not a mopar but need some help

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moparmat2000

moparmat2000

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hi y'all

this isnt a mopar and its brand X but i really need your help if your an automotive service tech or somebody who knows. i cant really afford to shotgun parts at this, and cant afford to get rid of this vehicle at this time. maybe somebody here has had this happen to a 99 chevy truck like this one, and can offer a way to fix it. so here goes with what i know, and what its doing and not doing.

the vehicle is a 1999 chevrolet suburban K1500 with oil leaking and oil burning 5.7 vortec V8 and 155,000 miles on it

it wont run, or more specific it wont run very well, i have to feather the gas, and it stumbles, stalls, and is hard starting, when it does idle at 1,000 rpm it idles smooth. when you can get it to rev up it doesnt pop or backfire so it hasnt jumped time

i borrowed an ECM from a friend who has a 1999 tahoe that was rolled, swapped the ECM, same symptoms, fuel pump makes a whirring noise when ignition is turned on, so i know at least this relay works, and ignition switch and the ECM switches pump on.

i do not have a fuel pressure gage or a code scanner, so i cannot tell if it has high enough fuel pressure, just know the pump is working from the sound. truck starts and idles smooth when it idles, but stumbles and stalls, and wont stay running, so i dont think its the crank or cam position sensors, otherwise it wouldent start, or would it?

i am down to 2 things i think it can be, either the fuel pump is still working but is not pushing enough volume and pressure, or the distributer module is going bad. was told not to get one of these from autozone as the china ones are junk, said if it that part thats badi should get a new delco one. distributer module from what im told has something to do with fuel pump, as well as spark.

my wife and i are going to buy a chrysler minivan next year, i just put new brakes, tires, and a radiator in this piece of crap to keep it road worthy. its my wifes car she bought years before we met, i want to kick this thing in the back door and send it off to somebody else but i got to make it last just one more year.

please help if you can
matt
 
Its hard to diagnose a vehicle over the internet, and even harder when the poster has no tools to diagnose with. That being said, you at minimum need a code scanner, it WONT tell you whats wrong, but it will point you in the right direction....
 
I'm going to agree with it could be the fuel pump I was told that there is a hose that hooks the pump to the sending unit that fails replace the small

Hose and that's it
 
plypete said:
Those things are notorious for intake leaks.
Click to expand...

Beat me to it, I work at a busy shop and we have had our share of chevy's here. Just doing a long distant diagnosis, but they are prone to intake vaccum leaks. Take a product like WD-40 and spray around the plenum area while it is running and see if the run quality improves. I use Carb or brake cleaner but that is a little dangerous if you haven't done it in the past.
 
heres the thing, the truck ran great no problems up until it was parked last night, then this morning it would not start for my wife at all, i screwed around with it and now it will cough to life, idle a bit and stall, i get a little throttle response, but not much. almost feels like its running out of fuel. god i hope its not the pump. its expensive unless its just the connecting hose, plus the tank is a 35 gallon one, and its got 3/4 of a tank of gas in it.

i can prob ask my friend with the rolled over tahoe if he will sell me the pump from it, if that ends up being the problem. sorry but i dont have a code scanner, or a fuel pressure gage everything i usually work on is old school computer. pre OBD ll my 94 chevy uses a paper clip bent to connect term A and term B, flip key on, and it flashes codes to you. look in the book, viola it sends you the direction you need to go.

what a difference 5 years makes this suburban is so packed with crap under the hood, same body style, my 94 has soo much room under the hood, you can even see the inner fenders.

if i dribble a little fuel in the intake manifold and it runs good enough till it runs low on what i put in, then stumbles maybe the pump tho is working is low on pressure.

its a thought, any ideas?

thanks for all your help so far.
matt
 
I had a 1996 1500 Chevy Silverado. It had the V8 vortec as well. It was actually a great truck, till it hit 286,000 miles. Then it would buck and stall, and shut down electronics randomly. What i used to do is open the hood, get out, smack the engine with my fist a few times and it would start and run fine that day for a while. I am not kidding, I literally did this, and it worked. I do not know why, but it did. Perhaps the Vortec feared me, and did not want to anger me further. After 2 years of not passing smog the state crushed it and gave me $2,000 for it. I owned it from 115k miles. Only GM I ever owned that was amazing. Try punching it, or kick its bumper.
 
No the fact that it runs better when you add fuel tells me it has a vaccum leak. But with out a scanner to see what codes are in there it really is guessing game.
 
moparmat2000 said:
.....when it does idle at 1,000 rpm it idles smooth.
Click to expand...

Try and fab up a fuel pressure gauge. Shouldn't cost too much. I had an Astro van that had the EGR valve sticking open at times (which sort of mimicked vacuum leak symptoms) so that may be a possiblility. I'm not too familiar with this model, but it sounds very fuel pressure related to me too. If it was a vacuum leak, I can't see how it could EVER idle smooth.
 
havent tried anything with adding the fuel yet. ran out of daylight. priced fuel pump rebuild kits, can get one with a delco pump on evilbay for $59. way cheaper than they used to be when my buddy had to change his. factory GM was all you could get back then. had to buy the whole damn thing along with integral fule level sending unit for the gage $350 is what they cost back then.

like i was saying this didnt progressively get worse like maybe an intake manifold starting to leak and vehicle running progressively worse every day. it went from running perfectly fine when it was shut off yesterday afternoon, to not even starting this morning, then when i got it started it ran like crap. but idles smooth until you fot the gas pedal and wouldent stay running. barely any throttle response, when i would open the throttle it would stumble and die or want to die. feels like it was running out of fuel.

i have a new spare fuel filter for my 94 chevy pickup. its the same filter as the 99, so i will swap it in tomorrow, quick easy test, cant hurt, last time i changed the suburban fuel filter was 2 years ago. starting to lean towards it being a fuel problem. now i got to get it from in front of the house, down the alley, and into my driveway which faces the alley so that i can trouble shoot it a bit further.

anybody else have problems like this with a similar GM

matt
 
Yes, I have had issues with them. If you don't think it is the intake leak, give the bottom of the fuel tank a few wacks with a rubber mallet as someone is cranking it. A lot of time the pump will start working but don't trust it to continue.
 
Oh boy does this sound familiar.
A. Its not the fuel pump.
B. it could be a vacuum leak, but............
C. it's most likely a timing issue. The hold downs on the distributor loosen, that allows it to move gradually and you get the problem you have.
Here's the butt kicker, as you have seen, everything in there is compact and a major P.I.A. to get to. I had one of these things cause me to chase my tail for a couple of weeks over the same issue.
 
hi Y'all

i figured it out, thank you for all the ideas of what it could be. i whacked the bottom of the fuel tank a few times, and she started right up and idles fine, rev the gas and it revs up just fine. a little stumble on restart. looks to be a fuel pump.

i ordered a replacement AC delco pump kit. this is something AC delco has done as upposed to replacing the whole pump and sender assembly for several hundred bucks. the pump kit was $59 shipped. so it was a pretty good deal, now i got a gas tank with 3/4 of a tank of fuel, and a syphon doesnt seem to work, so i have to drop it full of fuel, bummer

thanks again for all the ideas tho check
matt
 
Just an FYI. You can get most any parts store to read codes, for free. I don't know if they have the readers available on the tool loaner program, to take home.
 
Yep i knew about borrowing the code readers, but the truck didnt run to get it to the store so i could use their code reader. Once i figured out it was the pump by banging on tank and got it started, i drove it around to my driveway to get it off the street, and ordered a new pump.
 
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