Fuel pump noisy when been in traffic for over an hour

[Chris_Von_Bron]

I've a 'different' setup now so that there is no metering head and no hot unused fuel being returned the tank..... yet today after over an hour in crawling traffic, I could hear the fuel pump buzzing louder. I pulled over and opened the fuel cap and the hiss/vapour release helped (as well as a fresh top up of nice cold fuel).

I'm sure that this never used to happen years ago to the extent it has been more recently (i.e. the same as when it was stock compared to eliminating the return of hot fuel), but on days crawling in traffic for over an hour I still ultimately hear the fuel pump buzz louder and despite the measures taken below I'm still having the following issues:

So far I've:-

new pickup hose
changed the rollover valve, for why see third paragaph of http://support.delorean.com/kb/a42/fuel-smells.aspx
coiled tig wire in the new pickup hose to stop it collapsing
new, higher powered Bosch fuel pump



What I've not changed
fuel gauze on the end of the pickup hose as it seems okay, looks clean with no visible debris in the gauze, but maybe it is partially blocked and only noticeable when the tank is hotter?

What else is there?

neoprene around the coolant pipes that run under the tank
neoprene dam to help insulate it from hot air from the radiator



To be clear, the cooling system is running perfectly, this is purely hot tank scenario and when the noisy pump can't handle or take the amount of fuel needed, bunny hopping, stuttering and the car cutting out are what you're faced with until the tank/fuel have cooled down.

Any thoughts/suggestions are welcome. For those of you that sit and crawl on the freeway in the hotter states like Texas etc surely must have found how to solve this?

[Bitsyncmaster]

That is interesting that you still get pump buzz and don't have hot fuel returned to the tank. I was convinced the returned fuel was the problem (it probably is some of the problem). I made a cooler for that returned fuel.

[Citizen]

I am in Texas and when I first got the car (about 12 years ago) I had no problem in June/July/August, 98+ degrees, stop and start traffic. Then, a few years later it started doing just what you described, almost exactly. My solution was to:


1- Convert to the new (at the time) DMCH integrated fuel pump
2- Fabricate a hot-air dam and install it (at the time, I didn't know you could buy one from anywhere)

I have not had a problem since. But to be fair, in the last few years, I've taken active steps to avoid stop-n-go traffic on super hot days. And in fact, I haven't put very many miles on the car since then, not on purpose, it just worked out that way.

It's good to know removing hot fuel return didn't solve the problem. I had always suspected it was truly the hot air from the radiator causing the problem, and now with your real-world experience, I think it looks like even more that is the case.

Thomas

...

[Michael]

new, higher powered Bosch fuel pump


There you go. The new Bosch pumps are not quite the quality they were several years ago. They have been seduced by the dark side of themaking things cheaper while charging more and hoping brand loyalty and name recognition makes up the difference force.

I had the same issue and got a new pump which fixed it. I replaced it with a Bosch and it seems to be OK but I now keep a spare in the car(generic brand) just in case.

[dn010]

Explain your setup? If there is no fuel return line, you're restricting this new "high power" pump to a certain PSI with no relief. The pump will continue to pump as much as it can and have no way to send that additional pressure back into the system. For instance, if it's pumping at 100PSI and you're regulated at 60, and have no way to resolve the other 40, what do you expect? The pump will run hot if it cant efficiently push against the pressure.

[Josh]

Following. Here is my fuel system, yours should not be any different as far as I am concerned.

I am using a fuel pump out of a 2000 chevy tahoe, works great and cheap and easy to source. Maybe less so in the UK...

[DCUK Martin]

You still have a return line and it's still bringing heat back from the engine'e injector rails. Unless it's neoprene foam you've wrapped around the coolant pipes, it's likely helping the tank heat up, not hindering it. The tank sitting on top of the coolant pipes is still the dominant heating effect.

Change the pickup filter. Filters are blocked by stuff you can't see. Just cos it looks clean does not mean it isn't restricted.

[Bitsyncmaster]

I have Hervey's "hot air dam" installed in my car before I installed my return line cooler. My pump would still buzz on a hot day.

Here is my thread on my cooler.
http://dmctalk.org/showthread.php?1560-Fuel-pump-buzzing-cure&highlight=fuel+cooler

[David T]

It seems once you get the pump noisy it gets noisy easily afterwards. Must be that once it gets noisy parts inside get worn and it gets easy to make the pump noisy again. The fuel can get pretty hot and if you have the original pick-up hose it softens from the heat and can easily collapse under the vacuum or kink. My answer was to put a long spring inside the pick-up hose. I got a long one that is used for a screen door. Seems to have solved the problem. The newer design that DMCH sells would be a great upgrade as long as it is more reliable but they seem to have had some problems with them. Much easier to install. The "old" design is like building a ship in a bottle! Easy to make a mistake installing it since you have to do most of it blind and with one hand.

