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Hot truck, why, high boost, bad IAT, cooling issue???

A

Acesneights1

New Member
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Location
Northeast CT
I've tried everything with it. Mods are in sig but I have Heaths whol cooling setup. Still runs very hot on hills. Every thing clean clean clean. either my egts are too high or the rads not getting rid of the heat. I think a little of both. Rad is 1 yr old.
 
Acesneights1 said:
Actually when I put all the stuff on it was alot better but when I added the TM it went back to what it was.
Click to expand...

If the TM is causing the heat then it's high IAT from higher boost. Try closing the air box back up that you mention in your sig.

Leo
 
If youre still running GM4 thats your problem, IATs skyrocket on a GM4 when boost hits 10psi. Verify it with GMTDScan while driving. Driving empty it doesnt effect my engine temp though, but I imagine it would if pulling. On hills, which is an everyday occurence, my boost will go to 10psi and up sustained (which is the reason your TM may now be causing), the EGTs will go from 400 to 900 post turbo in about 3 seconds. Mine is on the vacuum setup, but I never got 10psi sustained (let alone the 13psi sustained I get for several minutes now) until I got my Engh Motors power chip. I know Heath says theirs works best with TM, so maybe you werent getting same sustained boost on hills with Heath chip and vacuum setup that you would get with Heath Chip and TM.

Relevance is that an ATT will solve your problem, since the backpressure drop wont make so much heat transfer from EGT to IATs
 
Aces, give the ATT a shot before dicking around with I/C... From results of others, solved the problem.

BTW, Kenny, do you have the equitpment to set to TDC -1.5?

And I'm sure his 2k is GM-8 ... but still.

I don't tow, but i'm always heavy at 9-10k, TM dropped my EGT's 100-200dg across the board.
 
Yes my tdco is at -1.5. I had it at -1.94 last summer but cut it back a little when weather got cold.
Buddy, what you are saying makes sense. IIRC egts on ills were around 1100. Can't remember what IATs were but I have the snapshots so I'll review data.
 
I had to go back and copy this from another thread but here was a snapshot of when it was towing on a hot day.

Snapshot created 7/7/2008 10:04:53 AM
__________________________________________________ ________________
ENGINE SENSORS
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Engine run time: 01:26:26
Boost pressure (MAP): 27.81 PSI
Desired EGR: 15.23 PSI
Desired idle: 806 RPM
EGR pressure: 14.29 PSI
EGR duty cycle: 0 %
Engine coolant temp: 227.9 F°
Engine speed: 2212 RPM
Glow plug relay feedback: 0 Volts
Glow plug voltage: 0.2 Volts
Ignition voltage: 12.8 Volts
Wastegate duty cycle: 0 %

__________________________________________________ ________________
INFORMATION SENSORS
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
PCM Calibration ID: 4805
Current DTCs: 0
Accel. ped. pos. 1: 1.9 Volts
Accel. ped. pos. 2: 3.18 Volts
Accel. ped. pos. 3: 3.31 Volts
Barometric pressure (BARO): 13.4 PSI
Battery voltage: 12.9 Volts
Fuel temperature: 126.4 F°
Intake air temp: 256.2 F°
Throttle position: 48 %
Turbo boost (Calculated): 14.42 PSI
Voltage reference sensor: 1.2 Volts

__________________________________________________ ________________
INJECTION PUMP SENSORS
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Actual injection pump timing: 37.31 Deg °
Cam reference missed: 0 Counts
Crank reference missed: 0 Counts
Fuel calibration: 150 Counts
Fuel rate: 60.31 mm³
Fuel rate - Cruise: 0 mm³
Fuel rate - Idle: 0 mm³
Fuel rate - Maximum transient: 70.62 mm³
Fuel rate - Throttle requested: 72.75 mm³
Injection pulse width: 1.94 ms
Injection timing - Measured: 15.1 Deg °
Injection timing - Desired: 14.8 Deg °
TDC offset: -1.94 Deg °

__________________________________________________ ________________
TRANSMISSION SENSORS
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
3-2 PWM solenoid duty cycle: 0 %
Cruise target speed: 0 MPH
Cruise speed error: 0 MPH
Current gear of transmission: 4 Gear
Current torque signal pressure: 55 PSI
Current transmission ratio: 1:0.06 Ratio
Error between desired and actual shift times for latest 1-2 upshift: 0.18 Sec
Error between desired and actual shift times for latest 2-3 upshift: 0.12 Sec
Force motor (PCS) - Duty cycle: 31.2 %
Force motor (PCS) - Feedback current: 0.51 Amps
Force motor (PCS) - Reference current: 0.51 Amps
Time of latest 1-2 upshift: 0.15 Sec
Time of latest 2-3 upshift: 0.22 Sec
TCC PWM solenoid duty cycle: 0 %
TCC slippage: 49 RPM
Transmission input speed: 1936 RPM
Transmission output speed: 1934 RPM
Transmission temperature: 192.2 F°
Turbine speed: 1452 RPM
Vehicle speed: 51.5 MPH

