ECU repairs

[Muzzaa72]

Hi guys , my Elise has had intermittent issues with loss of battery charge, spluttering and erratic gauges /idling. It seems to happen after a couple of hours of driving when everything is nice and hot or if out for a spirited drive with lots of bumps and hard cornering . Anyhoo, I have no idea where to send the ecu for repair. There seems to be a fair few online companies but am wondering if anyone else has sent an ecu away for repair ? Any advice appreciated as car has had New alternator , crank sensor , mfru and immobiliser bypass. The problems did however start after New alternator was fitted . The new alternator has been subsequently been load tested just to check not dodgy. This is why I am thinking the ecu is maybe not telling alternator to charge...Cheers ,m

[2F45T4U]

It does sound alternator related.. load testing is one thing but if the regulator is dodgey and youre not getting a nice rectified output it could be causing funny things to happen in the ECU

Try phoning Peter
http://www.remmington.info/test.html

Ive not had an ECU tested by them but ive spoken to him about inverter TIG and dyno repair and he's very helpful. He may even be able to help if you describe the symptoms.

[robin]

The ECU doesn't tell the alternator to charge on an S1 (or an S2 K, IIRC - probably does on S2 Toyota).

If your car has the B&C chip fitted to ECU that could be a cause, but it wouldn't be my first port of call. A stock Rover ECU is very unlikely to have any fault of this type (remember they made millions of them).

I would be looking for the battery moving and the leads touching the chassis. I would also check earth continuity front to back (both the forward and rear earth straps can corrode away - they might start to make intermittent contact). Often the battery ends up being loose on S1 because the crappy bracket that holds it in falls apart over the years/people fit funky batteries/stuff it in with block of wood/cardboard/etc.

Please be careful when using tools in the services compartment - it is quite easy to connect the battery live terminal to the chassis ... if you do that while the battery earth is still connected you will be lucky to end up with just a burn. Best plan is to disconnect the battery earth terminal first, then you're pretty safe. Also make sure you don't reconnect leads backwards as the ECU does not like that!!

There is a common live stud at the rear - later cars have an extra wire to feed current to ECU from battery - but old cars could suffer from voltage drop at that stud (though usually during cranking rather than running) - still it's worth checking the power stud on the back of the alternator and the earth stud near the ECU corner of the engine bay if I remember correctly.

Cheers,
Robin

[robin]

ps if disconnecting the battery be sure to disarm the alarm just before taking the cable off - otherwise it thinks you're trying to steal the car and goes mental

[Muzzaa72]

Cheers for the help guys . Will start having a look into those things . The car has spent a bit of time in a specialist where they have been checking replacing a lot of earth straps and continuity front to rear. A part of me really does think I have been unlucky with the new alternator and there is something wrong with the regulator but the garage is so certain that it is fine. I remember hearing my old one whirring away all the time but this new Elise parts one intermittently whirrs and it doesn't charge very strong either....max I have seen is 13.5 volts and with all lights on the voltage drops away slowly. And that's with a new battery ! Cheers, m

Sent from my HTC One_M8 using Tapatalk

[campbell]

Is it an Eliseparts "race" alternator?

[robin]

Measure the voltage from the stud on the rear of the starter motor to the engine block while the engine is stopped, then again while it is running.

Cheers,
Robin

[2F45T4U]

Agreed. charging is completely separate to the ecu/engine running so either there are 2 different issues here, or the alternator/lack of charge is causing rough running.

Either way, you should get to the bottom of the charging issue first.

its a conventional charging circuit, switched live for excitation (thin), then a high current charging wire (thick) straight to the battery (via the starter motor post)

Check all the points for corrosion, and check there is good continuity between the alternator and the block, If the new alternator is mounted on rubber bushes then fit an earth strap.

[Dominic]

Any updates Murray?

[Muzzaa72]

Soooo the saga continues... Sent ECU away for repair to Peter Remmington (nice chap and really knows his stuff! thanks for the tip!) Turns out the 5v ref line was shot and fried part of the ECU which he has now repaired. In doing the repair he found that the ECU was a remanufactured one that had been put in before I owned the car. The annoying thing is that the car is supposed to be a B&C 140 however the ecu had a standard map so when the previous owner replaced the ecu or (and this is probably what happened) the garage which replaced it (one in Aberdeen) found the ecu was faulty, they replaced it with a cheaper remanufactured unit which therefore lost the B+C chip and performance map...... am a tad raging but it does explain why the emissions have been poor ever since that repair was done as it can be traced quite well with all the MOTs. Am guessing a standard map with uprated cams etc doesn't do much for emissions?

Anyhow, got the ECU back and car is currently with Ken Brown (who I feel really sorry for because he has been banging his head off the wall with this car) and he put everything back together and fixed the loom. Upon testing, the car suddenly started loosing charge, at least while he was watching with volt meters, so he killed the engine and power to protect the ecu. After a bit of diagnostics he found that the new elise parts lightweight alternator (which was fitted at the beginning of this saga because my old one had bearings that were a bit gone) has a rogue diode or something along those lines.....which explains why there was intermittent charge/electrical issues and also why it passed the load test when we originally suspected and discounted the new alternator from being the route of the problem. When the alternator finally died it sent a spike to the ECU hence why it was fried....

Soo basically the new alternator shagged the electrics in my car and has cost me over £700 so far in repairs..... Ken has sent the alternator for full testing to confirm the cause but where does this leave me with elise parts???? Should I ask for money back if the alternator has caused a perfectly functioning car which was undergoing routine/preventative maintenance to die? I am waiting for exact proof before speaking to them but I would have thought they would be receptive to the idea of compensation given one of their products has caused damage and left me at the side of the M8.

Oh and I am sending the ECU back to Peter once we know the car is ok to get the B+C performance reinstated. Really hacked off about that because I was actively looking for a B&C when I bought the car and have lost a little faith in the provenance again. All the Dyno graphs etc supplied with the car are a load of crap now.... Although having driven along with more powerful cars it manages to keep up so there must be something different in it....

[Muzzaa72]

Is it an Eliseparts "race" alternator?

Hi Campbell,

yup it is the elise part 'race alternator' ...figured it couldn't hurt....at that point

[Muzzaa72]

Agreed. charging is completely separate to the ecu/engine running so either there are 2 different issues here, or the alternator/lack of charge is causing rough running.

Either way, you should get to the bottom of the charging issue first.

its a conventional charging circuit, switched live for excitation (thin), then a high current charging wire (thick) straight to the battery (via the starter motor post)

Check all the points for corrosion, and check there is good continuity between the alternator and the block, If the new alternator is mounted on rubber bushes then fit an earth strap.

Cheers! ye Ken fitted a tonne of new earth straps as a few were shot and he added some more around the alternator for good measure

[Dominic]

Jeesus, what a total PITA. At least you are now further down the road to solving the problems.

When you have the results of the alternator test, I would get in touch with EliseParts. They have always been reasonable to deal with for me, and sorted a few minor issues with parts I have had - albeit on a much lesser scale. Hopefully they will be reasonable about it.

[Muzzaa72]

Had the proof, it has been a problem with the new alternator. Spoken to elise parts and they are arranging a new one to be tested and shipped asap. I will then ship the faulty one back and I guess we take it from there whether some compensation is necessary to help me out with the repairs I have had to get to the ECU. The only fear is that the ECU took another hit from the alternator after being repaired. Think I will send it back to Pete to get it checked anyway.

[campbell]

Oh dear. Progress, though

A Sabre Head would be a neat alternative to the B&C "140" spec...