Chevy help

[XtrmWakeborder]

Ok, question for the car guys out there. I have a 95 chevy blazer with the 4.3l v6 in it. Everything ran fine today, and when i started it up it ran for a couple seconds and then just turned off and gave me the check engine light. It turns over fine, but doesn't start. Any ideas whats happening?
Thanks,
David

[JAY4SPEED]

My money is on the fuel pump. Could be a bunch of other things but most common we see are fuel pumps. Could also be a bad crank sensor, moisture in under the dist cap (common on those engines). Need your DTC codes to help any further.
Jay

[JAY4SPEED]

Can you hear the fuel pump come on when you first turn on the key? If not, you can crawl under it and give the bottom of the fuel tank a few bumps with your fist right in the middle with the key on. Cycle the key and see if she'll fire. Thats how we get some of the trucks into the shop after they've been towed in the service lot with a bad fuel pump.

[racecar.hotshoe]

also check the fuel filter.

[QuickJet]

PUMP!!! They are known for going out.

[YeLLowBoaT]

Start with the fuel filter( its the cheapest and if you have to replace the pump you will want to change it anyways.) but I would bet money is the fuel pump.

[TCHB]

1. Fuel Pump
Could be the EGR stuck open.

[IMPATIENT 1]

yep, sounds like the pump. they generally go out at the gas pump or during 1st crank of the day. but on the briter side, its a cheap pump and easy to do.get a strainer,new filter and pump kit when you go to the parts store.

[YeLLowBoaT]

still going to have to drop the tank. fwiw I have never heard of a fuel pump going out on a empty tank. :) Atleast in a truck you can just unbolt the 8 bolt or so and lift the bed of the truck up/off.

[IMPATIENT 1]

1. Fuel Pump
Could be the EGR stuck open.
with the egr stuck open, it'll still start and run, just lope real bad from the big vaccuum leak.
shoot some carb cleaner into the throttle body, if it busts off for a second, that tells ya ignition system is ok.95 blazer's don't have crank sensors, it all works thru the dist. reference. if it'll bust off on the carb cleaner, i'd stick a pump in it.

[Daytona100]

Put a fuel psi gauge on it and see where your at.

[3 daytona`s]

Don`t worry about it :)

[IMPATIENT 1]

Put a fuel psi gauge on it and see where your at.
that and put your test lite on the positive post of the battery, unplug the relay and touch the test lite to the gray wire's terminal.if it lites up, the pump is still "in the circuit", if its doesn't lite up, the pump is open and will have to be changed for sure. by touching the gray wire , it looks to see if the pump motors is still ok with no opens in it, when its good the ground circuit will pass thru it ,to your test lite and lite the bulb.easy peasy, helps if ya don't have a fuel pressure gauge.

[XtrmWakeborder]

Thanks guys! ***boat has always been a big help with these things. Tomorrow i'll go back over to my girlfriend's house and get to work. I'll let yah know how it turns out. Would it be a bad idea to unhook the fuel line before the engine and after the fuel filter and crank it over to see if its pumping?

[IMPATIENT 1]

Thanks guys! ***boat has always been a big help with these things. Tomorrow i'll go back over to my girlfriend's house and get to work. I'll let yah know how it turns out. Would it be a bad idea to unhook the fuel line before the engine and after the fuel filter and crank it over to see if its pumping?
nah, if your in a fix, just unscrew the fuel filter alittle and turn the key on. if its a tbi injected 4.3, its takes 14psi to start it on.if its the cpi 4.3(8th digit on vin will be a w if it is) then it runs 40-46 psi.either 4.3 should spray quite a bit out if its working.

[IMPATIENT 1]

fuel filter is a 13/16, the fuel line is 5/8 or 16mm(same thing as a 5/8)

[XtrmWakeborder]

Haha i hope i can fit under there to unscrew it! Stupid lowered cars. Never again. How much is this going to cost me to get it done ballpark? I know my dads was around $300.

[YeLLowBoaT]

3-500.

[IMPATIENT 1]

don't know how much you guys pay for labor rates there.i'm a gm master tech foreman at a dealership here in hugo, our labor rate is 75.00 per labor hr.. diagnosis, labor and parts should be around 300-340 range at our dealership, figure about 2.5-3hrs labor and @110-120 for delco parts.spring for delco parts so they're cover lifetime, parts and labor.you'll never have to pay for another fuel pump on that rig again, and if you keep it awhile without regularly changing the fuel filter, you'll be needin a pump again.

[XtrmWakeborder]

Damn, figures. Well i guess you gotta do what you gotta do right? I'll just check it all out first and then get back to you guys. Thanks again!
David

[IMPATIENT 1]

if ya need any diagnosis help, just pm me, i know those blazer very well.

[XtrmWakeborder]

Will do, thanks again bud.

[73kona455]

check fuel pump... pressure should be 55-62 psi if i remember right

[QuickJet]

check fuel pump... pressure should be 55-62 psi if i remember right
I think thats a bit much. It a 95 so it's not a Vortec engine and I beleive it's just a throttle body deal. Most GM throttle bodie injections(sits on top of intake not in front) take 12 PSI.

