Fuel Pump Change- What do I need?

[jagee]

I posted a thread a few days ago about how my car had been running bad and got some great advice from everybody. I was hoping I could get a little more. I pulled my fuel pump out today and found the top sealing boot busted, the top of the pump covered in gas and the fuel pickup hose busted. I found a kit on delorean.com and was wondering if there was anything else I should get or do while I have it out.

https://www.delorean.com/store/p-10212-fuel-pump-combination-kit-aftermarket-pump.aspx

[stevedmc]

I posted a thread a few days ago about how my car had been running bad and got some great advice from everybody. I was hoping I could get a little more. I pulled my fuel pump out today and found the top sealing boot busted, the top of the pump covered in gas and the fuel pickup hose busted. I found a kit on delorean.com and was wondering if there was anything else I should get or do while I have it out.

https://www.delorean.com/store/p-10212-fuel-pump-combination-kit-aftermarket-pump.aspx

If your fuel lines are all 30 years old it might be a good idea to replace all of them. Its not cheap, but neither are engine fires. If one fuel line is busted then all of them could be waiting to go bust as well.

You need to check the hose going from your fuel pump to the baffle as well. If it is busted you are going to need to replace it. If the fuel pump can't pickup fuel then its going to seem to be bad.

Some people prefer the stock fuel baffle. I prefer to have a tuna fish can directly under the fuel pump. Hervey sells a similar setup already packaged as a kit.

Hervey has lots of pictures of his stuff as well.

http://specialtauto.com/delorean-parts/fuel-injection.html

[Cory W]

The pickup hose is included in the kit. Really everything from the pickup screen right to the hoses connected to the hard lines leading to/from the rear are included. The aftermarket pump looks a little different but works fine. You need to reuse the banjo body (ring with barb you connect the hose to at the top of the pump) from your old pump, but its easy to swap and put in place. A pair of channel lock pliers are handy to hold the pump while tightening the dome nut at top of the new pump.

If you're not sure it's ever been done, it's a good idea to remove the baffle and clean the inside of the tank while you're in there. It can be done with the tank in the car, leaning over a fender, but you may even climb into the cargo area to reach all the way in. Take pictures inside the tank while you do it to see if you've reached back far enough, as well as to get a look at the tank.

you should also take a pic of the baffle assembly to see how it goes together before removing. (You need a 10mm socket to remove the nut and washers from the bottom of the tank. Do not overtighten when reinstalling)

The baffle needs to be disassembled in the tank to remove. You will need to squeeze the round baffle body and gently fold the circular base to get them out. There are also two metal clamps that help hold the pickup screen in place and hold down the baffle body. Check pictures below.

When you're putting everything back in place, make sure it's all lined up, and you won't need to rotate the pump when reinstalling everything. You don't want to kink the hose while making sure the feed and return hose clear the access panel.


How is your fuel gauge sender working? I recently cleaned my original one, and it works better than it ever has before. I sprayed carb cleaner into it and shook it around a lot. Let it drain out, put it back in place and filled the tank.

[TTait]

Go ahead and replace the fuel pump harness http://www.delorean.com/store/p-7163-harness-fuel-pump.aspx while your in there.

The pickup hose is really easy to kink when installing, if your not going to use the Hervey baffle (its not a tuna can, which can eventually rust and corrode depending on what you get - its aluminum) you need to be extra careful. Make sure the fuel level sending unit is out so you can get some kind of peek at what your doing when the new pump and hose go in.

[Cory W]

Go ahead and replace the fuel pump harness http://www.delorean.com/store/p-7163-harness-fuel-pump.aspx while your in there.

That's included in the kit too (http://www.delorean.com/store/p-10212-fuel-pump-combination-kit-aftermarket-pump.aspx) ;) Very good call, though.

