View Full Version : Overboost , How to stop getting codes.
Installed Turbomaster, getting 10.5 PSI.
How can I trick PCM in to not seeing this
High a boost pressure ( and fuel cut back )
Really don't want to cut
back on the boost spring if I can help it.
Nice increase in power....with the turbo master.
Get Kennedys boost controller, it will alter the signal so it reads a lower than acual reading.
Uncle Wally
05-13-2004, 17:54
I would talk to John to see if he knows of anyone that can reprogram your PCM to omit the boost signal. His chip for the 94/95 does exactly that. It works beautifully. No codes. Tons of power. Although it's not the only part to the equation.
Waldo
Before my engine up grade, I had a turbo master and set the spring for 8 1/2 lbs boost with no codes. I think at 10 psi you have jumped off the fence. Heath can re flash your computer and I am told that the results are remarkable. :D
patrick m.
05-14-2004, 14:44
you are really going to feel bad when you discover that the item you need to get rid of the "check engine" light, will also give you up to 12psi boost.
Was wondering if there was a " cheap " fix.
Myabe a resister or a zenner diode in right place.
Heath said he could program it for more power,and no codes. Just don't have the money right now.
Guess I'll have to back off on the boost.
Yes, a resistor is all you need. There should still be some posts here on how to make a "boost fooler"
You don't need a potentiometer if you get close enough with the resistor size. If you want, I can check to see what size my brother used.
Whatnot Please do, And where does resistor go?
Sense output, or Voltage in.
Thanks..
I think either will work but we used the output.
I guess I could just go out and check what the pot is set to on mine with an ohm meter.
I used a 20k pot but my meter is showing 7.5 and 9.5K from the wiper to each side.
I think when we put the resistors in my brother's truck, we just measured the resistance and used resistors that were close.
I don't know if I need the empty end connected to the ground lead but I do.
To do the same thing as I have with resistors, you would need to use about a 5K and 10K (should be close enough. Cut the center wire and put a 5K resistor in series with it. Then you might not need the 10K but if so, connect one end of it to the 5k resistor (opposite end from the sensor) and the other end to the black sensor wire. (just splice in without cutting the copper)
If this doesn't make any sense, email me. whatnot@ureach.com
MTTwister
05-18-2004, 19:45
rjwest -
Use a 10k - 15 turns linear pot from Radio Shack - < $4.00. Splice into the boost sensor on the manifold - green is to the ECM, and tap the other prong into the ground wire -black-. I set mine to 2K for the spliced wire, and -just back from a 3000 mi road trip- saw 13# boost on rare steep mountain passes, -shut off cruise at that point- and no codes. The overall theory was in the '99 or 2000 -I believe- archives - a short mention of how-to. Another site gave me a little more info. I can get the RS parts number later, if needed.
TurboDiverArt
05-19-2004, 02:50
Just to clarify and so I can understand what's going on. On the MAT on top of the manifold. The center green wire is the signal wire to the ECM. You put a resistor between the green ECM signal wire and the black ground wire. This basically shunts some of the voltage to ground lowering the signal voltage that gets sent to the ECM. This
I run a Turbo Master on my 1999, no codes. The ECM doesn't seem to care what boost I have as long as it isn't lower than it expects.
Thanks All!!!!! Just got the resistor, but no time yo install. going on a trip. Backed of on a boost a little. will run with obd2 scanner on, reset as required.
Fix it right when i get back.
patrick m.
05-19-2004, 14:30
Originally posted by AndyL:
I run a Turbo Master on my 1999, no codes. The ECM doesn't seem to care what boost I have as long as it isn't lower than it expects. i see in your signature, you have a "Heath" ecm. That is why you dont get codes for high boost, the programing prevents the code from setting.
Originally posted by Patrick m.:
</font><blockquote>quote:</font><hr />Originally posted by AndyL:
I run a Turbo Master on my 1999, no codes. The ECM doesn't seem to care what boost I have as long as it isn't lower than it expects. i see in your signature, you have a "Heath" ecm. That is why you dont get codes for high boost, the programing prevents the code from setting. </font>[/QUOTE]I had the turbo master installed for probably 6 months before the ECM, no codes then either. It was set to about 10 PSI.
TurboDiverArt
05-20-2004, 03:01
Originally posted by AndyL:
</font><blockquote>quote:</font><hr />Originally posted by Patrick m.:
</font><blockquote>quote:</font><hr />Originally posted by AndyL:
I run a Turbo Master on my 1999, no codes. The ECM doesn't seem to care what boost I have as long as it isn't lower than it expects. i see in your signature, you have a "Heath" ecm. That is why you dont get codes for high boost, the programing prevents the code from setting. </font>[/QUOTE]I had the turbo master installed for probably 6 months before the ECM, no codes then either. It was set to about 10 PSI. </font>[/QUOTE]You can run 10 psi without setting codes and having it back off the fuel? WOW, didn't know that. I just looked at my MAX values on my x-monitor and I showed a max boost at 11.3 psi. I don't know if there is a code in the computer but I don't remember seeing a check engine light. Heck, I don't remember ever seeing that high. Must have been a blip when getting on the parkway but the solenoid pulled it back. Maybe momentary blips don't set a code is the ECM can successfully pull it back under control. Just a thought.
Art.
