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tony_ack

VR6 Starting problem(s)

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Posted (edited)

Hi everyone,

I'm trying to fix a starting problem. 

Sometimes I turn the key and I get no crank. X-over relay kicks in but nothing from the starter. Sometimes it kicks in after a short delay (anything between half a second and about 5-6 seconds) Sometimes it doesn't start at all.

I also get an issue where sometimes the starter does spin but it's not engaging with the flywheel (it spins freely). There are a couple more intermittent starting issues but I'm pretty sure these are fuel management/crank sensor related.

I changed the ignition switch to rule that out - it seemed fine for a few days and then started doing it again.

I am planning to get a refurbed VR6 starter, but is there anything I'm missing that might be causing the problems?

Is there anything to look out for when getting a new starter? Differences in years, etc.?

I did get a MK4 V5 starter a while back but it's completely the wrong shape.

Edited by tony_ack

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Does sound like a starter motor issue. It's always good to change the ignition switch as it rules that problem out 👍

I thought the mk4 v5 starter motor was supposed to be the upgrade !!

Can you get yours off and get it refurbished?

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Engine earth fitted, clear of corrosion and tight?

 

out of gear, remove the small wire to the starter and put 12v positive to it (this bypasses the ignition switch) - don’t run yourself over!

clean battery / earth / starter connectors are essential for the starter to crank over an engine with compression, bad connections steal amps from the starter and volts (ecu will need to reach its minimum voltage to function) from other circuits as the starter trys to complete its task.

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I've had exactly the same problem, sometimes get no crank, sometimes a few second delay, sometimes starts instantly.

New starter motor has made no difference.

New ignition switch seemed to cure it but then happened again a few days later.

Battery is recent and strong, been on a trickle charge too.

What does that leave? Engine earth - are there more than one? Where are they?

Thanks!

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5 hours ago, Dox said:

Engine earth fitted, clear of corrosion and tight?

 

out of gear, remove the small wire to the starter and put 12v positive to it (this bypasses the ignition switch) - don’t run yourself over!

clean battery / earth / starter connectors are essential for the starter to crank over an engine with compression, bad connections steal amps from the starter and volts (ecu will need to reach its minimum voltage to function) from other circuits as the starter trys to complete its task.

I've cleaned them up a few times (including when I had the starter off a couple of months back) but maybe not enough. For the earths, are you meaning the bulky cable from the starter to the battery? Or the earth points on the head?

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Starter / battery

 

battery to gearbox

also any corrosion (or paint) where the starter touches the bellhousing

 

basically anything in the circuit that’s causing resistance (voltage drop).

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Tony, just wondering if the starter clutch spindle needs cleaning?. If it spins but doesn't engage it may be that the driver gear is being prevented from being thrown out. 

Hasan

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I finally managed to fit a refurbed Bosch starter today. All wiring was cleaned as I refitted, as was the bellhousing.

So the new starter cranks much better than the old one - I never thought the old one was weak, but I see now it must have lost a lot of power.

It's been cranking and starting on the first touch of the key all day, but this evening on my last journey home there was perhaps a 1/2 second delay between turning the key, and the starter turning over. It might not sound like much, but this is how the problems begin, and the occasional delays increase until eventually nothing happens. If the starter does kick in after the delay, it does so at normal full power, there's no hint of voltage drop.

I've now replaced the ignition switch and starter and cleaned up the wiring and earths. Is there anything else it could be?

I'm starting to wonder if the aftermarket immobiliser is involved? It's an old Laserline 996 that is literally falling to pieces - the install manual suggests one of the immobiliser circuits is between the ignition switch and the starter solenoid...

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The starter body earths on the gearbox housing, is that the current resistance in the starter circuit?

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47 minutes ago, Dox said:

The starter body earths on the gearbox housing, is that the current resistance in the starter circuit?

I cleaned up the contact area on the gearbox before fitting the starter. It wasn't bad, but benefited from a wire brush and a spray of contact cleaner

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16 hours ago, Cressa said:

Is there a relay Involved somewhere in this circuit? 

