battery changed-now wont start

daved · Post by **daved** » Mon Jan 09, 2012 9:24 pm

Hi all

The battery on my S1 Elise gave up the ghost a few weeks back so I replaced it, like for like, earlier today.

New battery in connected etc but engine won't run. Turns over very strongly and all lights on dash etc. Alarm etc seems to be working but when turning over there is no sign of the engine firing. Strong smell of fuel when trying to start

Can anyone give any suggestions on areas I should check? Haven't been able to do anymore checks than fuses.

Any suggestions welcomed

robin · Post by **robin** » Mon Jan 09, 2012 9:59 pm

Did it run on the old battery before you replaced it?

If you turn off the ignition completely, wait 60 seconds, then (in this order!) clear the alarm and turn the ignition to the run position (i.e. turn ignition on but don't crank) do you hear the fuel pump prime (I would guess you do, given the comment about the fuel smell).

Is it possible that you've missed one of the wires off the battery - the +ve terminal has a couple of wires on it and IIRC one of these powers the ECU. If the fuel pump primes, then the ECU is powered up, so only worth checking if the pump doesn't prime.

Does the rev counter skip up a few notches when you first turn on the ignition (it should, then return to 0).

Does the rev counter climb up to 200rpm whilst cranking? I believe it should.

Have you messed with ignition system at all? Rotor arm, distributor cap, coil (or connections to the coil) could all cause this.

Cheers,
Robin

daved · Post by **daved** » Tue Jan 10, 2012 10:32 pm

Thanks Robin

Checked all this and it all seems OK. Fuel pump can be heard priming and the ECU permanent live supply is reading OK when I checked with my multimeter.

Took plug number 4 out and turned engine over but not sign of spark.

Nothing ignition-wise has been touched.

My next though is crank sensor. Any ideas?

Car ran fine pre-battery change so I am head scratching.

Thanks in advance

Dave

robin · Post by **robin** » Wed Jan 11, 2012 10:26 am

If the rev counter is climbing up to 200RPM whilst cranking then the crank position sensor is working. If you find it hard to be sure, remove all four spark plugs and the engine will crank much faster giving a more easily visible increase in RPM on the gauge.

I would remove the distributor cap/rotor arm and take a careful look in there. A wise man once told me that all K-series ignition faults that are hard to explain come down to the distributor cap/rotor arm

You can test the LT and HT circuits with a multimeter, at least in principle. Another solution is to remove the centre HT lead (coil->distributor) at the distributor end and hold it close to the block with something insulated (or just wedge it there) then try to crank the engine and see if you see any sparks. If you do the ECU is triggering and the coil is working. At that point you need to look at the distributor cap/rotor arm/ignition leads/spark plugs.

The other possibility is that during cranking there is a huge voltage drop to the ECU due to excessive resistance in the ground path. Is it cranking well or chugging?

Cheers,
Robin

P.S. The other thing to test is that the MFRU master relay is actually feeding current to the engine harness; if you get a spark off the HT lead then it must be; if not then you'll need to use a multimeter to measure the voltage at one of the relevant sensors - e.g. IACV - the brown/pink wire should be at +12 when the ignition is on, not cranking. If it is the MFRU master relay is engaged and working.

BiggestNizzy · Post by **BiggestNizzy** » Wed Jan 11, 2012 10:34 am

robin wrote: A wise man once told me that all K-series ignition faults that are hard to explain come down to the distributor cap/rotor arm

Ahh this sounds like the problem I had, at first I thought it was water in the plug bores, then I replaced, leads and plugs and still nothing. Ended up removing the distributor cap and it was full of crud.

Swopped them out and it's worked fine ever since. (well that part of it anyway)

daved · Post by **daved** » Thu Jan 12, 2012 10:29 pm

Well tried taking cap off and nothing obviously wrong

Took king lead off and checked for sparking when turning over. Single spark seen each time when I stopped cranking.

Thoughts are now crank sensor or ignition coil although still keep thinking the car ran fine pre-battery failure and change.

Does anyone have any ideas?

Thanks

Dave

haggis catcher · Post by **haggis catcher** » Thu Jan 12, 2012 11:36 pm

My car was running perfect on my way to work one sunny morning. When I went to return the car would not start. I looked at everything, and called the RAC. He immediately found it was the coil. He swapped it with a spare, and the car burst into life. Is it possible it's your coil ?

