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1994 Spi Troubles


Best Answer mintlawmaisie1994 , 10 September 2016 - 01:13 PM

FS,

 

thanks for getting back, I was hoping someone else could respond as I figured you were working or on hols. Anyhow, it's too late my friend!! She runs!!

 

I figured it had to be something to do with the timing, so I started to look at the sparking order again. I found that the spark for 1 was at TDC as seen previously, BUT it was at TDC on the exhaust stroke, not the compression stroke. At TDC on number one's compression stroke, the rotor arm was at the 7pm position, trying to light up 4, which was on its exhaust stroke at the time. Simple :proud: !! Took off the dizzy, extracted the drive using a rear sub-frame bolt (nice and long to reach in, so it doesn't drop into the sump), spun it round 180 Deg and put it all back together again. Bingo, first turn and she's away!!! Off to run MEMS Analyser on it now for 10 mins and make sure everything looks fine. 

 

Thanks SOOOOOOOOOO much for keeping me sane and your encouragement to keep on tinkering.  :highfive:

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#1 mintlawmaisie1994

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Posted 10 April 2016 - 03:57 PM

Hi all,

 

I’m having a hell of a time with my early 94 SPI with a 3AS immobiliser. I’ve torn it all the way to bare metal and re-built it from the pile of rust I was left with, back to what looks like a half decent car.

 

During the re-build I checked all the wiring wire by wire, marking them as I went along, so should all be OK.....after a few burnt bits were repaired.

 

I also tested the relays with a 12 VDC supply, and they were also all ok. I made and include a check list of all the main relay checks/functions, in case anyone else finds it useful.

 

Here is what I have checked so far.

 

The flywheel is on the correct way, using handy punch marks on the end of the crank and flywheel body to line it up the same way it came off. I also fitted a new alignment washer thingy at the same time.

 

The crank sensor outputs 10 mV when it’s turning over, which seems low to me? It has a resistance of 1300 Ohms. I did notice that the wiring looked standard, but had no earthed screen over the wires, which the Hayes manual I have for minis up to 96 shows. Would this reading make the ECU think the engine wasn’t turning over and prevent a spark from being initiated? What is a good healthy signal out from the crank sensor?

 

I made up a wiring diagram of how the main relay box is actually set up, when I noticed it didn’t match the Haynes manual drawing. It’s in a Dropbox file which can be accessed from this link, along with other stuf so you can see what I'm describing.

 

https://www.dropbox....7sj3T4gH2a?dl=0

 

I’ve also cleaned and copper-slipped all the earth points and they are solid. I double checked the ECU earth and some other component earths to be sure they are all OK.

 

Managed to borrow a code reader from my local garage and after blowing off the dust, connected it with mucho eagerness. B******, it says ECU not talking, serial error. Does this mean a new ECU?  :ohno: .

 

The ECU does initiate a stepper motor reset when I turn off the ignition key. :D

 

When I first turn it on, the fuel pump relay chatters on and off. If I jamb it open, the fuel pump works like a good un and I see a fine spray of petrol on the throttle butterfly, when I turn it over, but oddly none in the bores, if I take out a plug and apply a match to the hole. I only checked plug 2, so now I’ll go and check the others at the same time.

 

How would I check to see if the ECU is trying to make a spark, but the coil isn't doing its job? It looks brand new from when I bought the car. How would I check the coil and the capacitor attached to it?

 

I put an LCB exhaust, so I expect the ECU will need to "learn" that, but otherwise the engine was bored out +20 with new pistons and rings, shells and a head skim, so its shouldn't be that different.

 

I did have to use a bit of gentle heat to get the lambda sensor out of the old manifold, so have my suspicions about that. Would that stop the spark, if I've cooked it?

 

Any next steps or checks I need to make would be much appreciated.

 

Gav



#2 FlyingScot

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Posted 10 April 2016 - 06:21 PM

Gav

You seem to have changed a bunch of stuff - I am on my travels but let me post a few comments....

