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blazer won't run- resolved

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solace22

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1990 k5, 350, 700r4. Tried to start it up this morning, typically "crank crank crank start!" Now it's "crank crank crank..." Then it acts like there is resistance and it can't turn over the engine. When I stop trying to start I hear a noise from the floorboard and it sounds like an old printer. "Brrrrrrrrr..."
if I give it a little gas when I start it it will start but fail to idle.
It's like the engine has resistance then when I stop cranking whatever it wound up unwinds. I tried taking it out of park down into drive and back up but no dice.
any ideas?
 
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Checked fuses under the dash. All were okay.
I hear the fuel pump kick on when I turn the key.
if I give it gas it will idle but it's like it really wants to shut off, as if it's all being told to shut off. Oil pressure gauge seemed to go to normal. I have no explanation for the "old printer" noise. I have a video of it if it would help anyone.
 
That noise mystifies me. The ONLY thing I can think of that was ever used on these trucks after shut down is the hot fuel module, and I can't remember if all the trucks got it or not. I think it was located under the dash, but I could be mistaken.

Should not cause a hard to start condition on a cold engine though.
 
dyeager535 said:
That noise mystifies me. The ONLY thing I can think of that was ever used on these trucks after shut down is the hot fuel module, and I can't remember if all the trucks got it or not. I think it was located under the dash, but I could be mistaken.

Should not cause a hard to start condition on a cold engine though.
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Mystified me too. Would a video help?
 
Is the noise the starter motor still spinning?
 
No start: https://youtu.be/rEPD46HvWhc
That noise, what on earth? It's like right under the "hump" which makes me a bit nervous that it's transmission related.



Also I do an outdoor type channel on youtube with my daughter. If you like that kinda thing subscribe! :waytogo:
 
have someone crank it for you,while you climb under it and see if its the starter
 
I am starting to think it is the fuel pump. Earlier you could hear it prime when key is turned on. Not anymore. I think the sound is a relay possibly. how hard is the tank to drop? I have a skid, and I presume 2 straps. I'm not going to cut out the floor. How low does it need to drop before I can unplug it?
 
Relay is bolted to your firewall IIRC. Shouldn't be running after the engine is shut down.

Tank is a pain normally. You can unplug the wiring before dropping the tank. Unbolt the ground from the frame.

Fill/vent hoses are the worst part IMO. You don't want to cut the large one as they are EXPENSIVE to replace, if you can find them. Sometimes easier to remove the clamps, then drop the tank a bit and work on them with the weight of the tank helping to pull them off.

Skid comes off kind of easily, but need to remove the filler panel below the tailgate to get at the bolts. Will need that off to get the tank straps too. If you can get the bumper off it will be easier, but if the bumper hasn't been off before, don't try.

No easy way to get the tank down from what I've found, especially if it's got fuel in it. You can only drop it so far until you need to disconnect the fuel lines. What I normally do is unbolt the straps from the back, let them hang down, then the tank will drop, angled rearward/downward, so you can get at the fuel line fittings.
 
dyeager535 said:
Relay is bolted to your firewall IIRC. Shouldn't be running after the engine is shut down.

Tank is a pain normally. You can unplug the wiring before dropping the tank. Unbolt the ground from the frame.

Fill/vent hoses are the worst part IMO. You don't want to cut the large one as they are EXPENSIVE to replace, if you can find them. Sometimes easier to remove the clamps, then drop the tank a bit and work on them with the weight of the tank helping to pull them off.

Skid comes off kind of easily, but need to remove the filler panel below the tailgate to get at the bolts. Will need that off to get the tank straps too. If you can get the bumper off it will be easier, but if the bumper hasn't been off before, don't try.

No easy way to get the tank down from what I've found, especially if it's got fuel in it. You can only drop it so far until you need to disconnect the fuel lines. What I normally do is unbolt the straps from the back, let them hang down, then the tank will drop, angled rearward/downward, so you can get at the fuel line fittings.
Click to expand...

