Fuel pump issues... maybe?

[RnrdTheFox]

Today I was ridding a trail up in the mtns. It was about 85 maybe. I was going along at about 10 mph and I felt the truck lose power. I pulled over and it would barely idle then it died.

I'm running duel pumps. The carter low pressure and a high pressure under the hood on the fender well on the drivers side. I thought that at one time I didn't hear the low pressure pump running. I sat there for about 15 mins and turned around and coasted for about 1 mi with the engine off. After that all was fine on the 25mi trip back to town?

For those of you that have had problems with duel pumps, is this it's calling card? Does the Carter start giving out then finally is stops all together?

Thoughts?

 

[wildbill]

Had thid happen on my truck when hot it was the pump under the hood getting to hot moved it to the frame rail and no more problems good luck. Bill %) ;D

 

[COBlu77]

Renard,
I couldn't get two pumps to work for very long at this altitude. I killed two Carters trying. IMO, they are not designed to work as hard as they have to at higher altitude and at the volumn a HP fuel return system requires. The LP Carter would give up on hot days and create a vapor lock. I've had 1 HP pump running without a problem for over 2 years. I never had any issues with cavitation on steep hills. I initially tested it with less than a 1/4 tank and parked on a 45 degree + hill and let it run - no problem.

Try bypassing the LP pump and accumulator with a hose from the tank to the HP pump. You shouldn't leave this as a permanent setup though, because the HP pump is meant to be a pusher not a puller. If you can't go to an in-tank pump use a 255LPH Walbro on the frame crossmember right in front of the tank and as close to the tank outlet as possible.

 

[RnrdTheFox]

Renard,
I couldn't get two pumps to work for very long at this altitude. I killed two Carters trying. IMO, they are not designed to work as hard as they have to at higher altitude and at the volumn a HP fuel return system requires. The LP Carter would give up on hot days and create a vapor lock. I've had 1 HP pump running without a problem for over 2 years. I never had any issues with cavitation on steep hills. I initially tested it with less than a 1/4 tank and parked on a 45 degree + hill and let it run - no problem.

Try bypassing the LP pump and accumulator with a hose from the tank to the HP pump. You shouldn't leave this as a permanent setup though, because the HP pump is meant to be a pusher not a puller. If you can't go to an in-tank pump use a 255LPH Walbro on the frame crossmember right in front of the tank and as close to the tank outlet as possible.

Yeah, I was hoping to not have to re-plumb things. If I went to a single high pressure pump in between the two tanks on the frame rail, do you think that would be an issue?

 

[COBlu77]

Yeah, I was hoping to not have to re-plumb things. If I went to a single high pressure pump in between the two tanks on the frame rail, do you think that would be an issue?

I couldn't get that to work either. The HP pump is too much for the electric tank switch (6 way Pollack). It would pull from both tanks no matter how it was switched. Other times it would refuse to actually switch back and forth and I'd think I was running off of the main while really draining the aux and then run out of fuel.

I haven't done it yet, but I was going to put a LP pump from the aux tank to the main tank and just fill the main tank with a switch from the fuel in the aux. I'm running a 23 gal main tank, so it hasn't been a necessity and I kind of like the idea of not sitting on top of the extra fuel (not to mention the weight savings).

 

[RnrdTheFox]

How long did it take you to kill your Carter pumps? I want to continue driving it every day to and from work to get a feel for things and whats really going on. Thinking I might go buy an extra pump to keep in the truck.

 

[RnrdTheFox]

I couldn't get that to work either. The HP pump is too much for the electric tank switch (6 way Pollack). It would pull from both tanks no matter how it was switched. Other times it would refuse to actually switch back and forth and I'd think I was running off of the main while really draining the aux and then run out of fuel.

Why would the HP pump pull from both tanks? It would be sucking more than the LP pump. What you describe, almost sounds like a bad switch. I haven't seen anything like this with my switch. Do you think you had a faulty switch in this case?

 

[Duke Nukem]

I've been running dual eletric pumps for about 1-1/2 years now and the system seems to work fine. My low pressure pump is a carter mounted on the frame rail close to the gas tank. I also have a fuel accumulator mounted in the engine bay that feeds my high pressure pump. I'm also running a single BC Broncos 25 gallon tank. There are various configurations that work for different people, but this has worked for me.

 

[COBlu77]

It ran fine while it was cool outside, but when June came around it started acting like it wasn't getting fuel and would eventually die leaving me stranded, until the LP pump cooled off. It eventually killed the first one and I took it back under warranty. The second one started doing the same thing immediately. I did the same with the first 6 way switch. I took it back and got a second. It too failed. This all happened over about a 2 week period in June when it was in the 90's. It drove me nuts until I just bypassed the whole mess and ran a line from the main tank to the HP pump. It then ran fine, so I re-plumbed everything with just one HP pump. All has been great since.

I was told by others on this board that had done EFI that the two pump set up would be unreliable and difficult and expensive to fix, especially out on the trail, but I was stubbornly determined to try and use the 2 pumps with an accumulator and both tanks on a switch. Many claim to have no problems with 2 pumps an accumulator and both tanks, but it didn't work for me. I drive mine daily and drive to where I wheel and it just didn't work. I have nearly 10k trouble free miles with 1 pump and 1 tank.

The 6 way switch can't handle the pressure and the Carter LP pump is not designed to run all out all the time. Heat and altitude aggravate the problem.

 

[COBlu77]

Here is a link to the recipe I initially used http://classicbroncos.com/img/efi-diagram.gif . I followed it exactly.

I've only seen 3 other Broncos here locally with EFI that are actually being driven. The first one told me he went through the same issues as me before going to just one pump. Another is using 2 pumps, but no accumulator and one tank. He trailer's his rig to trails and has had issues that he feels has something to do with the electrical relay that runs his pumps. The last here in Arvada, just switched to one in-tank pump.

 

[RnrdTheFox]

Here is a link to the recipe I initially used http://classicbroncos.com/img/efi-diagram.gif . I followed it exactly.

I've only seen 3 other Broncos here locally with EFI that are actually being driven. The first one told me he went through the same issues as me before going to just one pump. Another is using 2 pumps, but no accumulator and one tank. He trailer's his rig to trails and has had issues that he feels has something to do with the electrical relay that runs his pumps. The last here in Arvada, just switched to one in-tank pump.

Ha ha. Yep, that's the same recipe as me for the most part. Your just full of good news.

I'm going to run the setup until it happens again so I can validate what I thought was happening the first time. Hopefully, the pump won't give up the ghost the first couple of times and will come back to life after it cools down.

I'm also going to check my vent/emmisions setup. I did notice a good vacume on that tank. One thing I forgot to mention is that I ran the rest of the way down with the gas cap off. So, I need to rule that out too.

thanks.

 

[COBlu77]

I wasn't bashing whoever shared that info here, but I just wanted you to see what I did vs yours. After carefully buying all those parts (SS hose and AN fittings- never again), I didn't want to let go.

Carry your fuel pressure guage with you and hook it up when it starts sputtering. You'll see the pressure fluctuate. Then listen to both pumps. I'll bet the LP is quiet and the HP is loud. Be careful, because the LP pump failing blocks the HP from getting fuel and you'll burn it up too. Yeah, I forgot about keeping the gas cap loose.