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- Thread starter beefygeez
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njh
New Member
- Posts
- 366
- Location
- Sunny Dudley in the Dale.
More info.
Petrol/ diesel ?
Petrol/ diesel ?
eightinavee
Well-Known Member
- Posts
- 3,956
- Location
- UK.
This is almost always how a dying ECU behaves on a 3.5 Efi.
For me first culprit is the IAC valve is stuck. Ive had it twice already and it gives these symptoms...
Look at the motor and at the front just in front of the drivers side cylinder head is a alloy valve with two pipes going into it secured down with two 10mm headed m6 bolts (or were they 11mm's...), if you take this off and your lucky you can clean out the valve (ive used brake cleaner) and lube it up after (ptfe based lube) and check it moves freely. This fixed it for me for a while the first few times it happened.
What this valve does is vary open and closed to keep the engine at tickover , sort of like someone just covering the throttle by opening up the slide to air progressively and giving thus gives the throttle a little blip now and again, and when it sticks it misses that blip. Long term ive had to replace mine, but for quite a few months I had a really nasty short term bodge that consisted of a hole in the pipe leading to the iac that permanently allowed air in, size to keep the engine idling under most conditions was arrived at with carefull research (in other words I cut the hole bigger progressively until it idled). Lots of time it was too fast and it didnt raise the rev's for the extra load of the power steering pump etc, but it sort of got me round in a half assed sort of way for a bit.
9/10 your going to have trouble again with that valve as its getting worn, best long term cure is another good one...
Look at the motor and at the front just in front of the drivers side cylinder head is a alloy valve with two pipes going into it secured down with two 10mm headed m6 bolts (or were they 11mm's...), if you take this off and your lucky you can clean out the valve (ive used brake cleaner) and lube it up after (ptfe based lube) and check it moves freely. This fixed it for me for a while the first few times it happened.
What this valve does is vary open and closed to keep the engine at tickover , sort of like someone just covering the throttle by opening up the slide to air progressively and giving thus gives the throttle a little blip now and again, and when it sticks it misses that blip. Long term ive had to replace mine, but for quite a few months I had a really nasty short term bodge that consisted of a hole in the pipe leading to the iac that permanently allowed air in, size to keep the engine idling under most conditions was arrived at with carefull research (in other words I cut the hole bigger progressively until it idled). Lots of time it was too fast and it didnt raise the rev's for the extra load of the power steering pump etc, but it sort of got me round in a half assed sort of way for a bit.
9/10 your going to have trouble again with that valve as its getting worn, best long term cure is another good one...
eightinavee
Well-Known Member
- Posts
- 3,956
- Location
- UK.
The Efi system on an 88 RRcl does not have an IACV,all it has is a port which closes off slowly as the engine temp rises via heat from the inlet manifold,it is also heated electrically.The valve is a slow acting Bimetallic strip.
IACV's were not introduced until the Hotwire systems came out on 3.9 RR's.Swop the Ecu with a known good one before you start tearing into other things,its only 2 mins work.
IACV's were not introduced until the Hotwire systems came out on 3.9 RR's.Swop the Ecu with a known good one before you start tearing into other things,its only 2 mins work.
Ok, I stand corrected if its not a fast acting IAC, however, I did change out that part and it cured all my idle problems. Thats not bloke in a pub told my mates brother stuff, its what I did.
What is more I was put onto changing the piece by some other rangie classic owners who'd had idle issues when the fuel enrichment had gone off (ie the damn thing had got warm) and changing that out had fixed their issues too.YMMV, but it worked for me.
What is more I was put onto changing the piece by some other rangie classic owners who'd had idle issues when the fuel enrichment had gone off (ie the damn thing had got warm) and changing that out had fixed their issues too.YMMV, but it worked for me.
