivers seat are three relays. Well, two relays and a steering module. The two relays are main ECU power and fuel pump. The steering module is red and is responsible for powering the fuel pump while starting and while running. It essentially switches which circuit powers the fuel pump.

Upon starting the contacts in the flapper will power the fuel pump until the ECU receives the rpm signal via the cut out switch, which then sends a power supply to the fuel pump via the steering module.

The fuel pump is not on a timer or pressure delay like newer systems. If the engine isn't being turned over or running, the pump doesn't run.

To me in your case it sounds like it is either getting too much fuel or not enough. If you haven't already, inspect the fuel pressure regulator and test the fuel pressure. For it to die at idle, but be ok with some revs up, it really sounds like a fuel issue where it is overfuelling.

What are the plugs like, colour? Smell? Are the vac lines all in good condition? Have you cleaned the earth's at the back of the LH head?

The other two problems probably aren't related. The volt gauge thing is either a loose connection or poor earth and the temp gauge thing could be the power converter in the dash cluster. My 89 does weird things sometimes, especially when the weather is warmer.

[RRC James]

Under the drivers seat are three relays. Well, two relays and a steering module. The two relays are main ECU power and fuel pump. The steering module is red and is responsible for powering the fuel pump while starting and while running. It essentially switches which circuit powers the fuel pump.

Upon starting the contacts in the flapper will power the fuel pump until the ECU receives the rpm signal via the cut out switch, which then sends a power supply to the fuel pump via the steering module.

The fuel pump is not on a timer or pressure delay like newer systems. If the engine isn't being turned over or running, the pump doesn't run.

To me in your case it sounds like it is either getting too much fuel or not enough. If you haven't already, inspect the fuel pressure regulator and test the fuel pressure. For it to die at idle, but be ok with some revs up, it really sounds like a fuel issue where it is overfuelling.

What are the plugs like, colour? Smell? Are the vac lines all in good condition? Have you cleaned the earth's at the back of the LH head?

The other two problems probably aren't related. The volt gauge thing is either a loose connection or poor earth and the temp gauge thing could be the power converter in the dash cluster. My 89 does weird things sometimes, especially when the weather is warmer.



G'day. Thanks I've checked the relays and checked the steering module. Looks like SM was rebuilt with uprated parts at some stage. I think it is a too much fuel problem. Plugs get wet then have to leave it half a day or take out and clean to get it going again. Black smoke is pouring out the exhaust when it is going now and this was a problem for about a year long time before the car stopped running. Never got around to buying a tester for the fuel pressure and its gone into the shop today for a LR mechanic to work it out. I did test the AFM using a multimeter this morning and it tests fine, I used a digital and analog multimeter. Good news is I'll have an answer for everything this week.

I'll have a look under the dash when I get it back thanks for that. Worst case scenario is that its the gauge and I've got a spare one of those handy

Looking forward to having the car back sorted. Its been a long journey of break downs and googling to sort out all the intermittent problems.

Cheers

[350RRC]

Hi,

I'd suggest you compare notes with Richard, a few threads down the page.

1988 RR Classic not running on petrol. (https://www.aulro.com/afvb/classic-range-rover/275178-1988-rr-classic-not-running-petrol.html)

PA might like to comment............. the injection system you have is not closed loop and can keep loading fuel in when running rich AFAIK.

The NA Chev in my pos used to run really rich on petrol simply because the fuel return line was blocked where it went into the steel tank.Ran fine on gas.

Worth checking, DL

[Konradical]

G'day. Thanks I've checked the relays and checked the steering module. Looks like SM was rebuilt with uprated parts at some stage. I think it is a too much fuel problem. Plugs get wet then have to leave it half a day or take out and clean to get it going again. Black smoke is pouring out the exhaust when it is going now and this was a problem for about a year long time before the car stopped running. Never got around to buying a tester for the fuel pressure and its gone into the shop today for a LR mechanic to work it out. I did test the AFM using a multimeter this morning and it tests fine, I used a digital and analog multimeter. Good news is I'll have an answer for everything this week.

I'll have a look under the dash when I get it back thanks for that. Worst case scenario is that its the gauge and I've got a spare one of those handy

Looking forward to having the car back sorted. Its been a long journey of break downs and googling to sort out all the intermittent problems.

