• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

HOME MADE WASTE GATE SYSTEM AND P0236 CODE

MrMarty51

MrMarty51

Well-Known Member
Messages
18,227
Reaction score
42,343
Location
Miles City, Montana
The waste gate system on My 2000 K350 had began acting up.
It took it a very long time before it set the code P0236, waste gate system A or some such.
I messed with it, installed two vacuum gauges to the solenoid, vacuum was constant on the + side and seemed to work okay on the - side.
I used My vacuum pump and checked the actuator, it was moving freely without any binding whatever.
I then back probed and connected a volt meter to the 5 volt reference wire at the boost sensor, even when the turbo was acting up and not giving any boost, according to the boost pillar gauge, the reference signal of 5 volts was constant.
Hooked the meter to the signal out wire, went for a drive, vltages there seemed normal and with 0 to very low boost was, I think, around 2.15 volts, running wiit boost on the hills, it would climb, if I remember correctly, into the low 4 volt range, then, the boost pillar gauge would fall, go to 0 psi and 0 volts.
Installed a new boost sensor, same results.
The difficult task of getting back to the wire connectors at the back of the engine was accomplished and using the hand held bead blaster, cleaned the connections as good as possible.
That seemed to help quite a bit. I guess I should get back there and do some more cleaning then see if it would act as it should. Being in quite a bit of constant pain, makes this a very difficult task, so, My plan, pull the engine, clean it up, not that it is very dirty as it is relatively clean, then add in a new rear main seal then, climb into the engine compartment and clean and shine every terminal in there.
In the mean time I made up this bracket from an old bent air tank/compressor mount and built a manual waste gate controller according to instructions I found someplace on the innernet, except for instead of taking apart the good vacuum actuator, made My own bracketry.
I works quite well, I think.
Driving on the highway I have it adjusted to around 2 to 3 PSI of boost, according to the pillar gauge. On a heavy pull empty, it will get to around five or six pounds of boost.
Pulling the camper, on a fairly steep hill, it tops at around 8 pounds of boost.
At this setting, about one to one and a half turns of the adjuster nut will take it to ten or more PSI of boost.

here is a pic of the controller unit.
IMG_3277.jpg
 
The most noticeable improvement on a 6.5 is a turbo.
If you know you are sticking with the gm turbo and you want to be mechanical instead of vacuum control, run your current settings. Actually document the details.

Run a tank and track mpg. 0-60 time empty and loaded. Overheating potential loaded. 50-70 acceleration time for freeway passing.

Then give a half turn or so on turbo and do it all again at different settings. Many times results are surprising for people. Different truck to truck by gearing, weight, or drive styles. May take a couple months, but long term you'll be glad you set it up at your peak levels for your usage.

Od coarse,major improvements alter results...
 
The most difficult part is to make sure that geometrically the actuator is the same as the original.

Unfortunately, the code will always be there at different speed, at least it is on mine.
Mine is a 95, though.
 
Will L. said:
The most noticeable improvement on a 6.5 is a turbo.
If you know you are sticking with the gm turbo and you want to be mechanical instead of vacuum control, run your current settings. Actually document the details.

Run a tank and track mpg. 0-60 time empty and loaded. Overheating potential loaded. 50-70 acceleration time for freeway passing.

Then give a half turn or so on turbo and do it all again at different settings. Many times results are surprising for people. Different truck to truck by gearing, weight, or drive styles. May take a couple months, but long term you'll be glad you set it up at your peak levels for your usage.

Od coarse,major improvements alter results...
Click to expand...

I`ll take a run at this.
Current MPGs is right at 15, running empty at 70 mph, cruise control set.
I`ve never documented the acceleration. That`ll be the real fun one to do. LOL

JMJNet said:
The most difficult part is to make sure that geometrically the actuator is the same as the original.

Unfortunately, the code will always be there at different speed, at least it is on mine.
Mine is a 95, though.
Click to expand...
YUP, OBD2 on this one.
It has set the code twice with the manual controller on. After several shut downs and startups, the SES light goes out. I know the code is still stored but at least that pesky light is out. LOL
I was looking into a couple of the vendors websites, Might have been Leroys, I seen the Autoenginuity for the PC, less than 500 bucks. That is another item on My shopping list.
So far, a friend that has a repair shop, He has an OTC Genisys scan tool and lets Me use it whenever I need, or like to. I did check the timing offset, it is right on 2.0. I`m thinking I should do the timing offset relearn then see where it is set at.
Might improve fuel mileage some too.
 
JMJNet said:
The "-" (minus) sign is very important.
Click to expand...
Thank You.
The timing off set and actual timing must be two different things.
the little shop where the guy has the OTC scanner is closed on Saturdays and Sundays. I will get in there first thing on Monday and start looking at the timing and see where it actually is.
The off set was at -2.0, If I remember correctly.
 
If it's at -2.0 I bet it's pretty rattley. The older rigs would get stuck at that offset and be hard to get it to change. -.35 to -.75 is factory specs
 
ak diesel driver said:
If it's at -2.0 I bet it's pretty rattley. The older rigs would get stuck at that offset and be hard to get it to change. -.35 to -.75 is factory specs
Click to expand...
I goofed in My post, it was at -0.2
When I first got it fired up after installing the new timing chain/sprocket set, I went out to he college where there is the auto vo-tech school. Thinking they would surely have a scanner that`d read timing on the diesels. One student there was into the diesels, a farm boy. He hooked the scanner to the truck and messed with it some. No timing for diesels in the tool. A Snap On something or other.
We did the timing self learn procedure and lo and behold, the truck did not start, or maybe fired then died.IIRC
We then pulled the intake and etc enough to get to the pumps bolts, rotated the pump, top towards the brake booster, tightened it down then fired it up. It run pretty crappy for a while but then came out of that.
I will get back out to the shop on Monday morning and get this timing set where it really should be.
After doing the rebuild and cleaning of the battery cables at the starter, it cranks over faster than it ever has and fires up immediately. It does rattle just a little at first but then in a half a minute or so it sort of quiets down.
After that student and I were finished with My truck, He said that when He got back to the farm He was going to hook His Gensys scanner to some of their trucks and mess with them too, He had never hooked a scanner to a diesel before, Opened a whole new world to Him. LOL
 
Here is a pic of the wrench that I made for the left side injector bolt.
From an old S wrench, another never used wrench then the handle was one of those multi wrench things from a bucket of wrenches picked up from an auction sale. LOL
IMG_3280.jpg
 
PO236, 237, 238 and P1656 are the ones that should be tuned out and properly re-mapped in the PCM for a mechanical wastegate setup. The boost curve is dynamic per RPM and fuel rate in a stock tune and you should expect to trigger the codes and experience de-fuel even if you have your spring backed down enough to see "expected" boost levels at cruise speeds.
 
quadstar87 said:
PO236, 237, 238 and P1656 are the ones that should be tuned out and properly re-mapped in the PCM for a mechanical wastegate setup. The boost curve is dynamic per RPM and fuel rate in a stock tune and you should expect to trigger the codes and experience de-fuel even if you have your spring backed down enough to see "expected" boost levels at cruise speeds.
Click to expand...
YUP, it does set the P0236 code from time to time.
I will be working on the cleaning of the connectors at the back of the engine and looking for more connectors between the PCM and te boost sensor.
It did seem to help some when I cleaned on the connectors at the back of the engine a while back.
I got the OTC scan tool, got it set up and took some pics; I`ll start a new thread on the findings and You guys recommendations.
 
You must log in or register to reply here.
Back
Top