[jagee]

Thanks for all the input guys. I'm gonna drain the tank tomorrow so I can get the baffle out and take a look inside the tank. I found a link to a video on here that showed how to install the baffle so I should be good there. As for the sender I'm gonna get a new one because the bottom of it is corroded really bad and when I tried to clean out the hole in the bottom of it, part of the aluminum just peeled right off. The previous owner didn't seem like the kind of guy who would take care of things like putting something like Sta-bil in the fuel so the ethanol in the fuel is probably to blame for that. I could tell he had messed with the fuel pump before because the cover was busted and was also rubbing the fuel lines. So its probably a good idea to clean out the tank. What should I use to clean it out? Just a rag and some solvent? I was also so wondering about the check valve. Is it located inside the pump or somewhere in the line?

[DeLorean03]

B12 Carb Cleaner and a couple red shop rags worked wonders for me (:

[Cory W]

Just some rags/paper towel and some solvent, yes. You should also have a spray can of carb cleaner to deal with any left over solvent. You'll know you're done when the rags/towels start coming out of the tank clean. Make sure you have everything you need so you can do it all in one shot. It's not the most fun thing you can do on these cars.

I've seen a thread somewhere before talking about how the new DMCH fuel senders don't read quite right. There are two small holes on the bottom of the unit. One hole already has a small metal screw in it. Apparently the accuracy of the sender improves if you get another small metal screw for the second hole. Screw it all the way in to get full threads, but leave it only partially screwed in; you still want to let fuel in/out. I did this to a car I've been working on, and it seems to improve its accuracy.

The new pump still has its check valve on the pump, but it's not built-in anymore. It's removable, and therefore replaceable if you can source one. (That's why the kit includes a dome nut. You'll reuse the banjo body, but not the banjo bolt off the old pump.)

[TTait]

You will need to pump out the fuel, there is no drain.

If you pump the tank dry you can damage the pump, but as your replacing it anyway... I'd pull the fuel feed line off the FD and put it in a gas can and then jumper the RPM relay and pump it as dry as possible. The rest may evaporate overnight if you leave the tank fully open.

I've never cleaned out a tank from a running car - should take 15 minutes with B12 or carb cleaner. Even with red rags, have some paper towels for the end - they should come out clean and dry at the end.

Note that there is a ground wire inside the tank that stays in place. To clean out the tank you will have to lay in the trunk and get your whole arm in there - wear something you can throw away.

[Chris 16409]

A box of nitrile gloves will be your best friend!

[content22207]

... (its not a tuna can, which can eventually rust and corrode depending on what you get - its aluminum)....

Won't happen. My baffle after 7.5 years in the tank:

4854

4853

4855

What do you think the stud that holds the baffle down is made of? Steel.... (In the bad old days they made the entire gas tank out of the stuff).

BTW: I just pulled my pump & baffle out of the tank, photographed the baffle and uploaded/resized the pictures, posted this message, then put everything back together, in well less than half an hour -- one advantage of the straight down pickup design.

Bill Robertson
#5939

[DMCMW Dave]

Won't happen. My baffle after 7.5 years in the tank:


I have to agree with Bill on this one - I've seen a lot more trouble from aluminum dissolving in the bottom of the tank (from water that gets in there) than I have with steel. I pulled out an aluminum can-style baffle that was only about 1/2 left. It had just dissolved! Admittedly there was a lot of water in the tank and it probably would have made a mess of an aluminum fuel sender too.

Stainless would be best given the current state of gasoline, but I've yet to see anyone sell tuna in stainless cans.

The OEM baffle is fine as long as it has the bottom on it (missing from early cars).

The check valve is part of the pump. On the very early pumps it is built-in to the pump, on the later pumps it is a separate fitting screwed into the top of the pump. The check valve seldom fails although the early built-in ones seemed to have a problem.

[Canon20DFan]

If you're going into the tank anyway, get rid of the original Bosch pump and setup altogether. I've recently had fuel pump problems due to bad grounds - my pump was only getting 8-9 volts (check yours, I bet you'll be surprised). I highly recommend Hervey's Super Pump because: 1) I doesn't need a full 12 volts to run, but even better 2) it completely eliminates hoses, clamps and baffles. The pickup is the bottom of the pump. Why put back in a complex system of hoses that can collapse or split?

[content22207]

2) it completely eliminates hoses, clamps and baffles....

