Temperature Turbo Boost - new chip

[Dan Nicholas]

Hi everyone,

I have a 1996 6.5 TD 2500 pu. During the summer, I experience what I've read at this site to be a common characteristice of this motor (without an intercooler).

In the summer, when the manifold inlet charge reaches a certain temperature, the boost basicly is shut down (by the intake temp sensor). Black smoke billows from the exhaust under load etc. I can see virtually "no boost" from the boost gauge I installed).

I have a camper haul and of course, trying to haul without boost is a pain in the...!

1) As everyone knows, the intercooler is expensive, so I'm wondering if anyone has done any modifications that improved inlet temperature besides installing the intercooler (repositioning air intake...)?

2). I'm thinking about purchasing the "manual boost controller" and computer chip to improve performance (fuel curve, boost etc). Will this bypass the temp sensor "boost shut down"? In my mind it would. Would this be dangerous or would I risk damaging my motor if boost was not limited accordingly with air intake temperature? It must have been put there by Chev for a reason (I guess).

An insight or experiences would be appreciated. I'm trying to get the same power I have available during the winter for the summer so I can tow properly. During the winter, I can tow great as my boost kicks in and out properly (lower air intake temps), but in the summer, I basicly pull with just conventional diesel power from the 495 cube inches (no available boost due to intake temperature).

Thanks for any help you can provide!!

[pannhead]

the AIT sensor is there for a very important reason :eek: ...its turning down fuel and boost to save your engine from melt-down...removing or relocating the AIT sensor IMHO is asking for trouble....intercooling (or w/i)is the only way to reduce air intake temps..most people who tow agree that it is good long term investment...good luck ;)

[gmctd]

If you have not, install an Exhaust Temperature Gage (EGT), and check for a correlation between hi EGT readings and Boost falloff.

Could be some component in the vacuum system failing - Wastegate Solenoid, tubing, pump.

Checking at idle with standard 0-30" vacuum gage -
23" vac at pump = ~15" vac at wastegate servo - solenoid is about 63% duty cycle at idle.

Simple test is to move the actuating rod with your fingers - at idle, should take considerable force to open the wastegate, and it should forcefully re-close when released.

If not, it's a vacuum problem, not PCM.

Posting your findings will help in diagnosis.

[Bigg R]

DAN,

YOU DIDN'T SAY IF YOU STILL HAD THE PLASTIC ENGINE
COVER ON! YOU MIGHT REMOVE IT IF IT'S ON THERE!
THIS HELPS THE INTAKE RUN A LITTLE COOLER,ANY
LITTLE BIT HELPS! MY 95 DUALLY CAN RUN 220*OR
HIGHER AND BOOST NEVER CHANGES.YOU MIGHT WANNA
LOOK AT THE AIT SENSOR AND MAKE SURE IT'S READING
PROPERLY.THE FACTORY SERVICE MANUAL TELLS YOU HOW
TO CHECK THE RESISTANCE W/A VO METER AT DIFFERENT
TEMPS!

[whatnot]

Did you happen to use a T fitting to connect the boost gauge to the IAT fitting? If so, that may be causing part of the problem. I had mine that way ay first and it takes the sensor out of the airflow. Once the engine got hot, the IAT would read way higher than it really was.

I don't think the computer will bull that much boost, it mostly cuts the fuel back. I can run over 12 PSI of boost and it only cuts it back a little.

[dslpwr]

Start saving your money.
Intercooler is worth it if you do any towing

[Dan Nicholas]

Originally posted by pannhead:
the AIT sensor is there for a very important reason :eek: ...its turning down fuel and boost to save your engine from melt-down...removing or relocating the AIT sensor IMHO is asking for trouble....intercooling (or w/i)is the only way to reduce air intake temps..most people who tow agree that it is good long term investment...good luck ;) Thanks Pannhead...good advice, I don't feel comfortable totally removing safety mechanisms designed to protect the engine.

