Fuel odour and LOUD fuel pump

[Marty]

Since I got my car back from DPI 3 weeks ago I've clocked just over 200 miles. A few days ago I started to get a fuel smell inside the car. At the same time I noticed the fuel pump got VERY loud. Outside the car I can't smell the fuel - only inside. I've taken the cover off inside the trunk and I can't find any leaks. When the engine is running and I'm sniffing around the fuel pump, the smell is present but it's much less noticable than it is inside. Today I heard a very strange liquidy squishing/gushing noise from the centre of the car while driving. It made one loud SPLORSH kind of sound which lasted maybe 2-3 seconds. Is it the accumulator?

The car drives fine, accelerates fine, revs fine all the way up to about 6,000 rpm. I have Hervey's pump & baffle.

[Delorean Industries]

If you are smelling fuel from the front of the car I would suggest pulling off the tank boot and seeing if the pump has fuel up inside the boot. How long ago did you replace the pick up set up, and rubber components in the tank? If the clamp around the bottom of the pump is loose or the boot is rotting fuel will come up through the boot.

[Marty]

I can't really smell fuel around the top of the boot. It's VERY subtle. The smell is very strong INside the car. The pump/baffle/pick up hose/entire setup was new about 7 years and 2,000 miles ago.

Can you tell me what to look for, how to pull the fuel pump out, etc? I have 3/4 of a tank of gas. Do I need to drive around and empty it out first?

[Delorean Industries]

Seven years is a VERY long time in the Delorean fuel system world. Drive it around and take the fuel level down to a quarter tank.

Pulling the pump out of the tank will take just a few minutes-

-disconnect the pump harness
-disconnect the large hose clamp around the fuel tank boot
-carefully pull unit skyward

My bet is you will see some fuel down inside the pump boot.

[Marty]

Ok thanks Josh. I'll have to drive it a LOT to get the fuel level down, so it will likely be next weekend. Anyway, if the boot is rotted, why does that make the fuel pump so loud? Will I damage anything driving around in this condition?

[Michael]

When you pull the cap if you see fuel sitting on top of the pump you pretty much have it diagnosed. It does'nt take much fuel to create a strong odor in the cabin, especially in the fuel pump area as the cabin intake vents are right above it.

After you have the boot removed, run the engine and visually inspect the fuel lines to see if there are any leaks there. If not, you most likely have a loose or torn pump boot, and any sudden movement is allowing it to leak out in that area. A tear in the boot might be hard to spot so if you do remove it, check it over carefully.

As far as the noise goes, they may be related, or not. I guess it's possible it's somehow leaking at the fitting and getting starved? Just fix one problem at a time. I was in the same boat with the fuel smell and the occasional pump noise. I chalked the noise up to the common fuel pump howl we get in high temps, and after finding a tear in my boot I thought I had it fixed. Even after replacing the boot the smell was gone but the noise would still occur at times(and cause my car to starve as well) Only after replacing the pump did it solve everything.

[Bitsyncmaster]

When the boot or clamp around the pump is not holding the pump tight, it lets the pump rotate when it starts up. That can twist the pickup hose and the supply and return hoses. Over time that can lead to a loud pump and leaking fuel.

Hervey's power pump which had a foam cover around it because it's diameter is smaller, caused that problem with my car. The foam rotted, broke the pickup hose and tipped sideways. Maybe he uses a better foam now.

[Marty]

Sounds like my pump could be tipped or twisted then. Once I get the fuel used up I'll get to it. We have a club meet on Saturday, so maybe I can do it then.



As far as the noise goes, they may be related, or not. I guess it's possible it's somehow leaking at the fitting and getting starved? Just fix one problem at a time. I was in the same boat with the fuel smell and the occasional pump noise. I chalked the noise up to the common fuel pump howl we get in high temps, and after finding a tear in my boot I thought I had it fixed. Even after replacing the boot the smell was gone but the noise would still occur at times(and cause my car to starve as well) Only after replacing the pump did it solve everything.

Ok, thanks for the tips! The noise definitely coincides with the smell. When I first start up the car (after it sits overnight) the pump is quiet and there's no smell. But after about 20 minutes of driving, the pump gets loud and the smell intrudes the cabin at exactly the same time.

[Ron]

Please think twice about driving around with a fuel leak...

[Marty]

I don't have a fuel leak. I have looked everywhere. It's all dry.

[Marty]

Ok. I decided not to wait. I pulled the cap off and found the pump to be dry as a bone. I then pulled the boot out. It is in fantastic shape. It's basically perfect. There's not a mark on it anywhere.

Is the pump perhaps overworked because of some restriction somewhere down the line? Remember, I did have a sudden liquidy squish/gush noise from the centre of the car. I can't help but think something's wrong with the accumulator and it is trying to force the fuel through the blockage. Am I nuts?

[TTait]

Is there fuel present under the very center of the car?

If there is, its a problem near the accumulator - if not, means nothing. Even a small leak is a problem and it evaporates quickly. Could still be around the accumulator.

Look for a leak near the fuel filter, and of course in the engine compartment.

[stevedmc]

Vapors are very flamable. The problem needs to be fixed.

Check the hoses from your tank to the fuel filler cap. Make sure it is snug. There is also a vapor hose running from your K-Jet stuff to the fuel filler. Make sure that hose is good as well.

Autozone has universal hoses should you need to replace them. You may have to ask nicely to go in the back and match stuff up.

[jawn101]

I don't have a fuel leak. I have looked everywhere. It's all dry.

The fuel system is a sealed one though, if you can smell it you've at the very least got a cloud of flammable vapor. Be very, very careful....

[Marty]

Is there fuel present under the very center of the car?

If there is, its a problem near the accumulator - if not, means nothing. Even a small leak is a problem and it evaporates quickly. Could still be around the accumulator.

Look for a leak near the fuel filter, and of course in the engine compartment.

Ok, nothing at the centre of the car. It's dusty and dry. I ran the car for 5 minutes or so, and there were no leaks anywhere. The engine compartment doesn't smell, it's all up front, and fairly faint.

Stevedmc - I checked all the hoses around the fuel filler and they're all tight. No smell coming from there either. If I run the car for about 20 minutes, that's when the smell appears. However, I noticed the fuel pump is consistently noisy now. It used to come and go with the odour. Now it's noisy from the minute I start the car. I noticed a lot of vibration in the sender hose. I don't know how much is normal. But regardless, nothing leaked anywhere. I can only smell it inside the car. The smell is extremely faint around the fuel pump.

I have no idea where to check next.

[Marty]

Hooray! 99% sure I found it. A line wasn't attached down behind the driver's wheel! There was no clamp and the rubber was split a bit where it attached to a metal line. It runs from the driver's side front wheel well up to a tiny yellowed plastic part, I think it's the rollover valve, right at the filler (where it is fine). I will get a clamp on it tomorrow. Thanks Stevedmc, I think this was one of the lines you were talking about.

[Delorean Industries]

That is the roll over vapor hose running from the back of the car. 2-4-0 in the parts manual. I think it depends on who put the car together because I have seen plenty of cars without clamps on the steel line end with no visible marks from a clamp present. There should be a clamp on the smaller vapor line and no clamp on the larger brake booster line according to the parts manual. I have seen a number with out though.