7.3L Starting Problems
 

I currently own an F-250 with a 7.3L power stroke and am having trouble starting the engine and troubleshooting the problem. I have replaced the glow plugs, glow plug cables (under the valve covers) and the glow plug relay. I am still having to crank the engine for a very long time in the mornings to no avail until I shoot starting fluid into the air intake. At this point the engine fires normally until it cools off again and then the same old stuff.
Does anyone know what else may be the problem?
Thanks

Hi, Schauba, welcome to FTE!

Have you tested the Glow plug system at all? Using a meter (set to DC Volts) or a test light you should get power at one of the big terminals on the GPR with the key off. Turn the key on, the relay should engage and you should get power on both of the big terminals. I would start there if it were me. That will tell you whether the GP system is even trying to work or not. Test that and post up your findings and we can go from there.

Thanks Nate,
 

I have checked the GPR the exact way you said and did find out that it was intermittent. after replacing it I then checked continuity to ground of the GP's which in turn measured good. I lifted one of the valve covers and noticed that the cables to each GP required replacing. I decided to just replace the GP's and wires since I was already under the valve covers. Unfortunately none of this has helped with the starting problems so if you have any other ideas I am willing to try. Thanks

Don't use starting fluid unless you disable the GPs. If your getting power to both of the big terminals like you say, do you hear a 'click' when you turn the key on and see the amp gauge go down right after the 'click'?

Do you have access to Auto Enginuity or other diagnostics software?

are your batters 850CCA each? test out good?

does the motor sound like its cranking fast and clean just not firing quick? or a little slower crank?


those are a few things to check. but if you have access to software i would check the PSI of the IPR(Injection Pressure Regulator) upon cranking.

duggyb,
I may be able to get access to the software.
Batteries check good, 1000CCA and engine appears to crank normally.
Thanks

oldbird1965,
Will the starting fluid ruin the GP's.
Thanks

I am still at a loss but could the high pressure fuel pump have something to do with it?
Once I get it started evreything works fine.

You should not use ether on an engine with glow plugs, unless you are certain the glow plugs are disabled. Even then, it should be minimized. Using ether with glow plugs can cause damage of the expensive type.

Using ether with glow plugs lit could bend a connecting rod. You could try using propane but you need to turn it off as soon as the engine fires up because propane injection at idle can also bend a connecting rod. I had some success with that on my IDI but not with the PS. When I'm having severe starting problems, I've tried injecting hot air directly into the intake with a heat gun and have had some success with that. I think the biggest contributor to my hard starting (without the block heater) is my fuel injector seals. With the block heater, it always fires right up.

In other words, when the ether hits the red hot glow plugs, it explodes!