New fuel pump

[painterdave72]

Hi all.. I just replaced my fuel pump and did the spring in the hose etc.. the tank is clean. the filter in the tank is clean. boot and cover are newer and perfect. car runs and drives great but is now having a hot start problem after sitting for an hour or two.. it took me a min or two of cranking to get it to start.. but only after sitting for the hour or so.. if I drive it and shut it off it starts right back up.. any thoughts?? the accumulator is probably 10 yrs old.. but it never had this problem with the old fuel pump.. thanks guys.. ps I have a fuel pressure tester that I was going to hook up this weekend to check pressures..

[Parzival]

Sounds like you're losing rest pressure faster then the car can cool down enough to activate that cold start valve. I would recheck all of your connections. you may have a loose hose clamp that is allowing the pressure to slowly drop.

[painterdave72]

so you think a clamp is loose on the fuel pump?? I am positive they are not... and the car did not cool off when I got home. I just shut it off after driving for a bit and it fires right up any time.. just doesn't after an hour or so of sitting now....

[painterdave72]

its been a half hour.. I just went out and cheked the metering plate and it still has pressure.. I pushed it down a few times and has decent pressure still.. but wouldn't start .. it just cranked and cranked for a few seconds.. tried that a few times then it fires right up... any thoughts...?? lol

[Parzival]

so you think a clamp is loose on the fuel pump?? I am positive they are not... and the car did not cool off when I got home. I just shut it off after driving for a bit and it fires right up any time.. just doesn't after an hour or so of sitting now....

well, if its losing rest pressure slowly, then yeah, It will start right back up if you just shut it off.(not enough time to lose pressure)
now, give it an hour and You may have lost that pressure, and the engine might not be cool enough yet for the cold start valve to be activated by the thermo time switch in the water pump.
I think if everything is tight and the accumulator is in good shape, you should hold rest pressure for 2 hours. If you have Bitsyncmasters RPM relay, I think you get 3 hours because it re-primes the fuel pump at shutdown (I believe this is how his relay works).
for some reason or another it sounds like its not maintaining the pressure long enough (I.E. after one hour your car does not start) but will start cold (cold start valve assisting startup) and will start right after shut down(not enough time off to lose pressure)
So unless your accumulator just decided to go bad at the same time you changed your pump, or you have a bad check valve at the new pump, or something is loose. The pressure is getting out some how.

Did you also change your fuel filter?

Try priming you fuel pump several times before attempting to start it. You can do this by turning the key to the first position for a few seconds and then back to off, and repeat a few times. Then try to start it and see if it starts up faster. When I changed all my fuel injector lines mine was not as eager to start up as it was. This only lasted a short time tho. perhaps there's just some air in the system still that needs to be worked out? that's a complete guess but maybe.

[Bitsyncmaster]

I know the specification for holding rest pressure is just a 40 PSI test after 10 or 15 mins after shutdown. But I found the real test is how long it holds any rest pressure in terms of hours. My car would have a warm start issue if I tried to start it between 3.0 to 3.5 hours on a hot summer day parked in the sun on blacktop.

It just so happened my car would only hold rest pressure for 2.5 hours. So I made the my RPM relay extend rest pressure for another three hours by priming the fuel system (run pump for 0.5 seconds) at each hour interval after shutdown. So you need to hold rest pressure for at least one hour for my RPM relay to extend another three hours.

[painterdave72]

its the check valve that came on the new pump not working?? I still have the one from the old pump I can try swapping them out....

[painterdave72]

was that the car still had rest pressure after sitting for a half hour but took a few tries to start also for some reason..

[DMC-81]

Did the new pump come with an external check valve? Pics would be great.

Yes, I would try swapping them out as a test.

[David T]

One easy way to confirm a problem with rest pressure is to do the plug swap. If that gets it going then it is going to be the accumulator, the check valve, or the PPR unless you have a fuel leak and you would see and smell that.

