Another but different hot start problem:(

[ssaleen]

Ok, every summer and any warm days this car can really piss me off.
Mornings or cold start starts up perfectly. After it has ran at all unless it is super cold outside
It takes like 4-6 good cranks before it will start and smells bad of fuel.
It seems like to me it's flooding it's self out. It sucks to sit in a parking lot or the gas station
Cranking your car for 10 min while everybody is looking at you.
Does anybody have a clue why it would flood it's self out after running?

[sdg3205]

Cold start injector firing when it shouldn't be?

Next time you anticipate the problem on a hot start, pull the plug off the CSV before you start it.

[Elvis]

Also check the resistor and the bypass relay.


tons of informations about it here in the forum...

[Bitsyncmaster]

Cold start injector firing when it shouldn't be?

Next time you anticipate the problem on a hot start, pull the plug off the CSV before you start it.

+1

I found my car will start better in the summer with the CSV always unplugged.

[ssaleen]

Alright thanks I will try that!!

[Rich]

Ok, every summer and any warm days this car can really piss me off.
Mornings or cold start starts up perfectly. After it has ran at all unless it is super cold outside
It takes like 4-6 good cranks before it will start and smells bad of fuel.
It seems like to me it's flooding it's self out....


You describe what sound like a normal hot-start problem. What is different about it?

The bad fuel smell after finally hot starting may be just a lot of unburned fuel from the exhaust, so not different?

Your car may have a fuel leak between the pump and the fuel distributor. Or a bad accumulator.

Since cold starts and normal operation after starting are OK we rule out ignition and fuel pump.

It is important for the car to maintain rest pressure after hot shut-down, otherwise the engine will not start properly. For this one needs a good accumulator, good check valve in the pump, good seal in the fuel distributor and tight fuel lines.

Do you smell fuel also after the engine is off or for some hours after it is off?

[ssaleen]

You describe what sound like a normal hot-start problem. What is different about it?

The bad fuel smell after finally hot starting may be just a lot of unburned fuel from the exhaust, so not different?

Your car may have a fuel leak between the pump and the fuel distributor. Or a bad accumulator.

Since cold starts and normal operation after starting are OK we rule out ignition and fuel pump.

It is important for the car to maintain rest pressure after hot shut-down, otherwise the engine will not start properly. For this one needs a good accumulator, good check valve in the pump, good seal in the fuel distributor and tight fuel lines.

Do you smell fuel also after the engine is off or for some hours after it is off?


Well I figure it was different because a lot of other people were saying they smelled no fuel when it won't start.
My car smells bad like its flooded. Last night it did it pretty bad and I had to put the gas peddle to the floor and I barely got it started that way. Otherwise I never touch the gas when I start it.
I never smell gas other then when it's turning over for a warm start.
Then when it finally starts raw fuel comes out the exhaust for a bit till it clears out the cylinders.

[Rich]

My car smells bad like its flooded. Last night it did it pretty bad and I had to put the gas peddle to the floor and I barely got it started that way. Otherwise I never touch the gas when I start it.
I never smell gas other then when it's turning over for a warm start.
Then when it finally starts raw fuel comes out the exhaust for a bit till it clears out the cylinders.

A good description here. Thanks.

As you say, there is normally no need to open the throttle for starting.

If the engine is flooded then wide-open throttle can clear it just as you describe, with the fuel-smell from the unburned fuel and momentary rough running as you note.

So here is what might be happening. Loss of hot rest pressure --> vapor lock in FI system at time of hot-start --> incorrect fuel metering during startup --> long-cranking times --> flooding. Flooding is a symptom, not a cause.

Loss of rest pressure is typically caused by a failed fuel accumulator. Can also be from pump or fuel distributor leak, both less likely.

From the K-Jet manual:



Fuel accumulator

The fuel accumulator maintains the
pressure in the fuel system for a certain
time after the engine has been switched
off in order to facilitate restarting, particularly
when the engine is hot.....

[ssaleen]

A good description here. Thanks.

As you say, there is normally no need to open the throttle for starting.

If the engine is flooded then wide-open throttle can clear it just as you describe, with the fuel-smell from the unburned fuel and momentary rough running as you note.

So here is what might be happening. Loss of hot rest pressure --> vapor lock in FI system at time of hot-start --> incorrect fuel metering during startup --> long-cranking times --> flooding. Flooding is a symptom, not a cause.

Loss of rest pressure is typically caused by a failed fuel accumulator. Can also be from pump or fuel distributor leak, both less likely.

From the K-Jet manual:



Fuel accumulator

The fuel accumulator maintains the
pressure in the fuel system for a certain
time after the engine has been switched
off in order to facilitate restarting, particularly
when the engine is hot.....


I will check that out!! Thanks but I also forgot to mention that the whole fuel system is brand new with rebuilt injectors.

[Rich]

the whole fuel system is brand new with rebuilt injectors.

The accumulator is new? Good.

The fuel pump as well?

Try the flow plate test as a first cut to verify hot rest pressure. It needs to be ruled out because it is the #1 cause of hot-start K-Jet problems on a car with good ignition. Even new parts can be bad or incorrectly installed.

[ssaleen]

The accumulator is new? Good.

The fuel pump as well?

Try the flow plate test as a first cut to verify hot rest pressure. It needs to be ruled out because it is the #1 cause of hot-start K-Jet problems on a car with good ignition. Even new parts can be bad or incorrectly installed.

Yes the fuel pump is new also. I bought that whole fuel kit from hervey.

