3.5 efi V8 - cold start?

[BigSi]

Does anybody know about the ‘cold start’ on a 1986 3.5 efi V8 (from a Range Rover)? Apparently it’s the reason why the engine is a little irate when first started, but sorts it self out when warm. Has something to do with the automatic choke?  

It’s a Landrover 90, but with a Range Rover engine…….so what section do I use!!!!!

[Range Rover Blues]

IIRC the flapper system had an extra injector on the driver's side of the plenum.  Is this what you mean?

[BigSi]

Not sure? Had a guy look at it and said that the seal was ok on the plenum, but said that the fault was with the cold start as the choke was automatic. Hence why it runs rough when first started, but settles down when warm.

[Range Rover Blues]

I don't know the early flapper EFi as well but if I'm right and there is a 9th injector then try diconnecting it.

Otherwise I'm not sure but I can recomend a read through the Range Rover Haynes book of confusion.  The entire manual is in the suppliment mind you but it has quite a bit of detail on the EFi systems.  the flapper was never fitted to any other LR product AFAIK.

[jjsaul]

If you have flapper with 9th injector just unplug it...done that on both of mine and i have no problems with it at all.

[Coastcard]

As JJ above. You can just disconnect it (top drivers side of plenum - blue connector usually) to see if it makes a difference. If not then check all hoses and that you are running original dizzy cap, rotor arm and NGK plugs as RV8 is sensitive to these.

There is an Extra Air Valve on the front drivers side of the plenum chamber. Check its hoses and wiring connectors. This only opens during startup until warm, so could be relevant.

Other potential areas to check for this kind of issue is the temperature sensor behind the thermotime switch (that connects to the extra injector above) on front passenger side of the inlet manifold (check the wiring as well). This tells the ECU the engine temperature and as such will regulate fueling.

Plenty of diagnostics manuals on the various forums for flapper efi which will show in more detail where these things are and how to check.

Check all the basics (hoses, wiring etc.) first though or you could run round in circles.

Hope this helps.

[BigSi]

Thanks guys for the great info. Looks like I know what I'll be doing this weekend.......but then again, Isn't that what weekends are for!!!!!  :lol:  :lol:  :lol:  :lol:

[BigSi]

Some of you mention a ninth injector for the cold start system. Is this why there are nine points on the distributor cap? If say one of the terminals wasn’t making contact, for example the ninth injector, would this have any effect on my cold start problem?

Removed the blue plug on the top of the engine (2 pins inside), made a little bit of difference. After about two mins, it settled down and was fine (even leaving it for an hour).