Hot Start issue after new Catalytic Convertor and smog adjustments made

[skywalker77]

Good afternoon DMC community. [I'm a new Delorean owner as of this past June and have been having a blast learning as [I] go. [I]'ve spent a little more than [I] have wanted to making the car right but [I]'m happy to do it for the experience [I]'m having with my boys.

The car is finally back from the Delorean shop in CA after having smog passing issues. They made some mixtures adjustment, replaced the convertor and it passed. [I] got it home and it had trouble turning over after driving it for 15 minutes plus. This never happened prior to the adjustments being made. [I] spoke with Deloren and they informed me that the car may be running to rich as they attempted to adjust the mix prior to replacing the cat. Does any of this make sense to anyone? [I]s it possible that this could be the issue? The fuel accumulator has not been replaced but just about everything else has been under the hood.

Any help anyone could offer would greatly be appreciated.

[Delorean Industries]

Good afternoon DMC community. [I'm a new Delorean owner as of this past June and have been having a blast learning as [I] go. [I]'ve spent a little more than [I] have wanted to making the car right but [I]'m happy to do it for the experience [I]'m having with my boys.

The car is finally back from the Delorean shop in CA after having smog passing issues. They made some mixtures adjustment, replaced the convertor and it passed. [I] got it home and it had trouble turning over after driving it for 15 minutes plus. This never happened prior to the adjustments being made. [I] spoke with Deloren and they informed me that the car may be running to rich as they attempted to adjust the mix prior to replacing the cat. Does any of this make sense to anyone? [I]s it possible that this could be the issue? The fuel accumulator has not been replaced but just about everything else has been under the hood.

Any help anyone could offer would greatly be appreciated.

That process is backwards. The fuel adjustment must be made after replacing the converter not before. If you are flooding hot due to an extremely rich mixture it would need to be pretty far out of adjustment. The cause IF the mixture is truly adjusted correctly after the converter replacement is either the accumulator or PPR orings on the fuel distributor. If the vehicle passed smog I would doubt that it would be that far out of adjustment to be the cause of the issue.

[skywalker77]

Appreciate the response. [I] know they messed with the mixture prior to replacing the cat. [It has to be one of the two things you mentioned, [I] just found it odd that is happened right after they adjusted it and replaced the cat. [I]s it tough replacing the O Rings if it's not the accumulator? The accumulator is original from 83.

[Delorean Industries]

Appreciate the response. [I] know they messed with the mixture prior to replacing the cat. [It has to be one of the two things you mentioned, [I] just found it odd that is happened right after they adjusted it and replaced the cat. [I]s it tough replacing the O Rings if it's not the accumulator? The accumulator is original from 83.

If you do not have the experience or knowledge to work on the car I would not try tackling either. It is very easy to break off an accumulator line within the frame or damage the PPR piston etc without knowing what you are going after. There is plenty of help on the forums here including myself and other vendors. You will need to gauge if you are willing to take it on or not. It is a couple hours labor and about 160 in parts to do both. DMC CA may be the quickest and safest route.

[Rich]

.... [I] got it home and it had trouble turning over after driving it for 15 minutes plus. This never happened prior to the adjustments being made. The fuel accumulator has not been replaced but just about everything else has been under the hood.

A. When we talk about a Hot Start Issue it means the engine is warm/hot and it DOES crank (turn over) real well, but it will not start or it starts only after a LOT of cranking. You say yours has trouble turning over/cranking?

B. If it is a Hot Start Issue (turns over, will not start easily when hot) then the one of the first steps can be the pressure plate test to verify some level of fuel rest pressure when the engine is warm/hot. Drive the car, shut it off and remove the air cleaner assembly. Push lightly on the circular plate/flap at the air metering inlet on top of the manifold. It should hold a few pounds of force before moving and if you do move it a bit it should pop back up. If it doesn't then the system probably has low fuel rest pressure and the car won't start easily - or at all - until it cools off enough. Then it will start fine.

The air meter flap/plate is directly linked to a metering valve that sees the fuel rest pressure.

