We recently purchased  a 98.5 laramie slt, and we have fixed the boost sensor the tps and replaced the filter, we are now looking to replace the lift pump. We rented a fuel pressure  gauge and hooked it up and we got idle pressure of 19 to 20 and reed pressure of 10 to 11, we have been told that it should run a constant  pressure  of at least 14 to 16. When we removed it we noticed some wires were cut, yellow with a white tracer going into the ecm and it is both wires. We have done a lot to this truck and we are at a loss, when we rev it up the pressure  drops and the engine starts to run flat has no power. Please help us.

Oh OK I put the member info in. 

New fuel pump didn't fix it. This is depressing, he is going to drop the tank and see what's in there.

Can you fill us in on the codes?  

 

I know you dont want to hear bad news, but keeping them from us is just making us suggest things that cause you to  "blindly throw money" at the truck.   None of us want that, been there done that.  

Ok with alot of help we have figured out that the lift pump is going bad and with the previous owners the pump went out so that caused a lot of issues for us to figure out. We have came to the conclusion that it needs an injection pump and an ecm along with a new lift pump. But with those items being fixed it should keep us going for a long time. We just have to find the money to do the two high priced fixes. After that we will have front suspension and minor body work, then we will have a truck that will be our last truck we will ever need. The interior is in really good shape which is good cause it is leather and I will not have to redo it, aside from it needing a headliner it only needs a good cleaning. Thank you for all your help we will be posting how it is coming along, again thank you.

 

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Please do keep us posted. From talking to Cory last night you got a great deal on the truck even with the bad VP and ECM. The VP will get you going and you can save for the ECM. Might make it a little less painful.

Ok here is the latest, as soon as the rain stops he is going to check voltage on the wires coming into the lift pump then he is going to check the tank and see if there is any of the diesel crap in it, from there he is going to do the stuff you talked to him about. Hopefully that will get us some relief for now and allow us to start thinking about the VP and how we are going to fix such an expensive item.

I you have questions and a camera, take pictures. Sometimes it makes asking the question easier when all can see it.

Ok we have probably a stupid question. He got the tank out and the fuel module out and the module looks horrible, the screws on the sides that work the slide movement will not work, the metal has no support where it is suppose to be together, and it has been sitting on the tank bottom. We were  wondering if a gas sending unit is the same as the diesel one, I have looked for one on line and can only find the gas one or one with the pump, we don't need the one with the pump, it is oem (carter). Any help will be greatly appreciated and thank you in advance.

it's better to get the one that has the pump placed in the tank. much better then the carter on the side of the block. as for weather a gas one will work i'm sorry i don't have that answer.

We have an airtex on the block, just didn't know if a gas one would work or if you can run both of them together, or how you would get the power to the pump, if that's the  only one we can get. 

You don't want to run a gas fuel pump in a diesel, the seals will get eaten up.  Don't bother with 2 pumps, to complex.

So where do we find a fuel module aka sending unit for our truck. I can't find any on line and it is so screwed up that we think it is causing  all the fuel issues.

It is not the pump, it is the pick up unit with the float.

The sending unit and basket will work, but the fuel pump wont.

 

You could install a draw straw in your setup maybe or install a draw straw in a new fuel module aka remove the pump.

It is gonna be hard to find the old style fuel module without the lift pump.

This truck is all stock it doesn't  have the retrofit  pump it still has the stock sending unit with no pump.

I think what is being asked is is there any difference between a gas fuel module as compared to the diesel. I have module in mine from the intank pump from dodge. It looks just like the Liberty module that Vualcan sells minus the mods made for the fass and the mods I did for the air dog install. Are there any seals in the module? I dont remember any in mine when I modded it, all the fuels just clamped on.The only seals I remember are on the external connections.

I have another question about the modules in general. Does the fuel module not stay on the bottom of the tank all the time? It appeared that what to me when I did mine.

We can find one for a gas engine would that work.

Does any one know why it has to slide up and down cause we can fix it in position, but not sure if that will work.

And no it does not it moves everwhere, when we took it out it wasn't  even connected to the bottom it was just moving around the screws were  in the plastic part and the metal part was just there not attached.

It slides up and down to allow for it to sit on the bottom of the tank regardless of the tank size.

 

You could just mount yours so it sits on bottom.

 

As for the fuel module, they are the same between as and diesel, but you cannot take a new in tank style module, remove the pump and have it suck fuel.  You might be able to mix and match parts to make it work, but the pump in the tank is the pickup source for fuel. 

 

Can you find a module without the lift pump now days?  If you can and it is for a gas truck I don't see why it wouldn't work.  You could use the part number lookup tool to compare part numerous between the gas and diesel engine.

Ok I will try that. The book shows the same module for gas as diesel and with no pump on it all it has to do is read the fuel level and allow the lift pump access to the fuel.

 If the top plate of your fuel module and the fuel level sensor are still good then no sense in looking for a new unit. All you need is a draw straw 1 from Vulcan performance for like $70. 

So the draw straw will bypass the screwed up sliding mechanism?