HELP! Fuel problem

[Chris Buckner]

I’ve got a 96 5 spd 12v Cummins and it won’t start on its own. I have to put a rag with gas in the air intake and start it, but when it does start. It runs like a champ, I can full throttle it and idle it and it doesn’t die. So why won’t it start on it’s own?
*Side note it looks like they installed an electric inline fuel pump and I connected it to the battery and I hear it whining but not sure if it’s pulling enough psi or even works properly

 

[dieselshadow]

The mechanical lift pump that comes on these trucks stock is a great pump. I’d highly recommend restoring it back to factory and replacing the air leak prone fuel lines under the intake manifold.

When these lines leak, you lose your fuel prime to the injector pump which equates to a no/slow start.

Eliminate the fuel heater while you’re in there. It’s virtually worthless anyway.

Geno’s garage carries all the parts you’ll need.

 

[Chris Buckner]

The mechanical lift pump that comes on these trucks stock is a great pump. I’d highly recommend restoring it back to factory and replacing the air leak prone fuel lines under the intake manifold.

When these lines leak, you lose your fuel prime to the injector pump which equates to a no/slow start.

Eliminate the fuel heater while you’re in there. It’s virtually worthless anyway.

Geno’s garage carries all the parts you’ll need.

When you say lift pump do you mean the one by the engine block or the one in the fuel tank? If you do mean the engine block one should I just leave the electric inline pump alone?

 

[dieselshadow]

There wasn’t a fuel tank pump from the factory. Only the mechanical one on the side of the engine. The electric one is a bandaid someone installed.

Like I said before, I’d restore it to factory parts. It works very well and is very reliable. Get rid of the electric pump and fuel heater. Replace the engine mounted fuel pump and the fuel lines under the intake manifold. Replace the filter while you’re at it and you should be all set.

 

[Timd32]

Agree with the return to stock lift pump, delete the file heater. Change your Fuel Filter in general, most of us run Fleetgaurd filters.

Replace the old rubber lines with quality diesel set up, including the small elbow hose off the heater.

Check out Larry B's, and Genos Garage for some parts.

Follow the above items mentioned by DS, get rid of the inline set up.

Most of the time air in the system prevents the truck from starting. Includes the return lines.

 

[Timd32]

Double post.

 

[Ozymandias]

Why does everyone recommend to delete the Fuel Heater?

Doesn't make sense to me, depending on the location this is a vital part of the fuel system, keeps one from being stranded in the middle of a blizzard.

Just asking..

 

[Chris Buckner]

Thank y’all. Will definitely be doing that! And will update as soon as I do

 

[JR]

If it runs fine once started and no stumbling under power it's likely not specifically a lift pump issue. You've got a leak somewhere allowing air into the system while sitting. Mechanical injectors need fuel, not air, to pop. Air compresses too much and prevents the injector from firing.
What brand of lift pump is it? Location? Is the truck stock or modified? Did they eliminate the OEM engine driven lift pump and install a block off plate? If the truck is stock or lightly modified it is hard to beat the reliability of the OEM lift pump. The required pressures of a 12 valve requires an expensive electric lift pump to be done correctly.

 

[dieselshadow]

Why does everyone recommend to delete the Fuel Heater?

Doesn't make sense to me, depending on the location this is a vital part of the fuel system, keeps one from being stranded in the middle of a blizzard.

Just asking..

It's absolutely worthless. It doesn't add enough heat especially where and when you need it. There a significant volume of fuel in the filter and injector pump. You need that heat right off the bat when everything is cold. That heater is too little, too late, and always has been leak prone.

I ran my '95 Cummins in -55 weather in Alaska without that heater, proper fuel, and a good additive. No issues. I'd bet the P pump adds more heat to the fuel than the heater ever did. LOL

 

[Timd32]

Why does everyone recommend to delete the Fuel Heater?

IMO, I follow the above as well.

If in super cold plug in the block heater when you shut down.

The biggest physical reason I deleted mine was the plug area was cracking, I kept the bowl and replaced the coarse filter that is in there.

If I still had mine I would do a test with my thermal camera to check this out and see if I'm just following the herd on this one, I think this is in the buyer's guide article or the perfect collection as well, that's where I ran across this info the first time. I did not want to mess with this twice.

Replace the small filter screen for sure, you could keep the heater, mine was on there for 205k miles, so there was no harm in having it if it's not physically damaged, clean the bowl, change the screen, change the elbow hose, on this thing for sure.

Do the grid heaters work on the truck, I thought it was a bad idea to use this ether/fuel rag starting method with Grid Heaters, ON?