Worry about the accumulator or other fuel-rest-pressure causes only after you know if there is any fuel rest pressure when the engine is hot.

[David T]

The next time you have a hard hot restart try swapping the plugs with the CSV and the CPR. If that gets it started you have a rest pressure problem. If that is so you can start with replacing the accumulator. Do NOT try adjusting things to fix it.
David Teitelbaum

[skywalker77]

Love all the solid help, I am taking it to DeLorean CA to have them look at it. As a few of you mentioned, I don't want to screw anything up. I will be learning as I go which hopefully will be the fun of owning the car. With the money I have already spent restoring the car with DeLorean, they have a solid idea of what the problem is. Danny at the shop is a great guy and really seems have a ton of respect within the DeLorean community.

Looking forward to tinkering with this amazing car while gathering a ton of knowledge from all of you. Thanks again.

[skywalker77]

A. When we talk about a Hot Start Issue it means the engine is warm/hot and it DOES crank (turn over) real well, but it will not start or it starts only after a LOT of cranking. You say yours has trouble turning over/cranking?

B. If it is a Hot Start Issue (turns over, will not start easily when hot) then the one of the first steps can be the pressure plate test to verify some level of fuel rest pressure when the engine is warm/hot. Drive the car, shut it off and remove the air cleaner assembly. Push lightly on the circular plate/flap at the air metering inlet on top of the manifold. It should hold a few pounds of force before moving and if you do move it a bit it should pop back up. If it doesn't then the system probably has low fuel rest pressure and the car won't start easily - or at all - until it cools off enough. Then it will start fine.

The air meter flap/plate is directly linked to a metering valve that sees the fuel rest pressure.

Worry about the accumulator or other fuel-rest-pressure causes only after you know if there is any fuel rest pressure when the engine is hot.

Good evening Rich, to answer your question, the car does turn over after hot. It takes 2 to 3 times but it does turn over. Once running, it runs very rough until the engine catches and than it run fine.

[Rich]

Good evening Rich, to answer your question, the car does turn over after hot. It takes 2 to 3 times but it does turn over. Once running, it runs very rough until the engine catches and than it run fine.

Sorry, I still am probably missing your symptom description.

Stop me wherever this summary of the symptoms is wrong. For the purpose of this chat "turning over" means cranking with starter and it does not mean "engine running without starter".

1. With engine hot.
a. Engine turns over or cranks (start attempt with starter engaged) and will turn over or crank every time you try it.
b. It takes 2-3 such episodes of cranking, maybe quite long episodes, before the engine starts to run roughly on its own such that you can release the starter.
c. After it begins running on its own it takes >>15 seconds of rough running before it settles down and it then runs normally.

2. With engine cool-cold it will fire up fast and runs OK. Less than 5sec of cranking to get her going.

[skywalker77]

Sorry, I still am probably missing your symptom description.

Stop me wherever this summary of the symptoms is wrong. For the purpose of this chat "turning over" means cranking with starter and it does not mean "engine running without starter".

1. With engine hot.
a. Engine turns over or cranks (start attempt with starter engaged) and will turn over or crank every time you try it.
b. It takes 2-3 such episodes of cranking, maybe quite long episodes, before the engine starts to run roughly on its own such that you can release the starter.
c. After it begins running on its own it takes >>15 seconds of rough running before it settles down and it then runs normally.

2. With engine cool-cold it will fire up fast and runs OK. Less than 5sec of cranking to get her going.

Rich, everything you listed is exactly what is going on. Delorean CA truly believes the car is running to rich after adjustments were made to try to pass smog before cat convertor was changed. The reason, none of this was happening before [I] brought it in. [I]'m taking the car back to them in two weeks to see what they find. Keep in mind, [I] just spent $8,500 to get the car completely redone under the hood which took a couple of months. [I] took the car out twice today for a short drive and the hot start issue didn't happen. To add to this, getting a light smell of gas in the car. Good times!

[Ron]

$ .02

If you are smelling raw gas, it is probably the source of the problem -- ANY pressure leak will cause a hot start problem.

[kings1527]

Just curious. Did you ever find a solution to this problem?