THE ROVER SD1 FORUM

mentalmason · SD1 User Joined: 30 Jun 2008 Posts: 3

hi guys wonder if any one can help, ive just bought a c/86 v/plas efi, converted to manual, it has a rovertec adjustable ecu, when the car first starts its fine but as it wams up at about 2000 to 3000rpm there is a slight missfire? it has had new cap, leads, rotor arm, and plugs, the other day i plugged in a standard ecu number prc 7440 and it really spluttered about at 1000rpm to 2000rpm? so if any one can throw some light on this i would be most gratefull!!!!!!!

ramon alban · Posted: Wed Jul 09, 2008 2:37 pm Post subject: Re: rovertec ecu?

mentalmason wrote:

hi guys wonder if any one can help, ive just bought a c/86 v/plas efi, converted to manual, it has a rovertec adjustable ecu, when the car first starts its fine but as it wams up at about 2000 to 3000rpm there is a slight missfire? it has had new cap, leads, rotor arm, and plugs, the other day i plugged in a standard ecu number prc 7440 and it really spluttered about at 1000rpm to 2000rpm? so if any one can throw some light on this i would be most gratefull!!!!!!!

Hello Darren,

The PRC7440 ECU comes out of a Range Rover which probably requires a Lamda input that your Efi system does not support. Not to say it will not work, some do, some don't.

Check out this research I did, including 2 PRC7440's, on my TP Vitesse:

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I can't explain why I got acceptable results on one and not the other as I curtailed the experiments.

This begs the question as to whether the Rovertec ECU is suitable for your SD1 Efi system too. It may have been designed/modified for a different application.

Certainly your SD1 Efi system was designed for a standard Vitesse 4CU ECU, so unless you have some knowledge as to how/why it came to be in your car you might expect some misbehaviour.

Also one needs to know how the ECU adjustments are supposed to be made and monitored for normal behaviour.

Pity they dont come with instructions. Rolling Eyes

Now, down to the nitty gritty, it may not be the ECU that is faulty, all the other components must come under equal scrutiny.

At a guess the fault you describe with the Rovertec ECU fitted sounds like it may be a throttle pot issue, which you can review here:

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Also it may simply be an air leak or an intermittant wiring problem that only manifests itself when the engine is hot.

Have a look at all the other stuff on my website regarding Efi components description and diagnosis, test programs, air leaks (the Plenum essay) and electrical fault-finding and you have the basis of a a fully comprehensive test process.

Let us know if you need more info.

And good luck with your new car.

_________________
Ramon

mentalmason · SD1 User Joined: 30 Jun 2008 Posts: 3

hi ramon, many thanks for the reply, i will look at the links you sent and let you know, its going into a freinds next week for a rolling road tune and general sort out so will see what the come up with, will let you know the outcome!!!!!

regards darren