Falls on its face

[BigRigTech]

Missing - running out of fuel. You probably wouldn't notice it with old injectors but with new units set with a high crack pressure it will be quite noticable.

 

[dyoung14]

Missing - running out of fuel. You probably wouldn't notice it with old injectors but with new units set with a high crack pressure it will be quite noticable.

how to fix this? cause other wise it sounds as i need to pull them out and put the shity DPS injectors back in but if it gets my power back then i guess i got to

 

[dyoung14]

Hows your throttle cable? http://www.oilburners.net/forums/showthread.php?t=39932

I could never get my truck to accelerate above 2500 rpms until I fixed the go pedal

that was the first thing i checked

 

[88beast]

yep dps back in or id first crank the fuel screw maybe the pump is not turned up enough to get enough fuel to make pop

 

[flatlander]

i need to pull them out and put the shity DPS injectors back in

Would those be the shity DPS injectors from me?

I tried to talk you out of them.

Easy check on the throttle cable: Pull the throttle to Wide Open by hand and mark how far it goes, then have someone hop in and floor the pedal and compare. Adjusting if it differs:

If you have a pyro, turn the fuel screw up and test it. That might be it.

You also checked for fuel leaks, right? a loose injector can cause problems.

 

[dmaxjoe]

Maybe lift pump? My 91 would pop the filter light on when pulling heavy under hard acceleration above 2500rpm. Fuel pressure was dropping to zero in those conditions. New lift pump made it pull all the way to 3000 without a miss.

 

[Agnem]

Missing is usually not because your running out of fuel. Think about it... in order for it to miss, there has to be no fuel in the plunger chamber for just that one event. Almost an imposibility. What is more likely, is that an injector is sticking open, and dumping all the fuel that was in the high presure line on one injection event. By the time the next injection event comes around, the fuel that would have been delivered to the cylinder is instead used to rebuild presure in the line, and no injection event occurs. Injectors will often pop OK on the bench, but when you actually start running them, and heat and presure enter into the game, they can start to perform badly. My vote is this is an injector problem, based on the fact that this was a known good IP.

 

[dyoung14]

Missing is usually not because your running out of fuel. Think about it... in order for it to miss, there has to be no fuel in the plunger chamber for just that one event. Almost an imposibility. What is more likely, is that an injector is sticking open, and dumping all the fuel that was in the high presure line on one injection event. By the time the next injection event comes around, the fuel that would have been delivered to the cylinder is instead used to rebuild presure in the line, and no injection event occurs. Injectors will often pop OK on the bench, but when you actually start running them, and heat and presure enter into the game, they can start to perform badly. My vote is this is an injector problem, based on the fact that this was a known good IP.

so what should i do? pull the new injectors out? put the DPS back in?

 

[dyoung14]

Would those be the shity DPS injectors from me?

I tried to talk you out of them.

Easy check on the throttle cable: Pull the throttle to Wide Open by hand and mark how far it goes, then have someone hop in and floor the pedal and compare. Adjusting if it differs:

If you have a pyro, turn the fuel screw up and test it. That might be it.

You also checked for fuel leaks, right? a loose injector can cause problems.

I have checked for leaks multiple times,

The dps injectors seemed to have plenty of power and everything but they smoke like crazy idleing and the idle funny, like the engine is missing

 

[dyoung14]

Maybe lift pump? My 91 would pop the filter light on when pulling heavy under hard acceleration above 2500rpm. Fuel pressure was dropping to zero in those conditions. New lift pump made it pull all the way to 3000 without a miss.

im gonna stick a fuel pressure gauge on some time, but i got a holley blue electric pump on it, fuel pressure shouldnt be an issue

 

[DeepRoots]

you have the fuel pressure regulated to the range required by the pump yes?
have you cracked the injector lines yet?

 

[dyoung14]

you have the fuel pressure regulated to the range required by the pump yes?
have you cracked the injector lines yet?

no and no, so would to much pressure reall cause this issue? maube i should do something about this

 

[DeepRoots]

you'd want to talk to Mel. I'm a mech lift pump kinda guy.

But I recall him saying once anything over 10psi (???) would change the timing and generally screw with the pump.
You might wanna check into it.

 

[dyoung14]

well today i retarted the timing and found that it runs worse and the missing is starting at a lower rpm now so tomarrow evening im gonna put the dps injectors in it and see if that helps

Im always taking 1 step forward and 2 steps back thats life i reckon

 

[GOOSE]

well today i retarted the timing and found that it runs worse and the missing is starting at a lower rpm now so tomarrow evening im gonna put the dps injectors in it and see if that helps

Im always taking 1 step forward and 2 steps back thats life i reckon

Good things usually come from this method. Check out my dillema in the attached thread. Now I have cleaned and painted the whole rear and it has all new seals and brakes.

The two steps backwards usually lets you get a better look at things and get a better finished product as a result.

http://www.oilburners.net/forums/showthread.php?t=39905