Diesel Place banner
1 - 20 of 23 Posts

·
Registered
Joined
·
1,299 Posts
Discussion Starter · #1 ·
Hello gents,
Just looking for a little advice, and a direction to go to help with a new symptom that my 93 GMT-400 has developed.
Runs, and drives fine, but randomly will stall when stopping at an intersection. I have used isopropyl in the fuel at times, to keep water at bay, and have changed the fuel filter in the past. It kinda reminds me of a gas motor, if the float bowl was low. When it stalled, (a few times so far) it did start up immediately W/O excessive cranking. Next time it does it, I'll check my clear IP line, to see if it's full. I was thinking of increasing the mech. idle screw, to see if a higher idle will prevent it. Thanks for any advice.
 

·
Administrator
Joined
·
19,363 Posts
How many miles on the current filter?
Have you checked for contaminated fuel?
 

·
Registered
Joined
·
1,299 Posts
Discussion Starter · #3 ·
Unfortunately, the odometer is broke, and has been long B4 I owned the truck. (Famous plastic gear failure...I'm guessing) I wouldn't guess the mileage to be over 2K on the filter OKD. And no, I haven't gotten to troubleshooting yet. I'm on a weeks vacation right now, so I'ld like to investigate further. I thank you for your response, and am getting ready to get the truck in the garage.
 
  • Like
Reactions: OkDually

·
Registered
Joined
·
1,299 Posts
Discussion Starter · #4 ·
I just saw a similar thread, from many years ago, with a 90 6.2, and he mentioned his fix being the oil pressure sw. I wonder if that could be true with my 93? When I come to a stop, the eng. slows way down, and maybe the oil pressure drops to a point, where the sw shuts down the motor? Possible?
 

·
Registered
Joined
·
3,826 Posts
Possible, but Im pretty sure that just shuts the lift pump down. The IP has a small lift pump in it I believe, possibly, by a different name, but it should keep running. You may have vacuum building up in your fuel tanks? I'd definitely start with upping the idle just a hair though. Could just be getting too low and blipping out.
 

·
Registered
Joined
·
1,299 Posts
Discussion Starter · #6 ·
Possible, but Im pretty sure that just shuts the lift pump down. The IP has a small lift pump in it I believe, possibly, by a different name, but it should keep running. You may have vacuum building up in your fuel tanks? I'd definitely start with upping the idle just a hair though. Could just be getting too low and blipping out.
I adjusted the idle a 1/4 turn higher, and it seems better. Time will tell. I'll keep you posted.
 

·
Registered
Joined
·
5 Posts
I adjusted the idle a 1/4 turn higher, and it seems better. Time will tell. I'll keep you posted.
I just found a second fuel filter on my 83 C10. One on fire wall, one behind the Large air inlet of the intake. An 1.5" diameter spin on filter. I have not had my truck very long, it was dirty like everything thing else. So it was hard to see.
 

·
Registered
Joined
·
1,299 Posts
Discussion Starter · #8 ·
I have an 83 C-30 dually too. You can get "both" replacement filters at NAPA. Now that I think of it, my firewall filter is not factory, but agricultural, (I think), but is also available thru NAPA.
 

Attachments

  • Like
Reactions: OkDually

·
Registered
Joined
·
5 Posts
I have an 83 C-30 dually too. You can get "both" replacement filters at NAPA. Now that I think of it, my firewall filter is not factory, but agricultural, (I think), but is also available thru NAPA.
Yeah the person that had it before me change the fire wall filter to a spin on as well. So thats why i was surprised to see the other one when i removed my air filter and shined my light on the backend of the intake.
 

·
Registered
Joined
·
1,299 Posts
Discussion Starter · #10 ·
My firewall one isn't a spin on, but clamps on. I like it, cause it's easy to change, and is clear glass, and can see if water is in it. Your secondary filter is a bit of a pain to get at. Have to unbolt the bracket from the intake, and clamp it in a vice. Could be worse I guess.
 

·
Registered
Joined
·
5 Posts
My firewall one isn't a spin on, but clamps on. I like it, cause it's easy to change, and is clear glass, and can see if water is in it. Your secondary filter is a bit of a pain to get at. Have to unbolt the bracket from the intake, and clamp it in a vice. Could be worse I guess.
Oh wow! I didnt have to do that, but it wasnt that fun. Well as long as you got it is the main thing. Good luck, i am hoping to finish bleeding mine tonite and get it running again.
 

·
Registered
Joined
·
3,826 Posts
Yeah the person that had it before me change the fire wall filter to a spin on as well. So thats why i was surprised to see the other one when i removed my air filter and shined my light on the backend of the intake.
That's factory. The 82-83 trucks had a few extra things the later trucks didnt, the dual spin on filters was one of them. Just dont let it get this bad inside! I pulled this from my 5.9 donor engine. Had probably 100k on it, minimum....
644221
 
  • Wow
Reactions: 82Kbody

·
Registered
Joined
·
1,299 Posts
Discussion Starter · #13 ·
Yuk. that's a nasty one Nate. I hope you rinsed it off real good, before re-installing it. :)
 
  • Like
Reactions: roadhog0

·
Registered
Joined
·
5 Posts
That's factory. The 82-83 trucks had a few extra things the later trucks didnt, the dual spin on filters was one of them. Just dont let it get this bad inside! I pulled this from my 5.9 donor engine. Had probably 100k on it, minimum....
View attachment 644221
Wow. surprised is still ran! I have new filters in it now. New fuel pump. Bled out and running. It has not wanted to start easy or idle well since it i got it started. Drove it to work today and will see if it just need to be ran longer. I hope.
 

·
Ex- 6BT Square Body Man
Joined
·
9,891 Posts
I'd do the light load advance check.

644230
 
  • Like
Reactions: 82Kbody

·
Registered
Joined
·
1,299 Posts
Discussion Starter · #17 ·
Hi Bob, thanks for chiming in. On your "light load adv". check, I'm totally confused. They're calling it a mechanical "advance" mechanism, yet in their test, they're telling us it should retard the timing. (?)
To this day, I still haven't a means for checking timing off the crank. After 30 years of 6.2 ownership, guess I should get on the stick. I'll try pushing on the adv. lever anyway, just to see how it reacts.
 

·
Registered
Joined
·
1,299 Posts
Discussion Starter · #19 ·
So today I needed to take the truck out to run some errands, and it didn't stall once. Ran perfectly. It's a hot summer day, and I'm sure the oil was relatively thin, but the eng. temps were normal. I mentioned above, the only thing I've done so far was crank up the mechanical idle screw on the IP 1/4 of a turn. Not sure what the RPM difference is, or if it has dropped over time, but it doesn't sound like it's racing, or unusual. Maybe it's up 50-100 RPMs at the most. So, is the oil pressure sending unit beginning to stick, (?), or something other, IDK. But for now, I'll be rolling with it, till I need ta look deeper.
 
  • Like
Reactions: legendman

·
Ex- 6BT Square Body Man
Joined
·
9,891 Posts
Hi Bob, thanks for chiming in. On your "light load adv". check, I'm totally confused. They're calling it a mechanical "advance" mechanism, yet in their test, they're telling us it should retard the timing. (?)
To this day, I still haven't a means for checking timing off the crank. After 30 years of 6.2 ownership, guess I should get on the stick. I'll try pushing on the adv. lever anyway, just to see how it reacts.
I think timing by ear works best, I had all the timing tools a while back and they really didn't offer much benefit, plus it was really confusing on how to check the timing with those tools.
 
1 - 20 of 23 Posts
Top