Progressive loss of power, non turbo

Minuteman96

Registered User
Joined
Aug 28, 2021
Posts
43
Reaction score
7
Location
California
About three weeks ago I noticed my truck is really really slow. I’ll give it throttle but it feels like it’s even more gutless than it actually is. My first thought is weak injectors but I feel the pump might be an issue. I gave it a couple healthy doses of diesel Kleen and it didn’t help at all. I don’t know how many miles are on this engine. No sweet exhaust, some white smoke on throttle but it’s minimal, I did notice it slightly heavier tho one time when I gave it throttle to back out and I had never seen that before. I read that the timing can go out on these engines and am wondering if that’s a possible issue?

Also, new air filter has led to an almost helicopter whirring noise under the hood. Is that the normal sound of an idi? I had never changed the air filter for about 15k miles so I got used to it without a new filter.
 

Big Bart

Tow&Slow
Joined
Dec 22, 2020
Posts
1,481
Reaction score
910
Location
Newport Beach, CA
Some thoughts -

Check your air filter, if you have a exhaust leak under the hood or some blowby it could be clogged.

If not the air cleaner, yes you need to check the timing, the white smoke could be timing related.

Next would be a compression test to insure it’s not a lack of compression.

If not those, then time to have your pump and injectors tested and likely rebuilt.
 

Minuteman96

Registered User
Joined
Aug 28, 2021
Posts
43
Reaction score
7
Location
California
Some thoughts -

Check your air filter, if you have a exhaust leak under the hood or some blowby it could be clogged.

If not the air cleaner, yes you need to check the timing, the white smoke could be timing related.

Next would be a compression test to insure it’s not a lack of compression.

If not those, then time to have your pump and injectors tested and likely rebuilt
What are the tools required to check the timing on these things? I watched a couple YouTube videos but it looks like the ferrit meters are no longer around. How do you go about timing yours?
 

Jesus Freak

Registered User
Joined
Apr 3, 2022
Posts
678
Reaction score
471
Location
Crestview, FL
What are the tools required to check the timing on these things? I watched a couple YouTube videos but it looks like the ferrit meters are no longer around. How do you go about timing yours?
There's a really recent thread about timing these engines. There's a couple different devices, and from what I'm gathering diesel "mechanic" shops don't want to touch them. I think the thread is "timing a 7.3/6.9 IDI" or maybe with "how to time" at the beginning.
 

Big Bart

Tow&Slow
Joined
Dec 22, 2020
Posts
1,481
Reaction score
910
Location
Newport Beach, CA
What are the tools required to check the timing on these things? I watched a couple YouTube videos but it looks like the ferrit meters are no longer around. How do you go about timing yours?
There are still new timing tools available.(See link below.) You will need a meter anyhow if you change your IP or injectors. (Both change the timing.)

You can call your local shops and see if they have a meter. (90% do not, if they do, they charge $80-125 to time your IP.) Also in the the tech article section there is the “Timing registery” a list of members who have equipment and will help you check your timing.

Many members are buying DTI’s off eBay that are new surplus around $200.($400 direct from DTI.). Some struggle to get their damper/crank pulley pick up working. So I suggest buying their meter off eBay but their timing light ($100) specifically for their meter direct from DTI. That will put you around $300. But now the system is user friendly and easier to time with.

Here is a tech article that talks about the old models that are discontinued, current timing equipment that is available, and how to set your timing. But it would be worth checking your filters if you have not already done so. (Air and as mentioned above your fuel filter.)

 
Last edited:

Minuteman96

Registered User
Joined
Aug 28, 2021
Posts
43
Reaction score
7
Location
California
There are still new timing tools available.(See link below.) You will need a meter anyhow if you change your IP or injectors. (Both change the timing.)

You can call your local shops and see if they have a meter. (90% do not, if they do, they charge $80-125 to time your IP.) Also in the the tech article section there is the “Timing registery” a list of members who have equipment and will help you check your timing.

Many members are buying DTI’s off eBay that are new surplus around $200.($400 direct from DTI.). Some struggle to get their damper/crank pulley pick up working. So I suggest buying their meter off eBay but their timing light ($100) specifically for their meter direct from DTI. That will put you around $300. But now the system is user friendly and easier to time with.

Here is a tech article that talks about the old models that are discontinued, current timing equipment that is available, and how to set your timing. But it would be worth checking your filters if you have not already done so. (Air and as mentioned above your fuel filter.)

Okay so I gave it a heavy dose of diesel kleen and it definitely helped for a short bit, the loss of power is intermittent. I couldn’t get it any higher then 72 the other day, (I was trying to push it to see what it would let me do) and after maybe 10 seconds of stalling at 72, it finally jumped up past 75 and was doing fine. I don’t think there is air intrusion, I’m goin to order a couple of air filters and see where it gets me. Thank you for the information though. I might still invest in a meter just to have on hand
 

Big Bart

Tow&Slow
Joined
Dec 22, 2020
Posts
1,481
Reaction score
910
Location
Newport Beach, CA
Sounds like a fuel issue of some kind.