[painterdave72]

the pump came with a check valve.. I am going to swap the old one back on .. but have to wait till mon as I left it at work.. that would be the only thing that would have changed is the check valve on the pump...

[Chris4099]

How old are the PPR O-rings? They are cheap and easy to swap out, so I would try that first (especially if the current age is unknown). Assuming the check valve is confirmed good at the pump, then I would guess the accumulator would be the next culprit. They should last longer then 10 years unless you got an NOS one.

[painterdave72]

the ppr orings are relatively newer. maybe 5 yrs or so.. I took them out this morn and they look perfect still.. not flat or anything.. car still does it after sitting an hour.. I will change the check valve back to the old one next week... the accumulator is probably 10 yr.s….

[Chris 16409]

Just to confirm, you installed a new OEM style fuel pump?

[painterdave72]

yes.. problem is fixed I think.. I changed the check valve back to the old one... the one that came with the pump I could blow thru both ways and I noticed that the spring inside it was much thinner guage than the old one.. so im thinking this fixed the issue.. will go out soon and see if it fires right up after sitting for an hour and being hot..

[DMC-81]

If you want to buy a new one, here is the external check valve I have:

https://www.usplastic.com/catalog/item.aspx?itemid=85394&catid=945

It works great.

[painterdave72]

it still wont start when its hot even after putting the old check valve back in.. any other suggestions?? thanks...

[DMC-81]

it still wont start when its hot even after putting the old check valve back in.. any other suggestions?? thanks...

In that case, I would test your fuel accumulator:
http://dmctalk.org/showthread.php?16835-Hot-start-issues-do-these-details-sound-like-my-accumulator-is-bad

If it checks out, then I would change the PPR O-rings...they are cheap enough to refresh them. Mine visually looked fine, but after changing them out anyway, that solved my hot start problems when I was restoring the car.

My path was: Brass check valve + new original size accumulator + new PPR o-rings = no hot start problems. Along the way the problem diminished, but went away completely after doing these 3 things.

[painterdave72]

where did you buy your accumulator from?? I see all different ones .. hervey has one.. DeLorean go has one.. dmch has one etc....

[DMC-81]

where did you buy your accumulator from?? I see all different ones .. hervey has one.. DeLorean go has one.. dmch has one etc....

At the time (2016), I got the original size Bosch accumulator (part number 0438170029 ) from Summit Racing. Apparently the smaller ones do the job, but I opted to get the full size one.

[painterdave72]

they do not list it.. rockauto has one.. I do not know if it is full sized though....

[DMC-81]

they do not list it.. rockauto has one.. I do not know if it is full sized though....

You could search google for "Bosch 0438170029" and see if other part stores have one. Stock Wise Auto?

[JETS 81 DMC]

The cheapest Bosch accumulator # 0438170029 I found was at Rock Auto for $103.79 plus shipping. They show 3 remaining in stock today.
Same one is also for a PEUGEOT 505 1980-1986

It is the full size
https://www.rockauto.com/en/catalog/delorean,1982,dmc+12,2.9l+v6,1312343,fuel+&+air,fuel+accumulator,6048

[painterdave72]

I ordered the rock auto one.. hopefully that is the issue.. the car is still hard to start when hot after an hour or so.. it will eventually start but takes a bit...

[Ron]

Where are you guys seeing the part on Rock Auto??? The link takes me here:

59988

If I enter "fuel accumulator" into the textbox, all it gives me is AC parts.

[painterdave72]

I think I got one of the last ones they had. I checked today and they are not listed at the moment..

[Chris 16409]

Post a picture of the accumulator when you get it. I am curious if it is green or silver. I was told the last run of accumulators Bosch made were silver.

[painterdave72]

I just got it today.. it is indeed silver colored...

[Chris 16409]

Cool. It looks like you got one of the last ones.

[TTait]

My accumulator is 10 years old, and I'm having some hot start issues.

I'm assuming the units is best located away from the heat of the engine, but why can't it be relocated to some place more accessible? Its a PITA to replace.

Tom