7.3L, 225k injectors and glow plugs?

[Goin For Snow]

I know it has some dead glow plugs because it doesnt start like it used to. I have never replaced an injector either. Truck is in great shape and plan on running it to 300k.
It is worth doing the injectors just because?

 

[Scott]

There is a relay module in the glow plugs that goes out.
When that gets fixed, they start like a brand new truck.

 

[sledfreak89]

Yup. Glow Plug relay is usually the problem. BUT it still could be your glow plugs.

The relay will tell you.

I wouldnt do the injectors unless you have to. Ive heard of many many 7.3's going past 300k with stock injectors. It all depends how you drive and if it has a programmer on it or not. Stock injectors cant handle much hp.

-Matt

 

[WestMont]

If the relay is cycling rather quickly then it just may be one or more glow plugs out.
A quick check to see if they are good or not is to first pull all of the glow plug wires off the top of the glow plugs. Then hook up a test light to the positive side of the battery with the alligator clip. Then touch the tip of each glow plug where the wire plugs on to it and the light will light up if the glow plug is good and the light will not light up if the glow plug is bad.
They run them in a series so all it takes is one to be bad aand then the truck will be hard to start.

 

[clodhopper]

Sometimes the connectors at the valve cover gasket get bad also. My first 7.3 powerstroke had all three things go bad at one time or another. The relay was a once a year thing, the first set of glow plugs that came from the factory went bad (maybe from a stuck relay) and a few connectors at the valve cover gasket went bad too. It takes a deep well 10mm to remove glow plugs. If you do have a bad terminal on the wire harness, you used to be able to get the connectors from a navistar dealer but ford didn't offer them.

 

[Wheel House Motorsports]

dont bother with injectors. maybe do o-rings? thats a whole different project when you get in there as you get diesel/oil in the motor and have to suck it all out, its kidna a pain.

just google how to test the glow plugs, its really easy to do, then you know what actually needs fixing. also, get the nap 109 relay, not the 110 or whatever theres calls for, its about 1/3 the price and just mounted 90* different, works awsome and saves $$. dont use autolite or champion glow plugs, i did autolite 1111's and had to replace them as 7 out of 8 went bad in 5k miles. did bosch and rockin strong 10k later after lots of hard starting this winter..

good glow plug system and 5-40 full synthetic oil, starts at -15 F unplugged like its hot out.

 

[Eli]

dont bother with injectors. maybe do o-rings? thats a whole different project when you get in there as you get diesel/oil in the motor and have to suck it all out, its kidna a pain.

just google how to test the glow plugs, its really easy to do, then you know what actually needs fixing. also, get the nap 109 relay, not the 110 or whatever theres calls for, its about 1/3 the price and just mounted 90* different, works awsome and saves $$. dont use autolite or champion glow plugs, i did autolite 1111's and had to replace them as 7 out of 8 went bad in 5k miles. did bosch and rockin strong 10k later after lots of hard starting this winter..

good glow plug system and 5-40 full synthetic oil, starts at -15 F unplugged like its hot out.

Spot on!


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[vmax600]

Amp clamp testing...

If you have an amp clamp on a battery tester, you can test the glow plugs as a "gang" and have a pretty good idea of how many are down. Put the amp clamp on the 2 big feed wires off of the relay. Key on you should see an initial reading of 190-ish amps, then tapers off to 100 amps, then drops off to zero. Subtract about 25 amps per bad glow plug on that initial reading. Individual plugs can be tested with a simple test lamp. Valve cover gasket connections do work loose inside the covers. These, if the actual connectors aren't burnt, can be "zip tied" together and will stay put. I've done this several times. Usual sign is one bank goes down on the injectors...have fun! P.S. only reason to do injectors is due to failure. Find someone to do the "buzz test" with a scan tool, then a cylinder contribution test if available for this vehicle on the scan tool.