Hello there my friend. i hope you're well.
I have a question for you regarding the wiring loom on the cosworth. I had a bit of a fettle with the cps plug, loom side, to increase the contact tension. It didn't cure my mis-fire, but it did have a lessening effect. So, I'm pricing up to completely replace the whole lot for new, maybe reusing the plugs, maybe not. I'll have to see how I get on unpicking the terminal ends.
The question I have is, There are 2 tri-core wires in the loom (if my memory is correct). 2 normal looking wires with the third unsheathed and wrapped around the other 2 under a larger outer (black) insulator. For the map sensor and the knock sensor I believe. What are they arranged like that for? Can I get away with using 3 seperate wires for replacing them, or do they have some kind of emf effect, or insulating effect for which I'll need to either re-use them or replace like for like?
Also, what grade of wires should I be selecting?
I'm looking at some 16 Strand Copper Conductors - 0.5mm2 11amp rated, which I think should suffice for about 85% of the thirty odd wires that come from the ecu. Am I right in thinking this, and what else do I need wire grade wise?

Hello.
Have found that I have some suspect wiring at the ecu plug end of the loom. The fuel pump isn't running at all now when the ignition is at pos 2. Thought it odd as I hadn't altered anything per say. Checked voltage at the pump, and now only getting trace voltage, .6 of a volt. So back into the passenger footwell to check fuel relay and ecu have proper connection. As I'm looking at the ecu plug, noticed a couple of inch back from the plug what looks like a glint of bare core through the insulation tape thats been added at some point. I think whilst I've been manipulating the ecu plug checking my sensor resistance figures, I've disturbed/uncovered some bodgy wiring.. I love my ford. I'm going to strip it back and try to get diagnose the rogue short or open circuit. Where can I get hold of a clear wiring diagram so I can check for continuity?? Could you send me one please? (If you have one at your disposal) my email is: bimbocom@hotmail.com (That address always raises a smile, which was the intention)
Again, I thank you Tabetha in anticipation of your help and advice.
Justin

You are doing the right things, as I eluded to, the L1 on 3 door and the L6 ecu on the 2wd sapph without a shadow of a doubt both prime the pump first thing, on these they need the cps signal, as to the 4wd ecu L8, I don't know is the answer.
I would be tempted to get some easy start, a helper and sparay it into the intake(throttle body) as you turn it over, this will instantly identify either ignition at fault or fuel at fault, it's possible but unlikely the cts would stop it, certainly can make it very difficult, but every dodgy one I have seen has gone mega rich.
If the pump is made so that it runs constantly, it may not be fired by the ecu, could just be aconnection off the ignition, so check main feed to ecu, the main power feed is on the loom near the fuel pump relay.
tabetha

Thankyou for your reply tabetha.

I think based on the wealth of other peoples wisdom that I've received in the last day, my fuel pump is ok. I'm advised that it's the 3dr cosworth that primes and stops the fuel pump before start up, and that on the 4x4 it does continue to run. Only the fact that my cars not starting first turn of the key have I been able to notice/hear it constantly running, and put 2 and 2 together and come up with Italian.
My red top saph just cranks over and won’t start.
In my investigation so far I have,
Ascertained that I have a spark, and fuel up to the rail.
Unplugged all the injectors, the air charge temp sensor, the distributor plug, the map sensor, the ignition amplifier and coil, the amal valve, the throttle position sensor, the idle speed control valve and the 3 large loom multiplugs which are on the bulkhead over the rear of the engine. All these plugs and their corresponding sockets have been sprayed with aerosol degreaser and dispersant, air line or air duster blown, and wiped with blue roll. definitely no moisture remaining in those parts.
I have removed, checked and cleaned out the dizzy cap and rotor (was clean really but trying to be methodical).
I have removed, checked and cleaned out the map sensor and ignition amp. Again, there wasn't really any sign of moisture ingress.
I have checked the leads and plugs (new items less than 300 miles old)
After cranking the engine, then whipping out a plug quickly, the plug is dry and there is no sign of injected fuel.

Due to the current position of the car (nose in on a gravel drive) I HAVEN’T been able to check the Crank position Sensor plug, (mainly as it’s a twat to get to) nor have I been able to get at the engine coolant temp sensor (reason as above).
I haven’t yet cracked out a multi-tester or a fuel pressure gauge as I was hoping not to need to go that far.
I’m wishing away my working day now, as I’ve been advised that the CPS could well be the culprit, and I want to get home and try and get the car jacked up enough to get under and check it isn’t somehow harbouring water in it’s plug.

I’ll also be checking the pump relays, thanks for the id. Ford said £19.01 for one relay, with a straight face

My question to you tabetha is; Does that sound plausible as a likely culprit? I only ask because in an earlier post you stated that the pump wouldn’t prime if the cps was faulty.

The fuel pump primes first thing, but also under certain other conditions which are time/temp related, it primes then stops, or it doesn't prime at all.
If it doesn't prime first thing in the morning something is wrong, a lack of cps signal can cause this, but so can the ecu, There is no harm in wiring it direct to the position 2 feed,(keeping it through the cutout).
The point about your non start is almost definitely the distributor cap, age old problem, inside the cap is nice and warm/hot, it is then blasted with colder water causing the moisture inside to condense, causing arcing/crossfiring/misfiring inside the cap, odd that it should do it the following day, but certainly worth a look, clean out with paper towel, spray with wd40 then dry out again, check inside ends of leads in cap also, but yes potentially could be water elsewhere.
The fact that the pump does not cut off in pos 2 with engine stopped suggest that either it has a sticky fuel pump relay, or the ecu is telling it to run, maybe the 4wd ecu is slightly different in this respect, maybe just tap the fuel pump relay or unplug then plug back in all the time whilst the ignition is in 2 without engine running, if tapping it stops the pump the relay is sticky, if it stops then restarts once realy is plugged back in then it is being fed by the ecu instructions to do so.
The relays are boggo std type a or type b relays nothing special at all, cheap enough if you need a new one.
tabetha

Hmm... I humbley retract my first post. Just spoken to someone more familiar with my car than I am, and the fuel pump's supposed to stay running, I just hadn't been aware that it doesn't make pressure then shut off til start-up, it just runs. I have been advised by a helpful bloke at Woodford Garages M.S. that it could just be water in either the ign. amp or the map sensor plugs or terminals. Do you concur with that view tabetha?

Ok, reading through your posts, it can't be cps as the pump is priming.. It doesn't stop though.
And have a spark at number 1 lead and plug to engine lifting eye, so phase sensor must be working??

Sorry, it's a J plate 91' Sapphire cosworth 4x4 in moonstone, Red top. 130 thousand miles, had a pretty good life too, not been abused.

Hi tabetha,
I have a 4x4 saph cosworth. On saturday I had it washed round lunch time, one of these hand wash places. Drove it home. Then used it again around 7pm, all fine. Tried to start it sunday pm, wouldn't go, just cranking. Sort of half fired once, then just turning over. Left it alone for a head scratching session. When I returned to it, I noticed that the fuel pump wasn't shutting off when I turn the key to position 2, before the start position. Does this likely mean a faulty regulator?
Pump does run.
Fuel is at rail.

Really would appreciate your thoughts. Have priced up phase & crank sensor, and fuel pressure regulator, and fuel pump but don't want to be shelling out if more likely to be something else. Many thanks in anticipation of your time and attention.

Kind regards
Justin Wilkinson