[73kona455]

I think thats a bit much. It a 95 so it's not a Vortec engine and I beleive it's just a throttle body deal. Most GM throttle bodie injections(sits on top of intake not in front) take 12 PSI.
oppss.. u are right...couldnt remember which year was the vortec

[JAY4SPEED]

95 blazer's don't have crank sensors, it all works thru the dist. reference.
I know the '95 Blazer is a little before my time and I started with my dealership in '99. But, I seem to remember particularly the Central Port L35 W engine, it does have a crank (CKP) sensor at the standard location in the timing cover below the balancer. You made me go and look to check myself....lol. Check SI Document IDs# 1381587, 1376827, and 35271 for the '95 L35 motor.
I agree with impatient 1, the easiest way to test the for fuel pump operation would be to squirt some throttle body cleaner down the TB and see if it fires off. If that don't get it, check for spark. An engine needs 3 things to run:
1) air/fuel mixture
2) spark
3) compression
Your missing one of the three, air/fuel and spark being the most common. Supply your own fuel by using the TB cleaner, check for proper spark at the dist cap, then check compression last.
My money is still on the fuel pump.
Jay

[Kachina26]

95 blazers with the old cpi motor were notorious for 1, leaking fuel pressure regulator that would keep the pump from builing enough pressure to activate the poppet injectors, you can check this by removing the air snorkel and have someone turn the key to RUN, not start!!! Then open the throttle body and using a mirror and a flashlight, look for a nipple that is dripping on the passenger side of the setup. The easier but less scientific way is to open the throttle and take a sniff, if you smell gas strongly, then that's your problem. the number 2 most common problem, fuel pump not producing enough pressure during cranking to get the truck started. Funny thing is, once you get it running with a little brake clean or what have you, it will stay running. You need a fuel gage to correctly diagnose this. If you can get your hands on one, let me know and we'll go from there. Now, go sniff your manifold.
Now after having said all that, go check for spark first.

[wsuwrhr]

The fuel pump in the GMC Seirra C1500 was a bunch of fun.
Do whatever Kachina26 says.
Brian

[Beer-30]

You should be able to just cycle the key and hear the pump run.
Vortec started in '96, so it would be low-pressure TBI. You should still hear the pump before it cycles off.

[Kachina26]

You should be able to just cycle the key and hear the pump run.
Vortec started in '96, so it would be low-pressure TBI. You should still hear the pump before it cycles off. I don't have time to get into the GM website, but, according to Wikipedia The central-port injected L35 (Vin 'W') debuted in 1992, with better breathing for 200 hp (150 kW). Another CPI engine, the LF6, joined the rest in 1996.
I certainly remember the cpi units on the 94 blazers, I replaced enough of them. I bet I could still do it in 20 minutes. :D That was a nice 3.5 hour ticket :D Sometimes that book works in your favor.

[XtrmWakeborder]

Haha i wish i had the hook up of a gm tech around me! Well final answer was the fuel pump.... At least you guys gave me the heads up so i knew what to expect. Price came out to 160 parts and 369 labor. Kinda sucks, but oh well. :mad:
Thanks again for all the help guys!
David

[IMPATIENT 1]

I know the '95 Blazer is a little before my time and I started with my dealership in '99. But, I seem to remember particularly the Central Port L35 W engine, it does have a crank (CKP) sensor at the standard location in the timing cover below the balancer. You made me go and look to check myself....lol. Check SI Document IDs# 1381587, 1376827, and 35271 for the '95 L35 motor.
I agree with impatient 1, the easiest way to test the for fuel pump operation would be to squirt some throttle body cleaner down the TB and see if it fires off. If that don't get it, check for spark. An engine needs 3 things to run:
1) air/fuel mixture
2) spark
3) compression
Your missing one of the three, air/fuel and spark being the most common. Supply your own fuel by using the TB cleaner, check for proper spark at the dist cap, then check compression last.
My money is still on the fuel pump.
Jay
no 95 blazer's had crank sensors, they did start havin them in 96 thought in the true cpi motor, remember the 95 only had 1 injector with 6 poppets.the 96 had an injector controlin each poppet.
injector reference comes from the dist. on all 4.3liters from 88-95, then from 96 up they had crank sensors, check it out, i'm rite :p

[IMPATIENT 1]

95 blazers with the old cpi motor were notorious for 1, leaking fuel pressure regulator that would keep the pump from builing enough pressure to activate the poppet injectors, you can check this by removing the air snorkel and have someone turn the key to RUN, not start!!! Then open the throttle body and using a mirror and a flashlight, look for a nipple that is dripping on the passenger side of the setup. The easier but less scientific way is to open the throttle and take a sniff, if you smell gas strongly, then that's your problem. the number 2 most common problem, fuel pump not producing enough pressure during cranking to get the truck started. Funny thing is, once you get it running with a little brake clean or what have you, it will stay running. You need a fuel gage to correctly diagnose this. If you can get your hands on one, let me know and we'll go from there. Now, go sniff your manifold.
Now after having said all that, go check for spark first.
yep, i've done alot of the regulators and the hard plastic lines goin to the cpi unit. i've got a bore-o-scope and i pull out the tuneing valve and just look in at it, i don't even bother with the guage if i think somethings leaking internally.

[CHEETAH24]

no 95 blazer's had crank sensors, they did start havin them in 96 thought in the true cpi motor, remember the 95 only had 1 injector with 6 poppets.the 96 had an injector controlin each poppet.
injector reference comes from the dist. on all 4.3liters from 88-95, then from 96 up they had crank sensors, check it out, i'm rite :p
Wrong...95 s10 blazer had a crank senor, but only if it is a vortec. Part number is a 12596851.
now go to your parts dept and see..

[Kachina26]

yep, i've done alot of the regulators and the hard plastic lines goin to the cpi unit. i've got a bore-o-scope and i pull out the tuneing valve and just look in at it, i don't even bother with the guage if i think somethings leaking internally.
In all the years I was working on these things, I only saw one broken line, and it didn't break until I moved it :D Seldom used a fuel gage when I suspected a bad regulator, just gave it a sniff. I was too cheap to buy a boroscope.