1987 RRC 3.5L efi starting/hunting/hot stall problems

shocker · Nov 10, 2018

Above vehicle has been off the road for a year due to welding then illness (both myself and RRC), in the meantime it developed a problem in that it will start from cold but run, hunting badly, for a maximum three minutes. As soon as any warmth develops it stalls and will not restart until it cools a little.

Further, a relative who did not understand that efi was not a carb system (dementia) ran the idle and mixture screws in and out and the positions of both were lost.

I have been slowly replacing parts like the coil, fuel pump and rewiring various suspicious bits of wiring but have not solved things yet. I have a coolant temp sensor on order as I have been told that someone else had this hunt/stall problem and the coolant sensor was the fault. I am also wondering about the fuel temp sensor that does not seem to be available (at least for realistic money)...

...I could go on replacing parts until I see some improvement but it will take more years than I have left at this rate. Can anyone help here, please?
For instance, resetting the wayward screws- back in the days of carbs there were often rules of thumb to give a starting point to tune from, like "x" number of turns from fully in. The books all talk about using oxygen meters, but I do not run to one.

Anyway, all help gratefully received. Its an '87 so flapper 14cu, I would think (?)

discool · Nov 10, 2018

Start with getting a Haynes manual, all the information u require is in there which is far to much to place in a thread.
Yes you will need access to an exhaust analyser for the fine tuning, after u have the engine up and running without the issue u have at the moment.

shocker · Nov 10, 2018

Haynes is where I started, long ago. I must have gone around the houses so much that I have lost my way - to Haynes I shall return then! And I have that edition too....somewhere.

Many thanks, Discool. Anyone else?

classic kev · Nov 10, 2018

Just a thought - try unplugging the cold start injector. It's the one on the side of the plenum.

discool · Nov 10, 2018

The 9th injector was never need in the UK but in their wisdom LR found its something thing that would be useful in Norway and other Scandinavian countries in winter.

Anyway a snippet of info that maybe helpful copied from another Forum many years ago.

“For a cold start (cold engine) on the flapper extra fuel is injected into the plenum chamber by the injector that sticks out of the side of the plenum (top centre on the drivers side. This is controlled by the thermotime sensor which is the front of the 2 sensors on the top of the inlet manifold. When the switch goes faulty the usual result is overfuelling which may cause starting/running problems. (The rearmost of the 2 sensors is the temp sensor & when that plays up it also usually causes overfuelling & is the cause of many mysterious running troubles for which the ECU is usually wrongly blamed) Generally the cold start injector serves little purpose in temperate climes & many just unplug the electrical leads from the injector”

I did just that when I bought mine & it makes no apparent difference to the starting.

norseman · Nov 10, 2018

discool said:
The 9th injector was never need in the UK but in their wisdom LR found its something thing that would be useful in Norway and other Scandinavian countries in winter.
Generally the cold start injector serves little purpose in temperate climes & many just unplug the electrical leads from the injector”
I did just that when I bought mine & it makes no apparent difference to the starting.

+1
I've owned four RRC's over an 18 year period & never needed to connect the CSI.

Ratae · Nov 11, 2018

norseman said:
+1
I've owned four RRC's over an 18 year period & never needed to connect the CSI.

Disconnected mine years ago - just take the lead off it - & have never felt the need to reconnect it.

You need to replace the coolant temp switch (the one behind the easy one) if only to eliminate it.
On an '87 flapper RRC I'd expect to find a 4CU ecu. These are notorious. I've had my 1986 since 1994 & it's on its 4th. I currently have a spare which lives in the car. The afm has never given me any trouble.
I do have lpg & that is via a BLOS & has no connection to the ecu. The petrol side of things was done by switching the electric feed to the injectors so fuel is still circulating. Advantage is that if the car runs badly I can switch to the other fuel & see what happens.
The last ecu failure (whilst driving with engine at normal temp) suddenly started running very rough, plenty of black smoke & needed the revs kept up to stop stalling. Switch to LPG gave normal running - indicating a fuelling fault rather than an ignition issue - & swapping in a spare ecu also restored normal petrol running.
Other than trying a known good ecu I'd suggest having your own checked over by one of the ecu specialists. Ebay usually has a few but there are some unscrupulous sellers so it's a risk.
This worth a look: http://www.carelect.demon.co.uk/rrind.html (will also help you id your ecu).
There are a number of part numbers & I've got more than one but not noticed any difference. I did ask Lucas some years ago whether the various part numbers are interchangeable & the answer was basically yes.

The left & right pics in discool's post from the Haynes are pretty much a straight lift from the factory manual SRR660ENWM.
The butterfly throttle stop on mine is an allen headed grub screw & contacts the lever nearest the plenum. You adjust the throttle levers as in the pic after adjusting that.
On the flapper the tiny butterfly airgap is important. Worth cleaning that area as dirt can build up.

shocker · Nov 14, 2018

Sorry guys, been away from confusers for a while, but thanks all. I will work through all of this.
The CSI is disconnected.
I have a new coolant temp switch ready to be fitted, as said above, for elimination if nothing else.
Can anyone point me to a fuel temp sensor for sensible money? I have heard that these are a next step following the coolant switch. Im seeing old, used ones for £100 plus, 50 plus shipping from Australia and 25 from China including long wait. I think the wait is FOC.

