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Starting possible problem
Hi there,

1st question, how do you set up your account so that you get an email when a new post comes up on the website?

2nd and main question:

My car starts first time every time in sub zero or warm outside temperature, however it has always had a strange start up from warm issue.
If you go to a petrol station with a fully warmed up engine, fill up with fuel and start the car, it will fire up with no problems.
If you go for a long drive, park up and come back an hour later, the car will start but sound like it is running on 3 cylinders for 10 seconds before starting to purr again.
If I attempt to rev the car during this first 10 seconds the car will sound like it running on only 1 cylinder and eventually cut out and be very difficult to start again, it will also smell strongly of petrol at the exhaust.
If you try and start it after an hour with the throttle down at all, it will not start and flood the engine completely and smell of petrol at the exhaust and will not start until left to rest for at least 10 minutes.

Any ideas?

All the best.
I wonder if it's the fuel pick up hose in the tank collapsing (as they do) this would explain why it fires after re-fuelling as you have added cold fuel to the tank? Just a thought.
Membership Secretary DOC UK
2021's DeLorean event:
VIN#15768 Ex VIN#4584
Re the email notifications I believe that is done on a per topic basis, you need to click the subscribe button:


I agree with Chris, it certainly sounds like a pickup hose issue.

Do you know if the pickup hose has been replaced? If it has then perhaps it is not at the correct orientation and maybe kinked.

Maybe the in tank filter in the baffle has become blocked?

Best thing would be to (when the tank is low on fuel) remove the fuel pump and take a look.

If the pickup hose looks to be in good condition, then installing a spring down it will prevent it from collapsing. I made up a spring using some 0.6mm stainless welding wire.

If you buy a new pickup hose, I would still recommend putting a spring down it as it will prevent the pipe from collapsing in the event you get stuck in stop/start traffic.
VIN# 04708, Grey interior, 5 speed, October 1981
DOC 649
ex DOC 562
Thank you for both your replies.

I am actually low on fuel now, so that seems like a good plan, I shall remove, inspect and post my findings.

Thanks for the "subscribe" advice, I have wondered how to do this for years! :oops:
Here is a good video detailing the orientation of the parts in the tank which should help:
VIN# 04708, Grey interior, 5 speed, October 1981
DOC 649
ex DOC 562
I just spotted this on an invoice from 2013.

Does this suggest this might not be the problem?
Hmmm. Ok, ignore everything I wrote re the pickup hose and in tank filter as they are not present on the new style combo pump.

The new style pumps are known for the internal check valve failing within a relatively short period of time. The 'fix' for this is to install an external check valve.

This one appears to be the 'recommended' one used by folks on dmctalk: ... &catid=945
VIN# 04708, Grey interior, 5 speed, October 1981
DOC 649
ex DOC 562
Ahh yes the early ones did not have the check valve as Mike suggested so this would be the easiest (and cheapest) route to check first.
Membership Secretary DOC UK
2021's DeLorean event:
VIN#15768 Ex VIN#4584
I shall do it now! :wink:
I found these. The valve is rated for injection pressure and has a lifetime warranty (for what ever that's worth).

I shall update the results.

Can someone please explain why this valve 'could' cause bad running once the pump is running?
Is the fuel running back into tank & pump sucking air? And what does heat have to do with it?
I think the problems are generally when the engine has run until hot and then shut down for a period of time - not whilst actually running.

I guess the fuel is draining out of the fuel line back into the tank causing an air bubble in the fuel system? I am not certain, one of the pros will answer this I hope.

88mph - How are you getting on with the restoration?
Going well. It only needed a very light resto. I wasn't ever after a show-car, just a driver with everything working correctly.
To be honest it could do with new seat covers, but I've just spruced the interior, had the binnacle recovered & rattle-canned the front and rear fascias.
Had great fun sorting little issues (oil pressure sender, screen wash, stereo, etc) but its been MOT'd for the past fortnight and sat there waiting on DVLA to send me my V5.
Still needs a few things but hope to be out & about in it soon. Tongue
From the symptoms you describe it doesn't sound like a hot start issue, so before randomly swapping bits, do a simple hot start diagnostic first:

When the engine is nice and hot, turn off ignition and remove air filter box.

Gently press the metering flap down...any resistance? The metering flap should still offer significant resistance to being pressed down at least 10 minutes after engine off. If not then your problem is 99% likely to be one of the big three - either the fuel accumulator, primary pressure regulator, or check valve in the fuel pump
Richard H. DOC 365 VIN 1274
In theory, theory and practice are the same. In practice, they are not.
Poor running after hot start suggests you've still got at least some liquid fuel in the lines, enough to run the engine. You have to keep it running long enough to wirk the vapour through, then it'll run on all 6.

One running, the check valve does nothing. It and the accumulator are only there to maintain rest pressure so the fuel doesn't vapourise.
Martin Gutkowski
DeLorean Cars

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