5 litre struggle's to start when Hot

This topic contains 20 replies, has 7 voices, and was last updated by Anonymous 8 years, 6 months ago.

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April 11, 2016 at 6:32 pm #15505
Anonymous
Member since: January 1, 1970
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Hi Guys

My VP SS starts strait up when cold but after a 15 min or so drive has to crank over abit to get started again.

Any suggestion

Cheers Az
April 11, 2016 at 7:01 pm #15506
Immortality
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How old is the battery, is the alternator charging properly?

Make sure all the cable connects are clean and tight.
April 11, 2016 at 7:39 pm #15507
Anonymous
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The battery is only 6 months old & I’ve checked the voltage as well as battery terminals are clean and tight.
April 11, 2016 at 8:01 pm #15508
Immortality
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What size battery?

Have you checked battery voltage drop when cranking hot compared to cold?

Have you also checked the earth connections on the block as well as the starter cable connection.

Try another starter relay.
April 12, 2016 at 9:14 am #15511
sands vs
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Starter motor on the way out? Ignition module?
April 12, 2016 at 11:12 am #15512
VRSenator065
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What do you mean by hard to start, does it crank over like normal and not start, or crank slowly?
April 12, 2016 at 6:34 pm #15516
Anonymous
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It cranks over as normal but takes 4 – 5 seconds to start.
April 12, 2016 at 7:11 pm #15517
Immortality
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In that case I’d be looking at the ignition module or possibly the dizzy. May as well try the module first as it’s the easier of the 2 to check.

How old are the dizzy cap/rotor/leads and coil?
- This reply was modified 8 years, 6 months ago by Immortality.
April 12, 2016 at 7:53 pm #15519
Anonymous
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New sparks, leads & coil a month ago – cap and rotor 12 months +
April 12, 2016 at 8:01 pm #15520
Anonymous
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Might just be dropping rail pressure when it’s hot… crappy non return valve in the fuel pump, try flicking the key to run a few times before cranking and see if it changes.
April 12, 2016 at 8:47 pm #15521
Anonymous
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I was reading this on GMH Torana Forum</span>

The most common cause of this problem is leaky (dribbling) injectors. What happens is, when hot after switching off, the pressure in the fuel rail must be maintained for a few hours our at least until the engine cools down to normal. If the pressure drops off too quickly the latent engine heat will cause the fuel to boil inside the rail.

1. The rail is full of vapour (not liquid) for the next restart.
2. More importantly, if the fuel dribbles from the rail thru the injectors to the port & then inside the combustion chambers. When the re-start is attempted, the engine is basically flooded. If the throttle is opened (only for a short time) this clears the flood & the engine will start.

The best method of diagnosis is to leave your test gear on the engine. I am assuming you have a spark gap tester (to see the spark), a noid light (to see the injector pulse) & a fuel pressure gauge (to see not only the actually pressure, but to see how quick it rises or falls). These 3 tools are all you really need to diagnose basic EFI faults. Leave these on the engine, close the bonnet to warm it to full temp, open the bonnet & switch off, monitor the pressure, then try to restart (after 10-20 mins) & make sure you have spark & pulse etc. If the injectors are the cause then have them cleaned or replaced. If you have no spark &/or pulse then go down the electrical path of diagnosis. Your fault may not be fuel related. It may also being any one of a few dozen electrical items. But it’s much cheaper & more effective to diagnose the fault & replace the offending item, than it is to just keep on replacing parts, because somebody on the internet said to do so. I’ve seen owners spends many 100s, sometimes 1,000s of $$, chasing very simple faults, which would’ve been much cheaper if they diagnosed & not guessed.
- This reply was modified 8 years, 6 months ago by VRSenator065.
April 12, 2016 at 9:46 pm #15522
Anonymous
Member since: January 1, 1970
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Well that cut & paste work like shit, see if I can translate what Dr Terry said

the most common problem is leaky ( dribbling ) injectors and the fuel pressure in the rail is dropping. If the pressure drops to quick the latent engine heat will cause the fuel to boil inside the rail and leaving vapor

the dribbling injectors will flood the motor.

Smells like the problem – IJ. Thankyou all for your reply’s

Cheers Az
April 13, 2016 at 6:28 am #15530
cava454
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Leaking injectors. Mine did this. Lift the rail and slide a piece of paper under the injectors. prime the fuel system (don’t crank it).

Then wait for the results.
- This reply was modified 8 years, 6 months ago by cava454.
April 13, 2016 at 10:23 am #15532
VRSenator065
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Cut and paste at the moment sometimes pics up the html stuff, we are going to sort it soon. A work around at the moment is to open up notepad, paste it there then cut and paste from that, it strips off all the html guff that way.
April 13, 2016 at 11:32 am #15534
Anonymous
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“Paste as plain Text” fixes that :XD:
April 13, 2016 at 11:43 am #15535
VRSenator065
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^didnt know that, nice one
April 13, 2016 at 12:12 pm #15536
Anonymous
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VRSenator065 wrote:

^didnt know that, nice one

Doesn’t work everywhere and it may be a browser specific thing but yeah that’s how I get around it!
April 13, 2016 at 4:49 pm #15537
[TUFFVQ]
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I’d suggest the injectors also – mine sometimes does this too when hot.
April 13, 2016 at 5:56 pm #15538
Anonymous
Member since: January 1, 1970
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[TUFFVQ] wrote:

I’d suggest the injectors also – mine sometimes does this too when hot.

The “test” I suggested above will confirm/deny that also, if it’s “better” after the test it’s the non return or the regulator, if it’s “worse” it’s more than likely the Injectors….

Better than throwing parts at it hoping to “fix” it by accident..
April 15, 2016 at 1:18 pm #16145
[TUFFVQ]
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I’d suggest it’s not the regulator in my case as I have a Turbosmart Billet item. Could be wrong though
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