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Starting possible problem
#16
88mph Wrote: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

Great stuff, yes the DVLA had fun with me as well. I was COMPLETELY expecting it, so it was no surprise when the letter came though and I thought "there is no way that have sent my registration document that fast" and sure enough they hadn't, they just wanted some extra paperwork which I had already sent them (albeit I hadn't signed it though :oops: )

I found driving it quite a radical experience for the first 3-4 times.
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#17
OK, the fuel accumulator has already been replaced in the last 6 months, the fuel pump in the last 18 months, so that leaves the check valve or the primary pressure regulator, what is and where is the primary pressure regulator?

I will do the hot test and press the metering flap down just before I add the check valve - will I know what the metering flap is easily?
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#18
About 3/4 down this page: http://www.specialtauto.com/delorean-pa ... ction.html gives a good explanation and pictures.
[ATTACHMENT NOT FOUND]
Quote:will I know what the metering flap is easily?
Big round thing right in the middle of this picture, you will have to remove the airfilter housing first:
[ATTACHMENT NOT FOUND]
Chris
Membership Secretary DOC UK
2018's DeLorean event: http://deloreans.co.uk/forum/showthread.php?tid=5715
VIN#15768 Ex VIN#4584 1972 Bond Bug.
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#19
Wow, thanks Chris, very detailed, I can't go wrong with that.

I shall have it in bits later next week I hope.

As a side note (possible another symptom of the engine starting), this engine has aggressive cams on it (stage 2) and it doesn't enjoy being in gear below 2000rpm, as I haven't owned a stock engine before, is this normal? Or is this a side effect of a stage 2 engine? It is very bubbly/jolty below 2000rpm and isn't much fun to sit in, so I always keep it above 2000rpm.
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#20
I certinally cant see it having anything to do with starting. My old car I put 'lumpy' cams in and yes this was similar at low revs.
Chris
Membership Secretary DOC UK
2018's DeLorean event: http://deloreans.co.uk/forum/showthread.php?tid=5715
VIN#15768 Ex VIN#4584 1972 Bond Bug.
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#21
Be careful, there is a spring in there that will shoot across the room once that fitting is removed. Once the spri g is out use a small magnet retriever to pull the plunger out. Check the o ring and make sure its not torn or warped.
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#22
I have just reread the thread. Has anyone recently adjusted the mixture setting?

The next time it does this, remove the air cleaner and have someone crank. Push down the sensor plate and see if it starts.
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#23
OK, so all my check valve and clips have arrived.
It is way too windy outside to do anything today but before I start I have a nagging question in my head.

1. My car starts from cold
2. IT Doesn't start (nicely) when hot and left for a few hours
3. It WOULD have started if I left it for another 8 hours (or overnight)

That must suggest that the fuel ISN'T leaking back into the tank, otherwise it wouldn't start from hot OR being left for a days.

Might the problem be more of a flooding issue where the fuel CANNOT get back into the tank and is somehow leaking into the pistons under pressure, hence the heavy petrol smell.

I haven't checked the other things yet but what do you think of the above?

Cheers
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#24
Quote: That must suggest that the fuel ISN'T leaking back into the tank, otherwise it wouldn't start from hot OR being left for a days.

Actually it does suggest that you may have a bad chack valve. The failing check valves is a known issue in the new pump/sender combos, and to a lesser extent in the old Bosch pumps with the internal built in valve. Josh Schimek (NightFlyer) was the one who sourced the metal valve most of us use and this valve is now included from the DMC vendors with the new pump units.

Adding that check valve is pretty much a necessary mod now no matter what pump you run. What you are describing is very indicitive of losing rest pressure. The reson your car is starting once it has sit for hours is the cold start valve is aiding in the starting by adding fuel. Once the engine fires, the air trapped in the system is forced out. The thermotime switch will fire the CSV during cranking if the coolant temprature is cold enough (I think it's 95 degrees).

Again, you have a lot to check rather than just start replacing parts. I still think you have an improperly set mixture...which could cause the same thing and it's easy to check.


I personally think the cold start circuit is an unfinished part of the DeLorean. Most CIS cars have a cold start relay which activates no matter what the coolant temprature is if the engine cranks for 5 seconds without hitting. The DeLorean has the relay socket and the wiring, but no relay was ever made to plug into it. Have you ever tried the plug swap when this happens? Did you press the metering plate down (forcing the injectors to fire) during cranking? There is a hot start relay that corrects this and is readily avaliable from here:
http://dm-eng.weebly.com/

Before you order it though, you need to figure out where the problem is. Have you ever tried the plug swap when this happens? Did you press the metering plate down (forcing the injectors to fire) during cranking? You should stop restating the problem in your posts and start diagnosing with the tests given and then we can go from there.
AUTOMATIC TRANSMISSION FILTERS HERE Very Limited Supply Buy below or PM for more info

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#25
Great explanation, thank you.

I often forget the engine is as complex as it is, which is fairly advanced for 1980's.

I shall carry on with all other checks and check valve addition.

PS: Your car looks very cool indeed (the engine bay is highly enviable), I would hope to be somewhere close in a few years, I can't wait to get stuck in but I am still building the garage it will live in - should be there in a few months.
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#26
Trying to follow this for future reference. What is the 'plug swap' method?
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#27
I have the exact same problem with my car,so I'm following this with interest.The last time it occoured I removed the air box to push the plate to check the rest pressure but having not felt it before was unsure what a good one feels like.I did notice the cold start valve was buzzing with the ign. on and when cranking,so I disconnected it and it started after a few cranks.(maybe 5 secs)Not sure if thats coincidence or not but does explain the strong petrol smell,I need to replicate the fault and try it again.
If the fault was rest pressure how come the smell of fuel???
I tried the plate today after 2 days not used and it fall under very light pressure (obviously) ran the car and switched off and checked again and felt resistace as previosly felt when the car would not start.
I hope this may give an insight in to the problem as mine is exactly the same,and to add the idle fluctuates too.
Cheers Max
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#28
Next I'm going to check the thermo time switch,specifically the heater element to make sure the cold start valve (csv) is not constantly working even when hot causing the engine to flood hence the petrol smell.
Sound feasible?
Makes perfect sense to me.
Cheers Max
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#29
Quote:Trying to follow this for future reference. What is the 'plug swap' method
Swap the cold start plug and the plug on top of the round thing just behind it in the picture above.
Quote:Next I'm going to check the thermo time switch,specifically the heater element to make sure the cold start valve (csv) is not constantly working even when hot causing the engine to flood hence the petrol smell.
Sound feasible?
Sounds like a good idea to me.
Chris
Membership Secretary DOC UK
2018's DeLorean event: http://deloreans.co.uk/forum/showthread.php?tid=5715
VIN#15768 Ex VIN#4584 1972 Bond Bug.
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#30
You can test the thermotime switch with it in situ. One of the two pins should read zero resistance to ground and the other, the heating element, should be 30 odd Ohms.

If you find you need a new one, I have a spare lying around that I bought by mistake because I misdiagnosed the circuit first time around.

In the end my problem with this circuit was that there was no continuity between the grounding pin on the cold start valve and and the thermotime switch. The switch was doing the right thing all along but no ground connection was getting to the CSV, so it never fired.

Have fun!
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