Engine/Transmission (1994 - 1998) 370s worn out, now what?

[Woodenhead]

I have my truck apart for some head work and twins install and decided to send the injectors out to get the pressures checked. I was told 3 had low pressures (don't have numbers yet) and they had "irregular spray patterns" and scored valves. One option is to rebuild these injectors but it's not really worth the labor and parts since a new set is only $400. I've been happy with the 370s and don't feel like spending $1000 on other injectors right now so I think I'll just get another set.



What should I check for in the pump? Maybe pull the delivery valves and check them out? Anything else?



The truck was running fine when I took it apart so I'm not sure how much effect this had on performance. It did have the typical cold stumble but my fuel pressure was also a little low (10 psi loaded, 20ish rolling down hill) so a new overflow valve will likely help that.



Truck has 245,000+ miles. These injectors have 100,000+



Mike

 

[JGK]

Take the pump to a certified Bosch injection shop and have it bench tuned/tested. They'll calibrate each barrel to spec and make sure its working at its optimum. They may even turn it up a bit, though they can only turn it up a little via barrel adjustments. For more flow, cam plate and delivery valves will allow for full fueling capability.



-Jay

 

[Jim Fulmer]

Today's dirty fuel will beat up injectors! I wrote an article in the 12V Form about this not long ago. When I. I. checked my 370's they were bad enough that they had to replace 4 of them.



The spray pattern will be bad enough that they will shoot streams and not atomize the fuel.



Jim

 

[Woodenhead]

Thanks for the info fellas. JGK, ideally I'd like to pull the pump and have it calibrated/tuned but time and $$ just doesn't permit right now.



Jim, I did a few searches trying to find your article and can't find it. Any chance you can post a link.



Now I'm a little up in the air about which injectors to get. I've been happy with the 370s but I wonder if I'd be better off with something from DDP. It's $400 vs $1000, I'm not really concerned with a little smoke.

When the trucks back together it'll have a 3B/HX40 set and o-ringed head so I'll have the air to burn plenty of fuel. If I'm going to be tearing up injectors with crappy fuel maybe I'll stick with the good ol' 370s.

 

[JGK]

I hear ya on the $ and time thing, but if the engine has the head off it would likely only takes another 1/2 hour to an hour to get the pump out, taking your time. And if the shop can get it in, it should only take a half day for them to bench tune it. But its true, if their shop rates are typical, it could run you $250, give or take. Then again, with the miles you have on your's you'd probably find there's some wide variations in the output of each barrel.



FWIW,

-Jay

 

[Woodenhead]

I hear ya on the $ and time thing, but if the engine has the head off it would likely only takes another 1/2 hour to an hour to get the pump out, taking your time. And if the shop can get it in, it should only take a half day for them to bench tune it. But its true, if their shop rates are typical, it could run you $250, give or take. Then again, with the miles you have on your's you'd probably find there's some wide variations in the output of each barrel.



FWIW,

-Jay

If an hr + $250 was all it would take then I'd do it for sure, that's a small fraction of what the rest has cost so far. HT3B+Twins plumbing+o rings+valve job, mag and deck head+12mm studs+fuel return lines+water pump+serpentine belt+fan shroud+overflow valve+front main seal/kdp kit+gaskets+paint+now injectors more misc parts=good times and a couple $$. I'm trying to this right but spend the $$ wisely since I'd hate to end up getting it together and end up needing to tear it apart for more later. I'm having a hard time not doing a cam at the same time but man you gotta draw the line somewhere.



When you say wide variations in each barrel isn't that just adjusted while they do the calibration or does that require more time and parts ie. worn barrels and plungers?



Crap, this is gonna bug me until I just pull the pump and get it checked out. :{



Thank you for your input.



Mike

 

[Jim Fulmer]

Here you go!



https://www.turbodieselregister.com...4-1998/186738-12v-fuel-filtration-change.html



BOTW, if you know someone has posted a particular thread, so a search under there name then a topic. On this one I did a search under my name in the 12V form, topic was fuel filter.



I don't subscribe to every thread I post under, all I do is keep an eye out and do a search every once in a while!



Jim

 

[JGK]

When you say wide variations in each barrel isn't that just adjusted while they do the calibration or does that require more time and parts ie. worn barrels and plungers?

The check and adjustment of the output of each barrel is done as part of the calibration. They loosen the nuts on either side of the barrel/plunger on the top of the pump and turn them and/or shim them to get them within a few milliliters of output for each across all 6. They can be out of tolerance due to wear, but you'd have to have really trashed them for them to need replacement. I think they'll also check your governor to make sure it's working like its supposed to.



-Jay