CheersYeah could be a simple thing like the fuel pressure reg. If it doesn't allow a pressure drop in a high vacuum state (idle) it will squeeze more fuel out when the injectors fire causing the flooding effect. Or again if the diaphragm is split, fuel will be drawn into the system unmetered.

I did fail to mention the ECU, as you said you have already tried swapping and repairing.

Hope they get it going for you and you can get out and about in it in this soon to be (fingers crossed) good weather.

[RRC James]

Yeah could be a simple thing like the fuel pressure reg. If it doesn't allow a pressure drop in a high vacuum state (idle) it will squeeze more fuel out when the injectors fire causing the flooding effect. Or again if the diaphragm is split, fuel will be drawn into the system unmetered.

I did fail to mention the ECU, as you said you have already tried swapping and repairing.

Hope they get it going for you and you can get out and about in it in this soon to be (fingers crossed) good weather.


G'day. Called in this arvo. Mechanic said some strange things happening, said he was working on it just as I called and had to stop to come and pick up the phone... No fuel pressure when fuel pump pumping fuel, clamped return line, still no pressure but return fuel line working and feeding fuel back into the tank. I said is the fuel regulator diaphragm split, he did didn't bite. He said strange things happening as the car will run without the fuel pump relay... I though cranking circuit runs on its own without fuel pump relay and told him so, he didn't correct me. Just looked it up. I'm wrong. It needs the fuel pump relay for fuel pump to work. They said they will keep working. I've worked it out. What do you think? Cheers James

[RRC James]

G'day. Called in this arvo. Mechanic said some strange things happening, said he was working on it just as I called and had to stop to come and pick up the phone... No fuel pressure when fuel pump pumping fuel, clamped return line, still no pressure but return fuel line working and feeding fuel back into the tank. I said is the fuel regulator diaphragm split, he did didn't bite. He said strange things happening as the car will run without the fuel pump relay... I though cranking circuit runs on its own without fuel pump relay and told him so, he didn't correct me. Just looked it up. I'm wrong. It needs the fuel pump relay for fuel pump to work. They said they will keep working. I've worked it out. What do you think? Cheers James


And one more thing he didn't mention that I'm aware of. The oil in the engine smells like petrol

[Konradical]

He said strange things happening as the car will run without the fuel pump relay...

This is exactly what happened to me.. it was the ECU..

ECU would open the injectors so wide that the vacuum of the engine had to be drawing the fuel in..

Il find the link to my thread I had going on.

[Konradical]

V8 fuel injectors. (https://www.aulro.com/afvb/classic-range-rover/263912-v8-fuel-injectors.html)

Have a read.. I was pulling my hair out..

[RRC James]

V8 fuel injectors. (https://www.aulro.com/afvb/classic-range-rover/263912-v8-fuel-injectors.html)

Have a read.. I was pulling my hair out..

Wow I just finished reading it thanks for the link what an awful journey. Hows the car run now 9 years later?

My ecu is a little different to yours at the transistor? It did have the factory tamper screw covers on it, - maybe I drop into jaycar for a new transistor tomorrow. I'll go over my spare ecu and the one being used with the soldering iron also. The fella I bought it off had done a diesel conversion to his RRC. I may have bought the undiagnosed reason for him giving up on his 3.5 V8 on 4cu with the though it would solve a problem one day for me in its current state. Interestingly the ECU is the one part the LR expert, I picked the car up from today, didn't substitute. They were nice guys and did a bunch of tests and threw in plenty of moneys worth of 2nd hand spare parts so I can't sh%t can them but I would have thought they would know how to diagnose this car with 2 hours of paid time not keep saying strange this happening or "fuel problems". If they were happy to take it in should they be able to fix this type of system? He told me on the phone last guy that brought one of the flappers in ended up putting a carby on his WTF That would have been very handy information at the time of booking because I could have hung up the phone. Mate, I'm no good at fixing them or I don't work on them would have helped too... I digress


What do you think I should do to this?

156126

[Konradical]

Wow I just finished reading it thanks for the link what an awful journey. Hows the car run now 9 years later?