There's a relay on the starter itself which I've ruled out when I replaced the starter. There's the x-over relief relay, but I don't think that sits between the ignition switch and the starter? (I could be wrong...)

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Right so it's let me down again today. There is a click in the engine bay when trying to start which I guess rules out everything to do with the switch and immobiliser, and any wiring behind the dash.

That leaves the big positive from the battery to the starter (cleaned at the starter) the contact between the starter and gearbox (cleaned up when swapping over) or the big earth from the gearbox to the battery (will look at this again at it not a thorough clean as it was hard to reach)?


No idea why, but it always ses to start fine when it's completely cold.


Sent from my Pixel 4 using Tapatalk

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The plot thickens!!

I've been armed with a multimeter today to try to work out what's going on.

Normal readings (cold, left overnight, engine off). The engine started fine after I took these.

  • Voltage across the battery = 12.1v
  • Resistance battery negative to starter housing = 0.01ohms
  • Resistance battery positive to positive starter terminal = 0.01ohms

After being run (warm, engine just turned off)

  • Voltage across the battery with engine off = 12.25v
  • Resistance battery negative to starter housing = 0.01ohms
  • Resistance battery positive to positive starter terminal = 0.01ohms

When starter won't engage (engine obvs off, usually 10 mins - 3 hours after last been run, happened twice today)

  • Voltage across the battery with engine off = 12.1v
  • Resistance battery negative to starter housing = 0.01ohms
  • Resistance battery positive to positive starter terminal = 0.01ohms

 

So nothing obvious there... BUT...

When the starter didn't engage today, the relay definitely clicked in the starter when I turned the key. I wondered whether rocking the car back and forth in gear might help a little, so put it into third and rocked back and forth, with the ignition on... as I rocked the car I heard a two quick clicks from the fusebox area. Then I tried to start and guess what.... fired straight up!!

So when it happened again later (luckily both times were at home), I decided to experiment.

Starter got no power, so I'd rock the car a little (no fusebox clicks), tried to start... nothing

Then I'd rock the car a little more, the fusebox would click and the car started.

Also, I heard another fusebox click about 2-3 seconds after switching the engine off. Tried to start again... nothing.

I repeated it all, same results - I'm convinced the clicking is a relay that is causing the issue.

There is nothing in the fusebox diagrams related to starting, other than the x-over relief relay, which I've replaced with another (made no difference)

Now I'm wondering the aftermarket immobiliser is kicking in and killing the solenoid (and I'm getting the click at the starter because the solenoid kicks in briefly before the immobiliser kills the circuit?)

Bloody Corrados.

 

 

 

 

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Always nice to get a little further with your investigations, so well done and thanks for sharing.

Sounds like it's time to uncover your alarm/immobliser. 

I'm going to check my battery voltage, but that sounds slightly low on the voltage scale after just switching off

Good luck in having got this far 👍

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Perhaps a silly suggestion,  but are all the connectors behind the fuse box seated properly and is the locking bar in position? Also, are the wires going to the large red connector all ok? I had an issue with mine when I swopped out the autobox to a manual years back so i can't remember the connector or wiring unfortunately 

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Thanks - I'm going to do some investigating this weekend. The alarm/immobiliser needs taking out anyway as there are quite a lot of things going wrong with it. And I'll have a good look behind the fusebox at the same time as the control box for the alarm is nearby.

It happened a few times again yesterday, but rocking the car in gear with the ignition on always sorts it, so at least there is a workaround.

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Have the pins the relays connects to become loose?

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Bypassed the immobiliser yesterday, everything okay so far and the milliseconds delay when starting has gone too, fingers crossed.

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1 hour ago, tony_ack said:

Bypassed the immobiliser yesterday, everything okay so far and the milliseconds delay when starting has gone too, fingers crossed.

Looking good, well done in persevering  🤬🤣

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