Intermittent Miss/ Stumble ?????

[Blackdog]

Well about two weeks ago I started noticing a bad miss under hard accelleration while running my Comp box on, well when I turned the box off it didnt seem like it was doin it or it wasnt noticable anyway. So I then checked my fuel pressure and it was only 6psi at idle and the d@#n thing went to -7 under WOT. So we changed my fuel filter b/c it just needed to be changed and replaced my OEM lift pump for the 4th time and I got 23psi at idle along with my pusher pump. So then I went out and turned my Comp on level 5 and it never dropped below 14psi at WOT and ran great. So then I of course thought my problem was fixed, well now 3 days after replacing that pump it's starting to miss again. The thing is, it doesnt do it all the time when my Comp box is on and never does it when it's off. So I got to thinkin that it could just be a bad connection somewhere on the box. So I checked all the wires and everything looked fine EXCEPT, on my OEM MAP sensor harness one of the wires looked like it was bare in one spot where it had been kinked or twisted somehow from being unplugged on and off so much from tryin different things. Well I wrapped the end of the harness where it goes into the male plug with black tape really well to keep it from bending and took it out and it ran just fine. Well a little while later it started doing it again, so now I'm not sure what the problem is whether I trashed another pump in 3 days or that plug on my MAP sensors is bad. The thing is I'm not sure if that plug would even cause that. Any and all info would deffinately be appreciated. Take care!!

 

[SEmerson]

I have been told that you should not excede 15#'s max.

 

[Blackdog]

I wonder if this problem would have any similarities to those that Bill K. had when he talked about the screws inside the pump??. I guess it wouldnt hurt to check it out at least. Thanks

 

[JR2]

I see in your sig that you have a comp and a JVD box. Are you really running both?? at once??

 

[Blackdog]

JR2, yes I have ran both at once and to put it bluntly IT"S WILD!!. But at the moment I've got the JVD on a friend of mine's 99 b/c I don't need it really anymore b/c I'm not planning on pulling my 01 anymore with the addition of my 97. There are a few others from Mitchell's that are running both as well.



In regards to those screws, I checked them and both were tight. I'm gonna put a fuel pressure gauge back on it and see what's its doin now. If everything is fine there i'm not sure where to look b/c all of my connections seem to be fine unless there is a problem with my Comp box. Thanks

 

[MikeR]

Blackdog,



My Powermax3 has been doing this for over a year. I hardly run with my box turned on anyway it really doesn't bother me because it hardly does it when the box is on. I've noticed on mine that rather than a stumble, it's a subtle 'blip' surge of power. One day I had the box on and was sitting idling in the Mc Donalds drive though and it surged.



I know some electrical interference in the truck is making the box do it when it's on, but still haven't found what. I haven't been swapping parts to cure this problem, but over the past year of BOMing I have swapped 2 lift pumps, injectors, ecm's, watched very carefully with a fuel psi gauge and it's still there. Someday I'll throw in a new map sensor and see if that fixes it.