My ecu is a little different to yours at the transistor? It did have the factory tamper screw covers on it, - maybe I drop into jaycar for a new transistor tomorrow. I'll go over my spare ecu and the one being used with the soldering iron also. The fella I bought it off had done a diesel conversion to his RRC. I may have bought the undiagnosed reason for him giving up on his 3.5 V8 on 4cu with the though it would solve a problem one day for me in its current state. Interestingly the ECU is the one part the LR expert, I picked the car up from today, didn't substitute. They were nice guys and did a bunch of tests and threw in plenty of moneys worth of 2nd hand spare parts so I can't sh%t can them but I would have thought they would know how to diagnose this car with 2 hours of paid time not keep saying strange this happening or "fuel problems". If they were happy to take it in should they be able to fix this type of system? He told me on the phone last guy that brought one of the flappers in ended up putting a carby on his WTF That would have been very handy information at the time of booking because I could have hung up the phone. Mate, I'm no good at fixing them or I don't work on them would have helped too... I digress


What do you think I should do to this?

1561269 years? It's only just gone 12 months..

It has been pretty good. Fuel use is around 17-21L/100, but it needs a cam. There have been other little issues in that time, but running wise, it's been pretty good.

My ECU is the same as you picture, but the pictures I posted are of the opposite side. I removed both boards from the housing and inspected the circuit side rather than the component side.

What is the number on the ECU?

Keep all the components they swapped out, they are good trading items in the future.

If you can, have a electronics type fella have a look at the ECU and get it fixed properly. Nothing like "fixing" something only for it to fail 1000kms later.

[RRC James]

9 years? It's only just gone 12 months..

It has been pretty good. Fuel use is around 17-21L/100, but it needs a cam. There have been other little issues in that time, but running wise, it's been pretty good.

My ECU is the same as you picture, but the pictures I posted are of the opposite side. I removed both boards from the housing and inspected the circuit side rather than the component side.

What is the number on the ECU?

Keep all the components they swapped out, they are good trading items in the future.

If you can, have a electronics type fella have a look at the ECU and get it fixed properly. Nothing like "fixing" something only for it to fail 1000kms later.
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Thanks for the tip. Since your comment I have had it at a "LR expert" mechanic in Ringwood VIC. Guy was hopeless. Tried to lead me down the new fuel pump path followed by the "swap the injector rail over for another one I have sitting here" routine. The dickhead hadn't found the unclipped CTS. $150 an hour but has no idea... He used a pull tie to regulate the fuel in line and though that was some king of achievement. WOW. He replaced the 4 day old spark plugs and the 2 week old rotor button. I said stop working on the car I am coming to get it. I am assuming this bloke is retarded because he couldn't follow the land rover dealer training manual to diagnose the problem and just started swapping parts for $150 an hour. WOW. Land Rover expert... He said the last bloke that came in one of these swapped it out for a carby, no ****. I wish he told me that a week earlier because he can't fix 4CU but won't tell you until hes picked your pocket. Don't get me wrong super nice guy but either can't lay straight in bed or just a **** mechanic.

You've tip saved my arse, thank you so much. I got the rebuilt ECU back from injectronics this week. Injector banks were out of control over-fueling, they gave me the VASS test to prove it. Plugged it in this morning and dialed in the AFM and reset the timing and idle a few times. Car is now running better than ever!!!

[Konradical]

That's good news!

Pity about the fella you took it to, these things are just set to try us.

I'd be keen to learn more about the place you sent it to, location and pricing, etc. Can PM if you want.

Well again, good news and you can get back to Range Rovering!

[crispy]

Seems I'm having the same problems. Will start up but have to keep pumping the throttle to keep running before it just dies. Unplug the AFM and it runs fine, no black smoke and ticks over fine. Plug the AFM back in and it stops. Anyone got a spare ECU that I can try ? How do I test the AFM, what should the voltages be? Cheers...

[Konradical]

Can you leave the Flapper plugged in and remove the fuel pump fuse and see if it does it? Just want to isolate weather it's the fuel pump component of the flapper that is having this effect or the flapper itself.

I can't ad it, but if you search 'Lucas 4cu testing', there is a pdf from a GoMoG (http://www.gomog.com) that will give you all the testing info and procedures you need.