What exactly is the flow plate test. Is that checking flap under the air cleaner to see if it has some pressure after the car is shut off?

[ssaleen]

I just warmed it up then shut it off, and there is no pressure on that flap under the air cleaner?

[Bitsyncmaster]

I just warmed it up then shut it off, and there is no pressure on that flap under the air cleaner?

Masive leak. My guess would be the pump check valve since your engine is running.

[Ron]

Then you need to find where you are loosing pressure. I'd start by looking at the o-ring(s) in Control Pressure Regulator in the fuel distributor (since everything is new, but as said, you never know). Lots of threads about rest pressure...

[ssaleen]

Masive leak. My guess would be the pump check valve since your engine is running.

Where is the pump check valve at? I'm not sure about that one. Are you talking fuel pump?

[Bitsyncmaster]

Where is the pump check valve at? I'm not sure about that one. Are you talking fuel pump?

On top of the pump. It's part of the banjo fitting.

[ssaleen]

Where is the plunger in the fuel distributor with the o-rings on it? I took it off but all I see is the plunger under it
That doesn't have o-rings

[ssaleen]

On top of the pump. It's part of the banjo fitting.

Ok I'll check that!!

[Bitsyncmaster]

Where is the plunger in the fuel distributor with the o-rings on it? I took it off but all I see is the plunger under it
That doesn't have o-rings

If you mean the primary pressure regulator (PPR), it's under that large nut on the front right side of the FD. There is a "piston" and a spring that presses it down. The O-ring that may cause loss of rest pressure is on the piston.

[Ron]

Should have said *Primary* Pressure Regulator.
Anyway, check this out (2nd post):
http://dmctalk.org/showthread.php?1446-How-to-replace-hot-start-o-rings-in-fuel-pressure-plunger-on-Fuel-Distributer

Then this:
http://specialtauto.com/delorean-parts/images/Prim-press-regulator-1.jpg

Don't mess with the o-ring(s) if you don't see anything wrong (broke, cut, pinched, etc)...and look for a sliver up in the bore).

EDIT: I'm glad Dave is around to slap me in line every once in a while....

[Rich]

Then you need to find where you are loosing pressure....

+1

Your flow plate test confirms the situation.

With low or no rest pressure the car will not start hot, at least not very easily. Will start cold. Or if you wait long enough at the gas station.

Same problem can occur on VW's, Porsches, BMWs or anything else with K-Jetrtonic.

You are getting there, I see.

[David T]

To confirm the classic hard hot restart just do the plug swap. If it fires right up you are not holding rest pressure. Since you say you replaced the accumulator my guess would also be the fuel pump check valve. Since you say you smell fuel I would double-check that you have no external fuel leaks. Another possibility is that the Cold Start Valve is running all the time. Could be a problem with the Thermo-Time switch or the wiring. Is there anything plugged into the hot start relay plug?
David Teitelbaum

[ssaleen]

Thank you guys for all the good info. I couldn't figure anything out today but im gonna mess with it again tomorrow.
Ill also look at the hot start relay. Oh and I took the plunger out of the FD but the main part stayed in there and I didn't have time to try to get it out to check the o-ring. So maybe tomorrow ill have more time for that also.

[Bitsyncmaster]

Thank you guys for all the good info. I couldn't figure anything out today but im gonna mess with it again tomorrow.
Ill also look at the hot start relay. Oh and I took the plunger out of the FD but the main part stayed in there and I didn't have time to try to get it out to check the o-ring. So maybe tomorrow ill have more time for that also.

You have to work that "piston" out of the FD with a stick or other tool.

[ssaleen]

To confirm the classic hard hot restart just do the plug swap. If it fires right up you are not holding rest pressure. Since you say you replaced the accumulator my guess would also be the fuel pump check valve. Since you say you smell fuel I would double-check that you have no external fuel leaks. Another possibility is that the Cold Start Valve is running all the time. Could be a problem with the Thermo-Time switch or the wiring. Is there anything plugged into the hot start relay plug?
David Teitelbaum

The hot start relay plug, if your looking at the back of the car it is on the valve cover on the right just under the air box? If it is then there is a plug, plugged into it. Also I just checked the check valve in the FD and both o-rings are perfect.

[Ron]

The Hot Start Relay Socket is in the relay compartment behind the passenger seat (White and empty, as it should be, in the pic below):


http://i125.photobucket.com/albums/p48/jaq78/DSC06574.jpg

[ssaleen]

The Hot Start Relay Socket is in the relay compartment behind the passenger seat (White and empty, as it should be, in the pic below):


http://i125.photobucket.com/albums/p48/jaq78/DSC06574.jpg


That's wierd I just looked at my electrical box which has been the first time since I've owned my car, and it looks alittle different then yours. I think my plug may be black. It is the only plug that has nothing plugged into it and it looks to be in about the same location yours is in.

[DeLorean03]

Mine is black too. Nothing to fear there!

[Ron]

+1

Well hell! I have always told people that the socket is black (like mine; the pic is from another thread) and every time someone says they are white and it must be because I have an early VIN... LOL

[jawn101]

+1

Well hell! I have always told people that the socket is black (like mine; the pic is from another thread) and every time someone says they are white and it must be because I have an early VIN... LOL

Hey Ron - mine's black too. Remember a while back you and I had some interesting discoveries about the engine harness variances too, while troubleshooting a cold start issue I had? Different colored wires to the TTS and CSV than expected.

[Ron]

:hihi2: