Question on glow plug replacement strategy... 4, 5, all, and do I do harnesses?

It looks like I'm down to 3 working glow plugs, all on the driver's side.

I checked the relay... good voltage on the output side while "waiting to start". So the relay works.

The outside harness pins... what plug into the valve covers... have good connectivity to the relay. So I don't have any problems outside the valve covers.

I checked resistance on the in-valve-cover connectors to ground... outside pins to battery negative. On the driver's side, 3 of the 4 pins have very low resistance... so I'm presuming everything is good on 3 of the 4 cylinders. One pin has infinite resistance... so either under-valve-cover harness or glow plug

On the passenger's side, all four outside pins have infinite resistance... so either harness or plugs.

I have cold-start problems in cool weather... say 45 & below. When cranking, sounds and feels like it's only firing on a few cylinders, and blowing a lot of white smoke. Once it does start, no problems. No performance issues, no warm start problems. Batteries are less than a year old (NAPA), and haven't been abused.

I haven't changed any of these parts since I've owned the truck, so they're at least 8 years old and 50 K miles. I suspect they're original, which means 15 years and 225 K. The truck is a toy hauler, and sits sometimes for a couple of weeks between starts.

Now to the questions. Obviously, I'm going under the passenger's side valve cover. I'm thinking of replacing both harnesses while I'm in there, as well as all four glow plugs. Parts cost is much less of an issue than not having to go back in there for a long while. Or should I leave the harnesses alone unless I see signs of damage or aging? I'm less eager to go under the driver's side valve cover. A lot more crap needs to come off to get to the valve cover. With 7 working glow plugs, do i need to worry about the 8th?

Thanks in advance for your thoughts.

 

I would do them all and the harnesses, since you mentioned cost is not the issue here. If 5 are bad, how long do you think before the other 3 are? If it were mine, I'd do them all, and the harnesses on both sides.

 

Yea,all harnesses,plugs,gaskets,pig tails.then u can go another 225k or so...

 

I agree with you guys i mean your already under the hood might as well get it done now.

 

I would do everything while you're in there, if you can. We just did my glow plugs yesterday, and I wish I would have been able to do the wiring harness too. It wasn't too bad getting the valve covers off. The rear one on the driver's side is a pain - i had to use a swivel. The rear one on the pass side is a pain too, but you can peel back the insulation on the sidewall beside it and there is a little black box that comes off with two 5/16 hex head screws(Have no idea what this box is). Once you take this box off, it's not too bad. I'll have to get in there again before too long to replace my wiring harnesses - i've got some oil seeping through the plugs.

 

2x on what TyBragg said. Use a u-joint adapter on your ratchet and the bolts in the rear are cake. Plus, the driver side cover really isnt too bad. all you have to take off is the CCV and just two bolts that hold on that intake elbow that the vent hooks up to. While your in there, take a look at your intake boots as well. If you still have the red factory ones, and they are starting to tear and break down, Riffraff Diesel sells very nice replacements. They are a little pricey, but far superior quality.

Riffraff Diesel: Riffraff 94-97 Turbo Intake Boot