P24V No Low end power

T

turbom700

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Could use a little help here a little back ground on the truck first. Truck is a 2008 Ford(not that it maters) with a 1999 24v out of a school bus. Pump is a 215hp p-pump. Lines are schied stock size lines, and stock 24v injectors. HE351 with CR manifold. Timing set at 20 degrees Have 4gsk in the pump and have messed with pretty much everything in the AFC.

Truck start right up with no smoke at all idles great revs up. Give her some throttle and it will have tiny bit of grey smoke. Truck is a 6sp manual so 1st and 2nd it hard to load the motor up. If I put it in 3rd at around 1500 rpms and put my foot about 3/4 throttle it will accelerate but not smoke and start building boost once it reaches around 2500rpm it will be at 35psi and have a light grey smoke coming. Top end power feels just like I would expect. Bottom end just doesn't seem to have the "lugging" that I would expect. I think my 7.3 diesel with the tow tune has more power.(below 2300rpm)

I have tried no plate, ground plate, star wheel forward,star wheel back, smoke screw in smoke screw out. Have put shop air on the AFC set mid travel for 15psi full travel at 35psi, so I know the AFC is moving. Fuel pressure at idle is 25psi and running down the road is mid 30psi.

I feel like this truck should be able, 1 smoke when I lug it, and 2 have way more bottom end power. Must say I don't want it to smoke, put being a mechanical motor it should be able to then I can dial it back.

Bus when it was a VP44 had a 185hp tag on it, are my injectors just to small for what I'm wanting power wise? Or I'm I just missing something. Cruising 75 down the highway it will run 7psi at 6-700 egt. Seems normal.
 
turbom700 said:
Could use a little help here a little back ground on the truck first. Truck is a 2008 Ford(not that it maters) with a 1999 24v out of a school bus. Pump is a 215hp p-pump. Lines are schied stock size lines, and stock 24v injectors. HE351 with CR manifold. Timing set at 20 degrees Have 4gsk in the pump and have messed with pretty much everything in the AFC.

Truck start right up with no smoke at all idles great revs up. Give her some throttle and it will have tiny bit of grey smoke. Truck is a 6sp manual so 1st and 2nd it hard to load the motor up. If I put it in 3rd at around 1500 rpms and put my foot about 3/4 throttle it will accelerate but not smoke and start building boost once it reaches around 2500rpm it will be at 35psi and have a light grey smoke coming. Top end power feels just like I would expect. Bottom end just doesn't seem to have the "lugging" that I would expect. I think my 7.3 diesel with the tow tune has more power.(below 2300rpm)

I have tried no plate, ground plate, star wheel forward,star wheel back, smoke screw in smoke screw out. Have put shop air on the AFC set mid travel for 15psi full travel at 35psi, so I know the AFC is moving. Fuel pressure at idle is 25psi and running down the road is mid 30psi.

I feel like this truck should be able, 1 smoke when I lug it, and 2 have way more bottom end power. Must say I don't want it to smoke, put being a mechanical motor it should be able to then I can dial it back.

Bus when it was a VP44 had a 185hp tag on it, are my injectors just to small for what I'm wanting power wise? Or I'm I just missing something. Cruising 75 down the highway it will run 7psi at 6-700 egt. Seems normal.
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Did you pressure test for boost leaks?
 
Dumb question. Did any of the things you tried, no plate, ground plate, etc change ANYTHING at all?

Chris
 
Vincejax said:
Did you pressure test for boost leaks?
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Its one thing I thought of after I wrote it. Its hard to explain it builds boost fine just has no bottom end. I grabbed some block off plates I used on my boat for check for boost leaks and going to try that this weekend.

TheSilverBullet said:
How are you timing it and what’s controlling the wastegate?
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When I was putting the motor together found TDC on #1 marked the damper, found timing mark on pump(I think it was 14 degrees if memory is right) then spun the motor to the 7 degrees backwords to get the 20(ish) degrees.

