SUPERCHARGER ECU QUESTION ???

[Tony jinxy froude]

Ok, Nigel & myself have been trying to help a MK1 owner, she's an elderly lady who has a really nice SC, its an Automatic & due to a fault in either the ECU or dizzy she has been unable to drive it for the last 4 years, she has now managed to find a dizzy but the ECU is causing a small problem.
Ok here goes, the number on her ECU is 8966 - 17180 (175000 -0931 is the number underneath )
Kev Crazylegs has an ECU on the shelf which came from his sherwood SC Auto but the numbers on that are 89661-17110 (175000-0820 is the number underneath ) now these are both auto's but is there any difference in the ECU's apart from the numbers & can Kevs be used ??? .Over to the regular SC squad for assistance on this one , cheers, Jinxy

[JMR_AW11]

Ok, Nigel & myself have been trying to help a MK1 owner, she's an elderly lady who has a really nice SC, its an Automatic & due to a fault in either the ECU or dizzy she has been unable to drive it for the last 4 years, she has now managed to find a dizzy but the ECU is causing a small problem.
Ok here goes, the number on her ECU is 8966 - 17180 (175000 -0931 is the number underneath )
Kev Crazylegs has an ECU on the shelf which came from his sherwood SC Auto but the numbers on that are 89661-17110 (175000-0820 is the number underneath ) now these are both auto's but is there any difference in the ECU's apart from the numbers & can Kevs be used ??? .Over to the regular SC squad for assistance on this one , cheers, Jinxy

Here's the insides of a 89661-17110 ECU if you want to do a quick compare. It's the one Toni sold me a few years ago.

My guess is that the 17180 ECU will look the same except the numbers on the big chips in the RH corner will be different. Also, there may be changes to jumper links etc.

The different numbers on the chips mean slight differences in program code and mapping but you probably wouldn't notice (assuming the ECUs are otherwise swappable)

If the 17180 ECU really is duff, I'll still buy it

Do you get any error codes from it?

Denso ECUs are normally pretty bulletproof...

[Tony jinxy froude]

Hi Jeremy, the error codes are all over the place on this car , do you think Kevs ECU will work then seeing as they are both Auto's ? or am i going to have to find the exact right part , Jinxy

[JMR_AW11]

Hi Jeremy, the error codes are all over the place on this car , do you think Kevs ECU will work then seeing as they are both Auto's ? or am i going to have to find the exact right part , Jinxy

If it has the same pinouts and it has (exactly) the same circuit board as the one above (apart from the ref numbers for ROM code on the big chips) then it should be OK.

Best to ask on Mark and Lauren's SC forum. They might know this ECU already.

What do you mean by error codes all over the place?

Does it just flash erratic 'disco' codes?

[Tony jinxy froude]

Cheers Jeremy, the problem with that is that the ECU is still in the car , the car is not local & neither is Kev,s ECU so it will be a bit of a nightmare getting kevs one only to find it may not work with the car , cant get into Laurens exclusive club, dont own an SC , Jinxy
P.S yes disco lights is one way of describing it it flashes a 1-5 code from memory the constantly flashes all the time without a break .

[JMR_AW11]

Cheers Jeremy, the problem with that is that the ECU is still in the car , the car is not local & neither is Kev,s ECU so it will be a bit of a nightmare getting kevs one only to find it may not work with the car , cant get into Laurens exclusive club, dont own an SC , Jinxy
P.S yes disco lights is one way of describing it it flashes a 1-5 code from memory the constantly flashes all the time without a break .

I just looked on the SC forum and someone has linked to this thread already so you may get some help soon.

If you get really really stuck due to location etc she could post me the ECU to look at.

I've got a pile of SC ECUs (but not a 17180 )
and I can also plug the ECU into a jig and test it as if it is in a car.

(so I can watch the ignitor signals and also the injectors running etc)

I wouldn't rule out the possibility that the ECU is not actually faulty though.

Best to wait for someone from the SC forum to offer a bit more experience.

If the car was running OK and nobody dicked about with the electrics/wiring before the fault then I would be amazed if the ECU was the problem.

Try checking all the earths on the ECU connector. Also the earths on the engine?

Maybe it could be a bad earth...

