Hey everyone, my blazer has recently decided to start going haywire on me and i would like to fix the problems myself. I had a leak in the water pump and just finished replacing it, although the temp gauge did not show engine overheating. However, now the speedometer and odometer are not working, Also, the car runs well when first started, however, after about 10 mins of driving, while at a stop or coming to a stop i notice the oil gauge drops and the car stalls out, it does restart right away. Also, when making sharp left turns the engine cuts out momentarily sometimes causing the car to stall. Please help. I am a noob at this so i will do my best with the lingo.

1991 S10 Blazer
4x4
4.3L
135000 miles

i've changed the water pump and the distributor within the last year.
thanks for all your help...

 

You are probably looking at a fuel problem seeing as you didnt mention any trouble lights common with electrical faults.

The speedo is a cable that runs from the gauge cluster to the transmission output end. Try having a look to see it its come off the transmission side or something. Its a tube cable with a thing that spins in the center of it, the whole legnth of it. They do break.

 

Thanks ohsofly, i'm currently working on cleaning the iac valve to see if this helps with the stalling. is there anyway to check the map sensor to see if its faulty or needs to be changed?

 

I dont think its cable driven,at least both my 91's were electric.



For the stalling. Gm built in a safety feature that when oil pressure drops to low it cuts power to the fuel pump. That could be why when it drop oil pressure it dies. You need to check your oil sending unit (back of motor,on right side of distributor). if its good then you need to remove it,and install a mechanical gauge and really see if your running low oil pressure. these motors only need i think 6 psi for every 1k rpm. Both of my tbi's ran around 12-15 psi at idle. my vortec runs around 35 idle.

 

There's a way to check the MAP sensor. Take it off the manifold. Put a vacuum pump on the nipple of the MAP sensor. Back probe the sensor with a voltmeter. Turn the key on but don't start the truck. Pump some air out of the vacuum pump. I believe that for every ten inches of vacuum you pull the voltage output of the sensor should change by one volt. You can get a more precise version of the procedure by searching this forum and/or the wider Internet at large.

 

in for updates, ive got this same problem with idle/stall, runs fine when u first start it but when i get to running temp it will stall, spit, hesitate and wont restart for a bit. how do these spiders act do they just go bad or can the start to go bad ?

 

auto, so far i cleaned my throttle body and carb to the point of which they look brand new, and put a new IAC valve in as I found the old one was faulty, after I clean the crap outta it too. The car definitely runs more smoothly however, it still spits and stalls due to high idle. This isn't the best idea but because I don't have another mode of transportation I've been driving it like a manual, putting it into neutral when slowing/stopping/at a stop and then popping it back into drive when picking up speed again. My next project is to swap out the MAP sensor, as I gather this (along with a dirty IAC, carb, and throttle body) can cause the spitting and stalling due to the high idle. I'll be back in a coupla days as $ is a little tight so I don't have the fundage to purchase a new MAP sensor even though its fairly cheap ($30).
-matt

 

Sounds like a vacumm leak if its idling high and spuddering. Get a can of ether and while its running spray it around and listen for the engine to change idle,if it does you have a leak in that area. Dont spray it in the throttle body or it'll change regardless.

Also remove your egr and clean it(spray brake cleaner through it,get all the carbon cleaned out etc) and reinstall it and make sure its working. My 92's egr was spuddering etc in gear when it was stuck open by a chunk of carbon.

 

just an update...I changed the MAP sensor and still am having the same problems, so I'm gonna try chris' method of finding a leak in one of the vacuum hoses...Hey chris what is the egr and where can i find it? thanks for all the help.

nm found the egr. gonna clean it tomorrow and will search for vacuum leaks. when i was cleaning the throttle body i removed the ring that surrounds the wiring and part of the gasket peeled off, when i inspected it up close i noticed a tear in it and found that it was allowing air into the throttle body. could this be causing the same symptoms as a vacuum leak? and if so am i able to just purchase a new gasket?

 

"removed the ring around the wire"

Im trying to think of what your talking about..you talking about the little rubber washer thing thats around the wire that runs to the injectors? if your talking about that,or the round gasket that the air cleaner can sits on,that wouldnt cause the rough idling. The only thing that would cause rough idling is either the gasket the throttle body sits on,or the iac gasket. Which also reminds me. Take off the Idle control valve and clean it. its the round thing on the passenger side of the throttle body. it screws out,remove,clean,reinstall.

pic of iac
http://carphotos.cardomain.com/ride_...090_medium.jpg

You do have the tbi right? or is yours the vortec with the big pretty orange vortec symbol on top of the engine? I think they started around 92,not sure.