Well last night I had to get my '94 PSD towed. First time I run her in about 2 months. She was running fine at about 55mph then I noticed her bogging down. I managed to maintain 45 till I found somewhere off the road to pull into. At idle she sounded more like my old '87 6.9 than a 7.3 PSD. Loud, clacking, but running. The tow driver said "sounds like an HPOP". Never had any starting problems or running problems before. I just checked the HPOP level, it's oil was about 1" below top. From what I tried to read up on the HPOP last night, that's where it's supposed to be, right? I used an old cheap tire guage for fuel pressure reading, and at idle it topped it out at 55psi. Still runs and sounds just as it did last night. Any thoughts? Thanks

SchaefferUSMC

 

Sounds like UVCH problem. Pull the plug going to the valve covers and check for burnt pins and plugs

 

Picture here on the plug mentioned, center bottom on pic, two on each valve cover ...

 

Alright, just checked all the connectors, if you're talking about physically looking burnt, then I'd have to say passenger side forward plug, rear pin is what I'd describe as burnt looking. What all does that entail? A weekend of cussing? or just a lot of ATM withdraws? Thanks

SchaefferUSMC

 

The rear pin is a glow plug pin. Id Pull the valve covers and inspect the inside connectors or check the wiring at the idm to the injectors mine was burnt inside witty no Visable damage to the outside connectors

 

Yeah, check the UVCH harnesses with the actual covers off. It's kind of a cusser to get them off, but not that bad.

Easier to get the pass side off with the vacuum box out of the way, but being a 94, its glued on, so don't try and take it off.

They usually will burn on the inside of the harness in side the valve cover.
It's a high draw area so sometimes the harness will melt and make one of the injectors plugs loose good contact.

If its idling rough and shaking, I'd point towards wiring for the injectors.

Most tow truck drivers or diesel guys in general dont know squat about HEUI injection, so they just say big things to make themselves sound cool, Take their advice with a grain of salt. They like to trash this proven system.

Chances of this being an Hpop problem are slim to none.
Chances of it being a sticky IPR? That could be.

I'd go over the wiring first before getting into sensors, its one of the most common issues besides CPS. which is the other thing I'd check if you have one sitting around to swap in.

 

Yep, good advice. The IDM will shut down the entire bank if it sees a problem. One easy way to tell is to start the rig and feel the exhaust manifold. The side not firing will be cold. You can purchase replacement wiring harnesses from a variety of vendors. One source is Riffraff Diesel ...

Riffraff Diesel Performance Parts: Powerstroke Parts | Ford Diesel Parts | 7.3L Powerstroke Parts | Ford - 94-97 'OBS' 7.3L

Click on OEM/FACTORY

 

Clay is going to have the best OEM pricing.

 

Alright, I tore off the passenger side valve cover, and the front plug looked burnt right away, like melted plastic on the forward side. Inside neither looked bad, but since I already got 'em off, may as well, right? Now, 2 more questions. Where to get the replacement parts. I noticed yall gave a couple sources. I take it this is not something I would like to get from Advanced/Oreilly, etc? Also, my truck is totally stock, with around 184K. While I got everything tore apart, is there anything else I should look into replacing? Maybe glowplugs, or even injectors? I just hate tearing into anything twice, especially on older rigs where something else will be sure to fail in the near future. I appreciate all the advice.

SchaefferUSMC

 

Here's a little more info. I don't know too much about the injectors, I've never had to open up the valve covers before. But it seems on my passenger side anyhow, that I've got 2 different injectors. From front to rear, they are brown black brown black. With the brown colored injectors reading AA1821836CS and both black reading AOOO220058. Once again thanks.

SchaefferUSMC

 

Not to spend your money for you, but your ideology isn't bad on this either.

While you have the VC's off and if your not sure how old they are, glow plugs are a great thing to get.
Always buy Buru/Motorcraft plugs. Clay (riffraff) has those too.

As for injectors, thats up to you.
New O-rings cannot hurt it, but neither could an injector overhaul or upgrade. Your just looking at more downtime.
Jim, rosewood, our forum sponsor here can rebuild them for you however you like.
But then you'd want to get tunes to take advantage of the injectors and then you'll throw your whole house and bank account and childeren or whatever into making your truck more awesome, then soon it will be bigger than bigfoot and your neighbors will think you've lost your mind and you'll be crushing their cars for laughing at you.
OKay, so i went a bit overboard. but its addicting getting more from your truck.

Best thing to do would get the parts you need and replace the glow plugs.

There aer lots of glow plug how toos here on the site.
main advice is to not force them out. if they dont want to come out easy dont pull hard, if you do, you might be in for more work.

 

A little FYI. from Clay site.




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