[crazylegs]

so whats the difference between manual and auto ? if its none the price may have to go up

[Tony jinxy froude]

Cheers Jeremy, im hopeing someone on the SC forum will pick up this post & give me a difinitive answer as to weather i can use Kevs one or not because they are totally different ?. If that cant be established, then i may take you up on your offer & have you look at it & put it through your test rig if you dont mind . Ive checked all the earths on the car & all seems ok.
When we looked at the car, the engine would spin over but not fire up, there is power to the coil terminals but nothing from the coil to the king lead, we have also changed the ignitor pack & inner wing resistor pack to no avail, i then phoned Paul Woods who said told me to go through a series of tests, after this he concluded that it could be ECU or Distributor, if the dizzy is at fault, then its not sending a signal to the ECU & onto the coil pack hence no spark, if its the ECU at fault then the dizzy cant get the signals to the ECU & onto the coil. My money is on the Coil too, but cant go there empty handed & start any work until ive got both components with me , i'll give it a few days & see if i get anywhere, then i'll be in touch Jeremy . Kev , there is definately a difference in the Auto / Manual ECU's for the SC, something to do with torque readings, different sensors on the Auto gearbox selectors etc to stop you starting the car in gear & many more, so ner , Jinxy

[shish]

if they are both auto ecu's then i cant think of any reason why it shouldn't work...

not sure if you can use a manual ecu on an auto, i know you can do it the other way around though... but iirc some of the timing is different, maybe to stop it stalling and maintain correct idle /justguessing

[tonigmr2]

You can definitely use an auto ECU on a manual - I remember a guy who did that but he had to trace the pin outs. Other way round is difficult though because of the ECT stuff I'd suspect.

Anyway like Mark I'd be very surprised if it didn't work - and I'm assuming Kev's ECU still has the ECT unit attached so the whole thing is replaced??

If you get stuck I've got another auto SC ECU sitting here, in fact might go and have a look at the numbering.
T

[System-G]

There is a thread started up on the SC forum pointing people this way.

I don't know enough about the electronics of the ECU's to be able to comment. I was going to say Jeremy is the man for it... But he's already posting

EDIT: took about 20 minutes to post the above as am at work... I see others have already caught up...

[crazylegs]

probably still got the coil as well somewhere.

[JMR_AW11]

I just had a quick look through the code for a typical SC ECU and the fact that it can still flash some kind of code to the lamp is quite significant.

The SC ECU uses a 42pin MCU chip which means it is starved of control pins compared to the 64pin chip used on a mk2 MR2 ECU.

So it uses a simple I/O expander chip to get some more control.

The DIL IC in the top RH corner is a serial to parallel chip TD6335 and it uses this chip to control stuff like the SC relay, the signals to the ECT unit and also the W lamp for flashing codes. (it provides 8 output lines)

The MCU chip talks to this S2P chip using a firmware defined interface on its port pins.

So the fact that it can respond to the paperclip link in the diagnostic connector and clock out flashes means the MCU chip must be running to a fashion in order to be able to control the S2P chip.

The code/system for generating error codes and for flashing them out is pretty low level so it's quite worrying if it is getting this wrong.

All error code bits are stored in duplicate (mirror) format and the ECU is coded to reject any duff codes that don't have matching mirrors and it won't flash them out.

Any codes that get rejected get wiped and replaced with the default 'no error' condition under the premise that any genuine errors will quickly get detected again and stored correctly as mirrored pairs. The ECU housekeeps the error codes dozens of times a second so there's not much chance of it holding a duff error code for long.

I can't emphasise enough that this part of the ECU coding is very rugged and the ECU will try its best to spit out error codes even if the rest of the ECU was dying.

If it is messing this up then I would expect a problem with the regulated 5V fed to the MCU chip.

If the MCU chip runs and then stops then the ECU will sense this and constantly auto reboot itself at a rapid rate (fraction of a second). Think of it as a heartbeat detector with a built in resuscitator!

Therefore, the 'vital signs' inside any Denso ECU are that the 5V rail is OK, also that the reset line goes high and stays high (if it is pulsing up and down then the ECU is distressed and continually trying to reboot itself)

Also check the MCU is being clocked OK by its crystal.

If you have these then normally you should be able to get sensible error codes flashed out of the ECU.

Trivia: even the manual SC ECUs have the code for the ECT interface in them. i.e. the lookup table for the ECT is there and it can control the relevant pins on the S2P chip for the ECT.

