Auto fuel pump = polishing a turd?

[Darel]

Check my sig for my auto-equipped CTD. I've been thinking, it seems lately like nothing I do to this engine makes it want to feel any more powerful. Slid my plate forward, nothing. Straight-pipe and intake, nothing (not that that would do much anyway). Adjust governor lever, no diference. This is a non-CA truck, so I should have the 160 pump, right? Does this mean my pump is basically maxed out and nothing I do will make a difference? I'm figuring around 250 hp, over 600 tq. Am I just throwing time and money at a problem I won't fix until I get a whole new pump (which I won't do)?

I knew I shoulda got a stick.

Darel

 

[Cooker]

Your truck has a 180 pump, and you can build some pretty decent power with a 180.



I don't know where you shoud start to find a low power issue. Possibly low fuel pressure, or a boost leak.

 

[Bigramguy]

I think you should have the 180 as well. Have you checked the basics like dirty filters,cracked fuel lines or air leaks,boost leaks etc ? Possibly a bad overflow valve or lift pump ?



I have a similar truck and have tried several TST plates in it and they all worked very well,no problems making lots of power.

 

[CWeidenkeller]

Mine was/is a CA truck. Even with the EGR on it, sliding the stock plate forward made a helluva difference. Now with the #6 plate... holy toledo!!!! Sounds to me like another problem, 180 pump is supposed to be good for up to about 350 HP if I remember correctly.....



PS< If your not making any power, you won't be needing that DDT trans now, will you Just so happens I need one... .....

 

[LarryB]

Darel

Have you put a fuel pressure gauge on it yet? Even a temporary one just to check would be a help here.

 

[Strick-9]

Make sure you're getting full throttle travel.



Then adjust the governor so it doesn't defuel so much. That made a bigger difference on mine than taking the plate completely out! (did I say that?)



-Chris

 

[Cummins Corvette]

One possability is that you have maxed out the amount of fuel that it can push through the stock injectors. If you haven't experienced ANY gain since you started tinkering with it, then that is not it. It could be a problem with fuel delivery to the injection pump. That was mentioned already, and you need to check your fuel pressure to find out. Have you replaced your overflow valve? Have you replaced your fuel and air filters? Have you checked to make sure that it is really getting to full throttle on the pump while someone else is mashing the pedal to the floor? Perhaps your throttle cable has streached. A boost leak could be another culprit, however you should hear it, and it would send your egt through the roof.

 

[Joe G.]

I agree with Chris and Chris. Check to see that the throttle lever hits the stop. If it doesn't then the plate doesn't come into play. My truck is a '95 auto and it has the 160 pump. It goes VERY nicely!

 

[Darel]

Thanks for the tips guys. Here's what I know so far:

- no boost leaks (checked, and it makes a solid 34 psi at WOT with decent EGTs)

- overflow valve recently tested, OK

- brand new Scotty air with AFE filter, straight-piped exh. to remove plugged cat.

- governor is adjusted to the plate

- throttle lever has full travel

Fuel pressure seems to pop up a lot here. I guess that's my next thing to check. Could the injectors just be retarding the fuel pressure a lot, or do you all think it may actually be a problem like lift pump, etc. ?

Thanks again!

Darel

 

[Cooker]

What % torque convertor do you have?

 

[CTabor]

Have the timing checked, or better yet when you have it checked have them advance it.

 

[Darel]

No idea what TC I have, a PO did it, and he just took it to a shop about 4 years ago and said "beef it up". It's pretty tight, I think, b/c when the truck is warm at idle it'll run up to 23-25 mph on level ground.

 

[danandamy]

I have heard that alot of people have problems with the pos cat stopping up, you might want to do something about that



dan

 

[Darel]

Umm... I did already.

 

[Deezul1]

Put a fuel pressure gauge on it so you know for sure what it isnt.

 

[Darel]

BTW, are autos normally wastegated? I don't think mine is.

 

[Cooker]

Yes. Why do you think your truck is not wastegated?

 

[Darel]

I keep forgetting to look, and it's below zero outside now, but when I mash it, the boost never falls off, it just goes up to about 34 and stays up. I've never heard the telltale "pffft" and I really can't remember seeing one when I've been working in the general vicinity of the turbo. Plus, a PO did some little "hot rod" (as he called it) things and I'm thinking maybe he did more than he initially let on.

I just have to remember to look the next time I'm outside (above zero).

Darel

 

[Cooker]

You may have a non wastegated housing, but you can visually check for a wastegate (when it warms up)



The plate came with a boost elbow that would have addressed the wastegate opening too soon.