I sprayed the bolts and such down yesterday. still have to find someone to turn the key while I watch the throttle body. We just had daughter number 3 on the 10th so ive been super busy. My father who is usually not in the least bit helpful came up with a great way to drop the tank, we have an atv lift we will put under the tank to maneuver it around. Ive got a gas siphon around her somewhere Ill siphon as much gas as I can out prior. seems like a body lift would help with this stuff. lol I hope to get going on this in the next day or two. Ill let you know how it goes.
 
I'd suggest putting a fuel pressure tester on it first. You have autozones out there? They loan them for free.

Your siphon won't work well, if at all, if the hose in the tank is split. Fuel pressure tester will give you an idea if it's in the tank or not. ATV jack is a good idea if you have one. Just remember it won't come straight down until the fill hoses are removed. Have to be a bit careful not to break the fill neck off the tank.
 
dyeager535 said:
I'd suggest putting a fuel pressure tester on it first. You have autozones out there? They loan them for free.

Your siphon won't work well, if at all, if the hose in the tank is split. Fuel pressure tester will give you an idea if it's in the tank or not. ATV jack is a good idea if you have one. Just remember it won't come straight down until the fill hoses are removed. Have to be a bit careful not to break the fill neck off the tank.
Click to expand...

Yeah I thought about renting a pressure tester. Honestly I don't hear the pump kick on when I turn the key anymore, it did in the beginning but not now. I've checked the fuses so I'm nearly certain it's the pump now.
 
I've seen just as many GM vehicles with a bad wire going to the fuel pump from the fuse box,as bad fuel pumps...my friend who runs a repair shop has replaced a good many GM pumps only to find later,the vehicle still wont start,and it turned out to be the wiring wasn't letting enough or no voltage get to the fuel pump..many new pumps now come with a new plug to replace the oem one,that is often corroded or damaged..


I'd be unplugging the fuel pump wiring at the tank and checking for power with the key on before dropping the tank or buying a pump,and use a "real" bulb like a 1157 as a test light--those newfangled LED test lamps will light up bright even if only a few volts are present--the pump needs full 12V and some amperage to make it turn on and run...my friend got fooled by using the LED tester,now he uses a small headlamp bulb instead to check the power wire to the pump...ground wire is important too..

Sometimes whacking the bottom of the tank with a fist or rubber hammer with the key "on" will awaken a "dying" fuel pump and get it to run again,at least temporarily...that can indicate the pump is about done for,or it isn't getting sufficient power to it..
 
Alright. Fuel pump primes, sounds healthy.
checked at the injectors they pulse and spray nicely. No dribble etc. Plenty enough fuel to ignite.
You guys still think it could be the pump? Could any of the sensors the ecm is looking for be bad? I know these look at oil pressure etc after 2 cranks or so. Tps? This just happened suddenly. Not like it sputtered and died. Does this have a sensor to keep it from starting while in gear maybe? It's like something tells it not to start.
 
Definitely worth investigating where the problem is, especially with the noise you are hearing.

Make sure there is voltage getting to the pump...run a wire from the single red wire dangling from fuel pump relay connector to the battery + terminal. You can then test the wiring connector back at the tank to make sure it's getting there, and if it is, the tank ground is intact, and it's not running, you know your problem is somewhere on top of or in the tank.
 
dyeager535 said:
Definitely worth investigating where the problem is, especially with the noise you are hearing.

Make sure there is voltage getting to the pump...run a wire from the single red wire dangling from fuel pump relay connector to the battery + terminal. You can then test the wiring connector back at the tank to make sure it's getting there, and if it is, the tank ground is intact, and it's not running, you know your problem is somewhere on top of or in the tank.
Click to expand...

Looks like we posted at the same time.
 
Good timing. :)

Can you get your hands on the fuel pressure tester? Could still be a fair number of things, but checking spark wouldn't hurt either. Injectors won't fire if there is no distributor signal, but it's possible spark is iffy. If the tests are free, they are worth doing.

I had a leaking fuel pump hose for two years that caused all sorts of drivability issues. Very inconsistent performance at all times. Sometimes good, sometimes bad. Putting a fuel pressure tester on it immediately showed the fuel pressure problem.

Not likely to be sensors, but without getting your hands on a scantool or ALDL cable and laptop, I'd be guessing.
 
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