[chris williams]

I have always wondered if a modern style of fuel cooler, as is fitted to most diesel common rail engines nowadays would be beneficial to cars that suffer from hot fuel return (not usually to much of an issue in the UK!) something like this as an example: https://www.ebay.co.uk/itm/Genuine-Ford-Fuel-Cooler-1448707/252768544880?epid=1509730527&hash=item3ada2de870:g:cJQAAOSw3v5YoUll
As people may or may not know returned fuel from a common rail is very hot and these are fitted in one variation or another usually underneath the car to aid the cooling. I don't know exactly how or where it could be plumbed in but it may be an 'option'
Chris

[David T]

I have always wondered if a modern style of fuel cooler, as is fitted to most diesel common rail engines nowadays would be beneficial to cars that suffer from hot fuel return (not usually to much of an issue in the UK!) something like this as an example: https://www.ebay.co.uk/itm/Genuine-Ford-Fuel-Cooler-1448707/252768544880?epid=1509730527&hash=item3ada2de870:g:cJQAAOSw3v5YoUll
As people may or may not know returned fuel from a common rail is very hot and these are fitted in one variation or another usually underneath the car to aid the cooling. I don't know exactly how or where it could be plumbed in but it may be an 'option'
Chris

One way to cool the fuel (cheap too) is to wrap the accumulator/dryer with a coil of copper pipe and pass the returning fuel through it. Would take a bit of plumbing to do it safely but it would seem like a good idea.

[Chris_Von_Bron]

Explain your setup? If there is no fuel return line, you're restricting this new "high power" pump to a certain PSI with no relief. The pump will continue to pump as much as it can and have no way to send that additional pressure back into the system. For instance, if it's pumping at 100PSI and you're regulated at 60, and have no way to resolve the other 40, what do you expect? The pump will run hot if it cant efficiently push against the pressure.

Hi yes it’s same as corvette set up , the pump is a flow pump and the regulator sets the pressure , most cars are like this from around 2000 , modern ones use pwm pumps to control it ,

[DCUK Martin]

You still have a return line and it's still bringing heat back from the engine'e injector rails.

Apparently not....!

The reason for demand-driven pumps is efficiency. Not sure why saving a few tens of watts is a big enough deal to reinvent the wheel on our 35+ year old cars but hey ho, whatever floats yer boat :)

[DMCMW Dave]

One way to cool the fuel (cheap too) is to wrap the accumulator/dryer with a coil of copper pipe and pass the returning fuel through it. Would take a bit of plumbing to do it safely but it would seem like a good idea.

Honestly that design scares the crap out of me, as you end up with a fuel line wrapped around the dryer only inches from the right front tire and all the road crap kicked up by the tire. Sounds like an accident waiting to happen. Not sure how to do it "safely" unless you come up with a way to completely shield the receiver/dryer without obstructing the tire. And it only helps with the A/C running.

There is a reason BTW that you never see copper pipe in OEM fuel systems. Copper work-hardens and will eventually crack with vibration.

[Josh]

Honestly that design scares the crap out of me, as you end up with a fuel line wrapped around the dryer only inches from the right front tire and all the road crap kicked up by the tire. Sounds like an accident waiting to happen. Not sure how to do it "safely" unless you come up with a way to completely shield the receiver/dryer without obstructing the tire. And it only helps with the A/C running.

There is a reason BTW that you never see copper pipe in OEM fuel systems. Copper work-hardens and will eventually crack with vibration.

2x

This is a band aid fix too.

[Bitsyncmaster]

Honestly that design scares the crap out of me, as you end up with a fuel line wrapped around the dryer only inches from the right front tire and all the road crap kicked up by the tire. Sounds like an accident waiting to happen. Not sure how to do it "safely" unless you come up with a way to completely shield the receiver/dryer without obstructing the tire. And it only helps with the A/C running.

There is a reason BTW that you never see copper pipe in OEM fuel systems. Copper work-hardens and will eventually crack with vibration.

How many accumulators have you replaced because of damage from road debris?

[DMCMW Dave]

How many accumulators have you replaced because of damage from road debris?

None, but they are pretty stout compared to copper tubing. And the price of failure is somewhat less significant. Do you have the tubing shielded in any way?

[Bitsyncmaster]

None, but they are pretty stout compared to copper tubing. And the price of failure is somewhat less significant. Do you have the tubing shielded in any way?

