RS500 Running problems. Any ideas?

[andymann]

Recently developed slight erratic running and flat response, narrowed down to MAP ( manifold absent pressure sensor) sensor. Changed unit for new, engine now quite smooth, however on starting from cold I can only get exactly 1 mile before I loose all power, engine revs stick at about 3,000, drops to 600rpm no power, engine coughs and splutters for about 10 secs then recovers and is fine to drive for as long as u want. If starting from warm no problem at all? I suspect maybe the manifold cold inlet valve or the ECU, maybe fuel filter? Anyone else out there able to shed any light on this?
Had the injectors ultrasonically cleaned and filters changed. Bloke that helped me out now thinks it is the crank sensor or the phase detector under the distributor cap. Any thougts on which one to change first or just do them both as ajob lot?

14 june 04:RESULT Changed both units (ECT (BLUE) water temp sensor and Air charge sensor (BROWN) on inlet manifold as advised by Simon at Woodford garage (Totnes). Instantly cured the snag "what a top bloke"

>>> Edited by andymann on Friday 11th June 20:03

>>> Edited by andymann on Wednesday 16th June 11:39

>>> Edited by andymann on Wednesday 16th June 11:43

[andymann]

Mikey G said:

I have heard of a similair problem before. could be water temp sensor? i think there is a secondary temp sensor on the Cosworth engine specifically for cold running. could also try the fuel filter as you suggest, would change this as a matter of course anyway. Hope you sort it

[andymann]

Mikey G said:

I have heard of a similair problem before. could be water temp sensor? i think there is a secondary temp sensor on the Cosworth engine specifically for cold running. could also try the fuel filter as you suggest, would change this as a matter of course anyway. Hope you sort it

thanks for the tip

Regards Andy

I'll let u know

[andymann]

deltaf said:

Have you erased the ecu fault code memory too? Just a thought.... hth.

Could't monitor fault code last time as the MAP sensor was duff. got a mate coming round tommorow to take another look.

Regards Andy

Will let u know, if I find IT??

[andymann]

nighthawk said:

The Rs used a weber marelli system to control the fueling and ignition. Has/is your 500 running any mods and are all 8 injectors connected? coolant temp sensor might be a possible, and indeed it's one of the easiest and cheapest to replace. RS 500 didn't have a MIL to show the presence of faults in the system.

Have spoken to woodford Garage in devon (Via Passionforfords.com)Simon, who was spot on for tech help and has been fixing cosworths for the last 15 yrs. He believes it is almost definately temp sensor you descibe which can cause an intermittent fault like i am getting and affects the ECU causing temporary short cct/open cct conditions but only at certain temps if defective and i need to change this unit first as the phase sensor is perfect with no broken insulation at all. Thanks for the tip