K-Jetters still need a baffle because gas will slosh away from the pickup around corners and up/down hills. Any interruption in fuel pickup will cause the injectors to reduce or stop spraying.

Bill Robertson
#5939

[Canon20DFan]

Pardon me - I meant the Rube Goldberg baffle that comes with the stock fuel pump. I have the bottom of a Clorox bottle as my baffle.

K-Jetters still need a baffle because gas will slosh away from the pickup around corners and up/down hills. Any interruption in fuel pickup will cause the injectors to reduce or stop spraying.

Bill Robertson
#5939

[content22207]

Your baffle has a solid bottom. It holds fuel better around curves and up/down hills than a baffle with an open bottom, especially if that open bottom baffle flops up & down.

Bill Robertson
#5939

[Morpheus]

If you're going into the tank anyway, get rid of the original Bosch pump and setup altogether. I've recently had fuel pump problems due to bad grounds - my pump was only getting 8-9 volts (check yours, I bet you'll be surprised). I highly recommend Hervey's Super Pump because: 1) I doesn't need a full 12 volts to run, but even better 2) it completely eliminates hoses, clamps and baffles. The pickup is the bottom of the pump. Why put back in a complex system of hoses that can collapse or split?

Because you may run into a fuel delivery issue if you allow your tank to get below 1/4. I opted for Hervey's setup in my first car, and I would occasionally run into this problem. It may be more pronounced if you live in an area with a lot of hills. Granted, YMMV, but having the baffle toward the rear of the tank helps keep the pickup submerged during acceleration when the fuel level is low.

The newer (improved) pickup hose is thicker and more resilient than OEM, which should help prevent it from collapsing on hot days. This is a common complaint of the original setup, which is why the "alternative" configuration was conceived.

I would caution you to keep your stock baffle in a box somewhere in case you ever want to go back to stock; the originals are really hard to come by.

[content22207]

The problem is the open bottom baffle, which is only minimally effective at best. It's like trying to carry water in a bucket with no bottom. Flopping up & down exacerbates the situation. A solid bottom baffle will hold the fuel, especially if the return line dumps right back into it.

Bill Robertson
#5939

[Bitsyncmaster]

The problem is the open bottom baffle, which is only minimally effective at best. It's like trying to carry water in a bucket with no bottom. A solid bottom baffle holds fuel, especially if the return line dumps right back into it.

Bill Robertson
#5939

The return line can not dump more fuel than the pickup line draws. It will not keep your baffle full. A completely closed baffle should help with very little hills but will not work on long hill climbs.

[Canon20DFan]

I live in a mountainous area and have have 1,000x the problems with the stock Bosch fuel systems than I've had with the Hervey Super Pump. I've been towed home many times - not because my fuel tank was low but because the Bosch pump stopped working, for various reasons. Selling your stock baffle, hoses, clamps and screws could actually pay for a Hervey pump!

[content22207]

The return line can not dump more fuel than the pickup line draws. It will not keep your baffle full. A completely closed baffle should help with very little hills but will not work on long hill climbs.

Our baffles are not "completely closed" -- look closely and you will see small hose drilled around the base. These holes allow fuel to slowly enter the baffle as tank level drops below its edge, yet still hold it in place during movements that would otherwise expose the pickup.

The tank itself is triangular shaped. There is less volume in the back (the apex) than there is in the front (the base). As fuel moves towards the rear, it has not choice but to also rise in height. Of course there is a level at which this effect still can not keep the pickup covered, but anyone who drives their fuel tank that low is courting problems anyway (what about the so called "hot fuel" problem everyone is so worried about -- less fuel in the tank means more heat absorption). When Louie and I drove to New Orleans, we passed through a section of Alabama that did not have a gas station for at least 50 or 75 miles -- what would have happened if we tried to drive that on less than 1/4 tank? As AAA says, purposefully driving the tank low is a bad idea.

Bill Robertson
#5939

[Bitsyncmaster]

I agree and when my tank gets to 1/4 full I start looking for a gas station. I have run it lower around town and even once had the low fuel light come on.

