Intermittent Hard starting.....HELP!!!

[corey bonnevie]

I have a 91 7.3L IDI that has 170K miles on it. Noticed one day it refused to start. Turning over but not starting. Ran the Batteries dead. Noticed that I had some wetness around some injectors and the IP. Had the money saved and This truck is clean as a whistle and never gave problems so here we go,.....NEW Starter, batteries, electronic fuel pump(in place of the old lift), fuel filter, IP, injectors and all seals/gaskets/o rings, and return lines. No real change until the I changed the IP. At first she fired quicker than I have ever heard her. An hour later, nada. Now intermittently you can crank and crank and no start. And sometimes vroom! immediately. I have power going to the FSS and it runs great once started with no worries. Truck has good power and really doesn't smoke when running so I "don't think" its a compression issue. *** Frustrated Help Please!

 

[Golden Helmet]

My first thought is glow plugs, how old are they? Are they Autolite plugs? And does your wait to start light stay on for 10-12 seconds?

 

[corey bonnevie]

The guy who sold me the truck swore that they were new, and they do look it, they are def NOT original. I hear the relay clicking and the light stays on ususally 8-15 seconds, change anyway?

 

[DaveBen]

You should ONLY run Motorcraft Glow Plugs. Autolight glow plugs, and others are NO GOOD! They can swell and become difficult to remove and may break, causing you to remove the head to get them out.

 

[IDIBRONCO]

Another thing to consider here. Where did you get your injector pump and injectors? The only 4 good places to buy from are R&D IDI Performance, Russ (Typ4 on here), Conestoga Diesel (Mel/Agnem on here) and Classic Diesel Designs (Thewespaul on here). You can buy cheaper ones, but you'll most likely be buying them twice. Once from the others, and once from one of the four good suppliers. Even if they have a replacement warranty, replacing the bad parts that were supposed to be good when you bought them gets old in a hurry.

 

[corey bonnevie]

That's good advice. I bought a cheaper re-man IP but injectors were new. Something to consider! Thank you

 

[IDIBRONCO]

That's good advice. I bought a cheaper re-man IP but injectors were new. Something to consider! Thank you

You're welcome. It may not be your problem, but it may be. That's just some advice to file away for future use. Even if you have to write it down, it's good to know. If your pump turns out to be the issue, don't feel too bad. I think that most of us here have made similar mistakes. I had mine rebuilt by a shop that has been around for quite a while and they didn't last.

 

[corey bonnevie]

So while sitting in the parking lot I noticed fuel spots just to the front of the "Front" fuel tank...could this be causing an issue???Doing glow plugs as well being that they wont break the bank. Love this truck and the way it runs once it gets going, but this cat and mouse stuff gets old quick. Thanks all you guys for the expertise. Still learning, this is my first diesel! Ill post when we nail it down.

 

[Slicknik]

It's not injectors , you have an air in your fuel line , if it's intermittent like you said , if you see fuel or any sort of wetness/leak near the injectors or fuel filter or fuel pump , that's the problem , had the same issue . Air intrusion is it your issue 100%. Couple different ways to fix .

1. Replace your o-rings on the injectors returns lines , replace the heating element o-ring in the fuel filter .

2 switch to an electric fuel pump and don't use your mechanical one anymore

 

[corey bonnevie]

The only leak I see is underneath the truck bed at the front tank, All dry up top. Electric fuel pump is in, all injectors are new with new O-rings, all dry.

 

[Thewespaul]

It's not injectors , you have an air in your fuel line , if it's intermittent like you said , if you see fuel or any sort of wetness/leak near the injectors or fuel filter or fuel pump , that's the problem , had the same issue . Air intrusion is it your issue 100%. Couple different ways to fix .

1. Replace your o-rings on the injectors returns lines , replace the heating element o-ring in the fuel filter .

2 switch to an electric fuel pump and don't use your mechanical one anymore

Why would either of those solutions fix a leak near the tanks?

OP, Check the fuel tank for any soft spots where it could be leaking through in a rusty area, and check the quick connect fuel line connections for any leaks. Any leaks ahead of the lift pump will suck air when running which can cause a number of issues, get that fixed before spending any money on other parts. Also, if you can avoid it I never recommend replacing one injector at a time, they need to be replaced as a set if one is having issues.

 

[corey bonnevie]

Why would either of those solutions fix a leak near the tanks?

OP, Check the fuel tank for any soft spots where it could be leaking through in a rusty area, and check the quick connect fuel line connections for any leaks. Any leaks ahead of the lift pump will suck air when running which can cause a number of issues, get that fixed before spending any money on other parts. Also, if you can avoid it I never recommend replacing one injector at a time, they need to be replaced as a set if one is having issues.

All 8 injectors replaced! Doing the fuel tank and any observable problems in relation this week. Thanks for your advice!

 

[IDIBRONCO]

When you find and fix that leak, it will probably also fix your starting issue as well.

 

[corey bonnevie]

When you find and fix that leak, it will probably also fix your starting issue as well.

IDIBRONCO, Just wanted to let you know, I narrowed down the hard starting issue to exclusively after she had warmed up. Called the company who sold me the IP and they recommended cold water on the IP. After that and every-time afterwards, If you cool the IP, she fires....immediately. Its under warranty, so here we go; hope the next one is good. . But your original idea was correct. Thanks!!!

 

[Cubey]

If you have the mechanical pump still, check the short rubber hose at the pump. My 85's was a bit mushy and leaked. It uses less than 1ft of 3/8" hose. It might have been causing air intrusion issues for me, not sure. Losing fuel to the ground isn't good, in any case. It's a nasty, messy job for just 2 clamps and a short piece of hose! At least it was for me from the grime and diesel.