Signature600 said:
Dumb question. Did any of the things you tried, no plate, ground plate, etc change ANYTHING at all?

Chris
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No still feels the same, this is what makes me think its either timing, or my injectors are just to dang small. GSK are the only thing that made an improvent but that just because I have another 1k of rpm to play with.
 
I don't, I have heard about it and read a little bit about it so I'm sure I can figure it out. I just keep going back that this truck should be smoking like a freight train down low and its not. If timing was to far advance or to retard it would still smoke. Which leads me to belive these injectors are just to small.

I'm going to pull #1 find TDC again and check pumping timing if its in the 16-20 range I'm going to leave it and start looking for some p24v injectors.
 
You need to start from the pumps pinned position, dont have to have the pin, but the slott needs to be in the window. Then roll the engine back from there off the balancer.

These pumps will move after you knock the gear loose. It won't move on you if you start with the slott in the window. And you can verify it didnt move after pulling the gear loose.
 
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If you free rev it in neutral to say 3k rpm. Does it pop or have a stutter sound. On a hard no load rev?
 
no it revs just fine, starts just fine, It was 42 degrees this morning started right up with no smoke at idle.
 
I am thinking you have a pump issue, something may not be letting the rack travel forward.
 
zstroken said:
I am thinking you have a pump issue, something may not be letting the rack travel forward.
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Check that by pulling ther AFC and with the engine off moving the rack from back to forward? Or could it be something in the govnor set up.
 
zstroken said:
I am thinking you have a pump issue, something may not be letting the rack travel forward.
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RacinDuallie said:
Gov springs need adjusting
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Did it with both stock and 4gsk in it. What I find weird is the guy I bought the pump from said he had it on a twin turbo truck. Had the typical afc mods done but stock gsk in it. Thing would defuel hard at 2400 rpm. Would kind of make for a worthless twin turbo truck in my eyes.
 
turbom700 said:
Did it with both stock and 4gsk in it. What I find weird is the guy I bought the pump from said he had it on a twin turbo truck. Had the typical afc mods done but stock gsk in it. Thing would defuel hard at 2400 rpm. Would kind of make for a worthless twin turbo truck in my eyes.
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Pull the afc off, put some duck tape over the pump (make sure it sticks good) and take it down the block. If it fuels hard down low you now know you have an AFC issue. My guess would be towards the gov springs, adjust them a little tight so it idles a bit high (1000-1100) and see if it makes a difference in the fueling. I would not think timing could cause this issue.


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turbom700 said:
No still feels the same, this is what makes me think its either timing, or my injectors are just to dang small. GSK are the only thing that made an improvent but that just because I have another 1k of rpm to play with.
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If taking the plate clear out does nothing, then you have pump problems. Injectors can't limit fuel that bad

Chris
 
For what its worth, i had a 160hp 12v out of a fedex truck that acted very similar to what you describe until i upgraded the injectors.

Although it does sound like a pump issue.
 
I'm going to pull the AFC tonight and see what the truck does rained all weekend here so wasn't able to work on the truck. Garage is in the middle of cleaning for the new cnc.

How much oil should be in these pumps, I had it running once with the AFC off and oil was pouring out of the afc housing. Could that be affecting how the govorner works?

Wish I had some know good injectors to try, I just have a feeling these injectors been out of a 195hp bus are so tiny that giving the amount of time the pump has it simple cant supply enough fuel. Be like trying to fill a swimming pool with a straw.
 
turbom700 said:
Wish I had some know good injectors to try, I just have a feeling these injectors been out of a 195hp bus are so tiny that giving the amount of time the pump has it simple cant supply enough fuel. Be like trying to fill a swimming pool with a straw.
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The truck that i had these same issues with had a pump and injectors from a bus. The gov springs on the pump were always wierd. Couldnt get it to idle right, and if you loosened them off so it would idle it would be as you describe it, they were 4k springs.


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