Stalling? Tuning? - Help

[GDTDMC12]

Unsure if this topics should reside in Engine or Fuel categories.

Since taking possession of 16606 I've known that the tuning will need "fine-tuning". This said I've been having the following issues that may or may not relate to this. If anyone can advise, from the following explanation, what the cause and possible solution is I would be very grateful.

So when driving along there is the hum/rumble of the engine but then periodically the engine produces this choking noise and the car vibrates/jerks with the noise. In my mind it feels as though the engine is gasping for fuel (but this is an interpretation from my non-mechanical/technical mind). It is naturally most prominent when accelerating, and then when taking the foot off the gas/coasting it then splutters some more.  On the drive home today on the M1 there were moments when the rumble of the engine, which does seem to be exceptionally loud, suddenly quietens to a much more harmonious hum and acceleration picks up markedly.

As well as the above symptoms, today for the first time the car kept stalling on me. After a while I noticed that when approaching a roundabout (Yes I was in Milton Keynes - self-professed home of the roundabout), or junction at speed and coming to a halt often the car would stall and I would have to turn the ignition again, often while still in motion. At one roundabout the ignition would not start the car and I had to roll over to the curb/side of the roundabout and after 2 minutes of trying it finally started again. When I was able to slow down and change down through the gears slowly the stall did not happen, or it tried to stall but application of revs kicked it back to life. Naturally for the remainder of my journey, including my return to London I tried my best to slow down gently.

The car was idle in a back yard in Ohio for 25 years and has come back to life only since Christmas. If not tuning or mixture leaning issues then I was wondering if it could be to do with the RPM Fuel Pump Relay (part #101064). It is still running on its original although I do have a new one just in case the original does become problematic. However I'm not entirely certain how to diagnose if the relay need replacing - this could be it (?).

So this is the information I have, I hope I've described the problem(s) well enough.  Any help anyone is able to provide, offer, suggest will be much appreciated.

Thanks.

[Nick H]

(21 Jan 2017, 19:30)GDTDMC12 Wrote: Unsure if this topics should reside in Engine or Fuel categories.

Since taking possession of 16606 I've known that the tuning will need "fine-tuning". This said I've been having the following issues that may or may not relate to this. If anyone can advise, from the following explanation, what the cause and possible solution is I would be very grateful.

So when driving along there is the hum/rumble of the engine but then periodically the engine produces this choking noise and the car vibrates/jerks with the noise. In my mind it feels as though the engine is gasping for fuel (but this is an interpretation from my non-mechanical/technical mind). It is naturally most prominent when accelerating, and then when taking the foot off the gas/coasting it then splutters some more.  On the drive home today on the M1 there were moments when the rumble of the engine, which does seem to be exceptionally loud, suddenly quietens to a much more harmonious hum and acceleration picks up markedly.

As well as the above symptoms, today for the first time the car kept stalling on me. After a while I noticed that when approaching a roundabout (Yes I was in Milton Keynes - self-professed home of the roundabout), or junction at speed and coming to a halt often the car would stall and I would have to turn the ignition again, often while still in motion. At one roundabout the ignition would not start the car and I had to roll over to the curb/side of the roundabout and after 2 minutes of trying it finally started again. When I was able to slow down and change down through the gears slowly the stall did not happen, or it tried to stall but application of revs kicked it back to life. Naturally for the remainder of my journey, including my return to London I tried my best to slow down gently.

The car was idle in a back yard in Ohio for 25 years and has come back to life only since Christmas. If not tuning or mixture leaning issues then I was wondering if it could be to do with the RPM Fuel Pump Relay (part #101064). It is still running on its original although I do have a new one just in case the original does become problematic. However I'm not entirely certain how to diagnose if the relay need replacing - this could be it (?).

So this is the information I have, I hope I've described the problem(s) well enough.  Any help anyone is able to provide, offer, suggest will be much appreciated.

Thanks.

My gut instinct is that your car is suffering from fuel pick up issues. 
 A number of things could of happened.
1) The fuel pick up hose could be collapsing. Starving the engine of fuel. However this is more likely in warm weather. When the fuel in the tank gets too hot from heat coming from the cooling fans. 

2) The fuel filter in the tank could be clogged with muck. (How was the fuel system recommisioned 
after sitting for 25 years?)

3) The fuel pick up hose may have come off the pump. So will run ok with a full tank. But problems occur when fuel sloshes about going round roundabouts etc. 

4) Muck has got past the in tank fuel filter and is stuck in the pump inlet. 

5) The main fuel filter is clogged.

Of course it could be the pump or electrical issues but I think that's unlikely with the symptoms you described.

I think you need to take a look in the fuel tank as a first step. Some good videos on YouTube on how it all goes together.

Hope the helps
Nick

---

It could also be the routing of the fuel pick up hose in the tank and the orientation of the fuel pump.
Search "DeLorean fuel pump" on YouTube for Martin G's video on this.

Nick

[GDTDMC12]

Thanks Nick,

I'll get this problem investigated and take the possible causes you mention into consideration. Hopefully once resolved I will be able to post back to this thread to let you know what it finally was.

Cheers

[Chris Williams]

Nick has posted up some very good comments and are all worthy of checking out to start with. My only other comment would be for the relay, you can put a simple jumper wire in place to by-pass it to check it. Though this is clearly only a short term fix. I do have a good working spare if you need to try one.
Chris