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4561

Omega General Help / Re: ABS fault persists - do I scrap car?

« on: 08 May 2013, 22:57:01 »

Hi Sassanach, thanks for you reply. Apologies for not collecting my message, I am new to the intricacies of the OOF, but am learning. Funny no-one answered the phone. Thanks for the message.

I am not sure of the actual value of the resistance of my sensors, they fall between ranges. Main point is they are all about the same, so it's a mystery that the Tech2 could not see the front right sensor, because it was the same resistance as the other three sensors, and it was connected through to the ECU socket. Where I go from here I do not know. Sleep on it perhaps.

4562

Omega General Help / Re: ABS fault persists - do I scrap car?

« on: 08 May 2013, 18:05:11 »

Hi Kevin, thank you for your thoughts. I did check pins 4 & 5 at ECU connector, as advised, and these indeed did show 700 ohms, and when I unplugged front right sensor to loom connector they went to open circuit. The Tech2 had said it could not see front right sensor. I saw no reason to doubt the other sensors were connected OK.

I cannot imagine why the wheel sensors should record different speeds if they are working at all. The tyres are an assortment, all nominally 205 65R15. I have run on assorted tyres for years in all my cars, including mixing sizes on occasions, without ever upsetting the ABS systems.

As suggested before, I wonder if it is worth while swopping the ECU again (the one now in the car is the original one) and asking the Tech2 what it sees then, with a different front right sensor and a different ECU, and having established connection between front right sensor and the connector socket, and having different aluminium wires from ECU connector plug to PCB.

4563

Omega General Help / Re: ABS fault persists - do I scrap car?

« on: 08 May 2013, 17:41:47 »

Hi ex taxi al. Sensible question, but, sadly, all tyres are 205/65 R!5s. Worth checking.

4564

Omega General Help / Re: ABS fault persists - do I scrap car?

« on: 08 May 2013, 14:48:04 »

Thanks Kevin. I agree it needs competent diagnosis. I simply cannot think how to get one. I agree the fault must lie in the ECU, a sensor, or the vehicle wiring. The ECU I substituted was not bought from a scrap yard, I removed it myself from a car I scrapped last June after a failed water pump wrecked the engine; the ABS was working perfectly then so I assumed the ECU was OK.

I recall you suggested I should take the Tech2 man for a drive and let him compare sensor inputs. I doubt he would do that. I could put back the substitute ECU, then go back to him with different ECU and right front sensor and get a new Tech2 readout. Would that help?

4565

Omega General Help / Re: ABS fault persists - do I scrap car?

« on: 08 May 2013, 13:20:50 »

Have just fitted a used front hub with ABS sensor. ABS light stays on, after 2 mile test drive. Is it ECU after all? Could it be nothing else?

Is there any point in putting back the other ECU?

 

4566

Omega General Help / Re: ABS fault persists - do I scrap car?

« on: 06 May 2013, 12:14:36 »

Thanks Andy H. You could be right of course, though it seems unlikely that  a spare ECU of good history should demonstrate a similar fault. I suppose I could swop ECUs between cars, but my only other 2 litre manual R706FHD is the spare car I gave to son Jonny while I prepare his for MOT. He lives 20 miles away. I forget how much ECUtesting charges for a 'test and find no fault' service. I suspect it was £100, same as for a repair.

I still have on the bench the ECU that I exchanged before. If I swopped that with the ECU in R706FHD that would settle it.

4567

Omega General Help / Re: ABS fault persists - do I scrap car?

« on: 06 May 2013, 10:53:35 »

Good thinking, ex taxi al.

This morning, bank holiday, at loose end, I decided to reassemble using my old repaired front sensor. On start up the ABS light came on, then went out. I backed car out of garage, parked, and went indoors to change to go for a long test. Turned car round, ABS light came on again. Bother.

Any opinions? What should I do next? I can now change the sensor easily, but can I get one cheaply? They are not listed in Trade Club book; I bet they are expensive. I can get a right front hub with sensor for £26 on e-bay and fit that. I could go back to Downside Motors and have a second Tech2 reading. Please advise.

4568

Omega General Help / Re: ABS fault persists - do I scrap car?

