Mechanics

CHEVY BAD FUEL INJECTOR?

1995 Chevrolet Suburban

Engine Performance problem
1995 Chevy Suburban V8 Four Wheel Drive Automatic 193k miles

The motor and training are sound and we've never had any problems before now. The day it decided to act up we had put $20 in gas in it, drove 40 miles with no problems at all. Came home parked it for about 45 minutes, left again, drove about 3 miles and it stalled. Managed to get it running again and putted all the way back home. We changed the spark plugs, the diagnostic code indicated an 02 sensor, so we have replaced that as well. We've added heet to the fuel, and still have not been able to keep it running. One injector has fuel the other does not. I was told that, that was the problem. I have bought a new injector but if it just needs to be cleaned I'd rather do that. How can I clean the injector, do I need to take it apart to do this, if so, how? And this leads me to my 2nd question, to replace the injector how do I take it apart?
Thanks,
Laura
Avatar
LFiatoa
February 26, 2009.



Remove fuel filter, pour contents into clear container, if liquids seperate, then you have water in gas. This senerio is far more likely than an injector failing.

Test each injector electrical connector with a noid light, disconnect the injector electrical connector, attach noid light, crank engine and look for noid light pulse, if no pulse, then driver or fuse.

Injectors are attached to fuel rail, each has a clip that holds it to the rail and " O" ring seals on both ends. You must remove fuel rail, with injectors attached, then remove individual injectors.

To test injector, look for shop that can test injector function, and spray pattern. You must have specialized equipment to test injector.

Mmprince4000
Feb 26, 2009.
Ok, this is what I've done; replaced spark plugs, O2 sensor, changed one injector the other is fine. Searched all over for a vacuum line that might be off. Nothing. It continues to make a whistling noise or a " sssssshhhhhhhh" noise. After sitting for 2 days without starting it up she idled on her own for a good 7 minutes and with no noise, then started sputtering like she wasn't getting enough fuel at that very second the noise started again. It sounds like air. What could this be? Would bad gas cause this sound?
Again, thanks for all your help.

Tiny
LFiatoa
Feb 27, 2009.
Pressure test the cooling system and perform a compression test on all cylinders.

MAKE SURE the injector O rings are properly seated.

Mmprince4000
Mar 10, 2009.
Well, I've been slow at getting back. The whistling noise was there before I changed out any parts. Up to date these are the things I've replaced in the order they were done.
1. New Spark plugs
2. Added Heet to the fuel
3. New O2 sensor (had error code 44)
4. New fuel injector on the TBI as well as a new gasket on the injector assembly / TB (I completely removed the injector assembly.)
5. Added fuel injector cleaner to the fuel.
6. New fuel filter
7. Siphoned out all of the gas (about 5 gallons)
8. Added new fuel. (About 3 gallons)

The whistling noise is gone.
The test drive. Spits and sputters, will not make it up a hill, stalls, gas petal floored (nearly) truck not moving, the jumps forward.(Spit and sputtering)

Since most of all of the parts are original on her, I'm assuming the fuel pump could be the cause and the next item to change out. Or the Fuel pressure Regulator sensor on the TBI? Maybe?

Like I said in my previous post I have never had anything wrong with her before other than minor issues like the belt, battery, brakes, water pump, spark plugs, power steering pressure hose, and a clogged muffler? (She had dogged down before, but after we changed the muffler out she was fine).

Thanks for all the advice given and to come!
Laura

Tiny
LFiatoa
Mar 10, 2009.
Check fuel pressure with a mechanical gauge before replacing it.

It is also possible the CAT is clogged, if CAT is bolted on, unbolt it and look inside. The material should look like a honeycomb, if cracked or melted, then the CAT is the problem.

Mmprince4000
Mar 10, 2009.
That's a problem. I don't have access to a fuel pressure gauge, and there is no way she is drivable enough to make it to a shop. I believe the cat is welded on. I can't remember off the top of my head right now. I'll check it out tomorrow. Just a quick note. I ran diagnostics on it again, and again the code 44 appeared. Also I just thought of this, I did notice a different smell to the exhaust, hence the reason, (and previous post suggestion) I thought it might have been bad gas. Just wondering (I've never tried it) would sea foam work to clear this up? I'm not a big fan of adding " extras" to my fluids.

Thanks again ~
Laura

Tiny
LFiatoa
Mar 11, 2009.
Seafoam is an excellent additive and also removes moisture, so I would add a can to the tank.

Since all evidence points to bad gas, I would siphon all the gas out refill with fresh gas and add Seafoam and change the fuel filter again.

Always buy gasoline from a place that pumps alot of gas, in other words a place that (generally) has a lot of pumps and refills tanks often (2 times a week or more).
You can run into problems buying from the small places that only refill their tanks every month or so.
Also make sure you see an inline filter on the pump hose.

It MAY also be necessary to drop tank and look for sediment in bottom of tank clogging up the pickup.

Mmprince4000
Mar 12, 2009.
Hi all again,
As stated in a previous post, I siphoned the gas out and replaced the fuel filter. (I buy my gas at Murphy USA at Walmart, so I know the fuel is " fresh". After I bought the gas, I drove for 30 or so miles without any problems, after it was parked for 40 minutes and then tried to drive it again, we only got about 3 miles and it stalled. We were able to putt back home the 3 miles. Today I added the Sea Foam to the fuel and the oil, expecting it to smoke etc, etc, like I've seen on Youtube, I got a few puffs of smoke but nothing compared to what I saw. It did not magically fix the truck as I had hoped. Here's another " symptom" if you will. To stay running (not at idle), I have to gently pump the petal, if I attempt to hold it or " gun" it the engine revs for about a half of a sec and then it's like it is getting no fuel at all. It tries to cut out. I gently pump the petal again at a heat beat pace just to get it to stay at idle, as soon as I stop pumping, the truck stalls or almost stalls. I think the bad gas theory has been tested and that is not the problem. The only 2 things I know to do next is change out the fuel pump or the sensor on the TB assembly. If my fuel pressure is lost wouldn't repairing these items fix that problem or is there something else I am missing? Any other suggestions?
Thanks again for all the help!
Laura

Tiny
LFiatoa
Mar 13, 2009.
While you may have a bad fuel pump, check fuel pressure with mechanical gauge. Maybe you can borrow or rent one.

Also consider that since it ran fine for 30 miles, you may have debris in the bottom of tank that is clogging up the pickup.

I would probably drop tank after siphoning gas out, remove fuel pump assy. And inspect tank for debris in bottom.

I just hate to see you throw parts at it, when a fuel pressure test would give you definitive proof that pump or restriction in supply line is the actual problem.

Mmprince4000
Mar 14, 2009.
Hello,
I've uploaded a couple videos on youtube, could you please view them and give me your opinion.
Thanks.

http://www.youtube.com/watch?v=_0mqfYJn4jw

http://www.youtube.com/watch?v=tYnHUrmekCA

Tiny
LFiatoa
Apr 25, 2009.
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