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Technical MPI immobiliser problem. Swap ECU?

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Technical MPI immobiliser problem. Swap ECU?

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jiminwatford

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2001 Schumacher

The immobiliser is stopping the car from starting (so says the garage). It turns over but won't fire up. The previous battery got very flat and was replaced with a new one, It's had this problem since the new battery was fitted

I swapped the ECU and immobiliser like for like from a similar car but still it didn't start. I disconnected the battery, replaced the ECU, unplugged the immobiliser and plugged the new one in. I let the aerial part hang and taped the new key to it. I used the original key to turn the ignition on. I then reconnected the battery

So with this it should be using the new key to tell the immobiliser to start the car, right?

I tried it with another spare set (ecu, immobiliser, key) but still nothing

I took it to a garage who tell me the immobiliser is where the problem is

I would have thought replacing the components in the system would solve it

It's still with the garage who are trying to consult an auto electrician, but if they can't solve it, what else could i try?

The car is 80 miles away so i need some good ideas before i can go over there
 
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Has anyone checked the crank sensor at all?

And thinking about it the biggest help right now would be what trouble codes the ecu is throwing up to see if it's pointing to an imob fault or something else mechanical/electrical related
 
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We had similar issue with Cinq swap. In our case fuel pump didn't prime/work.
Had to reset inertia switch.
 
The fuel pump is priming (i can hear it start up)

The garage has said their tester is saying it's the immobiliser. I don't know what codes it is showing

My concern is if the auto electrician doesn't know or only has very expensive options i can try other things

I'm waiting for him to check at the moment, which in itself is frustrating

I have ordered a crank sensor just in case it comes in handy
 
jiminwatford said:
The fuel pump is priming (i can hear it start up)

The garage has said their tester is saying it's the immobiliser. I don't know what codes it is showing

My concern is if the auto electrician doesn't know or only has very expensive options i can try other things

I'm waiting for him to check at the moment, which in itself is frustrating

I have ordered a crank sensor just in case it comes in handy
Click to expand...
I'm not sure and there are other people on this forum who would know better, but doesn't the immobiliser cut the power to the fuel pump???
Or does it cut the 'ignition/spark'?

I thought it cut the fuel pump supply.

If this is right then surely it can't be a immobiliser fault if the pump is priming??

If anyone knows better please let me know as I'm not 100% that is correct.
 
Hi Jim
Is the code light on in the dashboard ?
If the light comes on briefly and then goes off the key is recognised and system is working correctly

If the light stays on either the key is not recognised or wire between Code ECU and engine control not connected or no communication between ECUs

When you swapped the ecu and immobiliser did you use them both from the same car ?

Is the 20A maxi fuse at the back of the battery ok if so you should have a 12v feed on pin 3 of the immobiliser ECU

You should also have a ignition feed on pin 8 of the immobiliser ECU which is supplied via a 7.5A fuse

You should have a Earth on pin 4 of the immobiliser ECU

You can check continuity between pin 6 of immobiliser ECU and pin 7 of engine ecu

I had the same problem and I realised it was the engine ECU that was at fault ,when I plugged code reader into OBD socket it was dead
You actually supplied me with one Jim ?

Let us know how you go on and in the meantime I will carry on thinking about the problem
 
Just had a look at my original post
Engine turned over , code light stayed on , fuel pump wasn't running
 
Thinking logically the CODE system diagnoses itself either the code light is on and tells you there is a fault or it goes off after 1 second when all is ok

Is the garage anywhere near Halifax ?
 
jaygrint said:
I'm not sure and there are other people on this forum who would know better, but doesn't the immobiliser cut the power to the fuel pump???
Or does it cut the 'ignition/spark'?

I thought it cut the fuel pump supply.

If this is right then surely it can't be a immobiliser fault if the pump is priming??

If anyone knows better please let me know as I'm not 100% that is correct.
Click to expand...

