Rover 420 gsi (turbo) cranking but not starting

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Dutchie
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Joined: Tue Feb 28, 2023 7:31 pm

Rover 420 gsi (turbo) cranking but not starting

Post by Dutchie »

Hello fellow Rover owners/enthusiast,

About a week ago I bought myself a non running Rover 420 gsi 1996 with a t16 turbo swap from a Rover 220(build somewhere in 1994?). It was still running with the current setup about 3-4 month ago.

At the moment it doesn't have spark/injection. So first I checked if I could read the data from the ecu.
With a bit of tinkering I was able to read the data, the mems ecu was at least able to pickup a rpm reading of about 200 rpm with either/both the crank or camshaft sensor connected.
When using the test functions, the injectors click, the coil creates a spark and the fuel pump can be turned on and off.

The mems ecu in the car is a mkc101960, which I guess has the 4 gap flywheel triggerwheel?

I did buy a new crankshaft sensor since the one I removed from the engine seemed to be bend before removal(the tip was shaved a bit, so must have happened before removal).

When the ignition is put in position 2 the fuelpump keeps running continuously running, fuel is passing by the filter and through the return line. When cranking the fuelpump stops.
I'm not sure if this is by design yet?

It could be the immobilizer maybe, but I'm not sure yet. It does arm and can be disabled with the remote. So stage 1 can be disabled.
What I've read about the other functions is that it cuts the engine once it's running and not receiving a code after a second, but I'm currently not getting at this stage.


nextstep:
Checking the flywheel trigger wheel for any damage and replacing the crank sensor with a new one/see if the engine has any spark/injection then.

But I would really appreciate some more input from more knowledgeable people with regard to these cars than me. Not sure how the immobilizer tricks with the ecu yet and if it is normal for a good working system to stop the fuel pump when cranking?


With kind regards,
Brian
rjessett
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Posts: 152
Joined: Mon Aug 04, 2008 11:33 am

Re: Rover 420 gsi (turbo) cranking but not starting

Post by rjessett »

I have just been working on a 214SEI that had exactly the same symptoms as yours, and I carried out the same diagnostics... Took a few weeks of messing about, but it did turn out to be the ECU. That was a variant of MEMS 1.6, just like yours....

What I found is, even though Testbook/T4 would fire the the injectors as part of a test, once the engine was running, the injectors would not fire at all. There was no issue showing with the ECU with the official Rover Diagnostics kit at all.....but there was still a fault.

For some reasons, the ECU variant I needed (4 gap flywheel. 5as imobilsation) seems to be a little harder to find, and the one I did find had a different fault on it. So, I ended up converting the car to MEMS 1.9 from a bubble 214, and the car runs perfectly....

However, your ECU *should* not be to hard to come by. Might be worth finding someone with one as a test (it will need matching to your 5AS) - or you swap to a 2 gap flywheel and get the earlier ECU (that does not need matching to 5AS)

When an ECU does not get the correct code from 5ASm it will indeed start to run, then cut out. Not what your seeing, so I dont think its a 5AS/ECU matching issue.

Where are you located? might be someone local who could help, or have the bits?
Dutchie
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Re: Rover 420 gsi (turbo) cranking but not starting

Post by Dutchie »

Thank you rjessett for your answer,

Already was kinda fearing some dreaded problem in the ecu not easily to diagnose. With your recent experience and solution, I'm afraid it could well be the ecu then.

Did your rover still had spark, and just missed injection?

What little info I could find of the mkc101960 mems is that it also uses a 4 gap flywheel, with the 5as immo. I guess I'm in the same boat maybe

I'm located in the Netherlands, just to make Rover ownership that bit more challenging.

Previous owner also mentioned that replacing the ecu may be the only fix, the issue of not running happend after he parked the car and wanted to start it a few hours later.

the fuel cutoffswitch was also popup under the dash so press that one to reset it.

