Intermittent starting issue

4.2 V8 32v Naturally Aspirated - 414 bhp
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rs4dave
Neutral
Posts: 16
Joined: Mon Apr 13, 2020 12:15 pm

Intermittent starting issue

Post by rs4dave » Fri Jun 04, 2021 2:47 am

Hi Guys,

Have had a weird problem rear its ugly head recently. Details below:

-car will start 1st time every morning with no issues
-after driving the car and getting it up to normal operating temperature (oil temp 95C and above) the car will not restart once it has been shut off.
-the car will only restart after the oil temp has dropped into the min-high 80s
-with the ignition on and the clutch pedal in you can hear the starter relay click when the start button is pushed but the car does not turn over

I have done the following:
-replaced starter relays
-brand new starter motor installed


Has anyone else had the same issue ? If so what could it be?

thanks in advance
Dave

coffey555
5th Gear
Posts: 1137
Joined: Wed Aug 17, 2011 2:41 pm

Re: Intermittent starting issue

Post by coffey555 » Fri Jun 04, 2021 10:36 am

Is the heat shield installed next to the starter motor? My mate had the same problem, changed the starter, still did it.

Then he installed the heat shield (which was somehow missing) and that fixed the problem.
Misano Red RS4 B7 Avant

mikep99
4th Gear
Posts: 716
Joined: Fri Jul 17, 2015 9:03 am

Re: Intermittent starting issue

Post by mikep99 » Fri Jun 04, 2021 11:03 am

Sounds similar to the issue I had.
I've come to the conclusion that when the under bonnet temps are high, the amps on the starter wire from the ECU drop for some unknown reason.
You can start it by shorting the starter wire with the positive terminal, there's a connector right next to it. See pics.
For the time being, I've put a relay on the starter circuit which lets the starter pull the power from the positive terminal when starting.
Not a had a problem since.... touch wood...

HTH
Mike
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rs4dave
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Posts: 16
Joined: Mon Apr 13, 2020 12:15 pm

Re: Intermittent starting issue

Post by rs4dave » Sat Jun 05, 2021 12:08 am

coffey555 wrote:
Fri Jun 04, 2021 10:36 am
Is the heat shield installed next to the starter motor? My mate had the same problem, changed the starter, still did it.

Then he installed the heat shield (which was somehow missing) and that fixed the problem.
Yes heat shield is installed
mikep99 wrote:
Fri Jun 04, 2021 11:03 am
Sounds similar to the issue I had.
I've come to the conclusion that when the under bonnet temps are high, the amps on the starter wire from the ECU drop for some unknown reason.
You can start it by shorting the starter wire with the positive terminal, there's a connector right next to it. See pics.
For the time being, I've put a relay on the starter circuit which lets the starter pull the power from the positive terminal when starting.
Not a had a problem since.... touch wood...

HTH
Mike
Thanks Mike, I'll give that a shot

mikep99
4th Gear
Posts: 716
Joined: Fri Jul 17, 2015 9:03 am

Re: Intermittent starting issue

Post by mikep99 » Sat Jun 05, 2021 9:15 am

Just make sure you short the side of the connector that goes to the starter, not the ECU

Mike

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Andyevo
2nd Gear
Posts: 193
Joined: Thu Mar 04, 2010 9:23 am
Location: Sunny Devon, UK

Re: Intermittent starting issue

Post by Andyevo » Wed Jun 09, 2021 6:54 am

Morning,

I had a similar issue a while ago, does it have an aftermarket alarm fitted by any chance?

Andy

rs4dave
Neutral
Posts: 16
Joined: Mon Apr 13, 2020 12:15 pm

Re: Intermittent starting issue

Post by rs4dave » Thu Jun 17, 2021 5:35 am

Andyevo wrote:
Wed Jun 09, 2021 6:54 am
Morning,

I had a similar issue a while ago, does it have an aftermarket alarm fitted by any chance?

Andy
Hey Andy,

Factory alarm, nothing aftermarket

rs4dave
Neutral
Posts: 16
Joined: Mon Apr 13, 2020 12:15 pm

Re: Intermittent starting issue

Post by rs4dave » Sun Jul 11, 2021 9:22 am

Problem solved - replaced the starter cable from the plug at the battery terminals all the way to the starter solenoid, used extra heat sheilding and changed the location from where it was originally run near the headers. Have not had an issue since.

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