[Dan Nicholas]

Originally posted by gmctd:
If you have not, install an Exhaust Temperature Gage (EGT), and check for a correlation between hi EGT readings and Boost falloff.

Could be some component in the vacuum system failing - Wastegate Solenoid, tubing, pump.

Checking at idle with standard 0-30" vacuum gage -
23" vac at pump = ~15" vac at wastegate servo - solenoid is about 63% duty cycle at idle.

Simple test is to move the actuating rod with your fingers - at idle, should take considerable force to open the wastegate, and it should forcefully re-close when released.

If not, it's a vacuum problem, not PCM.

Posting your findings will help in diagnosis. Thanks for your comments gmctd. I have done some of what you suggested.
1). new vacuum pump
2). check vacuum at wastegate servo (is within spec).

Boost all seems to run properly in cooler weather...little or no boost during hotter summer months.


I'll look at installing the EGT gauge. Thanks again!

[Dan Nicholas]

Originally posted by Bigg R:
DAN,

YOU DIDN'T SAY IF YOU STILL HAD THE PLASTIC ENGINE
COVER ON! YOU MIGHT REMOVE IT IF IT'S ON THERE!
THIS HELPS THE INTAKE RUN A LITTLE COOLER,ANY
LITTLE BIT HELPS! MY 95 DUALLY CAN RUN 220*OR
HIGHER AND BOOST NEVER CHANGES.YOU MIGHT WANNA
LOOK AT THE AIT SENSOR AND MAKE SURE IT'S READING
PROPERLY.THE FACTORY SERVICE MANUAL TELLS YOU HOW
TO CHECK THE RESISTANCE W/A VO METER AT DIFFERENT
TEMPS! Hi Bigg R. Actually, just by coincidence, I do have the plastic cover off. I took it off to install my boost gauge fitting and never put it back on! I did buy a new AIT sensor to install and try. I'm hoping the fix maybe as simple as that. Does your boost characteristics remain the same all yr round? What does it usually run at?
Thanks for the info!!

[Dan Nicholas]

Originally posted by whatnot:
Did you happen to use a T fitting to connect the boost gauge to the IAT fitting? If so, that may be causing part of the problem. I had mine that way ay first and it takes the sensor out of the airflow. Once the engine got hot, the IAT would read way higher than it really was.

I don't think the computer will bull that much boost, it mostly cuts the fuel back. I can run over 12 PSI of boost and it only cuts it back a little. Hey Whatnot. I haven't put a T in the IAT. I drilled and tapped the boost fitting directly into the top of the intake manifold. Does your trunk always run at around 12 lbs of boost on the highway? Mine usually runs around 5-6 lbs cruising around 68 mph (with cool intake temp). What yr truck do you have? Thanks for the reply!

[Dan Nicholas]

Originally posted by dslpwr:
Start saving your money.
Intercooler is worth it if you do any towing Thanks dslpwr. I know the intercooler is definitely worth it. Problem is I still have to tow until I can save the money (lol, woe is me).

In the summer, I actually see the same "low or non-existant boost" even when I'm not towing. Because of this, I'm wonder if there's an underlying problem to fix before determining whether an intercooler is necessary.

[whatnot]

Originally posted by Dan Nicholas:
</font><blockquote>quote:</font><hr />Originally posted by whatnot:
Did you happen to use a T fitting to connect the boost gauge to the IAT fitting? If so, that may be causing part of the problem. I had mine that way ay first and it takes the sensor out of the airflow. Once the engine got hot, the IAT would read way higher than it really was.

I don't think the computer will bull that much boost, it mostly cuts the fuel back. I can run over 12 PSI of boost and it only cuts it back a little. Hey Whatnot. I haven't put a T in the IAT. I drilled and tapped the boost fitting directly into the top of the intake manifold. Does your trunk always run at around 12 lbs of boost on the highway? Mine usually runs around 5-6 lbs cruising around 68 mph (with cool intake temp). What yr truck do you have? Thanks for the reply! </font>[/QUOTE]I have a "boost fooler" boost controller on it. It depends on the highway speed what the boost runs.