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I am here: http://maps.google.com/maps?ll=56.315464,-3.033783

robin · Post by **robin** » Fri Jan 13, 2012 9:54 am

I'm assuming you're on the standard ECU? What vintage - is the ECU in the engine bay or in the wheel arch behind the boot bag?

Does the rev counter climb during cranking? If it does then your crank position sensor is working.

One spark during cranking reminds me of an immobiliser issue.

On the S1 there are three immobiliser functions: crank inhibit, fuel pump inhibit, and ECU code lock.

The latter is perfomed by the immob unit that's behind the dash sending a code to the ECU to unlock it. There is a wire that carries the code. I've seen this wire be fractured on a car with the older ECU location (boot bag). It's easy to test with a scope but even easier if you can get the car to MMC where they can just plug in the Lotus Scan tool that lets them see what the ECU is seeing.

The coil is relatively straightforward to test. You're looking for a low resistance on the low tension side. You can do this at the ECU plug if you remove it from the ECU. You're looking for <1 ohm from pin 25 (white/black, it's one of the four corner pins) to pin 28 (brown/pink, 3 pins along the row from pin 25). Use digital meter on 200 ohm setting. Check that when you short the two meter probes together you get <=0.2 ohms first though. Also measure from pin 25 to pin 29 (black wire) which should be open circuit even on the highest meter setting range.

To measure the HT side you should measure the resistance from the king lead to the engine block - it should be 10K - 100K ohms if I remember correctly.

Cheers,
Robin

daved · Post by **daved** » Fri Feb 10, 2012 7:09 pm

Well I eventually tested the coil and there was a low tension side fault

Coil changed this afternoon and no difference. Car turns over fine, smell fuel etc, rev counter moving on turn over but no ignition. Still the same single spark as I release the key.

How can I check the coil is getting power and does anyone have any more test suggestion? I may yet admit defeat and call Green flag

Thanks in advance

David

robin · Post by **robin** » Fri Feb 10, 2012 8:06 pm

The coil is getting power because it sparks.

You need to test the code wire function. To do this you'll need a beautiful assistant a multimeter and you'll need to remove the plug from the ECU.

Locate pin 13 which should have a yellow and red wire running into it (though might also be black). Pin 13 is on the middle row of pins all the way to the one end

Be careful not to confuse with pin 24 which is at the other end of the middle row and has a yellow and brown wire.

Turn the ignition on but leave the immobiliser armed. Measure the voltage between pin 13 and earth which is pin 29 that you hopefully found before (black wire).

I suspect it will be zero though there is a slim chance it could be +5 or +12. Now whilst you've still got the meter wired to those two pins disarm the immobiliser. You should see the voltage change to some other level that will be between 0 and 5 but certainly different from what it was before. If it stays at zero then the wire is broken or the immobiliser is broken. Without the code the ECU won't start the engine. If you know anybody that uses an emerald you could also verify this as the Emerald doesn't use the code unless configured to do so - most people don't bother setting it up.

Cheers,
Robin.

daved · Post by **daved** » Fri Feb 10, 2012 9:46 pm

Thanks Robin

Tested before and after disarming and 0 volts.

Can you advise of any tests for the immobiliser to check its operation?

Thanks

robin · Post by **robin** » Fri Feb 10, 2012 9:49 pm

Your immobiliser is working in principle because it allows the fuel pump to prime and the starter to crank. If you really don't have a signal on the code wire it's either a failure in the immobiliser or the wire is broken. Where is the car currently?

Cheers,
Robin

daved · Post by **daved** » Fri Feb 10, 2012 10:09 pm

Thanks Robin

Car is stuck in garage.

When checking the rev counter again its definitely moving when cranking but looks a bit out of sync with engine turning. Could this have any effect?

robin · Post by **robin** » Fri Feb 10, 2012 10:14 pm

No. The rev counter will jump up/down then settle when you first turn on the ignition. Once it's settled if you then crank it will rise, but I don't suppose cranking speeds is what it's really designed for so might not be all that steady.

I mean where in Scotland - if you're in or around Edinburgh I might be able to pop over with a scope and look at the immob signal to rule it in/out as the cause. I might have a spare rotor arm too ...

Cheers,
Robin

daved · Post by **daved** » Fri Feb 10, 2012 10:19 pm

Aberdeen I am afraid.

Think I might have to get it recovered

Scottish Elises