The output from the crank sensor does seem low, see here

"Crank angle sensor (CAS) The primary signal to initiate both ignition and fuelling emanates from a CAS mounted next to the flywheel. The CAS consists of an inductive magnet that radiates a magneticfield. The flywheel incorporates a reluctor disk containing 34 steel pins set at 10° intervals.As the flywheel spins, and the pins are rotated in the magnetic field, an AC voltage signal is generated to indicate speed of rotation. The two missing pins (set at 180° intervals) are a reference to TDC, and indicate crankshaft position by varying the signal as the flywheel spins. One missing pin indicates TDC for cylinders 1 and 4, and the other missing pin indicates TDC for cylinders 2 and 3. The peak-to-peak voltage of the speed signal can vary from 5 volts at idle to over 100volts at 6000 rpm."

Maybe a TMFer can measure this on crank with their motor (I am travelling at the mo)

Code reader not reading the ECU - simplest is that the ignition isn't on (it needs to be to activate the main relay in the MFU and power up the MEMS ECU), you have plugged into the green plug rather than the white or the cabling is damaged.

A duff lambda sensor won't prevent firing.

Check the fuel cut off isn't activated (bulk head next to wiper motor) depress firmly.

Fuel spray from the injector when working looks continuous "like a shower" if it isn't when was the filter on rear subframe last changed ?

I am sure others will have some suggestions.

FS

#3 mintlawmaisie1994

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Posted 10 April 2016 - 08:31 PM

Hi all,

 

here are some more test results, to see if anyone can spot what's up.

 

Lambda sensor wires to ECU = OK

Resistance between the two white wires = 0 Ohms

Resistance between all other pin permutations = Open Circuit

 

Stepper Motor Wires to ECU = OK

 

White test plug wires to the ECU = OK

 

Throttle Potentiometer Wires to ECU/White Test Plug= OK

Throttle Potentiometer Resistance in Fully Closed position = 1200 Ohms between Y/Gr and P/Bk

Throttle Potentiometer Resistance in Fully Open position = 4380 Ohms between Y/Gr and P/Bk

Throttle Potentiometer Resistance in Fully Closed position = 5100 Ohms between Y/Pu and P/Bk

Throttle Potentiometer Resistance in Fully Open position = 5100 Ohms between Y/Pu and P/Bk

 

Inlet Manifold Temp & Air Cleaner Temp combined resistance 4160 Ohms at roughly 8 Deg C

 

Purge Valve Wiring = OK to ECU.

Purge Valve resistance = 0 Ohms

 

Coil Resistance between +ve and –Ve = 0 Ohms

Coil Resistance between Centre and +ve = Open Circuit

Coil Resistance between Centre and -ve = Open Circuit

 

Plug Lead 1 Resistance = 6830 Ohms – I would have thought this should be zero?

Plug Lead 2 Resistance = 7400 Ohms – I would have thought this should be zero?

Plug Lead 3 Resistance = 6300 Ohms – I would have thought this should be zero?

Plug Lead 4 Resistance = 6400 Ohms – I would have thought this should be zero?

Coil Lead Resistance = 11800 Ohms – I would have thought this should be zero?

 

Injector to ECU wiring = OK

Injector to Relay wiring = Needs to be double checked as my actual wiring is different to the Haynes manual wiring. The manual shows it connected to P3 but my P3 has nothing connected to it. (neither does your pic above) 

 

I haven't changed anything myself, it came wired like this and I've put it back exactly like it was except for a few splices within the loom. Someone along the line has done some changes it seems, but why would they? Unless there have been a few variations in the wiring over the years? e.g. my relay is a lot different to the one in your pictures above,it only has 4 resistors, and the they are all in the center, between the relays, so if the relay is different, then the wiring light be too. Its still the same ECU, loom, relay block and all other wired up bits, since I expected those to be straight plug-in and go. 

 

I'm now thinking that maybe 10mv at turn-over is OK after all, since I work with turbine flow meters which operate on the same principal. Tick-over would be may times faster than turning over, so the voltage should be much higher, as you describe, which makes me think (hope) its probably fine.  