« on: 05 May 2013, 21:10:38 »

Thanks Albitz.
 I have now cleaned up the hub and the sensor hole to receive my spare sensor. The old sensor consists of a coil of many turns of fine wire with a permanent magnet down its centre and a pole protruding at either end. The reluctor ring end pole is located very close to the steps in the reluctor ring, and is as wide as the gap in the teeth of the ring. I must work out how that creates an alternating current of frequency matching the  wheel rpm.

4569

Omega General Help / Re: ABS fault persists - do I scrap car?

« on: 05 May 2013, 15:21:34 »

Thank you for your support Gentlemen. You were right, of course. I have now removed the sensor, it came out in three pieces. I am now cleaning out the hole to accept my spare sensor, though I am not sure why. My spare is one I tried to get off an explod car with an ABS fault. It came out damaged. I have glued it back together again, but am not too confident in it. As I seem to be betting the farm on this sensor being the problem, it has to be a good one. On e-bay there are lots of rear sensors, but no front sensors. We all know why. The only front sensors come complete with front hubs.That is the way I shall have to go.

4570

Omega General Help / Re: ABS fault persists - do I scrap car?

« on: 05 May 2013, 11:50:06 »

Thanks Shackeng.

I now have the hub off the car. As advised last Friday by my best friend, Ray Hardcastle. aged 83 and now sadly dying of cancer, I put a hacksaw cut  across a diameter of the screw, hammered the hub body where the screw enters, and applied a screwdriver to the screw head - and it turned!

However, with the screw removed, the sensor is still stuck in the hole. I have applied WD40 and am giwing it half an hour to seep through.

Comments invited.

4571

Omega General Help / Re: ABS fault persists - do I scrap car?

« on: 05 May 2013, 08:35:43 »

Thanks Kevin. The guy with the Tech2 was a generous sales director of a local Vx dealership. I go along occasionally when I am in trouble and he takes pity on me plugs in his Tech2 and tells me what it reads. In this case it said right hand front sensor not present. It's still puzzling, because it is still there, and is not open circuit, about 700 ohms, same as all the others. More puzzling is that when I plugged spare sensors into the RHF socket the ABS light remained on. But maybe the car has to move before it accepts a new sensor and turns its light off. I am under the impression that the front reluctor rings have no way of misbehaving, unlike the rear rings which have.

The front right sensor is now the chief suspect. Pity its stuck in.

4572

Omega General Help / Re: ABS fault persists - do I scrap car?

« on: 05 May 2013, 08:22:51 »

Thank you dbug. I did not know that. I cannot see how I should have divined it. Perhaps the envelope symbol and the talk of PMs should have told me.

4573

Omega General Help / Re: ABS fault persists - do I scrap car?

« on: 05 May 2013, 08:15:47 »

Thanks Webby the Bear for that splendid demonstration of the easy out. I know them as screw extractors. I have used them in the past, the tricky thing can be drilling the hole in the screw centrally and as big as possible. I have two boxes of them on my garage shelf, missing the smallest extractors that I have broken off. I have found that if the head breaks off the screw or the hexagon rounds it is because the thread is rusted solid. then the only solution is heat.

4574

Omega General Help / Re: ABS fault persists - do I scrap car?

« on: 04 May 2013, 22:23:00 »

Thanks for the thought, Webby the Bear. No, I have not get it out yet. What is an easy out?  The screw appeared to be an internal allen headed screw.  I hammered in an Allen key, turned until I rounded the allen hexagon. When last I had a similar problem the screw came out all tight but the sensor was stuck in. I suppose I might do better if I take the hub off and work with it on the bench. Then I could get hold of it with a Stilson wrench. I could also heat up the hub casting. That would probably release the thread, but cook the sensor, which is suspect anyway.

Sassanach has offered me a spare hub he has, but communication is proving difficult..

No I have not checked the voltage on the sensor. I presume there are 12 volts across it, provided down the cable from the ECU. Would it help if I checked the voltage? I presume one side is earthy and the other +12volts.

4575

Omega General Help / Re: ABS fault persists - do I scrap car?

« on: 04 May 2013, 21:22:02 »

Thanks for the advice dbug. I have registered to send personal messages, but sassanach was not a registered recipient so I failed to contact him. Having announced my details anyway, I thank sassanach for his offer and appeal to him to make contact.