Sorry guys it's another flapper playing up!

Coastcard · Post by **Coastcard** » Sat Jul 21, 2007 6:50 pm

Have transplanted the new engine into my LR 110 (3.9 with a legacy flapper efi). I rebuilt the loom so all connectors are (hopefully) good.

My issue is sporadic in that it runs lumpy and very rich (black sooty smoke from exhaust, black plugs etc). However, sometimes, occasionally it runs sweet as a nut, which leads me to suspect something is sticking or loose. Today when it changed from rich to OK, she conked out and was hard to start again.

Initial impressions would lead me to the fuel system, but originally when this was happening I noticed that the purple and orange wires from the dizzy had a bad connection which seemed to sort it for a while.

So, my preference is to look on the ignition side, but in order to help me start more detailed diagnostics, could this be ignition or more likely fuel related?

I have diagnosed so far that there is a leak in the vacuum on the dizzy, but am assuming this shouldn't effect it this much. I also have what I assume is an ignition amp connected to a relay (not mentioned on the ignition upgrade thread) and it does have the in line resistor(?) on the coil.

Help appreciated as Summer is coming

and after a year refurb I would like to use the thing!

5000SE · Post by **5000SE** » Sat Jul 21, 2007 7:15 pm

This sounds very familiar.

Check your temp sensors or, more likely if it's erratic, the injection loom because you may have fractured wires. If the temp sensor gets 'cut off' by a break or dry joint in the loom, the car will think it's cold and go uber rich, hence black smoke.

ramon alban · Post by **ramon alban** » Sun Jul 22, 2007 11:23 am

5000SE wrote:This sounds very familiar.

Check your temp sensors or, more likely if it's erratic, the injection loom because you may have fractured wires. If the temp sensor gets 'cut off' by a break or dry joint in the loom, the car will think it's cold and go uber rich, hence black smoke.

I agree, this sounds like an intermittant connector or wiring problem. In addition to the suggestion, there is supposed to be an "engine" earth behind and below the LH rocker cover on a stud, for just that purpose. Check for a sound connection there too.

Coastcard · Post by **Coastcard** » Mon Jul 23, 2007 7:26 am

Thanks guys. I did check out the loom connections having rebuilt the ends and also have checked out the leads back to ecu plug. I will return to Ramons site and start again, 'cos as an intermittent issue it could be tricky to track down. (How could you doubt my soldering

) Couple of questions though:

1) The injectors timer plug connections are numbered and as such I know these are all OK, but does it matter which way round the wires/connectors are in the other 'sensor' plugs which are not numbered?

2) Can the efi temp sensor go sticky and produce these symptoms? I seem to recall seeing some measurements for this so will test it out as a first port of call. When I originally had this issue, I tried to find another and could only locate Intermotor ones, does anyone know who sells the Lucas ones?

ramon alban · Post by **ramon alban** » Mon Jul 23, 2007 9:10 am

Coast guard, Replies in red

Coastcard wrote:Thanks guys. I did check out the loom connections having rebuilt the ends and also have checked out the leads back to ecu plug. I will return to Ramons site and start again, 'cos as an intermittent issue it could be tricky to track down. (How could you doubt my soldering ) Couple of questions though:

1) The injectors timer plug connections are numbered and as such I know these are all OK, but does it matter which way round the wires/connectors are in the other 'sensor' plugs which are not numbered?

Temp sensor NO

Thermotime YES, as it has an internal earth!!

Throt pot YES

EAV NO

2) Can the efi temp sensor go sticky and produce these symptoms? I seem to recall seeing some measurements for this so will test it out as a first port of call. When I originally had this issue, I tried to find another and could only locate Intermotor ones, does anyone know who sells the Lucas ones?

Temp Sensor Sticky. because its electronic not mechanical, unusual but YES

Removed from the car, measure it with an ohmmeter and a pan of water and thermometer, as you bring it to the boil.

Rimmers or Range Rover dealers may have them still.

Replies in red

Coastcard · Post by **Coastcard** » Thu Jul 26, 2007 8:05 am

When it stops raining, I will go out and have a better investigation. Pretty sure the conectors were on OK, but I recall one disintegrated before I could note the connections, so will double check thermotime. Don't think this is the issue though because I disconnected cold start injector and it made no difference.

Update will follow

Coastcard · Post by **Coastcard** » Fri Jul 27, 2007 11:15 am

Oh bum!! Disconnected the cold start injector this morning (while running rich) and it sorted it! So to check which wire should be connected to which terminal on the thermotime switch (as not marked) here are the values

Thermotime switch (in manifold):

Terminal 1 = 280 ohms, Terminal 2 = 63 ohms (reading taken when engine hot if this makes a difference).

Thermotime timer connector (ignition off)

Terminal 1 = 0 volts, Terminal 2 = 38ohms, 0 volts

Thermotime timer connector (ignition on)

Terminal 1 = 0.02 volts, Terminal 2 = 38ohms, 0 volts

At the moment I have the terminal 1's together and the terminal 2's together. Is this correct?

Also is there a test for the connectors on the cold start injector to make sure that these are the correct way round as well.

Thanks and lets hope that this is the issue and not just the fact it was having one of its good days

Coastcard · Post by **Coastcard** » Mon Jul 30, 2007 4:00 pm

Right, it was having one of it's good days yesterday

. Started today and back to really rich and lumpy even with no Cold Start injector. It does improve very slightly as temp rises, but I am assuming that this is just the vast quantity of fuel vaporising and burning a bit better in the hotter engine. Still clouds of smoke from exhaust.

