89 4.3L problem

[blazerguy89]

ok, i have a 89 blazer with a 4.3L and the other day i went out to start it and it fired one then died. since then i have had it running a few times after pumpin the hell out of the throttle and took it to the store and it cut off on me and i couldnt get it to fire back up.when i finally got it running i started down the road and it cut off on me and i had to pump the gas again to get it running. i got it home now it wont start at all. if i pump the throttle it will try to start but wont stay running. it has good fire and i had my gf to spinit over while i watch the injectors and its sprayin fuel like hell in the TB. where is the best place to do a fuel pressure test? i dont know if these throttle bodys have a schrader valve or not. can someone help me?

[blazerguy89]

anybody?

[Solid10]

does it blow black smoke when it finally starts?

from what i've collected you're getting fuel, how about your spark?
If the spark isn't strong enough the fuel will just put it out

[Bill Wheats]

No they don't come stock with a schrader valve.
Three tests:
Turn the key to run and listen for the pump to prime for about 3 seconds.
Spray some starter fluid into the intake and see if it will start.
Check for spark

[Yogi]

When you say "it has good fire" what do you mean? How do you know this?

[Bill Wheats]

Where there is smoke, there is fire!

[blazerguy89]

no it dont blow black smoke when it finally starts, since i drove it to the store and it cut off on me i havent been able to get it started yet. it will blow a bit of blue smoke which is oil. i know it burns a little oil. and im pretty sure it has good spark as i tested it with a spark tester if anybody knows what that is?i pulled each plug out one by one and checked them and all looked good except cylinder #2 which had oil on it, so i know #2 has some oil bypass but the rest looked good other than a little bit of carbon on them, so i just cleaned them with a wire brush and one of them spark plug cleaners that run off air and put them back in. i can hear the fuel pump prime when i turn the switch on.

[blazerguy89]

ok, i just went out side to try the starting fluid deal and it still did not start so now im thinking its a spark problem. i can smell fuel when i try to crank it so i know its getting plenty of fuel.

[Yogi]

Since you have good spark, and you can see the injectors spraying fuel, it "should" start. You need to check the timing. It may have a bad dizzy gear or a bad timing chain.

[blazerguy89]

im going to check the spark again cause i think the sparks not hot enough. cause it runs fine if i can get it running. its throwing a code 24 and 44

[Yogi]

Quote: Originally Posted by blazerguy89

im going to check the spark again cause i think the sparks not hot enough. cause it runs fine if i can get it running. its throwing a code 24 and 44

All of the Diagnostic Trouble Code Info is in the "Performance & How-To Infos" sticky at the top of the 4.3L section. Code #24 says:

"24 - Vehicle Speed sensor circuit - Vehicle speed sensor signal showed less than 3 MPH for 2 seconds when engine speed was greater than 3000 RPM and transmission has not been in park or neutral for more than 4 seconds. Or vehicle speed goes from above 18 MPH to 0 in less than 2 seconds without applying brake."

Code 44 says:
"44 - Oxygen sensor or circuit – lean exhaust detected. - Oxygen sensor voltage was under 0.25 volts for up to 4 1/2 minutes of closed loop operation."

I would check all of the ground cables for good contact. The lean exhaust may indicate a weak fuel pump.

[blazerguy89]

thanks ill check that tomarrow, and let yall know what i find.

[Bill Wheats]

I think a bad pickup coil in the dizzy can cause those codes. Also, the pickup coil more often than not will be good but the leads going to them tend to get worn and cause intermitent no spark condition until they finally break.
You will need a Volt/Ohm meter and a helper to test them. Do a google search.
That's the first thing that I would suspect. Also a bad connection to the coil or ign module.
Good luck

[blazerguy89]

appreciate ur help bill, i will def. check them i have not been able to get into electircal checks yet as it has been raining here but no need to google as i know how to do these checks. as soon as the rain stops i will get to testing. thanks for the help and i will post when i figure something out.

[Bill Wheats]

If it was wet out when the engine was dying then replace the cap and rotor.
If it still won't start then start running some tests.
Good luck.