Just some epoxy that holds it in place. It is soft copper so I think it would just bend if something hit it.

[DCUK Martin]

There is a reason BTW that you never see copper pipe in OEM fuel systems. Copper work-hardens and will eventually crack with vibration.

Kunifer is fine for fuel, as it is for brake pipes and is commonly available this side of the pond.

My TVR has an in-line heat exchanger on the AC return.

http://www.powersperformance.co.uk/store/slug/fuel-cooler/

[Bitsyncmaster]

Kunifer is fine for fuel, as it is for brake pipes and is commonly available this side of the pond.

My TVR has an in-line heat exchanger on the AC return.

http://www.powersperformance.co.uk/store/slug/fuel-cooler/

You own a TVR? I have sold a few of the "run sensors" for them which is a modification of my RPM relay.

[DCUK Martin]

You own a TVR? I have sold a few of the "run sensors" for them which is a modification of my RPM relay.

Fb.com/mys6cerbera

From the 90s Griffith onward, they're all EFI AFAIK. Pump control on mine is the ECU.

[Bitsyncmaster]

Fb.com/mys6cerbera

From the 90s Griffith onward, they're all EFI AFAIK. Pump control on mine is the ECU.

Some early ones used Kjet. But the run sensor just controls the fuel pump like our RPM relay does in the D.

[CFI]

I was planning on buying an air dam from Hervey, but it looks like his store will be closed for the foreseeable future. Can someone tell me approximately what size the dam is so I can make my own?

[Michael]

I was planning on buying an air dam from Hervey, but it looks like his store will be closed for the foreseeable future. Can someone tell me approximately what size the dam is so I can make my own?

I am planning to do this next time I get my car on a lift. One member here had a working theory that the coolant pipes caused the fuel pump to get hot(by heating the fuel tank and fuel). He dropped his closing plate and attached self adhesive heat barrier to his tank along the coolant pipe areas. Seemed like a good idea to me. I have everything except the time but soon...just in time for winter maybe.

[jorge figueroa]

solution to the problem of overheating of the pump and the gasoline tank in deloreans.
Many deloreans including mine have always had this problem of having the gas pump very hot when you make a long trip around Puerto Rico. And in some cases total failure.
The problem arises from the poor design of the delorean cooling system.
Especially the tubes that pass under the gas tank. These tubes are heated by the coolant that comes from the engine to the radiator, heating the tank, gasoline and the pump to temperatures too high for its proper functioning.
As a result you hear a loud buzzing inside the car (pump too hot) and the possibility of failure.

For some time I was looking for a solution to this problem, and finally found in home depot a type of tape that is used to insulate tubes in the air conditioning system of homes or businesses. (To see photos).
It is an aluminum tape with high density foam insulation.
Using my own delorean I did heat transfer tests with one of the cooling system tubes and found that the heat transfer is practically zero.
With my delorean engine running I put my hand on the coolant pipe with the insulation and felt no heat at all.
If my hand did not feel any heat the tanks of the deloreans either

61057610586105961060

[BABIS]

solution to the problem of overheating of the pump and the gasoline tank in deloreans.
Many deloreans including mine have always had this problem of having the gas pump very hot when you make a long trip around Puerto Rico. And in some cases total failure.
The problem arises from the poor design of the delorean cooling system.
Especially the tubes that pass under the gas tank. These tubes are heated by the coolant that comes from the engine to the radiator, heating the tank, gasoline and the pump to temperatures too high for its proper functioning.
As a result you hear a loud buzzing inside the car (pump too hot) and the possibility of failure.

For some time I was looking for a solution to this problem, and finally found in home depot a type of tape that is used to insulate tubes in the air conditioning system of homes or businesses. (To see photos).
It is an aluminum tape with high density foam insulation.
Using my own delorean I did heat transfer tests with one of the cooling system tubes and found that the heat transfer is practically zero.
With my delorean engine running I put my hand on the coolant pipe with the insulation and felt no heat at all.
If my hand did not feel any heat the tanks of the deloreans either

61057610586105961060

is the insulation tape applied only to the sides of the tank or even to the coolant pipes?