 

[JR]

The purpose of a fuel heater is not to physically increase the temp of the fuel but to prevent wax particles from forming and plugging the filter as it is pushed through. Filter plugging generally doesn't happen while sitting nor immediately after start up Unless you have a really bad (unclimatized) batch. The fuel in the lines and tank will be ok but the filter will be plugged up in MOST cases. There is no substitute for properly climatized fuel and a heater is by no means an end all solution but if properly working could make a difference under the right circumstances. There is definitely a reason why manufacturers continue to install them, and it ain't for cost cutting reasons

 

[Timd32]

The purpose of a fuel heater is not to physically increase the temp of the fuel but to prevent wax particles from forming and plugging the filter as it is pushed through.

Backup info on this attached..... I deleted mine due to it's not a daily driver and rarely used in real cold weather. It's like $70 bucks from Larry B's so not a bad deal to keep it.

16MB File...
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.cumminsfiltration.com/south-pacific/sites/cumminsfiltration-empty.bitnamiapp.com.south-pacific/files/LT32599_01%20Fleetguard%20Products%20%26%20Parts%20Technical%20Information%20Catalogue%20Fuel%20Filtration.pdf&ved=2ahUKEwifl9CU_6_kAhUGIjQIHR-rD8M4ChAWMAB6BAgFEAE&usg=AOvVaw0XIODX6kzY1tH6uvemqqFb

Link below for basic fuel system stuff.... most Diesel Parts Houses carry some form of Larry B's stuff, so you. Might be able to find local.... hoses and the sort could be found local at a decent truck shop....

http://www.fostertruck.com/dodge/fuel-system-parts.html

 

[GAmes]

........ but the filter will be plugged up in MOST cases.

And that is the problem with the 12 valve fuel heater. It is positioned in line before the lift pump, long before the filter. As such it is totally ineffective to prevent gelling and is a constant source for leaks. I deleted my fuel heater shortly after joining the TDR. Many trips later into the great white north and never a problem. Industrial 5.9 Cummins do not have a fuel heater.

 

[JR]

And that is the problem with the 12 valve fuel heater. It is positioned in line before the lift pump, long before the filter. As such it is totally ineffective to prevent gelling and is a constant source for leaks. I deleted my fuel heater shortly after joining the TDR. Many trips later into the great white north and never a problem. Industrial 5.9 Cummins do not have a fuel heater.

So it is essentially an "inline" heater? That definitely sounds like poor placement. I guess I have not looked closely enough under the hood of one. Regarding heaters on a 4b and 6b we have two at work, both in small cranes with the canister style heater. Maybe it was part of a cold weather package, which often includes hydraulic tank heaters, coolant heaters, oil pan heaters, etc. that we have to request Everytime we order a new crane and not be standard equipment. But they are definitely there. I'd have to look to be sure but I am pretty sure they are both Fleetguard housings. I ASSumed this would have been pretty much standard across the line on a 12 valve engine, and you see where that got me

 

[Chris Buckner]

If it runs fine once started and no stumbling under power it's likely not specifically a lift pump issue. You've got a leak somewhere allowing air into the system while sitting. Mechanical injectors need fuel, not air, to pop. Air compresses too much and prevents the injector from firing.
What brand of lift pump is it? Location? Is the truck stock or modified? Did they eliminate the OEM engine driven lift pump and install a block off plate? If the truck is stock or lightly modified it is hard to beat the reliability of the OEM lift pump. The required pressures of a 12 valve requires an expensive electric lift pump to be done correctly.

I Don’t seem to lose power once started and running, , the truck is stock with no visual upgrades done. I do not see a block off plate or anything done to the lift pump.

 

[Timd32]

Could just be the old lines then, you could start small and do the rubber lines and look for any areas that appear wet or have dirt built up.

But your Grid Heaters are working? They pull quite a bit of amps when you turn the key on, unless it's pretty warm already.

 

[JR]

I Don’t seem to lose power once started and running, , the truck is stock with no visual upgrades done. I do not see a block off plate or anything done to the lift pump.

So you have an electric pump inline with the factory lift pump, that in itself could create its own problems. If one is anemic or fails the other will really struggle to pull/push fuel through the other. Aside from looking for and fixing any leaks I'd eliminate one of the pumps from the equation. It is possible this was done because the OEM was weak so you'll have to verify you are getting adequate flow from it.

 

[dieselshadow]

Return to stock fuel system, eliminate electric pump and fuel heater, replace rubber fuel lines under intake manifold, enjoy a reliably starting truck.

 

[Timd32]

So you have an electric pump inline with the factory lift pump, that in itself could create its own problems.

Ha.... yeah forgot the OP that was yesterday's task, I'm already past that step.......I'm on to just the bad lines...