The point of having the pickup in the rear of the tank is going up hill requires more gas (power). Going down hill of course would be bad but you would not suddenly stop and be able to coast safely to the side of the road.

[content22207]

Speaking for myself, I have never experienced any of the problems simplified baffles and pickups are supposed to suffer (baffle rust or disintegration, fuel starvation, etc). Perhaps a poll for all forum users to respond in one place would be in order.

Bill Robertson
#5939

[sean]

Our what would have happened if we tried to drive that on less than 1/4 tank? As AAA says, purposefully driving the tank low is a bad idea.



I agree and when my tank gets to 1/4 full I start looking for a gas station. I have run it lower around town and even once had the low fuel light come on.

I think this is the key, keep gas in the car and any baffle will do. Get low and attack some hills, expect some problems.

[content22207]

Jim Edwards (Flyinglow) is missing his tank stud. If he ever rematerializes, and if he goes through with his planned carb conversion, he won't need any sort of baffle whatsoever.

I only include baffles for other carb converters because I still need to eat.

Bill Robertson
#5939

[TTait]

Won't happen. My baffle after 7.5 years in the tank

Sorry Bill, I was misinformed. I know you have had good results, but I had seen a can once that had started to rot along the seam where the bottom met the sides, and then it has spread into the steel. Obviously that car had water in the tank for some time.

Hervey's setup does not suck to the bottom as well as yours, but I think the baffle may have a larger volume to help compensate?

Did you get your pickup tube and screen from Hervey, or source your own somewhere?

[Canon20DFan]

The Delorean fuel estimation system is just that - an estimation. I never trust my fuel guage enough to go below 1/4 tank.

Because you may run into a fuel delivery issue if you allow your tank to get below 1/4. I opted for Hervey's setup in my first car, and I would occasionally run into this problem. It may be more pronounced if you live in an area with a lot of hills. Granted, YMMV, but having the baffle toward the rear of the tank helps keep the pickup submerged during acceleration when the fuel level is low.

The newer (improved) pickup hose is thicker and more resilient than OEM, which should help prevent it from collapsing on hot days. This is a common complaint of the original setup, which is why the "alternative" configuration was conceived.

I would caution you to keep your stock baffle in a box somewhere in case you ever want to go back to stock; the originals are really hard to come by.

[David T]

All of the internal parts should be pulled, cleaned, and examined. To clean them use Acetone. You should be using Nitrile gloves, a respirator, eye protection, and a fan. Work in a well ventilated area, preferably outdoors. The baffle parts should be salvageable. Replace the pick-up hose and return hose, both boots, and if necessary the fuel pump and the short wiring harness. Be very careful with the hard metal fuel lines so as not to kink them. If the outer fuel hoses are in good shape, just the outer covering is coming off, you can recover them with a couple of wraps of electrical tape. The original fuel sender is not reliable so it should be replaced. Be careful not to over tighten the stud in the fuel tank but if you do break it loose some have had success in reinstalling it. Heat it up and quickly stick it back into the bottom of the tank. It will melt itself back into place. You must be very careful when reinstalling the pump to keep the pickup hose from kinking. Many have added an internal spring to keep the hose from kinking or collapsing under vacuum. That fuel pump can suck HARD! Hard enough to collapse a soft pickup hose! Especially on a hot day with the radiator and A/C heating up the fuel tank. Be sure to wipe out all of the junk in the tank. After using up a tank of gas, replace the fuel filter. Do not remove the fuel tank for better access, it doesn't help unless you are fixing rust or paint.
David Teitelbaum

[content22207]

Hervey's setup does not suck to the bottom as well as yours, but I think the baffle may have a larger volume to help compensate?

A tuna baffle is almost exactly the same size as a Hervey baffle:

4889 4891 4890

Of course it doesn't matter how big a baffle is if it can't hold fuel. A bottomless 55 gallon drum is just as useless as a bottomless thimble.

For comparison purposes, those pictures were taken in 2003 (pictures in Post #11 are the same baffle, taken this morning).

Eeek:

4892

Bill Robertson
#5939