Won't start when hot

[Ron]

Based on his current post, he was running on the startup fuel only? Can it rev up like that? Could it be driven like that? So if he didn?t swap the plugs back immediately, would the problem sort itself out after a few minutes? If so, any guess on how many minutes?

I sounded to me like the CSV was compensating for a lack of fuel during start-up. It would be hard to guess whether it would rev or not. If low pressure was the problem, it would probably rev a little then go too lean...depends on why it's low. (Assuming that the few minutes is waiting on the WUR/CPR to max out (oil ~100?F), it wouldn't take minutes this time of year.) Probably not drivable in either way.
Same with not swapping the plug back -- Without knowing all the pressures (primary, control, rest, hot, cold), there are too many variables to make a reasonable guess about that.

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At this point I can see the CO being WAY off, since it was played with.
If no luck with that, I'd suspect that the WUR/CPR may have problem.
Again, imo, all of the pressures need to be checked.

A gauge set is cheaper than the time, effort and parts thrown at a DeLorean solving fuel problems...sooner or later!

[82DMC12]

A gauge set is cheaper than the time, effort and parts thrown at a DeLorean to solve fuel problems...sooner or later!

Anyone with drivability problems should be buying a K Jet gauge before literally anything else. Can't believe the number of people I have tried to help on Facebook who have thrown tons of parts at it but still haven't put a gauge on it. Not talking about OP, just saying in general.

DeLorean Ownership Welcome Kit -

• Set of three manuals
• K Jet pressure gauge
• Actron Dwell meter
• Multimeter
• Timing light
• Hood backup release cable

[Ron]

+1

(...you left off jumper wire ;-)

[82DMC12]

+1

(...you left off jumper wire ;-)

Probably a couple other things too! But so much could be answered with a small tool investment! Actually they don't need the manuals anymore since they are already posted here in the Resources section. I have all three manuals but I actually go here more often than I crack them open. Nice to be able to search a PDF.

[Deloking]

The quote below is from the DMCH website in the Knowledge Base section ?hot start issues ?. I had hot start issues and the nice folks at DMCH suggested I try this and it worked.
3 - Fuel Distributor P/N 102807 Internal Pressure Regulator - The fuel distributor contains the primary pressure regulator for the fuel system. There is a tiny o-ring inside (about 1/4 inch diameter) that can occasionally fail and cause loss of fuel system rest pressure. The O-ring can be replaced in the field. It is not listed on the parts section of the service manual, if you suspect this issue contact your DeLorean Motor Company Dealer

[Rich]

The quote below is from the DMCH website in the Knowledge Base section ?hot start issues ?. I had hot start issues and the nice folks at DMCH suggested I try this and it worked.
3 - Fuel Distributor P/N 102807 Internal Pressure Regulator - The fuel distributor contains the primary pressure regulator for the fuel system. There is a tiny o-ring inside (about 1/4 inch diameter) that can occasionally fail and cause loss of fuel system rest pressure. The O-ring can be replaced in the field. It is not listed on the parts section of the service manual, if you suspect this issue contact your DeLorean Motor Company Dealer

You're right, it is one of the 5 most likely causes of a hot-start problem mentioned in the Knowledge Base section of the DMCH website that was linked in post #3 of this thread. Glad our buddies at DMCH pointed you the right way when you had a hot-start issue.

The PO for this thread reported having solved the hot-start problem in post #15: a missing non-return (check) valve which meant fuel rest pressure couldn't be maintained per specs after any engine shutdown.

This, in turn, allows fuel to vaporize in the system after a hot shutdown which leads to a very lean startup mixture (and a non-start) unless the engine first cools enough before starting.