Done a number of tests.
Checked out cold start /thermotime circuit - fine.
Checked out temp sensor circuit and sensor resistance - fine
Checked out injector circuit and resistor pack - fine
Fuel pump and tank are brand new. Have nothng to test fuel pressure with though.

Am I correct in ruling the ECU and AFM out on the basis that it can run beautifully when it wants to?

Going back to square one, could ignition cause it to appear to run really rich (weak spark)?

EDIT: Just run low on petrol and as it was running out, started running OK, so thinks could it be fuel pressure regulator? Can these stick at a high pressure forcing too much fuel in? There is no leak via the vacuum pipe.

This is driving me mad, so all help appreciated.

ramon alban · Post by **ramon alban** » Mon Jul 30, 2007 6:06 pm

Coastcard wrote:
Have nothng to test fuel pressure with though.

Remove the fuel connection to the Cold start injector and take the pressure gauge off your footpump.

Fix the gauge to the pipe and bingo - fuel pressure measurement.

The fuel pressure should vary between 26 and 36 psi as the engine speed and load changes. If it is high or low continuously the pressure regulator is fubar.

Am I correct in ruling the ECU and AFM out on the basis that it can run beautifully when it wants to?

No the ECU can display intermittant fault condition. You need to find a way of obtaining a subsitute to eliminate the possibility of yours being faulty.

The AFM in unlikely to show intermittant faults if it passes the simple tests.

EXCEPT - wiring problems to either can always be intermittant.

Going back to square one, could ignition cause it to appear to run really rich (weak spark)?

I would have thought so because intermittant or missing sparks would mean unburned fuel which would hang about and later contribute to a richer bang, next time a spark occured.

One possibility is the ignition amplifier which usually goes on the blink before total failure. (cant remember if this has been mentioned before?)

EDIT: Just run low on petrol and as it was running out, started running OK, so thinks could it be fuel pressure regulator? Can these stick at a high pressure forcing too much fuel in? There is no leak via the vacuum pipe.

There is no logical relationship between running low on petrol and a faulty fuel pressure regulator. The regulator has three possible fail modes, I believe. Stick open, stick shut, breached membrane.

This is driving me mad, so all help appreciated.

Its driving me mad too but keep your pecker up

Coastcard · Post by **Coastcard** » Fri Aug 03, 2007 1:01 pm

Thanks Ramon, I dented (oops) the fuel regulator getting it off, so getting replacement hopefully tomorrow. Was running Champion plugs, so bought NGK. Bought replacement Bosch coolant temp sensor. A fellow LR enthusiast is lending me known working ECU, AFM, resistor pack, dizzy cap and leads, so... hopefully with some logical working we shall see this resolved in the next few days.

Pecker still up

Coastcard · Post by **Coastcard** » Sun Sep 30, 2007 6:17 pm

Just for completeness... after god knows how many hours/days diagnosing this one, it was the ECU. At least hoping it was, I haven't had a chance to fully test it, but runs a lot better now!

New ECU now has loads of dials on it which I am trying to work out (see other thread)

Thanks for all the help.

ramon alban · Post by **ramon alban** » Sun Sep 30, 2007 6:54 pm

Coastcard wrote:after god knows how many hours/days diagnosing this one, it was the ECU.

All of which goes to show just how difficult it is to diagnose faults by forum. The only suggestion made regarding the ECU was this: ---
"No the ECU can display intermittant fault condition. You need to find a way of obtaining a subsitute to eliminate the possibility of yours being faulty." --- amongst a raft of other inaccurate guesses.

For the most part, I am usually pleading for owner/enthusiasts to take the time and trouble to do the methodical test program to diagnose the faults, rather than choosing the scattergun approach of random replacement.

However, you did try all the tests within your compass and still came up short, with the ECU substitution solving the problem.

Consequently, when it comes down to it, and because they are pretty easy to find on Ebay, etc, most owners would do themselves a favour to obtain a small set of good system spares such as ECU, AFM, TP, Regulator and etc to enhance their ability to solve these problems!

Even if changing (say) the ECU and/or AFM proves that it is NOT faulty, that is a positive result because it takes away doubt and forces the microscope to be focussed elsewhere.

Well done and thanks for the feedback.

ChrisJC · Post by **ChrisJC** » Mon Oct 01, 2007 9:16 am

ramon alban wrote: Consequently, when it comes down to it, and because they are pretty easy to find on Ebay, etc, most owners would do themselves a favour to obtain a small set of good system spares such as ECU, AFM, TP, Regulator and etc to enhance their ability to solve these problems!

Agreed - I keep a complete set of flapper spares, I even carry most of them with me in the vehicle for roadside repairs, including ECU!

Chris.

Coastcard · Post by **Coastcard** » Tue Oct 02, 2007 11:27 am

Agree 100% with Ramon.

Forum is great for a first stab at the common symptoms and faults.

Then, I followed the diagnostics in a structured fashion and got KNOWN working replacement items for most parts apart from the ECU, which took some time (the chap I thought had one, didn't) and I wasn't prepared to chance stuff off ebay.

The system is not hard to diagnose if you approach it logically, but definately worth having a set of spare components - most of my time was spent going around in circles because it took time to find them!

Post by **demo2** » Tue Oct 02, 2007 1:45 pm

I had the same fault when i 1st did v8 conversion, intermtitent, was the ecu as well.