__________________________________________________ ________________
STATUS FLAGS
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Shift lever:
Drive 4

Cruise control:

TCC mode word 1:
TCC is being forced off
TCC enable solenoid valid
Low threshold for COPETCC selected
Use hyst. for vehicle speed
TCC is in release mode, slipping
TCC is in locked-adjust mode
TCC is being applied
Negative slip recently prevents apply

TCC mode word 2:
TCC PWM is on
• Perform release
Perform apply
Min. threshold occurred
• TCC Bus. is valid
NDT occurs
Delay is in progress
Min. throttle occured

IOD port A:
Glow plug relay - Closed/Open
• Stepper motor inhibit - Run/Inhibit
Service Throttle Lamp - On/Off
EGR vent enable - On/Off
• Shift A - On/Off
• Shift B - On/Off
TCC enable - On/Off (4L60E only)
• Force Motor enable - On/Off

IOD SOD status register:
Coolant temp. pullup select - On/Off
Trans. temp. pullup select - On/Off
Fuel calibration temp. select - On/Off
Check Engine Lamp - On/Off
PWM1 - Reset/Normal
PWM2 - Reset/Normal
PWM3 - Reset/Normal
PWM4 - Reset/Normal

System status word:
FM shut off due to low battery
Force Motor pulse in progress
• Power is On/Off
COP2 is being serviced
Delco instrumentation PROM
• Powertrain is in motion

Discrete flags:
Brake - On/Off
• A/C Compressor - Engaged/Disengaged
Power enrichment - Active/Inactive
Kickdown pattern - Active/Inactive
Four-Wheel Drive Low - Active/Inactive
Cruise low - Active/Inactive
Diagnostic - Requested/Not requested


__________________________________________________ ________________
 
IATs were 260 which IMO is way to hot. Where's Scrufdog when I need him. I am seriuosly thinking of doing a top mount and then dropping a hoodscoop on it. I'm talking a real functional hood scoop. The only problem is that will look gay so I will have to lift the truck to compensate....:devil:
 
Acesneights1 said:
All I did was the JK mod. It still pulls cold air from fenderwell.
Click to expand...

OK, in your sig it sounded like you may have cut holes for more air flow. JK's mod wouldn't be your problem. If I could lend you my ATT to try I would. I guess you'll have to bite that bullet yourself and join the ATT team:grouphug:

Leo
 
Heat is a product of inefficiency coming from the GM-8 turbo.

You have a full exhaust kit on the 2000?

What are your EGt's when running hot like that to have 260 IAT's?
 
Wow, thats one hot truck. And this is his 95 with a GM4
51MPH@2200RPM, 228*F water, 256*F IAT, 14PSI boost, and it looks like PCM was defueling you since APP was requesting 72mm3 and PCM was only giving you 60mm3. Or you were running stock program and it the PCM is smart enough to know it should give more fuel but doesnt.

You do need an ATT :)
 
Confused, if we are talking about your GM'4'd Tahoe, then put an ATT on it and your IAT's will drop a ton. If still not good, then dick with an intercooler. The GM-4's are super inneficient.
 
Maybe there is something missing, I don't know. I am running a GM4 and my truck and camper together gross about 18K. My coolant temps have never passed 200deg F and my EGT's have not gone past 1000deg F. Of course mountains in NC are just hills compared to some parts of the country. Yet the heat and humidity can be almost unbearable. And it maybe that I am just lucky or blessed!
 
Aces - swap IAT sensors on your trucks....perhaps the sensor is not reading properly...

EDIT - forget it....thought it was IAT's alone and not ECT's as well....
 
Matt Bachand said:
BTW kenny, when does that fan engange?
Click to expand...

Not sure but it's the Heath Dmax fan. Yes I am talkng about the 95. The 2000 is all stock and yes that one has a GM8. The 95 Has the Heath V2or as was called when I bought it the Maxitorque. as far as de fueling it shouldn't be. The IP is weak. On real hot days if the trucks been working it won't start hot. usually have to do the water trick. I don't know. I'm going to look at an Excursion Sat for 13k with a stroke. I may be asking a little much of this truck.
 
chrisk1500 said:
Aces - swap IAT sensors on your trucks....perhaps the sensor is not reading properly...

EDIT - forget it....thought it was IAT's alone and not ECT's as well....
Click to expand...

Yeah and on top of all that what GMTDScan doesn't show is EGTs which were around 1100. The ATT could be the solution. it's just a decision I have to make. It needs an IP as well. It's been fine all winter but I know when the weather gets hot the no start return.
 
Kenny I really didn't mind the ATT thread hi-jack but looks like you got more going on than meets the eye , and I wanted to let guys assist the trouble shooting without it getting confusing to search engines & thread context mixed in with ATT comments, hope you don't mind.

In addition to other recommendations, have you ever looked at the "mystery gasket" between upper & lower, when I was still full S configured mine had rotted on back side and I was constantly blowing hot EGR into intake stream upping my temps.
 
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