Hard Start on my 7.3 IDI New Injectors

[jonmatthews96]

Hello, I'm new to the site so help me out guys.

I have a 1990 7.3 IDI and it's been having problems starting, even after I put the new injectors in. Not sure if it's losing prime or not. I have an Electric Lift Pump on I bought at NAPA, New front tank (back one is disconnected), All new fuel lines, IP was put in last August, and new Injectors put in last week. I do have a sticky valve, so not sure if that would effect it. Any Help is good help to me. I spoke to an Administrator a little while back about my truck. Not sure of what his username is on here, but his name is Corey from Quakertown, Pa. but like I said, any help is help at this point. Thanks Guys

 

[nic55kel]

Assuming that once it has started it runs fine:
It sounds like you had starting problems before the new injectors?
Return line leak is most likely. It was all apart to install the injectors.
Even if it doesn't visibly leak fuel externally it may well let air in when sitting.
With the electric lift pump you should be able to push all the air out pretty quickly - not sure how good the NAPA pump is.
A facet electric pump will do it in a few seconds.
If that isn't it I would suggest verifying that the glow plugs are cycling correctly.
If you have fuel, heat and adequate cranking speed and even only fair mechanical condition it has to start.

 

[nic55kel]

Forgot to ask is it hard starting cold, hot or all the time?

 

[jonmatthews96]

Thanks. I kinda had a feeling it's something with the return lines. Because there are no wet spots around any injectors or where hoses connect, anything like that. It almost sounds like its losing prime somewhere between the IP and the chamber. It's a hard starting all the time as well. After I check my glow plugs, if they're all heating up and working right, should I take off the return lines and basically put them all back on? Including the cups that sit on top of the injectors?

 

[icanfixall]

WElcome to the forum. Please tell us where you bought these parts. We know injection pumps are rebuilt and not new so thats not an issue here. But where did you get the injectors. Are they new or rebuilt. Now how did you remove the injection pump from the engine. Can you see and moisture in the valley pan under the injection pump or the intake manifold. Either you have an air leak causing the fuel to drain back as it sucks in air or the pump is not good.

 

[jonmatthews96]

The injectors are STANDARD injectors, new not rebuilt. There is no moisture at all anywhere.

 

[cpdenton]

How about the fuel filter area? Any signs of leakage around the fuel heater, filter, ar that area. It could be letting air in around there. That's what mine did.

 

[jonmatthews96]

I did just find where I believe it's taking air in. The front injector of the passenger side, is leaking around the o-rings. So I'm going to put o-rings on it and hopefully that'll fix it.

 

[icanfixall]

Might be the reason for the hard starting. Also the filter to injection pump line has a rubber fitting called an olive in both end of that. They are 5/16 size. Also the line from the manual lift pump has just one at the top. Not the bottom. This is a 3/8 line so thats the size of that olive. Most any fuel injection shop will have them or contact Mel aka agnem or Russ aka typ4. These members here have been helping and selling the good stuff for many years.

 

[robndon]

My 1990 7.3 very hard to start after sitting for a while, seems like it looses prime. Changed the glow plug relay that was only showing 9 volt on the glowplug side. I'm gonna try suggestions found on the forum. Look for leaks around injectors and pump. Thanks