I own a 1992 Chevy S-10 Blazer 4x4 with 4.3L Vortec, auto trans. My once faithful truck first started running rough, then stall, wouldn't start for an hour. Changed fuel filter-it drove 15 miles fine, then run rough, then stall.Hour later it starts, runs about 4 miles to home and dies. I put on many parts recently including dist cap/rotor, plugs/wires, fuel filter, air filter, checked all vac hoses and computer codes. I am getting full voltage to starter, full power to all plugs, and just did a fuel pressure test which checked out 100%- so I know my fuel pump is working, my ignition is working too. The fuel pressure regulator is underneath the intake manifold and have no way of testing it.Could this cause it to not run? Also, a manual said that if the low oil pressure switch is defective it won't start-is this true?Why isn't the computer giving up an error code?The computer checks out also-WHAT COULD IT BE!??
2007-08-01 16:10:52 · 8 answers · asked by bryan s 1 in Cars & Transportation ➔ Maintenance & Repairs
ok first check your oil, if there is fuel in it you need to remove the manifold and replace the fuel " spider " yes it could cause this problem......
the oil pressure switch is a safety feature that GM uses, when you turn the key the fuel pump turns on for 2 seconds and then shuts off until it sees oil pressure....easy test, install fuel pressure gauge and test when running for several minutes. if it stays fine then leave it on shut the vehicle off and see if it bleeds off, this could show an answer to my first statement
none of these items you mentioned are computor controlled so they wont send a code....hope this helps
2007-08-01 16:18:12 · answer #1 · answered by Christian 7 · 1⤊ 0⤋
To answer the question of the oil pressure sender, it could cause it to stall, but it would not cause the rough running. If the fuel pressure checked out ok, then the regulator is good. Did you check it with a pressure gage? The problem here is that not all problems get detected by the OBD. FOr one, if the computer itself has failed, it may not report a code, even if there is a problem. If you haven't looked at the fuel pressure while the engine is running rough, do that. It can tell you that maybe pressure intitially may be ok, but suddenly drop off at some point. GMs are known for fuel pumps that act very intermittent that way.
If all of that checks out ok, there is something else which may occurr that won't set a code. The mass airflow sensor measures the amout of air into the intake. If there is a downsream leak. In otherwords, a leak between the sensor and the throttle body, there is more air getting into the engine than is being measured and that can cause problems and may not set a code.
There is yet another problem that may cause this is power to the computer. Make sure that all (and I mean all) power and ground are good to the computer. When you check ground make sure that resistance is less than 2 ohms to chassis ground. If all of that is good it may in fact be the computer itself.
2007-08-01 16:40:41 · answer #2 · answered by adrianne M 4 · 0⤊ 0⤋
Whenever there's an onboard computer, there's no way you can know for sure without taking the car to the guy with the diagnostic equipment.
I have friend who has kniption fits because his car always starts to falter and miss when the "check engine" light comes on. All it ever needs is an oil change, but the computer tells the engine to start missing so the owner will take the car in to the dealer to spend money.
My solution is to drive a 41 year old car. I never have complicated problems. When my car runs bad, it's going to be fried points, a vacuum hose that fell off, a bad advance bellows or some other problem that's easily diagnosed.
Good luck.
2007-08-01 16:32:57 · answer #3 · answered by Anonymous · 1⤊ 0⤋
some of the answers are possible but i have had more EGR valves stick that causes what you described it hangs up when hot usuall from excessive carbon then as it cools(metal expands when hot and contracts when cool)it closed then the car works fine till it gets to normal temps again just did 1 today same problem and have seen 5 in the last month (i live in a small town so 5 is a lot)
2007-08-01 17:29:35 · answer #4 · answered by thefixer0508 2 · 0⤊ 0⤋
Was there a check engine light when it was running? Check out automotiveforums.com and register. They can help and it is vehicle specific unlike other forums. It does sound like an injector problem to me. Check out the wiring going to them first. From the sound of your problem, I doubt it will be the oil sensor... Good luck...
2007-08-01 16:20:42 · answer #5 · answered by Anonymous · 0⤊ 0⤋
get rid of serpentine belt get rid of distributor cap and plug wires. take be conscious to which way the distributor rotor is pointing, then get rid of the distributor. place rag in hollow to evade something from falling in. Drain coolant down, a minimum of to a level under the intake manifold. Leaving AC compressor lines linked, get rid of compressor from block and tie up out of ways maximum suitable you will get rid of better radiator hose get rid of intake plumbing from throttle physique. Unplug all wiring linked the throttle physique. Disconnect throttle cable and cruise administration cable besides. You did no longer point out in case you have been doing the decrease intake manifold gasket, or the better gasket. The Vortec motor additionally has an larger plastic manifold that bolts to the genuine of the metallic intake... Unbolt the intake manifold and get rid of with the help of lifting on the instant up. do no longer slide forward or backward. place rags/plugs in each and every intake port on the heads to maintain any debris from shifting into the motor. sparkling mating floor on the heads of any gasket cloth and wipe sparkling. Do same on intake manifold. setting up is opposite of removal. Take specific care to torque the intake manifold to the right torque in the right series. i'm constructive there are some small stuff that i'm forgetting. i've got not carried out certainly one of those for approximately 6 years... this would properly be a well timed technique and while you're having any doubts, take it to the keep!
2016-11-10 23:38:01 · answer #6 · answered by ? 4 · 0⤊ 0⤋
Two most common fuel-related blazer problems: fuel pump and "octapuss" CPI/injectors. Need to read integrator learn value from the ECU - should be 128.
2007-08-01 16:15:00 · answer #7 · answered by Anonymous · 0⤊ 0⤋
drain your fuel tank
cant be your fuel reg. if your pressure is good
i dont think an oil pressure sw. is going to keep it from running buy a ford next time good luck
2007-08-01 16:21:53 · answer #8 · answered by fordman022480 3 · 0⤊ 0⤋