If you are only running at 6 Lbs of boost then I really doubt that it is the IAT causing the trouble unless the sensor is bad.

If you don't get anywhere with it, you can always just put a Turbomaster on it. If you do a search on it you will see that some here don't like them and some wouldn't be without it. Either way it is much better than a non-working electronic control system.

[rjwest]

I have noticed loss of power in summer, but not that dramatic. just shifting sooner on hills, and
not as much pulling power, no real loss of boost
around 6-7.5 psi . The loss of power always
was co-incident with high coolant temp ( above
center mark ) and high oil temps. 220 plus.
I guessed it was due to HOT engine.( hot westher)

I switched to 180 deg high flow thermostats,
little bigger exhaust, Cleaned out oil cooler,
Lost a cat somewhere, I think the 180 stats made the biggest differance, Takes longer on hill to
heat up...

Much better, but will still lose some power as
compared to cooler weather. But this is normal.

[Dan Nicholas]

Thanks RJ. That's useful information knowing that there should be a loss, but not as drastic as I'm seeing. In the summer, are you also seeing a high exhaust temp (due to higher overall operating temp)??

[Marty Lau]

Dan;
You might want to talk with Bill Heath, he uses a mist injecton to cool the intake air and add power and it is like less than 1/3 the cost of an intercooler. Now your limited to your water supply but Bill says that most people get about 3 tanks of fuel out of a 12 gallon tank of water. If you only need it on hills and passes should work good, if you run so hard you need it all the time then air to air IC is a better choice.
Water injecton is a proven concept it has been used in Aircraft engines for over 60 plus years.

[rjwest]

No noticable differance in EGT, Except, Less power
for same egt readings.....Lose power ( pcm cuts back )push throttle , lose more power,
I found that trying to keep throttle at " just
before PCM cuts back, gets most power,

I suspect you may have a problem other than temps,if its VERY noticeable.

I do think 180 stats made a diff, but MPG may go down. Than I keep adding things so it's hard to tell.
I may look into Heath MIST system, Just installed
a turbo master from Heath, Very satisified with
Kit, Well engineered, Put a few miles on it
empty. Won't be able to tell how good untill I load up and take a trip...

I can tell when FUEL is low cetane Lower MPH
and power.

[Dan Nicholas]

16ga and Rj, thank you both for your advice and comments. Very useful info. I think I'll install my new intake temp sensor ($20) and then address lowering the coolant temp (180 stats). I suspect that even with a lower coolant temp I still may have to look at the water injection (or intercooler if I win a lottery!!). BTW, 16ga, I think I could put up with filling the water tank since the only time the lack of boost really bothers me is when I tow. Low boost in day to day driving I can live with. Thanks again!

[Barry Nave]

on my set up I don't need to use the water injection only when towing the TT up grades.
I have A IAT that does not read the air temp but the temp of the housing. On hard pulls the temp will go to 200*,that as high as I will let it go, 14-15psi max boost. With water the temp will drop to 145* and hold.
If I lose any boost the EGT will max out yet the fuel is not cut and the black smoke pours.
Also I have an in dash boost control,so 12 psi in my norm. If I lower boost the EGT goes up.
Had a vac hose trouble at one time.
More boost has a cooling efect though it also gets the IAT up.If I towed as a full time RV'er I would then go air to air.
I'm luckey if I get the TT out 3 times A year.
Construction summer's. The new pool also has some thing to do with that :D

[Marty Lau]

Bnave;
On your H2O injecton how large of water tank do you have and were do you have it?

[Barry Nave]

Does my imagestation work when clicked on?
I have all pic and details on the water system.
Have'nt been there my self lately. I'll CK out and see if it's still up.