So maybe a manual ECU would work (to a fashion) on an auto. (no guarantees though )

[Tony jinxy froude]

, & err Jeremy, you really should get out more Im still struggling with calculators !! i think i'll be in touch with you in a couple of days, lets see if we get any other replies from the SC forum guys then i'll take it from there, i dont want to get this wrong, as i say its a favour really for an elderly woman who hasnt experienced her MK1 for 4 years, so im keen to get a smile on her face, i know how she feels to a certain degree as mine has been off the road for repairs for about 6 weeks & im dying to get back behind the wheel again, her husband is not at all clued up on these things so it would be nice for me to make the journey over there & finally get it running for her, she said if i can get it running she will turn up at JAE her very first show since her 10 year ownership, will be in touch Jeremy . Toni, i would be interested to find out what the number is on your Auto ECU too , Jinxy

[JMR_AW11]

, & err Jeremy, you really should get out more Im still struggling with calculators !! i think i'll be in touch with you in a couple of days, lets see if we get any other replies from the SC forum guys then i'll take it from there, i dont want to get this wrong, as i say its a favour really for an elderly woman who hasnt experienced her MK1 for 4 years, so im keen to get a smile on her face, i know how she feels to a certain degree as mine has been off the road for repairs for about 6 weeks & im dying to get back behind the wheel again, her husband is not at all clued up on these things so it would be nice for me to make the journey over there & finally get it running for her, she said if i can get it running she will turn up at JAE her very first show since her 10 year ownership, will be in touch Jeremy . Toni, i would be interested to find out what the number is on your Auto ECU too , Jinxy

OK but your best bet is to go there with Kev's ECU.

I'd be amazed if they changed the ECU pinouts for that model year.

I have early ECUs like Kev's 17110 and also the last ECU type (dizzy +AFM type) = 89661-17220 auto and 89661-17230 manual

and they are all interchangeable (on a manual car at least)

Kev's is an auto ECU so should be fine.

Are you handy with a voltmeter etc?

One test you could do is look at the VC pin from the ECU.

This powers the TPS and the AFM and should have 5V DC on it.

This 5V is the lifeblood of the ECU so if it is not there (it comes from inside the ECU) then either there is an external fault that is killing it or the ECU isn't getting adequate power (poor power connection to the main 12V input) or the ECU itself is dead. (repairable though...)

It should be +5V +/- 0.5V typical with the ignition on.

You can access the 5V at the ECU or the TPS or the AFM. It's OK to unplug the TPS to get easier access to the 5V pin because the 5V will still be there on the wire from the ECU.

Also you could look for pulses from the ignitor whilst cranking the engine.

I think you can do this on the diagnostic connector on the IG- pin. (assuming the SC has this pin)

This pin is usually separate in its own little sub connector.

I've never messed with this IG- pin but I would guess it bangs out a pulse with every ignition event to drive a tacho meter used by a technician.

It might be able to kick over the needle on an old style voltmeter (on AC Volts) as you crank the engine but that is just a guess. I assume you won't have access to an oscilloscope or a tacho meter.

Otherwise you could try using a modern DVM on the ACV range to see if it shows a voltage as you crank the engine. If there is a voltage on AC then there is going to be a train of pulses. a train of pulses means the ECU is trying for a spark...

Maybe someone with a healthy SC could try this, but make sure you use the voltmeter connections on the meter (ultra high impedance) and not current (ultra low impedance) or you could damage this output from the ignitor.

[Tony jinxy froude]

Hi Jeremy, thanks for your input, im not too good with a multimeter ( my dads an electrician too !! ), but i did use a noid kit on the injectors which showed up no pulses going to the injectors. I will try Kevs ECU & see how i go on, if i still have problems i'll get back to you & see if you would mind having a look at the cars current ECU for me. Over to Kev now , cheers, Jinxy

[JMR_AW11]

Hi Jeremy, thanks for your input, im not too good with a multimeter ( my dads an electrician too !! ), but i did use a noid kit on the injectors which showed up no pulses going to the injectors. I will try Kevs ECU & see how i go on, if i still have problems i'll get back to you & see if you would mind having a look at the cars current ECU for me. Over to Kev now , cheers, Jinxy

No probs.

I assume you've checked all the EFI/ECU fuses are OK?

Also, the SC ECU uses a different numbering system for the flashed error codes compared to the UK NA.

[Tony jinxy froude]

Yep Jeremy, it was the first thing we checked, we knew the error codes were different from the N/A & they are aslo different from the manual codes too it appears, as it threw a different code when we selected "drive" instead of "park" also a different code if the air con was switched on , just plain weird !! , Jinxy

[Mk1 Turbo Powered Steve]

A knight in shining armour, helping out a damsel in distress
Jinxy, your the man