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Setting tps on 93 6.5 diesel

Turn the key on, don't start the engine.
With a voltmeter, check the voltage across the dark blue and black
wires of the TPS.
It should be .5 to .75 volt at idle and 4.2 to 4.5 volts at full throttle.
If the readings are off loosen the screws and adjust the TPS until you get
it in range.
If it will not set in those ranges you may need a new one.
 
I just completed the top-end of the engine,it was down a cylinder and tps got bumped,just drove it and overdrive was dumping black smoke and on return trip it wasn't catching OD...fixing to put the meter on it now.
 
Any codes? Always check before assuming and further messing things up. Regardless you get to adjust the idle, cold idle, and TPS every 6 months by the book. Most of the time it's just verifying the idle speed is correct and cold advance is working.

Black smoke? Is this stock and a turbo engine? It should not smoke ever stock with a turbo. Timing, stuck wastegate, boost leak, or exhaust leak come to mind.
 
The vacuum holds the Wastegate closed. This is why you have black smoke ... no turbo boost when you need it. A few ways to fix it including a turbomaster and boost gauge. Better turbo's out there now.

Why did you swap turbo's? What do you use the truck for?
 
I changed because they had a whole lot of bandaids on this truck,wastegate on oem was sealed shut due to heat and carbon buildup,mech actuator seized,and the new one I can't figure which way is closed. Hanging down or tied up, same results after running temp reached or 10-12 miles of driving. Some low grumbling/vibration under hood that goes away when foot off pedal,no lock on converter,free rolling to stops.
 
What Chris said is correct about the limits on the TPS . But , and there is always a but , there needs to be a linear transition from the low value to the higher reading . You should see a constant increase in the voltage reading , with no dips or dropouts , when pushing slowly on the gas pedal . This can be seen on a scanner or a DVOM but you can not have any opens or drops in the voltage .
It would help if you list the truck you are working on .
 
Well, it's a 93 c3500 silverado dually with 230k miles I bought for 3k$ 6 months ago,for five months she ran like a champ,would spin tires on gravel with tractor and bush hog on it...that was with failed turbo,2" of head gasket blown out in front of driver and a bad fan clutch and leaky 4core aluminum racing rad..replaced tps before doing complete top-end, Heath diesel cooling upgrade...temp remains as advertised but she's catching overdrive at 40mph and loading up(if it catches)and freewheeling when pedal released. I've dealt with same issues in past but all were different issues causing same affect.
 
6.5headache said:
freewheeling when pedal released
Click to expand...

Normal. Unlike other transmissions or newer rigs that try and keep the throttle "on" and push you through a stop sign... This engine will cut fuel when you do. The transmission then freewheels with an unlocked converter and you watch a good RPM drop. Again "Normal".

Do you know if the fuel was turned up?

IMO you need a boost gauge to know what the turbo is doing. Over 14PSI on the GMx krap turbo(s) you are heating the air more than adding more mass. Anything over 2200RPM the GMx turbo is a restriction as well. The wastegate needs to be wired shut, but, that's risking too much overheated boost and another head gasket... You need a turbomaster or a better turbo for towing. 1993 was set for 6 psi of boost and later years with the vac system went higher. 14PSI is the redline of the GMx turbo's.

Have you checked the air filter?

Some turbo parts...

 
With the smoke you say you get, what do you know about the IP & injectors, and timing ?

Look at the line marks on the top of the IP & cover, are they lined up? might play with minor moving of the IP, moving the line towards the ds is advancing the timing, you can also push the advance leaver in at idle and you should hear slightly more rattle, if the timing is too far either way it will smoke more, advanced will give more rattle all the time, a happy medium is tough to find to a untrained ear...
 
Your boost psi is mainly governed by how much fuel the IP is throwing at the motor, yes the gate will release psi but if the IP is not putting out enough fuel the heat is not going to be their to see higher boost psi...
 
WarWagon said:
Normal. Unlike other transmissions or newer rigs that try and keep the throttle "on" and push you through a stop sign... This engine will cut fuel when you do. The transmission then freewheels with an unlocked converter and you watch a good RPM drop. Again "Normal".

Do you know if the fuel was turned up?

IMO you need a boost gauge to know what the turbo is doing. Over 14PSI on the GMx krap turbo(s) you are heating the air more than adding more mass. Anything over 2200RPM the GMx turbo is a restriction as well. The wastegate needs to be wired shut, but, that's risking too much overheated boost and another head gasket... You need a turbomaster or a better turbo for towing. 1993 was set for 6 psi of boost and later years with the vac system went higher. 14PSI is the redline of the GMx turbo's.

Have you checked the air filter?

Some turbo parts...

Click to expand...
Please explain GMx,the truck came with a GM1 turbo, I got a GM4 to put on it...as I said,this truck "hauled ass" with tractor and bush hog on it,with a blown gasket,sized turbo and the entire boot gone around the wire that reads water in fuel...now complete top end new,new rad,hayden fan clutch,9 blade duramax fan and 137 gpm water pump. However, I think I may have found my issue,never heard or felt till yesterday,but mid-shaft support bearing has roughly inch and a half of wobble play.
 
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