Power Problem

[bobt]

Hi, This question is regarding my son's '98 6.5TD with auto. He just recently bought this vehicle and is occasionally experiencing a loss of power, especially when pulling a trailer. He says it sounds like the turbo is kicking in and out and he loses power. He put a code reader on it and got a fault code P0236 which is supposedly a "Turbo Super Boost Sensor A" problem. Also gets "CKT range/performance." Anyone out there know what this means and what the fix is?? Thanks,
Bob

[Patrick m.]

First thing to do is replace the filters. This is more important for you, as this vehicle is new to you and you may not know the service history.
The next thing is check the wastegate control system, it consists of some plastic vac tubeing that is prone to cracking.
Also, since he is towing with the truck, get some guages so engine monitoring is possible. The most improtant are boost guage, and EGT guage. (pyrometer)

[bobt]

Thanks. Good suggestions. Filters were replaced. He will do gauges soon. Still need to know what causes P0236 and what the fix is.
Bob

[Plowboy81]

Well P0236, nothing else, that code means that Turbocharger Boost Sensor A is going bad. I went through my shop manual for that code and it indicates it is the boost sensor on the upper intake. Ant hard to find it if you look right on top of the upper intake, it looks just like a MAP sensor and is bolted to top of the intake with two bolts, it has a wiring harness with three wires on it, right next to the air temp sensor that screws in. Watch and make sure you dont loose the little orange or pink, cant remember what color, rubber gasket on the bottom tube the pushing into the intake. Helps when you go to push it back in to put a little vasalin on that rubber gasket to help it go in. Replace the boost sensor on the top of the intake and that will fix the problem, no more code. You can scan the diagnostic procedure if you want. A warning on the boost sensor, if you can get it at a parts store, don't buy it from GM. They may be able to get it for you alittle cheaper at the parts store, take the old one with you, I know they can get the Map sensor on the firewall but there not the same the plugs want match. So make sure you watch that or back to the store. As far as the gauges go watch were you mount the connectors that go to the motor you may get a wrong reading if not in the right place. For pulling I recommend a B&D chip.

[Patrick m.]

i worked GM dealers for 15 years and i cant recall seeing 2 failed map sensors, though i hear of them very frequently.

[DennisG01]

Does he get black smoke when he loses power? From my experience with that code, I'd lean towards a cracked vac line or bad wastegate solenoid. The solenoids don't have a tremendous life expectency (there's a little check valve inside it that corrodes), but on the plus side, they're only about $30 and it takes all of 2 minutes to change out.

Before you buy anything, try this first:

Spray some WD-40 into the vac line that's on top of the wastegate while the engine is running. Do this every day or two for a week or so. If it's the solenoid that's bad, it may help free it up. By the way, this is good preventitive maintenance for the future.

[Robyn]

Grab up a little hand held vacuum gauge and check the vacuum at the vacuum pump (Front RH side of the engine. (belt driven) should have 26" and steady. If the gauge is wobbling or low toss the pump and replace it.
(Most parts stores have these)

If vacuum is good at the pump check the vacuum at the solenoid (LH Valve cover near the back (Little gizmo about half the size of a ciggy butt pack with plastic lines going to it)

Sould have fiull vacuum here. Now if this is good check the vacuum at the waste gate actuator on the turbo itself.

The vacuum here may be lower but if real low then the solenoid is probably the culprit.
These little creatures are a common problem (Not chronic but they do fail)

Make sure when the rig is shut off that the rod on the wategate will move back and forth freely.

The plastic lines are also a common source of issues. You can use simple rubber vacuum line and just be sure its run so it does not contact hot or sharp stuff. ( Been there done that) The plastic lines are available through Ma General only and look nice but are not real durable.

Also make sure the connections are good on the solenoid electical plug too.
These are a good connector and unless thay have been molested they are usually trouble free.

Ma General is the place for a fresh solenoid. I have not found any in the aftermarket yet

You can also step up and install a unit called a turbo master and with this you would want to install an aftermarket performance ECM.
Now this would be part of an upgrade with big exhaust, gauges and other goodies.

The simple fix will be to fix the issue with the boost system.
Now there is also the possibility that if you find everything seemingly in order that the Boost sensor has issues. (Little sensor on top of the air plenum There are two, the boost sensor is black and sort of a rectangle shape the other is intake air temp sensor the sensor on the firewall is the atmospheric pressure sensor)

Now just a thought, is this a 1500 or a 2500 series??? a 1500 series truck has some other sensors.



Good luck and let us know

Robyn