 

The fuel cutoff is definitely pressed, I do it every time I check anything.

 

The ignition was switched to the first position with the ignition light on, but to the next position and not turning over, maybe the engine needs to be be turning over or running? 

 

The fuel spray is not like a shower, but makes the butterfly wet, so maybe it is partially blocked. There is a new filter, but I don't have a lot of petrol in the tank, and had trouble with the petrol lines, so I think I'll get some fresh petrol and flush the delivery line. Is it easy to clean the injector? Are there settings on it which need special knowledge, or could I just take it apart, clean it and put it back together again?

 

Is it possible to reload the program into the ECU, or repair it if its damaged? I looked on Minisport and couldn't see any, but Minispares had rebuilt ones for ONLY 300 quid, so that's out the window.  

 

I've also put some photos of the lost motion doohickie onto dropbox.

 

Thanks for the expert help this far, invaluable!!

 

Gav



#4 FlyingScot

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Posted 11 April 2016 - 08:07 PM

Would be better on a new thread Gav as this is a pinned topic, I'll move it later when I have access to a PC?..

Coils readings look wrong, but not sure how good your meter is, see here for Daves readings (Kernow Cooper) http://www.theminifo...-testing-coils/
Throttle position sensor readings are correct.
Domt understand your point about combined resistance of inlet manifold and air cleaner sensors? These are two different sensors and feed two different inputs on the MEMS.
Don't bother cleaning the injector at this stage.
Diagnostics works with ignition light on
Multi Function Units (MFU) changed on various versions, but wiring should be the same even if layout on the circuit boards are different. Does it still have the part number on it? (Just wanted to check it is an SPi one)
ECU can only be repaired at the board level by specialists like ATP but they are pretty hardy and usually it's the last thing to replace.
Can you give me the part number on it MNE101050 or similar?

FS

#5 mintlawmaisie1994

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Posted 22 April 2016 - 04:23 PM

FS, 

 

sorry about continuing this on a pinned thread. I don't know how to move it to another one  :errr: .

 

Anyhow, I've finally figured out that I have an MPI Relay Pack, not an SPI one. Should have just looked at the label, it says YWB 100970. Doh!

 

Now to figure out which ECU I have. It looks like an MEMS 1.6 with horizontal lines on the side and the single 36 pin plug and vacuum connection.   

 

I've double checked all the wiring on the engine loom, over the last 2 nights and all seems well. I'll upload it onto my drop-box folder later tonight. I'll also try to see if my wiring loom corresponds to an SPI or MPI wiring diagram.

 

Gav



#6 FlyingScot

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Posted 23 April 2016 - 12:00 PM

Gav I've moved it for you ;-)

From your description it is a MEMS 1.6 but if you give me the part number from the label I can confirm what one.

I have both relay packs here and I'll do a check comparison over the weekend; pretty sure from memory they are not the same but I'll update the posted thread on relay packs.

FS

#7 minidaves

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Posted 23 April 2016 - 12:14 PM

mpi relay pack wont work a spi 



#8 FlyingScot

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Posted 23 April 2016 - 12:22 PM

mpi relay pack wont work a spi

Yes but several of the functions do...which is why I wanted to compare :-)

FS

#9 mintlawmaisie1994

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Posted 23 April 2016 - 08:03 PM

FS,

 

I definitely have an MPI relay pack, it's a YMB 100970. Now I've removed the engine loom and re-traced and buzzed every single wire from all of the connectors. I drew the engine loom actual wiring diagram and stuck a copy in the dropbox folder, in case you need to see it:

 

https://www.dropbox....7sj3T4gH2a?dl=0

 

It ran perfect when I first got the car and I didn't change a thing. Could this mean I have an MPI ECU as well? 

 

The next thing I need to do is check my actual wiring up against an MPI wiring diagram and see if that tells me anything.

 

All the part number detail is (maybe deliberately?) rubbed off the ECU label, and all I can read is the number 111207595.