Sheesh, I feel like a beginner again.

After years of diesel, I buy a RRC just for the winch et al, get cornered into using it as a daily drive (well, in this case more like yearly) and end up having to learn vintage petrol F.I

SPS (thats a snivelling PS) anyone got a 4CU ecu for sale ? He snivelling-ly begged...

FFG · Nov 14, 2018

Does it have an ignition amplifier as replaced a few on the TVR. Probably just poor quality new ones now so its pot luck.

shocker · Nov 14, 2018

Hmmm, my LR workshop manual shows the hotwire CUX system for 1987 models, not the flapper CU thats fitted. I cannot even find a fuel temp sensor...and I cannot tell which the coolant temp one is short of taking things apart and matching like for like. I do have the 87 haynes book but I can rarely understand their pictures, will just have to try harder.

Yes FFG, it has an ignition amp on the side of the dizzy. That had been a niggling back of the mind thing until I went off on the sensor journey. Any ideas on where to come by one? Other than scrap yards and potentially buy more trouble?

discool · Nov 14, 2018

What temp sensor are u looking for the thermo time switch EAC1385 which is obsolete or EFi temperature sensor EAC3927L. (Now superseded to (EAC8496)
The thermo sensor is also a Jaguar part.
This link may be of interest to u https://www.pistonheads.com/gassing/topic.asp?h=0&f=12&t=1191416

Plus a copy of a page in my 3.5 RR parts book.

shocker · Nov 14, 2018

its the efi one
thanks Coolio

norseman · Nov 14, 2018

Is your W/S manual a genuine LR?
My '87 RRC (manuf. in June of that year) has a 'flapper' & as far as I know only the last of the 3.5efi's (3.9 production started in Oct '89) had the 'hotwire' system.

jamesmartin · Nov 14, 2018

norseman said:
Is your W/S manual a genuine LR?
My '87 RRC (manuf. in June of that year) has a 'flapper' & as far as I know only the last of the 3.5efi's (3.9 production started in Oct '89) had the 'hotwire' system.

they did , i remember hot wire ecu that did both 3.5 and 3.9

shocker · Nov 15, 2018

genuine LR manual, flapper 3.5 on my 87

Ratae · Nov 15, 2018

Transition from one model variant to the next can cause confusion as older - but still brand new - cars will still be for sale alongside the new one.

The manual number I posted earlier - 1986 to 1989 - covers late carbs, flapper EFi, hotwire EFi, VM 2.4 & 2.5 & is a 2.5" thick book.
As a part of the book it includes several LR published supplements. The hotwire supplement (LSM180WS2) is dated 1988 & states it is the 13CU ECU which the carelect site above says was North American & Swiss markets only.
No mention of other ECUs in the rest of the manual.
Carelect shows the 14CU & hotwire AFM 3.5/3.9 as RRC & Disco 1990 onwards.

ETA. I am aware there have been some DIY conversions from flapper/4CU to hotwire/14CU but not seen one or seen a good 'how to' with pics.

FFG · Nov 15, 2018

ignition amp is Lucas part number DAB118 for 3 pin or DAB127 for 2 pin - you can but DAB118 but you may need a 3 to 2 pin converter cable. Some are questionable quality so it is pot luck unless you can find any NOS.

shocker · Nov 16, 2018

on the 4CU flapper engine, the coolant temp sensor is the one very close to and behind the TTS...is that right? And no fuel temp sensor on the rail?

also,ignition timing marks...I can only see one cut in the bottom pulley and the scale on the front case has the quadrant of metal but no markings left visible...I was expecting the usual old BL set up

and thanks, again, FFG

discool · Nov 16, 2018

shocker said:
on the 4CU flapper engine, the coolant temp sensor is the one very close to and behind the TTS...is that right? And no fuel temp sensor on the rail?

also,ignition timing marks...I can only see one cut in the bottom pulley and the scale on the front case has the quadrant of metal but no markings left visible...I was expecting the usual old BL set up

and thanks, again, FFG

Look at the copy of my parts book page, it gives u the exact position of all three temperature sensors they all take their reading from the coolant. The sensor for the dash gauge is the single terminal item next the the thermostat housing.
As for timing marks, they were there when the vehicle left the factory, TDC in the middle with degrees either side, if i remember correctly on the pulley edge, but it was a long time a go and haven been near a crankshaft pulley since

Sent from my iPad on a train

Ratae · Nov 16, 2018

The timing marks are stamped flat on top of the pulley - actually the torsional vibration damper - & not a series of slots in the edge. Item 6 in this link: http://new.lrcat.com/#!/1230/73417/75066/6009/75200
They will probably need a quick clean & rubbing a bit of white paint across with a finger can help show them up.
You need to look down on the crankshaft pulley from above.
This is the best I can find on a quick google & is a Rover SD1. The pulley layout on the RRC is different but it does show what the marks are on & what they look like: https://www.ebay.co.uk/itm/Rover-Sd1-V8-Crank-Pulley-Damper-Breaking-Engines-/283245100290

1987 RRC 3.5L efi starting/hunting/hot stall problems

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