Cooperrw
05-20-2004, 03:36
I currently run the JK boost controller and see 12 lbs of boost with no codes to date. I am waiting on a reflashed ECM from Heath that should be here any day and then I will go back to the Heath Boost controller that I removed because I was setting codes. I spoke with Mr. Heath when I ordered the ECM and he said the ECM is programed to work with his controller. tongue.gif
A properly set up program/chip will need NOTHING to produce the appropriate boost levels.
A mechanical wastegate control that does not implement boost psi into it's activation only directly regulates one thing: turbo drive pressure.
The PCM won't set a code or defuel for transient high boost conditions. I think it needs to be over the limit for 20 seconds or so. If you set the controller to 10 PSI you may be fine. I think 11 or 12 steady state is probably too high, though.
TurboDiverArt
05-21-2004, 02:35
Thanks for all the information. I
Cooperrw
05-21-2004, 04:16
If I'm hearing you correctly JK I do not need any boost controller if the computer has the proper program run on it! I see from reading other post that people are useing both a chip/reflashed computer and some kind of boost controller............now I'm confused :eek: I will have to say that what you are saying makes sense because the computer controles everything under the hood. My reflashed ECM arrived last night so I think I will run it with out any boost controller to see what performance is gained.....if any. :rolleyes:
If you have the Heath reflash you will not need a Turbo-Master or adjustable boost controller.
Cooperrw
05-21-2004, 14:20
Thanks for the info AndyL, I have to replace the four wheel drive acuator then I will get that ECM installed. :cool:
Originally posted by River Rat:
Thanks for the info AndyL, I have to replace the four wheel drive acuator then I will get that ECM installed. :cool: Make sure you get the new style.
I would hate to go back the waiting for 4x4 to engage in my truck.
OK, back from trip, backed off boost to 9 psi.
Got overboost code only one time. BUT,
There is a " hidden defuel function "
that will limit power when an overboost condition
occurs. momentary surge in boost above 9-10
psi, usually occurs when upshifting from 2nd gear.
or high rpm in third gear withh TCC locked.
condition stays set untill ign turned off.
or reset by " laptop", OBD2 scan tool reset would not clear it.
If I had a " defuel' condition occur,will climbing a hill I could reset it on the fly., Big differance in power.
Got to get the " boost fooler installed.
The extra few lbs of boost makes a BIG differance.
RJ--
How are you hooking up a laptop ?? Can you reset timing and all with it ??? Thanks.
My '96 will run approximately 25psi from shortly after launch to the speed limiter on a GM stock program, and my boost control.
I pulled the Pull Off hill with the "Z" reflashed ECM, but I really disliked it. It did have a touch more HP with the extra fuel up top, BUT the majority of the change was just in how the pedal worked. I think the OE pedal works as good or better.
We are in the process of removing a few of my custom alterations and the OE turbo has been reinstalled. This will make it a better test subject.
We will be working on the programming end of things, and trying to combine the best attributes of various existing OE programs as well as some custom additions, AND unique features to make one final product with say a couple of performance level options.
As for Eproms, my chips (at least the big ones) will not set DTC 78, do not require boost controls, and can produce in excess of 14 psi at sea level easily if the truck is healthy...
Scooby: No the laptop can not set timing, I know of no laptop that can do that function.
I am using CARCODE , it does not read all diesel
functions but gets a lot of them. it does have a way of writing instructions, but I do not know what instruction set is, I think it's top secret...
Kenedy. Just looking to get enough usuable horespower to make driving with a truck camper
enjoyable. was getting close with turbomaster
but have to solve Bo0st defuel mode...
Wanted to get the vacuum pump off, 1 less fail item, but it looks like a reprogram would have been a better way to go, If the tran and injector pump could be reprogrammed, than I think it would be a real good truck.
Really dis;ike the NO TCC lockup below 50mph and no lock up in 2nd, Really big power differance in
second with TCC locked up.
Also, I notice a big lose of power after driving several hours, could this be fuel temp to high?
I see 130-140 degrees on laptop...Seems I need much more throttle and boost after several hours driving.
Originally posted by rjwest:
Kenedy. Just looking to get enough usuable horespower to make driving with a truck camper
enjoyable. was getting close with turbomaster
but have to solve Bo0st defuel mode...
Wanted to get the vacuum pump off, 1 less fail item, but it looks like a reprogram would have been a better way to go, If the tran and injector pump could be reprogrammed, than I think it would be a real good truck.
Also, I notice a big lose of power after driving several hours, could this be fuel temp to high?
I see 130-140 degrees on laptop...Seems I need much more throttle and boost after several hours driving. I still prefer the vacuum system. Sure it is expensive to replace the VP, but they generally run 100k+. Solenoids seem to live a bit longer if you give them a shot of WD 40 through the line to the turbo once in a while.
As for the temp thing, I'd venture to guess that it was intake air temp so long as coolant temp was normal on the scanner. We can make these things run nice, BUT if you don't have full time intercooling, you are trading off quality for quantity...
Kenedy: Will high IAT cause a " Hidden" code to set that will cause a " Defuel" mode:
IE Loss of power, untill PCM is reset or ign key shut off.
I am well below any Exhaust gas temp that I assume will cause a problem. Keep it below 900Deg post turbo...
I am assuming the cause is boost, but since I can't
find what is set in PCM, I am not sure.
I relize the intercooler is best, but money is an issue, Keep putting more money in, could probably buy a DMAX or cummins.
If the transmission locked up sooner and locked in second than maybe I could justify the intercooler.
Was going to put in a std shift, than I read all
dual mass problems. Also Read DMAX std shift problems. Maybe a dodge is a better choice...
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