[blazerguy89]

ok so i tested all ignition componets and everythings good. if i let it set over night then try to start it then it will fire for about 5 seconds and die and i cant get it started after that so im going to replace the fuel pump tomarrow and see if that fixes it cause all the ignition components are testing out good. i did a ohms test on the coil and ignition module and checked out the ignition coil pickup, tested good. every time i check it out it seems to be leading right back to a fuel delivery problem. there has been a lot of parts replaced on this truck before i bought it about 3 weeks ago so it seems as if someone might have been chasing the same problem. i also figure that after studying up on the vehicle speed sensor that the sensor is bad and that is what is causing it to bog down at highway speeds, and when it does this the ses light comes on so i got a speed sensor out of a parts blazer that i know runs good just the body was eat all to crap so the guy gave me a few parts.

[Bill Wheats]

Quote: Originally Posted by blazerguy89

ok so i tested all ignition componets and everythings good. if i let it set over night then try to start it then it will fire for about 5 seconds and die and i cant get it started after that so im going to replace the fuel pump tomarrow...

Are you saying that the battery dies after 5 sec?
or the spark dies after 5 sec?
or the injector spray dies after 5 sec?
When you say it fires, that would mean to most that the plugs are firing.

If you lose spark after 5 sec then replacing the pump isn't going to do anything but give you a diferent pump.
To test the pump, find the test wire on the pass firewall and feed it +12 fused voltage and see if the pump runs.

Spray some starter fluid into the intake and try to start it.

If you are getting intermittent spark issues, I look torwards the pickup coil in the dizzy and test it. The wires can brake internally after long use-common problem. Test with a volt/ohm meter when the engine won't start.

Or just keep replacing parts...

[blazerguy89]

no i mena the whole engine dies after 5 seconds.its not spark because after it done this last night i pulled each plug back out and checked the fired and all good. fuel pump pressure is 8psi i think.

[Bill Wheats]

Could be your oil pressure switch. It feeds +12 voltls to the pump when the engine is running.
Find you Fuel pump test lead. It's usually on the pass side firewall but might be need the break boster. Give it +12volts fused power then start the engine.

Good luck.

[lesterl]

could be some bad gas, have someone crank it and while they are doing that spray some carb cleaner into the TB, also have you checked the map sensor?

[blazerguy89]

well guys i believe i have overlooked one of the most simple things i could have done. i put a set of plugs in it today and put a spark plug non fouler on cylinder #2 and it fired right up, i know i said i checked this and all checked good but i also wasnt the one looking at the plugs i was just turning it over so never hurts to check things more than once!!! come to find out the plug in cylinder #2 was a dead plug. on cold startups i still have to hold the pedal to the floor while starting it and it will fire up. it still idles a little ruff and i hear a vaccum hose leaking somewheres but havent found it yet. i took it up and down the road 2 or 3 times and it seems to have alot more pickup than before but dont know if im out of the woods yet. just going to drive it around a few days and if it does this again then i will have to test further. i do believe that the #2 cylinder plug being dead was causing it not to start. i have noticed my oil pressure gauge has been showing a little lower but dont know if this is normal or if it started when all this happend. i will let you guys know how it does in the next few days and i really appreciate everyones help, yall have been really helpful. thanks everyone!!!

[Bill Wheats]

The most common vac leak on the 89's is having a stuck egr plunger. Small balls of carbon from the exhust port find their way to the plunger/intake manifold seat and cuse the plunger to be held open.

Some times rapping the EGR with a socket wrench or a large screwdrived while the engine is running will change the leak temporarily. Or you can disconnect the vac line to it, add another vac line and suck in then blow into it to force it to close. You should hear a pop noise then no more leak.

My advice would be to pull it, Clean it with a garden hose. Spray a bunch of carb cleanner into the exhust port, let it sit for a while then run the engine for ~15 seconds to blow all that crap out. Then reinstall the EGR.
Do a search on cleannig egr's here.

Good luck

[blazerguy89]

well guys the truck kept cuttin off on me randomly and kept fouling the plugs out so i took off the throttle body and found out that the fuel pressure regulator valve was done for so i replaced it and it runs like a champ now. thanks for everybodys help!!!!

[Yogi]

Nice work! Congrats!!

[Solid10]

[blazerguy89]