this weekend the ses light came on and autozone said it was the turbo boost sensor. they couldn't tell me anything else because they don't know much about diesels. i am not familiar with this sensor so you guys will have to fill me in. where is it located? where can i get one? does it hurt to drive with it inoperable? the light went off for a while but then it came back on so i assume it is the same thing.

Do you have a F(L65) engine or an S (L56) look at 8th letter of VIN,


What code # did they say it was, could be the WG solenoid or the actual MAP sensor in the intake, need to know your configuration to better assist with troubleshooting, pretty easy fix if we know code; In meantime verify vac system is leak free and vac pump is pulling 20+" vac on main line, my main is white from back of vac pump to vac fittings check there for vac.Edited by: Turbine Doc

its the f


ill have to go back and get the code

Okay F is a little easier as it's not EGR less stuff to leak & check, check vac at pump if that is okay then back track from WG on back of turbo it goes to the WG solenoid if vac pump checks okay at WG solenoid in should be same as at vac pump, output of solenoid will vary depending on boost demand from PCM vac there will be 15"-20" if solenoid is functioning, tee into it and observe while driving for changes. If no change possible bad solenoid, JK says sometimes can be resurrected by spraying WD 40 in it, but also only around $30 new IIRC.


Make sure when using vac gage to not pinch off tube or you will get constant false reading of what is trapped in hose.


You got boost/EGT gauges if not that should be next on list BEFORE TM, you will need them to set TM for best performance and know when to back off especially since you aren't WMI or IC, plus will give you physical indication if boost SES code is real or PCM input.

what is wmi and ic?


yeah im plannin on guages sometime this summer. ill go back to autozone and get the code tommorrow. hopefully it is the solenoid so that i won't bother replacing and just put the turbomaster on.

Water Mist Injection or Intercooling to knock back heat produced from compression by turbo, too hot a charge air from boost being jacked up is not a good thing, if you will remember from high school physics as you compress air more it's temp goes up.


If you are new to Diesels you might want to check out http://www.bankspower.com/ they have some pretty good info in the FAQs on Diesels in general and how to build power safely.

when i first installed my turbomaster i had it turned up to peak at about 15psi. it seemed okay until the first long grade at full throttle when after running about 10 sec. at full boost the ses light came on as the computer kicked into limp mode. shifted to neutral, cut off ignition and restarted and was fine. the code it set was for too much boost and the problem was solved by backing off the turbomaster to 12 psi. hope this helps

Just last week I installed my own home-made TurboMaster. I was code free the entire week and could actually hear my turbo whine for the first time ever. There also was a definite performance increase when pulling hills.


Then this past weekend I pulled my boat for the first time since the install. A hundred miles or so into the trip as I passed a car the SES light came on. Pulled into the next gas station and pulled a 78 code outta the computer. Just as I suspected....overboost. The SES light was gone after restart.


Ordered a boost gage last week too, but haven't gotten it yet. I'm anxious to see what kind of boost I'm getting. I'm sure I'll have to loosen the spring a little to lower the boost. But so far, I'd have to say my home-made TurboMaster is worth every penny of the $4.50 I spent making it. Edited by: w_huisman

the code i got is PO236


turbo boost range sensor

Start by looking at vacuum supply from the vac pump and vacuum delivered to the wastegate.


A good vac pump will produce 25"hg with a steady needle. You will see 15-20"hg at the actuator. Hard to beat a properly functioning vacuum wastegate system with an electronic boost controller.


I'd also look at a set of gauges soon...

i was kinda waitin to get guages until i got a new downpipe


what is better, pre or post pyro? and if i go post, do i have to mount on the downpipe or can i mount on the start of the 4" pipe?


im sure the vaccum system with a boost controller is hard to beat, but i am lookin for symplicity and trouble free. that is why i am leaning towards the turbomaster.


ill check the vaccum tommorrow when i get home from work. Edited by: steiner43511

The TM is okay I'm running one now (I started with a JK boost control at 1st) but you may still need a fooler (Buy or build your choice).


With TM only it may (repeat-may) set codes from pressure being higher than what PCM recognizes as a valid range, once you get a reflash that will be reprogrammed to allow the higher boost without setting codes.


I can't advise strong enough on the need for gauges before doing anything that adds fuel or boost to the engine, in the big picture they are cheap insurance, also a handy tool when diagnosing and asking "what is wrong with my truck" adding fuel or boost adds heat, the 6.5 is not forgiving in that dept.

Do you still have the SES light?


I am not possitive but I think the sensor on the firewall is the same as the boost sensor. If so, you could swap them and see if you get a different code.


What kind of gauges are you going to get? I wish I had known better whn I ordered. I was lazy and ordered a gauge marked for post turbo because there was already a fitting welded in my down pipe. I now wish I had ordered a pre-turbo marked gauge. (I might switch it over anyway)


Also, I wish I would have gotten a 30 PSI gauge. (if you run anywhere near stock then a 15 psi is fine.

Not the same 2 different connector keyways they won't fit unless you make them fit

well the light went off last night after i raced my buddies cummins up a hill.


i cant decide on pre or post. a hear that a lot of people wish they would have done the pre over post. should you worry about the thermocouple breaking off in a pre?


ill see if the light comes back on today.

It is very unlikely that a tip would break off.


Which ever way you go, you might want to consider getting it from Kennedy. His have the plug together thermocouple which is worth the extra cost.

Either location is acceptable I'm post turbo, when post turbo you have to remember there is a 200-300 drop across it, which gives you a 1000 EGT limit post turbo.


What did your vac testing show, you might want to try running with a vac gauge teed int WG act line to see if vac is dropping off when under load.

well i havent tested the vac because the light hasn't been on. i havent noticed any power loss and it feels and runs like normal. it doesn't smoke anymore now either. thanks everybody for helpin me with my problem. im sure it will return though and then i will check the vac.


now i am worried about my harmonic balancer. i have heard some horror stories about them. anybody have info they can give me? im wondering how much vibration can you feel when the balancer goes out? sometimes mine has a little vibration and sometimes nothing. i think i will start another thread with this topic.

Rule of thumb I've heard 100K is a good time to change one concequences too grave to ignore it, look for very spongy rubber or cracks in the rubber, which are indications it is nearing the end of it's service life, heat and exposure to oil can impact when if this becomes a problem, IIRC $80 GM part direct new, cheap insurance vs engine rebuild I think

well the light is back on and it is smokin again. i installed the turbomaster tonight, but i have it backed off so it is probably only makin 3-4 lbs of boost. im not going to go crazy till i get the straight pipe and guages. i unhooked the batteries till morning so hopefully the code will reset.


code - PO236


where is the turbo boost range sensor? Edited by: steiner43511

OK stupid question time


Whats the difference between the pre / post gauges themselves. How high would my gauge need to read to be able to handle pre turbo temps?