 

............seems like someone in the cars history has made a few changes. 

 

 

Gav



#10 FlyingScot

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Posted 23 April 2016 - 08:19 PM

It's not an MPi ECU that's a 1.6 or later but not a 2J, so SPi it is. So the MFU has been changed from standard but as I wrote above I need to check the actual differences side by side.

FS

#11 mintlawmaisie1994

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Posted 24 April 2016 - 07:20 PM

Update, 

 

I checked all the relays with 12 VDC and they all work fine, connecting the correct S and P terminals as they should do and all the way to the end of the relevant cable, so I'm sure the relays signals are getting to the correct part of the engine (starter, fuel pump and PTC manifold heater) or at the ECU 36 pin plug. They don't match any drawings I can find, relating to early or late SPI's, and I'm bu99ered if I can see how it ran fine when I bought it. 

 

I also got a loan of a Sykes Pickavant ACR4 and tried several things to see if I could get comms with the ECU. I tried Rover 1, Rover 2 and G2 application pods, all  with no joy, same message as before, communication error. I was using cable 30211600 with the three round connectors and answered no, when asked if I was using cable xxxx while using G2, which I guess is a multi-pin cable for later cars.   

 

I tried this, with the existing loom and test plug, which is wired as per the drawing in dropbox, i.e. how I got the car. Next I direct wired to the ECU, through pin 26 (+ve) and pin 8 (-ve) as per the wiring diagram I drew. I attached the tester to pin 22 (Black/Green), 27 White/Yellow and 7 Pink/Black. No Joy

 

Next I tried direct wiring the ECU through pin 11 (+ve) and pin 28 (-ve) as per the Rover manual I was sent by some kind soul (thanks by the way!!). I attached the tester to pin 15 (Black/Green), 10 White/Yellow and 30 Pink/Black. Still no joy.

 

Question is there a way to check the ECU I have and confirm what each pin is supposed to be? Are there any company's or individuals out there who can do this? I've included a pin-out list of my ECU plug, versus how it should be and nothing matches. How did this car ever run I wonder?

 

I don't really fancy pulling out all the pins and re-assembling the ECU plug as per the diagram in the Rover manual,but it looks like that might have to be the case. If I end up doing this, I'll solder on new sockets, as some of them felt a little loose when I was testing. Its also looking more and more like I've got a dodgy ECU  :unsure:. If I do that, I'll probably put a new relay module in as well to make it standard.

 

Does anyone in Aberdeenshire have an SPI which I could try my ECU into, or conversely, try their ECU into my car and see what happens?

 

Failing that,does anyone have a spare ECU that I could try and if it works I'll buy it off you. 

 

I could also just buy one off flea-bay, but I'm not sure that will solve the problem.

 

Gav


Edited by mintlawmaisie1994, 24 April 2016 - 07:24 PM.


#12 FlyingScot

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Posted 24 April 2016 - 07:30 PM

Failing someone loaning you or being able to test your ECU . ATP can test and if necessary refurbish your ECU.

I'm assuming that in using the SP ACR you had the ignition ON.

FS

#13 mintlawmaisie1994

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Posted 25 April 2016 - 04:03 PM

FS,

 

yep, ignition was on when everything was in the car. When the loom and ECU was out of the car, I powered it with a 12 VDC, 0.5 amp power supply.



#14 mintlawmaisie1994

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Posted 25 April 2016 - 04:04 PM

FS,

 

do you have contact details for ATP? 

 

Found them...


Edited by mintlawmaisie1994, 25 April 2016 - 04:06 PM.


#15 mintlawmaisie1994

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Posted 01 May 2016 - 06:50 PM

Update,

 

ECU gone for checking now. Fingers crossed. 

 

Checked the coil again and its 1.6 Ohm between +ve and -ve and 7100 Ohms between the Centre and +ve.

 

I also applied an external 12 VDC to the +ve and-ve, expecting to see a large voltage between the centre and earth. Nothing...is this right? 






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