Working on a customer's 02 F-350 7.3 that had 3 bad glow plugs on the passenger side. Since I had to replace them (I did all 4) I went ahead and installed what I thought was a better gasket / harness and used NAPA 600-3500. Got it all back together, started it up expecting great things, and it ran like crap. Since the gasket / harness came with a new external plug I used it to ohm out the glow plugs and injectors and it showed the two front injectors as open - I'm sure I got the (internal) injector connectors on correctly and secure with the clips but now it's showing those two open - the back two are fine. I didn't ohm out the connectors on the new gasket / harness before I installed it because it was new - anybody have any problems with this part? I'm looking at pulling that side apart again tomorrow (I've got practice now). Also, the check engine light is on but no codes.

 

You need a scanner that can talk to these trucks... they are not obd2 compliant... they speak their own special powerstroke language. AutoEnginuity, snap on solus, ngstar... you gotta have a beefy scanner.

There ARE codes if the cel is on.

 

I guess it could be possible that those two weren't seated fully. But until you pull it back apart you won't know for sure.

 

I doubt the customer will spring for a scanner for his particular truck - but if I plan on working on many of these, I'll have to get one. Thanks

 

that harness is made by Dorman and there was similar reported issue with one from Dorman in the later part of last year or so. I think they are hit and miss on quality as I have used one with no issues from advance auto parts for a truck I was flipping.

NAPA AUTO PARTS

 

Here is one of the threads with a quick search.

https://www.ford-trucks.com/forums/1...ew-harness.htm

https://www.ford-trucks.com/forums/1...or-issue.htmll

there is another one with Napa harness

Those worked last when i first posted them. Not sure why those links are dead now.

 

I have been running a NAPA harness for about four years with no issues. But it has been four years. If I had to do it again, I would get those from bob or clay.

 

I put a Napa one on mine a few weeks ago with no problems.

 

I have used many Dorman gaskets and have had no issues ( yet ) . I agree on the scanner upgrade . I have Snap On and Matco scanners that are great on these . The Matco was MUCH cheaper ! It is just an OTC branded as Matco .

 

The Matco truck was at a body shop near my shop so I stopped there to ask about scanners and ran into a Ford certified diesel guy with lots of experience with 7.3s - we put his SnapOn Solus on this truck and the buzz test showed #1 and #3 injector bad (tiny buzz inj 1&3, loud all others) -another (high - low) test indicated it was the injector, not the harness (?). Anyway, now I know a guy that can scan this thing - reasonably, too.

 

So it was running fine until you replaced the harness but it wasn't the harness that was the problem? Are you ordering new injectors for the customer? I'm interested to see if the injector replacement solves the rough running problem.

good luck

 

So this "customer" is allowing you to throw parts at this thing without a conclusive diagnosis? For what "shop" do you work? Internet forums make overnight technicians anymore.

I'm in agreement with the above post that states: Sounds like you're chasing your tail and may likely spend a lot of money for somebody else based on a "buzz test" that really doesn't mean anything without other tests at this point (since it allegedly ran fine before you removed the valve covers).

Good luck.

 

Thanks for the warm welcome cleatus - no the vehicle was not running fine before I changed the harness, it had glow plug problems at a minimum, and did not run well. The customer got this vehicle from a private seller who cut them quite a deal - I'm guessing because he got quotes to fix the many issues this truck had and decided to bail. As for the "overnight teh" comment - we all have our areas of expertise...................how many nuclear devices have you assembled? Have a nice day.

 

Cleatus makes a good point..The buzz test/codes confirmed what u wrote in your very first post. It did not rule out the harness by any means. You are going to have to pull the v/c again. Either plug the old harness back up and run the same test you ran in the first post or check the resistance on the front injector coils at the injector which is a little more difficult.


It could be the injector coils but I would want to verify with the harness possibly being suspect. While i had it open, I would also check the continuity from the main plug at the v/c harness connector to the two suspect inj leads.

 

I'm not sure on the specs, but you should be able to check the resistance on the new harness.

If you are gonna be working on these trucks, some kind of scan tool is invaluable. However if it's a one time deal it might not be worth it.