Sputter at ~2400RPM

Buck88

Buck88

Simple Man
Joined
Sep 14, 2006
Messages
233
Hey guys, tried to do a search but no luck.

Truck listed in sig is having a bit of an issue. I noticed the other night that when I rev in neutral I get a sputter around 2400 rpms. I have never noticed it before, but I dont really spend a lot of time reving in neutral.

I dont notice anything in WOT driving. However I dont do a whole lot a beating on the truck.

My first thoughts were timing, but I am beginning to think it may be the 370 marines crapping out in one way or another. The truck runs fine beside that issue, but does seem to shake a lot at idle.

lemme hear your thoughts!
 
It's best to start with the cheap simple stuff first. It sounds like it could be a fuel pressure issue, do you have a fuel pressure gauge installed? Low fuel pressure could be a result of the obvious stuff, clog in a fuel line, dirty fuel filter, pre heater screen, bad OFV. If it's not the fuel pressure it could be an issue with the 370s, you can have them clean and pop tested. Timing may also be an issue like you mentioned.
 
My truck does this same thing and im convinced its something inside the pump like the governor acting up or sticking. runs fine under a load but when it pops mine shoots grayish smoke out. mine i know isnt fuel pressure, it holds a steady 32psi, my timing is at 24*, and i have a torktek 060HP OFV. and it never did it with my old pump, that one would rev clean right out to 4K... hope this helps...
 
My 96 model is doing the exact same thing and it's completely stock, I'm thinking mine could be low fuel pressure
 
Thanks for the input guys.

My timing is @ 16.5*. It's very conservative due to financially not having the option of replacing a HG right now. HX40 is singing to 40psi, does anyone think it would hurt to try bumping timing to say 18*?

I think when the money comes in I will try and get the injectors pop tested and cleaned up, maybe try and get some new era 370's with the proper spray angle. Does new era retro fit 370 marines?
 
Mine just started doing this when i put the 5x16's in, but mine does it up around 3k. Im going to bump my timming up more hopefully this week, i'll let you know if it fixes it.
 
Mine was fuel pressure related, welded a stock ofv **** and drilled one .060 hole . At 102psi i have ZERO popping, sputtering, whatever and ive fought it for years, changing the injectors, timing, fuel pump etc.
 
YOUNG GUNS15 said:
Mine was fuel pressure related, welded a stock ofv **** and drilled one .060 hole . At 102psi i have ZERO popping, sputtering, whatever and ive fought it for years, changing the injectors, timing, fuel pump etc.
Click to expand...

You have 102psi fuel pressure and the I.P. is still alive??
 
How doesn't that cause internal problems with the pump?? I read some where that 45 was max on p7100... Enlighten me on this guys??
 
i always heard that over 50psi fuel pressure wrecks the seals in the pump. he might be talking about boost pressure though i would hope with twins and not the 66
 
I know of more than one person who runs 40-50 psi idle with a pressure then with a regulator increase fuel pressure at a 1-1 ratio with boost and have not had any issues, I would be in this group but my lift pump couldn't keep up LOL
 
So about what psi would the stock l.p. chit out?? Sorry for the derail, interesting stuff!
 
My 94 does this but a little different. At idle revs fine &1st&2ndgear is fine. But 3rd-5th about 1800rpm is max sputters around barely gaining any rpms. I hqvnt had the truck long. I'm going to.do a full tuneup when I get back to_Oklahoma and maybe its just fuel filter or lift pump?
 
52 psi at idle for me and at WOT it'll get down around 47. Before i got my fuel system tuned in it would run around 32 idle and 20 WOT and after running it for a few minutes it would idle up a couple hundred rpms and sputter around 3700. I replaced the OFV and worked on my fuel pressure situation and now it runs like a whole new truck.

Another thing to check is your intercooler boots and clamps. If they are a little loose and have a small leak it will pop and cackle sometimes. Its always the little things that get ya
 
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