Liam's Z4C race car project

[Liam22]

It won't turn over.

Ignition-on makes all of the typical noises:

• Fuel pump primes
• Throttle butterfly does a self-check
• The things that hum, hum

Turning the key to start does nothing. No solenoid click. Nothing.

I could probably rig up a permanent 12V supply to the fuel pump but I don't know what that would help with?

 

[enuff_zed]

It won't turn over.

Ignition-on makes all of the typical noises:

• Fuel pump primes
• Throttle butterfly does a self-check
• The things that hum, hum

Turning the key to start does nothing. No solenoid click. Nothing.

I could probably rig up a permanent 12V supply to the fuel pump but I don't know what that would help with?

I agree, if it was turning over maybe, but if nothing at all......
What about the engine earth strap?

 

[enuff_zed]

I assume you must have a kill switch fitted for racing? Not a fault with that?

 

[Vanne]

If its the same as the Z4m, then there is a separate cable running to the starter, check the earths, mine did something very similar a few months back.

 

[Liam22]

Good tips - keep them coming!

I recently replaced the earth strap when I was having battery trouble. Since then I also replaced the battery and primary cables. For the last couple of weeks it has been cranking/starting better than ever.
I checked the battery isolator. Seems fine.
Replaced the starter today and I'm confident all the connections are good.

But remember the car started fine, then conked a few minutes later. What are the chances that it ran out of fuel *AND* developed a fault that prevents cranking all at the same time?

I see where you're going with suspecting the DME, Martin. But everything seems fine at ignition-on. I can see coolant temp by OBD-2, etc.

 

[1536Z4]

What about the engine earth strap?

[ref]bigwinn[/ref], is your man for sorting that out

 

[Vanne]

I wasnt talking about the earth strap, i was talking about the earth wire how its fastened to the boot floor. (not underneath the car, but in the boot), so from the batt terminal to the boot floor, that connection.

edit: if you try to jump it from the front, under the hood, does that work? if it does, then for sure its the rear earth wire i mentioned.

 

[Zedebee]

Do check the connections on the battery terminals are properly tightened. If not quite right they could be capable of delivering enough amps to bring the systems to life, but not enough to crank. A momentary interruption to the supply might have caused the motor to die in the first place.

 

[Liam22]

I wasnt talking about the earth strap, i was talking about the earth wire how its fastened to the boot floor. (not underneath the car, but in the boot), so from the batt terminal to the boot floor, that connection.

Ah! Gotcha. But I don't have the battery there. It's in the passenger compartment and earths to the body through the FIA isolator.

edit: if you try to jump it from the front, under the hood, does that work? if it does, then for sure its the rear earth wire i mentioned.

Tried that. No joy.

Do check the connections on the battery terminals are properly tightened. If not quite right they could be capable of delivering enough amps to bring the systems to life, but not enough to crank. A momentary interruption to the supply might have caused the motor to die in the first place.

Good advice. And I did recently replace the Lithium battery. But the terminals were tight. Thinking it might be a faulty battery I disconnected it altogether and rigged up a conventional lead acid. No joy there either.

The last thing I can do is remove the FIA isolator and earth directly to the body. Then I'm gonna have to start thinking about replacing the EWS and DME.

(I've also tried the spare key!)

 

[mac27040]

have you checked your getting voltage to the starter motor? if yes then it might be a dodgy starter motor even though you have replaced it recently.

 

[Liam22]

I bypassed the FIA isolator and then got the multimeter out.

12V to the starter and 12V to the trigger wire!
So it must be the starter...
Hit it with a hammer and the solenoid released.
What are the chances that mu spare starter was stuck?!

Now the soloenoid clicks but no motor. In fact I can hear the starter "fizzing" when I hold the key to 'start'.

New starter motor ordered.
But I'm still suspicious that the battery is failing somehow. Will try again when the new starter arrives.

 

[Vanne]

Which fia isolator are you using? It took me forever to decide which one to run..yeah def could be that, or maybe something shorted out in the isolator.. that would def be my next port of call.

 

[Liam22]

Nope. I already bypassed the isolator to rule it out. It is fine.

I'm using a Cartek electronic isolator. Never had any trouble with it but find a good location when it can be bolted onto the bare metal of the body.

Mine uses 3 rivnuts to get adequate earthing but it's not the best way.

 

[Vanne]

Glad you found the culprit.

 

[Liam22]

All sorted.

New starter motor (200g heavier, sigh) and it cranked like I've never heard it crank before. Took ~5s to fire so it had also run out of fuel.

What are the chances that it simultaneously ran out of fuel with a failed starter? And that my spare starter was also duff?!

Freaked me out.

Onwards to Donington Park on the 12th October :driving:

 

[Mr Tidy]

Glad you got it sorted Liam and good luck at Donington.

Hopefully you'll post a video!

 

[Wursle]

Liam I’ve looked back through the thread and can see you’ve done lexan rear window and side windows. I can see your rear screen install. I was just wondering how you removed the side windows and what they look like now they are installed? Are they difficult to install and how are they for water getting in?

 

[Autoholic]

Just stumbled across this thread and binge read the whole thing in one go. Thank you for documenting all this here and it is a very impressive journey! Will continue to follow!

 

[Liam22]

What are the chances that it simultaneously ran out of fuel with a failed starter? And that my spare starter was also duff?!

That wasn't quite the end of the saga. I didn't notice until I was bleeding the brakes that the engine light was on. Diagnostics said crank position sensor failure. WTF?!

When I realised that the CPS sits right below the starter motor I figured I must have dropped the starter on it and either damaged the connector or the sensor.

With a week to go before the race at Donington I ordered a new sensor off Ebay and new aluminium bolts from BMW. Then Royal Mail misdelivered the new sensor. Couldn't get one until the Friday morning before the race. Eek!

The connector itself looked fine but thankfully the new sensor did the trick and I was on my way to Donington after lunch

The race itself was great, but I was robbed of a class win. The winner had a 60s penalty for pitting outside of the window but as I had been lapped the penalty neutralised.

https://youtu.be/H6tNfVg8dco?si=vkU0bQf-sn0ixLSG
[youtube]H6tNfVg8dco[/youtube]

 

[Mr Tidy]

I loved that video Lee.

Such a shame about the last corner though.