Hi all, is there a kind soul in the house who has come across a 1988 3.5 RR SE automatic.That starts great and runs evenly while it is getting warm. As soon as it does the tickover becomes erratic and the engine tries to stall. If I keep the revs on it will run for a short while and then dies.
Help please, I have tried all of the connections but can find nothing.

the title of this thread reminded me of a very large construction site years ago - think it were Glaxo Stevenage - were during the winter there was always a fight over who got the bog nearest the heater cos the other ones were fooking freeeeezing

sorry carry on there

Does it run long enough to actually drive it? Or does it stop before you get it in gear? Or am I reading the post wrong? (wouldn`t be the first time I got hold of wrong end of stick). Could it be fuel starvation rather than an elec fault?

Hi. No its a fair question, I don't think it is fuel as I can rev it and it responds. If I let it go back to tick over it dies. Putting any pressure on the engine, steering or engaging gear causes it to stall/stop.

This is a bit early an engine for me and I don't even know if this has a crankshaft sensor but there's a thread only a couple before yours on a 4.0 dying after 30 mins. with a very positive answer.

If it's not a crankshaft sensor then the same basic idea would still seem to fit, something electrical/electronic heating up and then failing.

Hi dogsbody, Thank you for that, I have had a look, but as you say mine is a bit more stone age than that one. At the moment I am looking at the Coolant Temperature Switch and the Thermotime Switch, I have found that the wire snap clip is missing from the second switch so it is not a perfect closure. I will replace both switches and the cover, one at a time of course. If that cracks it I will post the outcome. If it doesn't then its back to square 1.

I have just returned from a great pay and play day at Sibbertoft where my 1988 Range Rover SE Vogue 3.5 EFI Auto with flapper MAF performed faultlessly - apart from the same problem that btbc192 has described.

The fault has only arisen since I had the car in for a tune (it was running rich). As far as I know the garage only adjusted the mixture and throttle position sensor.

The tickover problem only seems to arise when the car has been running at full operating temp for a while. If I then leave if for say 15 minutes then it will restart and idle smoothly until the engine has warmed up a bit more.

When the idle is erratic it will still drive smoothly as long as I am pressing the throttle - it runs fine then.

I have re-adjusted the throttle position sensor back to spec (290mV +/- 20 mV according to my Haynes manual) whereas the garage had it at about 380mV. This has not improved things.

In the past I have checked the coolant sensor resistance and that seems fine. My understanding is that the thermotime switch only affects the cold start injector when the engine is being cranked, so should not affect normal running?

It does seem that the retuning has caused the problem somehow, but any suggestions for a cure would be very much appreciated.

Pete

'stone age' I understood engines back then.

Have you tried the old trick of getting out in the pitch dark and sticking your head under the bonnet and looking for sparks.

O.K. I know it's how I used to track down faulty H.T. leads and cracked distributor caps on Ford Anglias etc. but it would only cost a bit of fuel and time.