[jorge figueroa]

friends of the community of deloreans owners
Greetings from Jorge Figueroa of Puerto Rico.
Some time ago I reported some progress using thermal insulation on some Delorean gasoline tanks with very good results.
In this case you will see how I thermally insulate the gas tank of my DeLorean 01279.
In the first photos you can see that the coolant pipes are already physically touching the surface of the tank.
transferring heat more directly by heating the gasoline which overheats the fuel pump causing it to fail.
The gas tank was cleaned with industrial acetone.
Acetone dissolves any varnish residue from old gasoline.
The thermal insulation used in this case is the same for hoods and firewalls.
Everything was thermally insulated including some surfaces on the chassis where the gas tank is located.
and using very flexible pieces of thermal foam, the spaces between the fiberglass body and the chassis were blocked
to prevent the hot air produced by the radiator from reaching the top of the gasoline tank where the fuel pump is located.
Later I will send photos of this foam insulation.

The final result is incredible.
The fuel pump on my DeLorean has never failed again, you can't even hear it, no more humming noises.

My friends, there are many sellers of parts for Deloreans that offer good products for our cars.
But over the years I have noticed that they never offer a real solution to problems.

It doesn't matter if the fuel pump is the original style or some modern version if the heat transferred from
the coolant pipes to the gas tank is not controlled they will all fail again and again.

70192701937019470195701967019770198701997020070201 7020270203702047020570206

[Michael]

My solution from a few years ago. With the new pump designs today, IMO, it'swasted energy.

70208

[ssdelorean]

My solution from a few years ago. With the new pump designs today, IMO, it'swasted energy.

70208

Would you still think it is wasted energy if the original fuel pump was being used? It seems that set up is more prone to heat causing pump buzz. I have no experience with the new pumps out there.

[Michael]

Would you still think it is wasted energy if the original fuel pump was being used? It seems that set up is more prone to heat causing pump buzz. I have no experience with the new pumps out there.
I would because there isn't an oe pump on the planet that doesn't suck as they are all cheaply made junk.

The time and energy spent on heat shielding is better spent on a new pump and never ever worry about that crap again.

[Bitsyncmaster]

My cure for the buzz.

https://dmctalk.org/showthread.php?1560-Fuel-pump-buzzing-cure

I've since replaced my pump with a Tahoe unit and have never heard anyone with the new GM pumps complain about pump buzz from hot fuel.

[r00b]

Insulation works both ways, you don't want to wrap your entire fuel tank. Just the sides is fine though. I used pipe insulation on the coolant pipes that pass around the tank, it's the kind of insulation that is similar to pool noodles. I cleaned the pipes with a brillow pad first. I didn't use insulation on the tank.

7021370214

[David T]

Anything you can do would help. One owner wrapped a coil of fuel line around the A/C accumulator to cool the fuel. A vendor used to sell a big rubber shield to direct the air from the radiator down and away from the fuel tank. Only seems to happen when it gets really hot and you are low on fuel. Even with the buzzing the car will still run and not vapor lock (the fuel can't vapor lock when it is under pressure).

[jorge figueroa]

My friends, I am from Puerto Rico, which is a tropical island in the Caribbean.
On the island there are an average of 20 Deloreans and this server has worked on almost all of those cars.
The temperature in Puerto Rico is on average 80 to 100 degrees all year round.
Not all Deloreans develop this problem and it depends a lot on the care and maintenance that has been given to it over the years.
I have worked with all types of fuel pump (aftermarket) for deloreans.
DMC, SPECIALTAUTO, D-INDUSTRIES ETC, DELOREAN GO ETC.
and in a group of deloreans the pumps have failed miserably.
and they have failed for a simple reason: extreme heat.
All car manufacturers try to avoid heat sources near gas tanks.
Any heat source that passes near the gas tank is blocked by heat shields. (aluminum, stainless, thermal fiber)
Another reason for the problem can be found in the condition of the wiring or circuit that powers the fuel pump.

[Timeless]

My cure for the buzz.

https://dmctalk.org/showthread.php?1560-Fuel-pump-buzzing-cure

I've since replaced my pump with a Tahoe unit and have never heard anyone with the new GM pumps complain about pump buzz from hot fuel.
Delphi pump here. No problems with noise/buzz even in S. FL extreme heat. (EFI engine)

[82DMC12]

80F - 100F is not that "hot".

[ssdelorean]

... >>snip<<
A vendor used to sell a big rubber shield to direct the air from the radiator down and away from the fuel tank. Only seems to happen when it gets really hot and you are low on fuel. >>snip<< .

You can see said vendor's ad for this product from a 1986 DeLorean World mag in a post Patrick provided with the tortion bar jig instructions here: https://dmctalk.org/showthread.php?241-What-have-you-done-to-your-DeLorean-today&p=281828&viewfull=1#post281828 (Page 931, Post #9035). Ad title: "Fuel Pump Troubles?"

Useless Trivia: 16506 (my vin) is running the multi-piece prototype deflector where this one piece-product was made from.