Hello everybody. This is my first post as a new member. Didn't think I'd need help this quick. That is why I bought a first gen Cummins a couple of months ago. Anyway, its an early 91 non-intercooled 5.9 with all the syptoms of a bad lift pump. All my reading so far makes it sound like the injection pump is done too but in most cases they are talking about the P7100, not the VE Bosch pump. I can only do about 50 mph before the pedals to the metal and it is not the turbo and the filter is new. The question is, is the injection pump truly pooched or should I change out the lift pump first and try it? Also, any comments on something like the FASS system to replace the mechanical lift pump would be appreciated. PS - I had planned on installing a fuel gauge but have not had the truck long enough. That'll cost me. Thanks everyone. Mark

 

check the fuel pressure first, that will tell you a lot about what might be happening. with a stock truck, and with a stock lift pump it should be between 3 and 6psi I believe.

when the lift pump goes south, it sometimes leaks fuel into the crank case, so check your oil level to make sure it hasn't risen, or smell of diesel.

One of the tell tale signs of an injector pump on it's way out, is hard starting if I remember right. if it starts the same as it always has, you might be ok in that department.

if it has no power, it could be that your throttle cable has stretched and so you're no longer getting full travel and therefore not able to hit a true wide open throttle, or your fuel pin is sticking inside the afc and you're not getting any afc travel, which will cause a severe lack of power in a stock truck.

 

Hi Rick. There sounds like some hope. I'll definately check into those items. Unfortunately I work away from home so it'll be a couple of weeks before I can get at it (had to get my 74 Datson 260Z out of storage to get to work). I'm definately going to order up a new lift pump and fuel gauge kit so their waiting for me when I get home. Thanks for the input. Mark

 

I forgot to mention Rick. The truck starts good as ever, idle and in town driving same as always. If I hadn't gone out on the highway, I probably wouldn't have known I had a problem. Thanks again.

 

well when you're able to actually have a look at it let us know what you find out!

 

I'll let you know how it goes. I'm definitely hoping the fuel pin is dirtyand stuck. I've been doing a little reading and I might as well turn the pin and rotate the star wheel while I'm at it. I've seen people turn them 2 turns cw, 3 turnscw and turn till it bottoms out. Any thoughts on that? Thanks - Mark

 

I'd advise leaving things alone until you get it running right. Too many times people dive into there injection pumps and do all these cheap, cool mods and then can't figure out why the truck won't...(insert problem here). It makes it difficult for us members to try and diagnosis problems when many things have been done. Not saying your guaranteed to have problems...but you never know.

If you take your time, get things running right first, THEN do one mod at a time...getting the truck running right after each mod, you should...in theory...have less issues.

These are just my opinions.

BTW: I have been driving my truck now for almost 2 years and have yet to do any mods to my IP. I have everything...just have not done things yet. But when I do, it will probably take me close to another year to finally get all the mods done.

 

Hi Rick : Thanks for stepping in there. Your absolutely right about getting the truck running first. I should know better but as you say, I'm sittin' here reading about all the cool things I can do but I'm not at home to do them. So now its back to the pin first (still hoping), then replace the lift pump and install a fuel gauge and take her from there. Thanks for the wake up call. Rgds - Mark