The V8 Owners Forum -

Hi guys,

My RRC 3.5 EFI 1989 started running very bad on gasoline (irregular rpm) and it just goes down and shuts when I try to rev it. It runs smooth and faultless on LPG though, so I'm prone to think the engine is overall ok.

I personally believe it may be due to faulty injectors. 3.5 injectors are different from the more common 3.9 ones, and it is quite a challenge to track them down and buy some.

I finally found these 3.5 LUCAS fdb 313, which seem absolutely identical to mine, but have a different part number. Unfortunately I was unable to get them (lost the auction).

Any advice on where to find 3.5 V8 EFI injectors up to model year 1989?
Any help would be really appreciated.

Thank you in advance!

Can you get the old ones tested locally? That might be better because if you buy some more 2nd hand ones, they too could be damaged.

Chris.

I'd say it unlikely you have several faulty ones. They can dribble and have a poor spray pattern - but that normally makes the biggest difference to low speed running. You could easily check for a burnt out one by measuring the resistance - and also check the resistor pack. You could also check for operation by unplugging the ECU and grounding the feed each one in turn - you should here it click.

Could it be fuel pump gone, then?

I think so... it seems unable to provide enough fuel pressure...

FurtherSouth91 wrote:Could it be fuel pump gone, then?

I think so... it seems unable to provide enough fuel pressure...

Disconnect the cold start injector hose and insert a pressure gauge (you can adapt a tyre pressure one at a pinch)

You should see about 36-38psi engine stopped About 28psi at idle.