When you look at the air filter it would be very dirty or oily to restrict air to a point it does not let enough air into the engine. So take a peak, you will know when you see it If that is a issue.

It could also be a dirty fuel filter restricting fuel flow and pressure. The diesel kleen may have help to clear a path through it temporarily.

Do you have a mechanical or electric fuel pump?

I ask because many have suggested they can have issues with electric facet pumps not keeping up with fuel demands at hwy speeds. Some have to had to use 2 pumps others find the Holley Red pumps are sufficient.

Potentially you could Have a mechanical fuel pump starting to fail.

Lastly if could be the IP is hanging up and not continuing to advance. Generally due to the cost of a rebuild a IP being $800-1,100 with a good core. We try to rule out the cheap stuff first. Folks feel bad when they buy a IP and injectors to find the real issue was a fuel pump, filter, tank switch valve, or air intrusion.
 

Minuteman96

Registered User
Joined
Aug 28, 2021
Posts
43
Reaction score
7
Location
California
Sounds like a fuel issue of some kind.

When you look at the air filter it would be very dirty or oily to restrict air to a point it does not let enough air into the engine. So take a peak, you will know when you see it If that is a issue.

It could also be a dirty fuel filter restricting fuel flow and pressure. The diesel kleen may have help to clear a path through it temporarily.

Do you have a mechanical or electric fuel pump?

I ask because many have suggested they can have issues with electric facet pumps not keeping up with fuel demands at hwy speeds. Some have to had to use 2 pumps others find the Holley Red pumps are sufficient.

Potentially you could Have a mechanical fuel pump starting to fail.

Lastly if could be the IP is hanging up and not continuing to advance. Generally due to the cost of a rebuild a IP being $800-1,100 with a good core. We try to rule out the cheap stuff first. Folks feel bad when they buy a IP and injectors to find the real issue was a fuel pump, filter, tank switch valve, or air intrusion.
The air filter is good to go. The fuel filter only has maybe 10-15k miles on it, but I meant in my last response I was going to order a couple of FUEL filters, not air filters and see what a new one does. IP could be getting tired but I’ll rule out her stuff first and see what the deal is.

I do however have a different issue now. The previous owner had a overland light of some sort on the bumper and I pulled it last night because I’m going to be welding up a custom bumper for my truck. Now I have no power on Acc and when I try to start it. No crank, no accessories nothing. When I jut put the key in the ignition, it registers that my door is open but no headlights, nothin. I’ve got negative voltage at my stater solenoid when it’s on. I’m not great with electrical stuff, what the hell is goin on?
 

DaveBen

Supporting Member
Supporting Member
Joined
Sep 29, 2010
Posts
1,750
Reaction score
465
Location
Ukiah, Ca
You probable shorted the "trigger" for the starting to the solenoid. This is the wire that tells the solenoid to "start". It comes from the ignition switch "start" position and goes the solenoid. This goes nowhere else.
 

Minuteman96

Registered User
Joined
Aug 28, 2021
Posts
43
Reaction score
7
Location
California
You probable shorted the "trigger" for the starting to the solenoid. This is the wire that tells the solenoid to "start". It comes from the ignition switch "start" position and goes the solenoid. This goes nowhere else.
Which wire is it?
 

Attachments

  • 46067CB4-5836-40D5-8109-43311DFF8A57.jpeg
    46067CB4-5836-40D5-8109-43311DFF8A57.jpeg
    267.3 KB · Views: 11

DaveBen

Supporting Member
Supporting Member
Joined
Sep 29, 2010
Posts
1,750
Reaction score
465
Location
Ukiah, Ca
It is the top wire with the plastic (rubber?) cover.
 

DaveBen

Supporting Member
Supporting Member
Joined
Sep 29, 2010
Posts
1,750
Reaction score
465
Location
Ukiah, Ca
That solenoid looks funny. The left wire on the big terminal (bolt) is the wire going to the starter, when engaged. It is NOT capable of the current required to start a diesel motor. It should be at least 8 ga or bigger.
 

Minuteman96

Registered User
Joined
Aug 28, 2021
Posts
43
Reaction score
7
Location
California
Well you may be right and I’ll look at that, but apparently in the process of removing the light, the battery terminals decided they didn’t like their connection and after some cleaning with a steel brush, it’s working again. Weird how that works out but my terminals needed to be cleaned so that works out. Thanks for the help, I’ll definitely look at that wire. Wouldn’t hurt to beef it up with a bigger wire whether it needs it or not.
 

Big Bart

Tow&Slow
Joined
Dec 22, 2020
Posts
1,481
Reaction score
910
Location
Newport Beach, CA
I would suggest you pull those wires off the starter solenoid and wire brush them. (Unhook the batteries first.) They look questionable, that is the wiring that feeds the glow plugs, the fuse box, takes a charge from the alt, and runs back to charge the batteries.

Two yellow ones are the glow plug fusible links.

The one with the red tape I believe feeds the fuse box in the cab for all your electrical in/on the cab. If you keep having issues unravel that red tape and see if something bad is lurking under there.

Guessing the big red one goes to the batteries.
 
Last edited:
Top