1992 Chevy blazer S-10 4 door
4.3 Vortec
212,000 miles
Push button 4x4
A/C
Automatic

Worked on lots of cars , but this one has me stumpted :

problem one :

Hot/cold engine ALWAYS starts on a dime . Runs great when cold . Everything fuctions normally . When it starts to warm up ( idling in drive way ) , it instantly dies . No stumbling or anything , acts like some one turned off the key . Starts right back up , and will run for a bit and then poof , it shuts off .
When driving , it runs normally when cold . When it warms up , it starts acting like a troubled child on crack ! It will drive normally for a few minutes , then it will completely loose all power , then it will kick back in , then out , then in , and after a bit of this it will drive normally . Then it starts cutting out again . Its not sputtering , its like some one is clicking the key on and off . I just bought this thing because the previouse owner could not find the ptoblem . Its a problem that is not consistant . One day its fine , and the next 3 days it acts up .


Here is what I have ruled out as possible causes :

Intake manifold gasket leaking water into cylenders
Distributor cap / rotor / carbon tracking
Fuel filter
Injector cleaner used
Air filter
Vacuum hose leaks
Loose coil to dist. cap wire
New fuel added to tank

Tried to set the timing , but I couldnt find the timing bypass wire . Every website and book says its some where else , and they are all wrong ???


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Problem 2 :


Transfer case wont go into 4H . It will do 4L and 2H . Its not the plunger thing under the battery , its not vacuum lines , its not the switch , etc . I know that its the TCCM or the Encoder motor on the trasnfer case . When I puch the button , the TCCM clicks , and the Encoder motor makes ..... well , encoder motor noises . When I try to go into 4H , the drive shaft coming out of the transfer case just wont lock up , free spins by hand ......... Oh , and the switch always does one of 3 things : No lights , both lights on , or both lights blinking . How do I tell if its the Encoder motor or the TCCM . I have read that taking the Encoder motor out can cause big problems if you try to test it outside the vehicle . True ? Can the Encoder motor itself be repaired by me , or is it not servicable ?

Thanks for the imput people .

 

I don't know about the 1st problem, but as for problem 2. Chances are it is the encoder motor because if it is bad, the computer (TCCM) can't tell what position the case is in, so it just goes to the extremes (4L and 2H). As for repairing it, I'm pretty sure your best bet is to just replace it

 

I think your right , probably the encoder motor . Sure wish this thing had a manual shift lincage for the transfer case . Not just because its more reliable , but for the same reason I like manual transmissions compared to autos .

Any one know what one of these encoder motors is worth ? I was thinking under $100 , used from a junk yard .

 

i think your first problem is either 2 things, 1 gas, 2 .bad ground.
ive had a similar problem to this in a ford ranger, it was a beater, but i did litteraly everything possible i could do to fix this but. change the fuel pump. i swapped injectors, i swapped the whole motor, everything. i sold it cause it did that exact same thing, buddy took the line hooked it to a v6 malibu fuelpump in a gallon bucket. truck ran perfect. still on the road today actually. i was pissed. that could very well be the issue in your case,. or
it could be the ground on the motor. i have had similar issues with a 305 that was carbd, it didnt completly shut down. it still ran but had no power. ended up being the motor ground connection on the frame rusted free. i dont even know why it ran... that very well could be your issue
i would deffinaly say its either gas or ground. is your oil milky?

 

Oil is clear , no blown head gasket . I think your right , probably an electrical issue . I will take a look at the gounds .

Cant figure out why it only acts up when the engine is warm ....

 

make sure you check not just the ground on the frame but on the motor. that could be it. also i know it sucks, but fuel pump wires could be bad too... dropin the tank in em aint much fun, but it could be the issue

what ive been thinking is. im sold on the ground being bad to be honest. but i think that its fine when its cold cause the metal is conducting fine. but as soon as theres heat in the block, it makes a possible gap, which makes the truck cut out. i know its a long stretch, but stupid stuff happends.

 

Well , I got bored and decided to go tinker with the Blazer again . Here is what I tried :

Replaced :

Coil
Dist Cap
Air Filter
Fuel Filter
Engine oil
Oil filter
Spark Plug Wires
Rotor
Spark plugs
Engine & Body Ground Wires
Fresh Premium Unleded fuel
Fuel Relay
Intake Temp sensor
Manifold pressure sensor / map sensor
Air Idle motor
Throttle position sensor
And a few other gizmos that im not sure what were .

Its running really good now , but im not sure if the " cutting out " problem is solved , because it so random . It will take a day or two of driving it to see if the problem is solved .


No I didnt buy all those parts from Napa . I found a guy that is parting out an S-10 , so I bought all the parts listed above ( Plus alot more parts ) for $60 . All the filters and tune up parts were brand new ! He had the maual lincage to the transfer case though :-(

As far as the 4x4 is concerned , I removed the electrical connection to the encoder motor , and cleaned the connections , then I banged the encoder motor with a wrench . Still wont go into 4H .

 

holy cow, that was all out and overboard! sounds to me, like theres no reason for anything to go wrong now! best thing todo is take er for a big ol tour, and see what happends. the only thing left i can think of it the fuelpump.
what were the old grounds like from frame to motor?
and what year was the parts truck? shud have bought the whole transfercase and parts for the dash, and just converted it over to manual shift rather then electric.

 

Thought about buy'n the whole parts truck , but he wanted $650 for it . I only have $100 into mine , well $160 after the used parts I bought from him . The ground wires looked ok'ish visually , but I didn't mess with them - Just made additional ones in alternate locations .

Oh , and his truck was a '93 , BASIC truck - no options at all , manual everything (except trans) / no A/C .

 

Well , I drove the Blazer 125 miles today . About 50 miles freeway , and 50 miles back roads , and 25 miles of stop and go traffic in the city . I cant say with 100% certanty , But I think its fixed . It was probably the ground wires as suggested . I wish I could say for sure , but I changed so many things its hard to say . Of course it will probably start acting up tomorrow . I will let ya know .