But before trying that I may as well just go and check the flywheel/replace the crank sensor. and see if it at least still has spark.
I did read about another example with the same problem of having no injection and going through multiple ecus and in the end putting a life 12v wire on the fuel pump with a switch in between fixed that.

A bit more information, mostly for verification.

Seen a few diagrams of the cam sensor now which aren't completely clear about the pin connection for the cam sensor.

Pin 10 of the 18 pin connectors is a brown-red wire going to the blue wire of the crank sensor, pin 15 of the connector is a blue-green wire going to the red wire on the crank sensor.
They should be connected correctly, even if they would be swapped around it should still pick something up and at least give spark although it would be out of face?
The previous MOT back in sept last year did mention it having high emissions, so maybe one of the 2 sensors was acting up already back then.

With kind regards,
Brian
rjessett
Club Member
Posts: 152
Joined: Mon Aug 04, 2008 11:33 am

Re: Rover 420 gsi (turbo) cranking but not starting

Post by rjessett »

Yes - in my case I had spark, but no fuel from the injectors. I sort of prooved that by squirting carb cleaner into the inlet manifold - and the car ran for a few seconds on that!

In term of the cam and crank sensor - normally an engine wont run if it just has a crank, but I found on the turbo, you could run the car on either the cam or crank sensors beign disconnected (run, but badly) In the case of the cam, from my understanding, the cam sensor just helps with emissions and running when cold. The cam sensor does go wrong, but the Rover Coupe Owners Club do sell them in thier club shop. normally, they are hard to get hold of

But - I dont think those sensors are your problem

I think it would be worth getting a tried and tested ECU, and matched with the 5as. I can programme and match ecus,and fobs off the car - but I dont have any tested ECU's of that type in stock. I think its vital to make sure an ecu is tested on a car, else it could be a lottery.

If you struggle to find that ECU, you can fit an earlier one, but you will need to also fit the 2 gap flywheel.
James3990
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Re: Rover 420 gsi (turbo) cranking but not starting

Post by James3990 »

Have you checked the timing of the engine?

Although saying that, your problem sounds electrical. Is the wiring loom OK on the conversion sections?

Maybe try different 5AS & ECU.
Rover 220 Coupe Turbo
Rover 220 Coupe Turbo Racer
Dutchie
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Joined: Tue Feb 28, 2023 7:31 pm

Re: Rover 420 gsi (turbo) cranking but not starting

Post by Dutchie »

Haven't checked the timing of the engine yet, I guessed it would be semi-fine and still be able to pickup enough to give spark.

A diffrent matched ecu set is on the list, also considering a standalone like speeduino at the moment. The mems ecu malfunction may seem to become a more common problem.

The wiring loom is kinda dodgy, since it has been tinkered together quite a while back when the car was still in the UK(plates still in the boot).

Still have to meassure the signal from crank/cam sensor at the ecu with a scope, but seems to be good enough to give a rpm reading of 200 in the ecu.

Also haven't checked yet if anything changes if I disconnect pin 13, although it it most likely won't change a thing. Wiring could certainly be an issue somewhere in the loom.
Dutchie
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Joined: Tue Feb 28, 2023 7:31 pm

Re: Rover 420 gsi (turbo) cranking but not starting

Post by Dutchie »

Update:

Car is now running with another ecu.

Had the car running with a speeduino standalone ecu no problem, but since I do not have any plans for more boost I ended up getting a replacement ecu(found one just 2 weeks ago.)
Building everything back to stock was a breeze since I made sure everything was still intact and the standalone was pnp with the oem loom.

With the new oem ecu the car ran but just for a few seconds and stalled, it was obvious it was working now but the immo was the last obstacle in the way. Ended up removing the immo and making it a free running ecu with pin 13 disconnected, and it is now running fine once again.

But the question remains how long will the replacement ecu last and why did the previous fail? Must have been a short circuit due to oil or degrading wires.
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