7.3 wont start unless pluged in

[mktransport]

I have a 2002 with 422000 miles on it. My truck will not start unless i plug in the block heater, even when it is 80 out. its really annoying and i'm tired of paying mechanics to not fix it. glow plugs replaced with relay. injectors replaced. No one has checked compression yet so I guess i'm heading there unless anyone has any suggestions

 

[95_stroker]

Once running, how is the power? Does it have significant blowby? 422K is a good number of miles and it may be a compression issue.

 

[Crumm]

X2 on the compression. With new glow plugs and relay it should fire right up. With low compression it wont.

 

[Zookie400]

welcome to the forum.

+1 on the compression check.

also, just for fun, test the batteries. i was chasing a glow plug issue once, and it ended up being batteries.

 

[jbuller]

smoke?

how much blue smoke does it throw out the tail pipe when idleing?

 

[powerstrokeguy]

wow thats a good chunk of miles. Yes compression comes to mind.

 

[Dogman]

Check compression, injectors O-rings, load test batterys. just my

 

[Hoss 350]

Just my two cents, the guys saying compression are probably headed downthe right path, but I'm still curious about plugs and relays.

Have you jumped your relay (just run a jumper between both posts) to see if it starts easier afterwards? I've bought bad parts from the auto parts guys before, and this is a really easy test.

However, if it is strggling to start at 80, I still think compression is a big issue.

 

[Potentialbuyer]

You can do a crankcase pressure test to determine the mechanical condition of your engine. It's a lot easier to do than a compression test. If you can't get the tools to do it, it shouldn't cost that much from the dealer because it only takes about 10 minutes.

 

[Zookie400]

i didnt know ford had a spec/tool for these engines......i know the dealer i worked at didnt, but they didnt have a lot of things.

we do that test on the CAT 3126's and its a great test, much easier than the compression test. it only tells you if you have a blowby issue, it wont tell you what cylinder(s).

it is quite simple too....your CCV pipe runs through a specified orifice, and on the engine side of the orifice you have a in/Hg pressure/vac. guage. if its pushing too much blowby, it will build pressure because of the orifice, and tell you if you have what is usually a cracked ring or burnt piston on the 3126.

i would love to know the specs for the 7.3, so i could test mine when the time comes.