89 s10 blazer shuts off after engine warms up

[Tattoo Prince]

Hi im new to the forum. I have a 1989 chevy s10 blazer 6cly 4.3l rear wheel drive that had been sitting for a while. Got up and driving but shut off going down the road. Added some new parts like starter, batt, plugs/wires, complete distributer, map sensor, tps (throttle position sensor), fuel pump/filter, cleaned trash out of tank/line, ESC (eletric spark control), took out and cleaned injectors/tbi to make sure gas flow (getting 10.5 to 11 psi from pump), took off catalytic converter to make sure not exaust, checked for leak in vacuum lines on tbi. But will crank and idle fine for about 10-15 mins then starts to bogg down and wants to shut off. Mash on gas it will rev up but when let off boggs down and quits. It Cranks back up and will idle for minute or two but shuts off shortly after. When engine hot and try to mash gas it wants to bogg down and have to pump peddle to keep running. Been all through Haynes manuel and feel like hit a brick wall on ideas. If anyone could help lead me into right direction it would be greatly appreciated...thank you for your time.

[Tattoo Prince]

Thank you for the advice, i will definitly check the oil pressure out. Had a fuel pressure guage hooked up on an initial check and was getting around 11psi but didnt leave on to see what would happen. Right now wont stay running long enough to do a test drive but may give me a good reading of the pressure before shuts off.

[Jsdirt]

Sounds like it's running pig rich. Are you getting black smoke out the exhaust when it bogs?

 

If that's the case, make sure the injectors are spraying correctly, and not dribbling a stream of fuel. Make sure the MAP sensor hose isn't leaking or torn - that will also make it run pig rich. The exhaust will burn your eyes.

 

Also be sure the fuel you put in there is fresh, and isn't separating due to ethanol that soaked up too much moisture, or, isn't mixed with something else.

 

Ignition problems will also do this. Remember, just because parts are new doesn't mean they're good - double check everything you've installed. Seen that cause some big time tail-chasing ...

[Tattoo Prince]

Theres no smoke. Replaced vac lines to tbi and map, still seems once hot wants to shut off when press gas, injectors seem to be spraying good. Only thing i notice is the oil pressuessue needle on dash drops off right before shuts off and floats during start up. Emptied tank and put fresh gas in.

[Tattoo Prince]

Gonna go pick up a scan tool to see if reads anything during shut off. Light goes off durining initial start up.

[Tattoo Prince]

Replaced oil pressure sensor and coolant temp sensor with no change. When hooked up tester got 1 blink pause then 2 blinks which book says system pass. Not sure what else can do?

[Jsdirt]

Scan tool won't do you much good on this vintage. I would get a mechanical oil pressure gauge and read the oil pressure directly from the block - you can unscrew the sending unit at the rear of the block, near the distributor, and use that.

 

The dash gauge is notoriously inaccurate, even on the new vehicles. If oil pressure is dropping way off, the fuel pump will cut off. It uses an oil pressure sensor to activate the pump when the engine is cranking, and in the event of a crash and the engine stops, it will cut the pump off for safety.

 

Would be good to know if the engine is on it's way out.

 

 

If that checks out ok, I would hook up a fuel pressure gauge and tape it to the windshield and go for a ride - you need to see what the fuel pressure is doing when it dies. If the fuel pressure drops, you know you've got a pump or wiring problem. If not, you probably have an ignition problem.