Need some serious help please

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Sunfly
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Re: Need some serious help please

Post by Sunfly » Fri Jun 05, 2020 2:33 pm

jrh wrote:
Fri Jun 05, 2020 9:53 am
External coil details posted off to Tomcat yesterday.
That's it, I have no copies.
I was always able to get working spares for the '94 Probe so never had to resort to the external version but definitely the way to go.
Thanks Jon, I am really grateful for your help as always. I will get it copied as soon as I get the details and then speak to Trev about maybe posting it to the Oracle. I'm sure it will be useful to others.

On that subject I found the link to the Canadian guys resume' of the PCM codes very useful indeed, which is why I did the spreadsheet to get an overall picture of why I had a "Check engine light" even though after clearing the minor codes I had no codes showing. His page said that in Canada at least, after 96 the multi plug diagnostics changed from, OBD1 to OBD2 and thus I would not be able to read codes on my 97, not either with a diode nor an analogue multimeter. but only with a proper code reader. I don't know if that is the case with the British models? (maybe someone knows more) however the spreadsheet I did, pointed pretty compellingly to the CPS2 sensor and only CPS2 sensor, as I've changed the dizzy four times which must surely eliminate the internal CPS1. Though I wasn't keen on prodding around with the PCM circuitry,(I'm seriously colour blind so I cant see the wire colours so well) I made an appropriate disconnection and what do you think I found! Instead of 520-580 ohms across the sensor, I've got an open circuit on CPS2, even though I've got no 02 code (CPS2 failure) showing.

Certainly a CPS2 failure ticks all the boxes except the missing code so I have a new one on order which will arrive on Monday. I will get Paul at Berkeley Heath to fit it as arthritis aside, I don't have the lift, tools or time to do it myself. So fingers crossed that's the problem. If it is I will get things back to normal, then look into whats needed to fit the external coil to protect the dizzy in future. Bloody Probes...!

jrh
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Re: Need some serious help please

Post by jrh » Fri Jun 05, 2020 4:07 pm

Well done on your diagnostics, it certainly points to that CPS2 as being the problem.
Strange it should fail though , it only generates a 'pulse' as the 'blade' moves through the gap. Generally a pretty rugged device.
Fingers crossed.

Sunfly
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Re: Need some serious help please

Post by Sunfly » Fri Jun 05, 2020 4:34 pm

jrh wrote:
Fri Jun 05, 2020 4:07 pm
Well done on your diagnostics, it certainly points to that CPS2 as being the problem.
Strange it should fail though , it only generates a 'pulse' as the 'blade' moves through the gap. Generally a pretty rugged device.
Fingers crossed.
Quite so but it might be wiring just as easily as the sensor. Lots of mentions of the plug and socket in the garage of course, but the sensor itself is rarely mentioned. Might be a securing screw fallen out for all I know. I just hope against hope that its as simple as the CPS.

Sunfly
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Re: Need some serious help please

Post by Sunfly » Mon Jun 08, 2020 6:22 pm

Well, I'm very pleased to tell you all that the Flying Machine is flying again. It was indeed the Crank Position sensor. If you take a look at the photo you can see that it was rubbing on the tension pulley for the alternator, but that wasn't what stopped the car. It was an open circuit fault on the sensor itself, though having said that its highly likely the sensor failed because of a short between the sensor and earth, both being in contact with the pulley.

Image

Though its been a pain in the bum, I have learnt a lot about the car I didn't know before and I think the best thing I did was read the Canadian Guys brilliant blog about the effect of Probe 24v "Check engine light" codes on the car (there's a link further back in this post). I thought it was so useful as a diagnostic tool that I set out the symptoms of each code in a spreadsheet (also in this post) and from that there really was only one contender.

Though I'd considered the CPS, when I pulled the codes I got IAT and HEGO codes and some spurious codes but no 02 CPS code. However when I read his blog it was obvious that only two codes could stop the car from running, 02 and 04, but 04 - the slow cranking sensor is internal to the dizzy and I've changed that 4 times, so the 02 had to be top suspect. Then he mentioned that in 96, they changed the diagnostics from OBD1 to OBD2 and OBD2 cant be read with a diode, or analogue multimeter as I was using, so those two bits of info convinced me to suspect and measure the CPS. Instead of getting 520 to 580 ohms I was getting an open circuit so that would seem to be that. Off to hospital she went. £101 including parts and labour that I didn't think was too bad.

I've never heard of OBD2 fitted to a British Probe so maybe it was just Canada (He lived in Canada) but mine is very late (August 97) so maybe its a bit of a hybrid with an OBD2. Is that a possibility? If it is OBD2 then sadly, that means I wont be able to read the codes myself in future but at least I know the problem.

The other bit of red herring nonsense that confused me was the handbook stating that if you saw the engine light, the cause was the fuel shut off switch. Yeh that and about twenty other faults, Ford! Anyway, happy days because the FM is back in business and she will go to the Tewksbury Classic Vehicle Festival on Sunday August the 23rd. Hope you do too cus its a great show.

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Re: Need some serious help please

Post by cpt black » Mon Jun 08, 2020 6:33 pm

Great news there Bob,£30 part and shes away again

jrh
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Re: Need some serious help please

Post by jrh » Mon Jun 08, 2020 6:45 pm

Lovely news Bob, really pleased it's fixed.
Well done for pursuing the crank sensor as the reason for failure.
In the end though, that was 'mechanical' failure rather than any 'electronic' component and just shows how important it is to get everything back together perfectly.

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