Lousy Torque, Need Help

[redwoody]

I am having some power/torque problems. Here's what I have:

1) 2000 7.3 PSD F-250 Short Box
2) 60 hp "mild" Superchip chip purchase way back in 2001.
3) AFE Stage II Air Filter Kit
4) 4" Exhaust and downtube including Flowmater silencer

Other useful information:
No black smoke that I have ever seen.
Engine seems to run fine.
I do use Stanadyne Fuel additive.
I get fairly good mileage when not towing - 18mpg to 20mpg at 75mph.
I get 9 or 10 when towing the trailer at 75mph.
New fuel filter.
Fresh Oil (Delo 400)
No 'puter codes.

The problem seems to be low torque. It takes a long time to get up to speed and it now stuggles to pull hills out of overdrive. Truck is used almost exclusively for towing an 8000 lb, 12 foot high trailer. Truck does not "pull" as well as it did when I had only the chip and a K&N Air Filter. I installed the exhaust to keep temps down/help air flow, and the AFE filter kit when I discovered fine dirt particles occasionally getting past the K & N filter and was hoping to gain better mileage and power too. Besides what seems like low power/toruque, I am also getting serious turbo flutter, and I hear quite a bit of air filter whistling (the filter noise is no big deal.) I could really use some help to solve this problem. I've screwed up something. Any help appreciated. Thanks.

[Marty]

I get 9 or 10 when towing the trailer at 75mph. = really fast... and dangerous with 16,000lbs rolling down the interstate (I hope its on the interstate lol )

If you had just the drop in K&N air filter there is a possiblity of crud getting into the engine (you know this). This sometimes can result in prematurely scored cylinder walls which in these high compression engines kills them. You will lose compression and loose "pull." However I'm not sure if this is you're problem. A sensor of some sort is probably more likely your issue. Are you leaking any fluids? Also what type/size exhaust did you install, include the DP size.

[redwoody]

nope, no leaking fluids. the entire exhaust system is 4" (14 guage) including the downtube. thanks.

[mschn99]

I dont like throwing parts at things, so you will need to manually test this...but check your boost levels....sounds like a possible bad map sensor to me....but check your boost levels at idle, accell, and WOT....

if you happen to have a scan tool available that will monitor the MAP pid, watch it in corrolation to your true values as well.....

[redwoody]

Originally Posted by Marc

I dont like throwing parts at things, so you will need to manually test this...but check your boost levels....sounds like a possible bad map sensor to me....but check your boost levels at idle, accell, and WOT....

if you happen to have a scan tool available that will monitor the MAP pid, watch it in corrolation to your true values as well.....

I don't have a scan tool Marc but I do know a shop in town that does. I will run it over there.
I've been wanting to install guages (trans temp, boost, pyrometer). Can you tell me where a good place to purchase? with good/easy instructions for installation? thanks again.

[mschn99]

Talk to the forum vendors, they will hook you up with a screaming deal!!!

[Diesel Nut]

Gauges should always be the FIRST mod you make! That way you know whats going on.

My first question to you would be what your egts are. I am guessing high. we don't know.

Second question would have been is boost lower than normal.

I would suggest the above and also look over everything from the turbo to the motor. Look for a boost leak. It sounds like a possible boost leak, or like Marc said a bad or dirty MAP sensor.

[redwoody]

Originally Posted by Diesel Nut

Gauges should always be the FIRST mod you make! That way you know whats going on.

My first question to you would be what your egts are. I am guessing high. we don't know.

Second question would have been is boost lower than normal.

I would suggest the above and also look over everything from the turbo to the motor. Look for a boost leak. It sounds like a possible boost leak, or like Marc said a bad or dirty MAP sensor.

ok ok I will get the guages and get back to you. I just hope a driveway mechanic (me) can handle guage installation! I will get back to you guys when I get some boost numbers. If I remember right, they were around 14 psi with no load, full throttle. I'll be curious to know how much when towing.
thanks again.

[scott193102]

that sounds low if you ask me, i think mine is around 22psi.

[Marty]

14 sounds about right stock to me, maybe a little low, but then again he was throwin that down unloaded. The stock turbo can only handle 25psi, and I think the PCM or something keeps it from attaining 23. I think with a stock setup, your turbo will only see about 17psi at full throttle w/ a load. I could be wrong but these #'s are coming to me from some stuff I've read previously.