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