Fuel Injector problem

If your fuel injector is spraying fuel without the engine running, then the computer is most likely malfunctioning.
The fuel injector should not spray fuel until the cylinder calls for fuel. If the engine is not rotating then no fuel should come out of the injectors.

Read the guide below on testing fuel injectors, it will help you figure out whats wrong

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

I did disconnect the battery when i changed the fuel injector so i could charge it on the bench. then re installed it. thats when it started up with out the check engine light. will the computer reset it self when you disconnect it like that? does it sound like my fuel injector is good, along with the fuel pressure regulator? is there any way to test that on the TBI ?
If the fuel regulator went bad could it blow the injector and force the fuel out through it? Any way to test the ECM? I dont have any friends with a 454 suburban or truck from the early 90's to trade with.

  A fuel injector works on electronic pulses sent from the computer. When these pulses are received the injector sprays fuel. The timing of these pulses is congruent to the rotation of the motor, especialy the cam shaft. It's not like the old days of balancing the carb. so the fuel mixture is right. The computer does all of that for you--or--it's supposed too!   If the fuel regulator went bad the fuel would not be forced through the injector. The injector needs electricity to open and let fuel through. If the fuel regulator was bad, when the injector electricaly opened, more fuel would flow through. In order for the injector to open the cam must tell the computer to send an electrical pulse to the injector so fuel can be sprayed, at the right time, through the right injector, on the right side.  

So i could test this by disconnecting that injector and turning the key to on, Then there should be no flow through it because the signal from the assumed to be bad ecm couldnt tell it to open?

Yes sir.

Is there any way to have the computer checked out before i spend $$ on a new one?

thank you for the help too !!!!!

Yes , absolutely have the computer checked out. If you can find a garadge with the proper scan tool ( a tech 2) it may be cheaper then going to the dealer; but a dealer has the proper equipment for this. A tech 2 scan tool, or the equivalent, is necessary to test your computer..keep me posted

Engine Performance problem 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

To me it sounds like you have a crankshaft angle sensor going out or the PCM injector drivers is having a problem I would try the crankshaft sensor first. Here is a guide to show you what you are in for when changing the sensor out. Both will make the injector flicker like that but just in case let's check the injectors as well.

Here are some guides to help you see what's going on.

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

and

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

and here is the location of the PCM (below)

Here is how you change the injectors in case you need it. (below)

Please let us know what you find. We are interested to see what it is.

Cheers

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.

Pressure test the cooling system and perform a compression test on all cylinders.

MAKE SURE the injector O rings are properly seated.

1994 Chevy Suburban, getting no fuel to injectors. We cleaned the the throttle body, had some sludge build up on the back, were the fuel pressure regulator is, cleaned it keeping debris from fallin in throttle. after wards i lost fuel flow to injectors. replaced the pressure reglator, no rebuild, had fuel coming from the rail, hand coming up the TB, put it back together and still no flow through the injectors, worked fine proir to the cleaning (which the motor was running) it has had the EGR valve and solenoid and MAP sensor Canister purge sensor and all vacum lines replaced. Fuel pump relay and filter are new, i can hear the fuel pump running when you turn the key, and here the relay open and close circuts with key turn. distributor and ignition coil and module are new, cap and rotor, and plugs and wires, and a new ECM and prom. also IAC valve, and throttle position sensor. i am not sure where i should go from here i got fuel all the way just not to the injectors. please help

Vehicle is
94 Chevy Suburban
K1500 4x4 5.7 V8 350
TBI 2 injector system

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

Hook up a noid like on the fuel injector harness and tell me if its blinking while cranking engine over-let me know

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.

Got a steady light. No pulse.

[quote:294a591a2a="mmprince4000"]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.[/quote:294a591a2a]

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

Check the wiring on the distributor-Do you have power on one side of the injector harness-No pulses could mean the computer and wiring from injector/s to computer

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.

Yeah power to one side only. I have had to replace the distributor and ignition module on it a few times cause it was damaged when I got them. Is the pulse triggered by the ignition module in the distributor

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

Inspect and test the distributor magnetic pick-up coil the one that hooks up to the ignition control module-

Engine Mechanical problem
1997 Chevy Suburban V8 Four Wheel Drive Automatic

97 chevy 5.7L 350

I needed to replace intake manifold gasket. Removed it two years ago. I had thoroughly cleaned the intake manifold and its surfaces. I have no garage, live in the hot New Mexico sun. So I waited for a moderate day but hurt my back so two years went by.

I had put a clean white towel over engine block and was laying the manifold back in place until the last day. Long story/short, some New Mexico windstorm had blown a little dust down into the fuel delivery ports (for lack of better term).

This is a high mileage vehicle so I do not want to pull the heads but I need ideas how to get as much dust as possible back out of those ports even though there is very little.

I plan to blow them out with air compressor. The perhaps shove some rags with carb cleaner on them and wipe around.

Any other ideas? Or should I just give in and pull the heads? Even if I pull the heads will I be able to access those square ports entirely?

Also, can I assume it is safe to dunk the whole fuel injector assembly and injectors in carb cleaner?
Thanks in advance.

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.

If valve was open, then dust is already there.

I would try a vacuum with a small attachment.

If all valves are closed, then I would use compressed air.

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

Well I can't seem to see what she is trying to describe, but I will listen after work.

Is your truck throttle body injected as this one or port FI?

Yes, It is TBI. What I was trying to describe in the video is that there is an "air" sound or a shhhh sound. You can hear it best when she stalls. This sound was never present prior.
Someone had told me to look for a vacuum line going into the Trans, but I can find it.

Just a short recap.
Ran perfect prior. Put about 10 gallons of gas in at Murphy USA, drove 40 miles without problems. Parked it for about an hour, went to leave again and she drove fine for 3 miles then stalled, and continues to stall, putted back home. Parked it.

Changed the:
Spark plugs
Fuel Injectors
O2 Sensor
Inline Fuel Filter
Added Heat
Siphoned out the gas.
Add 3 gallons new gas
Added Sea Foam

I've have searched for a vacuum leak but can not find one.

I can hear the fuel pump engage. (Assuming it's not that at this point.)

To rev the motor I have to "tap" the accelerator petal - If I "floor it" it cuts out and stalls.
Sometime she will idle roughly, if I take it out of Park she want to stall.

So I finally installed a used PCM and that fixed the problem! Thanks for hanging in there with me on this.

Thanks again for all your help. :)

Laura