I'm sure i can hear the fuel pump turn on with the ignition. At the minute i only know what the garage has said, that it's the immobiliser
 
dadandlad said:
Hi Jim
Is the code light on in the dashboard ?
If the light comes on briefly and then goes off the key is recognised and system is working correctly

If the light stays on either the key is not recognised or wire between Code ECU and engine control not connected or no communication between ECUs

When you swapped the ecu and immobiliser did you use them both from the same car ?

Is the 20A maxi fuse at the back of the battery ok if so you should have a 12v feed on pin 3 of the immobiliser ECU

You should also have a ignition feed on pin 8 of the immobiliser ECU which is supplied via a 7.5A fuse

You should have a Earth on pin 4 of the immobiliser ECU

You can check continuity between pin 6 of immobiliser ECU and pin 7 of engine ecu

I had the same problem and I realised it was the engine ECU that was at fault ,when I plugged code reader into OBD socket it was dead
You actually supplied me with one Jim ?

Let us know how you go on and in the meantime I will carry on thinking about the problem
Click to expand...

Thanks for that. There's a lot i can't do but given the opportunity i can pass it onto the garage

I don't think the code light stays on. I think the engine light might stay on

The ecu and immobilisers were from the same cars respectively
 
Hi Jim
Problem stinks of FPS fault ,very common with a flat battery
Might be worth asking them to stick there hand under dash and trying a reset

Skipton is about 20 miles from me give me a shout if you need help ?
 
dadandlad said:
Hi Jim
Problem stinks of FPS fault....Skipton is about 20 miles from me give me a shout if you need help ?
Click to expand...
If you get a FPS fault on a MPI it shows 'FPS' on the dash -so it's possible but unlikely.
If the original ECU & immobiliser were swapped over & yet the fault continued then it could very well be a problem with the loom, it's over 15 years old & nothing lasts forever.
dadandlad: good to see there are people willing to help other members out (y)
BTW i'm 220 miles from you -any chance of helping me with my Sei :)?
 
If you get a FPS fault on a MPI it shows 'FPS' on the dash -so it's possible but unlikely.
Not sure if Jim knows which light is on the

If the original ECU & immobiliser were swapped over & yet the fault continued then it could very well be a problem with the loom, it's over 15 years old & nothing lasts forever.
Click to expand...

Got to agree nothing lasts forever but swapping ECUs wouldn't clear the FPS fault and neither would it repair a loom problem ,FPS is the easy one to check

dadandlad: good to see there are people willing to help other members out
BTW i'm 220 miles from you -any chance of helping me with my Sei ?
Don't mind helping anyone out if I can
Where are you based as I do tend to travel about a bit so you never know ?
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Click to expand...
Click to expand...
 
I've seen a thread where someone had a FPS fault & it wasn't shown on the instrument cluster!.... but as James thinks the pump is priming that rules the Fuel Cut Off switch out.
The micro ECU's are noted for being a tad fragile compared to the other ECU's but seen plenty of threads were a garage has jumped to the conclusion that it's faulty, changed the ECU & it still hasn't fixed the problem.
The battery change/starting issues might just be synchronicity -I'd be looking at a connectivity (loom) problem or a sensor having pointed its pinkies at the sky.
 
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Bit awkward with the car being so far away from Jim

I had a problem with the micro ECU on my Schumacher which had me on a wild goose chase for a short while but a second hand one funnily enough supplied by Jim sorted it

The only sensor that I can think of right now that would stop it from running is as mentioned earlier the crank position sensor

If it turns out to be the crank sensor it might on fitting of the new one need a phonic wheel reset

Trouble with problems like this is the labour costs can go through the roof if the garage involved doesn't understand the car
 
Cheers Ouby for the link
No I didn't strip the ECU but will certainly be having a look now ?
 
James have they tried a noid light on the car?
Non-starting car i always check
1. Fuel supply.
2. Spark.
3. If the spark is arriving at the right time.

(If one or both coil packs has died it might fool the garage test equipment into thinking the ECU is faulty).
Be warned: IF the ECU is actually faulty they often take out the coil packs, so don't just bung the coil packs from the working car on it in case it kills them.
(Swap the ECU, the immobiliser & the coil packs in one go).
 
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