1.1 Fiesta - Engine cranks, but won't start

Check the Crank Position Sensor first, if the ECU doesn't get an all clear on this circuit it won't prime the fuel pump.

power the pump separately and see if it works

The CAS circuit must be good for the ECU to prime and run the pump. Open or short and it wont.

Ground the pump relay to make the pump run and try cranking the engine is also a double check for a faulty CAS.

Tim..

Wow, 3 great replies all in the space of 1 hour on a Saturday evening!

I must come here more often!

I have more reason to suspect the CPS as this is in the vicinity of the clutch lever - the cars clutch cable had snapped after only 3 months use since the last one snapped. It turned out the original cable had sawn through the retaining bracket at the firewall - part of the clutch pedal abutment bracket.

It was a right pig of a job to fix, seats out the car and all. In the end I had to convert over to a manual clutch adjustment mechanism, involving the new bracket, pawl, adjuster screw, and a new clutch pedal!! All because Ford no longer have the old abutment bracket with the pedal stop for the auto adjuster mechanism.

I believe the problem was my old dad who insisted on connecting one end of the cable to the pedal quadrant first, and then using a crowbar to jenny the clutch lever to the cable. I know he slipped a few times, my guess is he dropped the crowbar on the CPS!

Well, I'll find out tomorrow if its damaged or not, and keep you posted. What kind of resistance should I read across the CPS?

I didn't try powering it, but did get a resistance of just over 10 ohms out of circuit, which would indicate the pumps coil is not open. However, no matter if the pump is working or not - I should still see the ground signal from the ECU at the relay coil.

in proper condition the cable can be pulled back with fingers or pliers to connect it. probably it was looped the wrong side of the bracket.

cps 200 - 450 ohms

mrcheerful

Ok, I measured the resistance of the CPS / CAS, and also verified its wiring was ok, by taking the reading at pins 5 and 6 of the EDIS connector (unplugged of course) and got a reading of 260 ohms which is within range.

I then tried grounding the fuel pump relay and sure enough the pump worked. Cranking the engine still wouldn't start the car, but at least I could smell petrol.

Could the CPS still be buggered even though its resistance seems ok? I'll go looking for one in a scrapyard I think...

Any other ideas?

I'd prefer to measure output from the CAS duiring cranking than try to decide whether its good or bad from a resistance check.

Look for at least 3v AC during cranking.

The fact that you smell petrol from the exhaust means that the injector is firing (it is yes?) which means the signal from the CAS is good and that the ECU is receicving the signal, but not necessarily that the EDIS unit is healthy.

Injection should equal spark- check the coil pack next.

Tim..

Right - I checked its voltage during cranking and only got 1.4 - 1.6v AC - would this be a definite fail?

I think the petrol smell was simply because I've got the air cleaner removed and the bonnet open and could smell the petrol being primed to the CFI unit.

Hmm... how to check for spark without the right gear - undo a sparkplug and rest it on the engine looking for fireworks?

Doh!!!!

After all this I asked my Dad to make sure he had strapped all the earths to the negative of the battery which he insisted he had. I took a look and one of the three earth straps was loose!

Reconnected it and everything is working again!

Most embarrasing - still I got to learn a bit about the Ford fuel pump and ECU, I'm sure it will serve me well in the future.

Thanks for all your help!