easing off the throttle instead of side stepping...

[xohcef]

So I just got done putting in a set of injectors in my 93. The pump is pretty maxed out with a ground pin and all the small tweaks plus ratcheted to the head. Put some miles on it and noticed obviously if I let off a little hard it'll pull some air and start chugging. I've read of this but was wondering if there was a fix or is letting off a little easier is my only deal? The other thing is I run an A1000 fuel system. Should this happen with that pump?

[RCCUMMINS89]

Correct.... regardless of your lift pump, it'll keep doing it. I see you have a 5 speed, if you are like ME, you'll have to learn to not push in the clutch when you let off. It won't do it if the clutch is engaged. I don't know why, but I had a habit of pushing in the clutch at the same time i let off.

[xohcef]

Thanks for the response RC. I'll keep your method in mind and try it out. BTW Thanks to the hungry diesel for a 374 spring for christmas!!

[RCCUMMINS89]

Thank you

[BC847]

The other thing is I run an A1000 fuel system.

There's a asswipe Genius over on another forum who swears the A1000 pump fixes that issue. (He is full of sthi IMO BTW). He, and his minions, believe the injectors becoming air-bound, is caused by cavitation in the IP. I'm sorry, but that is not possible . . . period.


Bosche calls the issue (as seen in thier instances of it) "Combustion Gas blowback". As I understand it, in those instances that Bosche saw, they developed a special Delivery-Valve that helped. Unfortunately, I don't know what application they used those DVs.

As Eric said, the best thing we can do about it for now, is to learn to roll off the throttle instead of side-stepping it.

[xohcef]

I'll just have to get used to it then guys thanks! One quick question for you though RC. I'm going to be getting on that governor spring install this weekend and was curious as to what you mean by trimming is involved? Am I just going to have to cut a coil off and rebend it to hook into the governor/throttle shaft?

[RCCUMMINS89]

You can either cut a few coils off and re bend it to TRY and match the stock governor spring length....Or you can put it in there as is, re index the throttle "upwards"(as to idle higher) ONE notch, and then re set the power screw as to regain the original idle.

If that doesn't make sense let me know. I shortened mine and it is merely impossible to get it perfect length.

[xohcef]

So basically what you're saying is the 374 is longer? I already have an aftermarket idle adjustment with two small heims and a threaded bar. With that being said since I have turned up the pump it has idled higher, I have since used the idle adjustment rod to lower the idle back down and it has been adjusted down quite a ways. Do you think if I just put the spring in as is and I just tightened my rod back up it might take up the slack that you're talking about instead of making it go away by either trimming the spring or re-indexing the shaft? The only reason I am wondering this is I have quite a ways to readjust my idle bar and it's easy enough for me just to do this step on the linkage?

[AHineman]

There's a asswipe Genius over on another forum who swears the A1000 pump fixes that issue. (He is full of sthi IMO BTW).

Yep.

[xohcef]

There's a asswipe Genius over on another forum who swears the A1000 pump fixes that issue. (He is full of sthi IMO BTW).

Yep.

Proof, hmmm, first hand, right here....... Go tell this asshat that it will happen A1000 or not. Even at 15psi idle pressure.

[AHineman]

I had the problem with my old IP and lpplp but haven't noticed it with the new pump and air dog set to 32ish psi. May just be I learned to drive it since all those parts were added, as I was having fun driving it stupid with the new twins back then.

[xohcef]

Question then AHineman. How do you get away with 32psi? I've heard seals don't stay too friendly or intact with those kind of pressures.

[AHineman]

John Russin made a retainer for the front seal of my pump.

Also...I'm not saying that is the answer to the problem, just that I haven't had it happen since then. I have lifted quickly off the throttle but not purposely tried to kill it. Other things apart on it now or I'd try it for you.

[xohcef]

Well now, ain't that special.

[RCCUMMINS89]

I was having issues with stock injectors and an he351cw.... but I haven't had it do it in probably 2 years. As soon as I trained myself to not push in the clutch, it never happened again.

Wait, that's a lie.... once I was getting on it going down hill and hit the governor so hard that it stalled the truck even when it was still floored.