MASSIVE BACKFIRE result of injector cleaning?

[Matthew Jeschke]

Okay, so I replaced my bad knock sensor, and while I was at it I decided to clean the fuel injectors. I may have opened a bag of worms. I followed this procedure:

Basically opened fuel injector w/ DC power supply and blew carb cleaner through them both ways.

I then cleaned the valley cover and cylinder heads really well. Lastly I wet shop rags with Berryman Fuel System cleaner and wiped down each intake port on the cylinder heads. Nothin too major.

The intake manifold had been VERY expensively cleaned. I dried it out very carefully making sure no water was in it anymore (or so I think).

I put the truck back together. Cranked it w/o fuel. Didn't seem to be any problem. So I put back in the relay for the fuel pump. I primed the system a handful of times by cycling the key but not spinning the starter. Then I went to start the truck..

Massive popping noise. It was bad so I shut it down immediately. I thought about what happened. I wondered if some solvent got into the cylinders. I took back out the fuel pump relay and went to start it up again. Wow, massive popping even worse this time. I don't think I heard anything like engine blowing up noise or metal on metal but it wasn't good. I immediately shut down the motor.

Overall I MAYBE ran the motor for 3 seconds under power where it was popping if even that. It scared the hell out of me.

I pulled all the spark plugs wondering if something got dropped in a cylinder (although I was VERY careful about that. I taped all the cylinders shut (see picture) while I was working.

When I pulled two of the driver side spark plugs it sounded like fluid came out of them. I wonder if I have a stuck open fuel injector that flooded the cylinder with excess fuel while I was priming the system?

I hope I didn't damage anything inside the motor. I turned the crank with a breaker bar several times in each direction. It seemed to stick at various points in the beginning but was inconsistent as to what point it hung up in the motor...

I kept turning it (probably dump thing to do) and it got better.... Maybe I had left a shop towel in one of the intake ports? I really don't think I did as I was SUPER careful about that too.

Bit rattled, any words are appreciated.

Note picture says coolent, but it was gas. Two of the spark plugs were wet. I checked the oil and doesn't seem to be any other fluids in it, at least on the dip stick.

I left my garage with all the doors open and a big fan running. It smells horribly of gas.

 

[Matthew Jeschke]

I went back, haven't tried much more but scanned the computer for codes.

Had a P0107 and noticed the MAP sensor was unplugged. While I was at back of intake I noticed my brake booster was unplugged.

I wonder if this whole mess is a result of too little vacuum and MAP sensor being unplugged / confused as to how much fuel to dump in. I don't know if this will run off mass air flow sensor alone? I've ran these the mass air flow sensor unplugged but never with the MAP unplugged (and a massive vacuum leak).

 

[PNWYukon]

DTC P0107

CIRCUIT DESCRIPTION
The manifold absolute pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on the engine load. The MAP sensor has the following circuits:

• 5-volt reference circuit
• Low reference circuit
• MAP sensor signal circuit

The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The PCM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The PCM should detect a low signal voltage at a low MAP, such as during an idle or a deceleration. The PCM should detect a high signal voltage at a high MAP, such as the ignition is ON, with the engine OFF, or at a wide open throttle (WOT). The MAP sensor is also used in order to determine the barometric pressure (BARO). This occurs when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is operated at WOT. The PCM monitors the MAP sensor signal for voltage outside of the normal range.

If the PCM detects a MAP sensor signal voltage that is excessively low, DTC P0107 sets.

CONDITIONS FOR SETTING THE DTC
The PCM detects that the MAP sensor voltage is less than 0.055 volt for more than 4 seconds.


Yes, it looks like if your MAP was unplugged it would set this code.

 

[Matthew Jeschke]

thx, yeah I plugged it back in but code is still there. not sure if it takes a little while to go away.

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[PNWYukon]

CONDITIONS FOR CLEARING THE MIL/DTC

• The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
• Clear the MIL and the DTC with a scan tool.

 

[Doubeleive]

if you are sure you didn't leave anything in there then it could just be the chemical cleaner burning off

 

[Matthew Jeschke]

It's official connecting rod on cylinder 8 is busted. I'm pretty sure it was the injector. Got stuck open and in the couple minutes I let the pump prime it flooded the cylinder. Here's a borescope video of me spinning the crank. You can see the valve move but the piston says in the same place.

https://drive.google.com/file/d/1FQ6d0fIJPBdM6j8IInIBfijfgS20g8Ag/view?usp=sharing

 

[wjburken]

It's official connecting rod on cylinder 8 is busted. I'm pretty sure it was the injector. Got stuck open and in the couple minutes I let the pump prime it flooded the cylinder. Here's a borescope video of me spinning the crank. You can see the valve move but the piston says in the same place.

https://drive.google.com/file/d/1FQ6d0fIJPBdM6j8IInIBfijfgS20g8Ag/view?usp=sharing

Yeah - it looks broked

 

[Rocket Man]

So was there anything wrong with the fuel injectors that made you decide to clean them that way or were you just doing maintenance? Sorry about the outcome either way.

 

[SnowDrifter]

It's official connecting rod on cylinder 8 is busted. I'm pretty sure it was the injector. Got stuck open and in the couple minutes I let the pump prime it flooded the cylinder. Here's a borescope video of me spinning the crank. You can see the valve move but the piston says in the same place.

https://drive.google.com/file/d/1FQ6d0fIJPBdM6j8IInIBfijfgS20g8Ag/view?usp=sharing

Holy shit. DAMN

You think this was around before or after the injector service?

 

[Matthew Jeschke]

So was there anything wrong with the fuel injectors that made you decide to clean them that way or were you just doing maintenance? Sorry about the outcome either way.

Just maintenance while I hadnintake off to fix broken knock sensors haha... They were FILTHY dirty but worked.

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[Matthew Jeschke]

Holy shit. DAMN

You think this was around before or after the injector service?

It was right after. I did it in my garage :/

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[JGib]

A little old but thought I should leave a comment. When i replaced my engine with a gm long block, the instructions made it very clear to make sure the intake was clean before installing it on the new engine.
I prepared myself with a few cans of cleaner but before starting, thought i would consult with a friend of mine who owns a shop. They do many engine replacements. Asked about the intake cleaning and he told me to not spray anything in the intake. Said it was very difficult to remove liquids from inside the manifold. Just a note. If ya plan on cleaning intake, use something that evaporates (which is probably what was used here so not applicable) Anyhow, if ya feeling froggy and decide to use, lets say soap and water, plan on an extended drying time as shop air, shaking, cussing, might not get all the liquids from the runners.

 

[Matthew Jeschke]

A little old but thought I should leave a comment. When i replaced my engine with a gm long block, the instructions made it very clear to make sure the intake was clean before installing it on the new engine.
I prepared myself with a few cans of cleaner but before starting, thought i would consult with a friend of mine who owns a shop. They do many engine replacements. Asked about the intake cleaning and he told me to not spray anything in the intake. Said it was very difficult to remove liquids from inside the manifold. Just a note. If ya plan on cleaning intake, use something that evaporates (which is probably what was used here so not applicable) Anyhow, if ya feeling froggy and decide to use, lets say soap and water, plan on an extended drying time as shop air, shaking, cussing, might not get all the liquids from the runners.

Oh wow, is possible it was water then [emoji17]...

You are definately not too late as I am building another motor and planned to use the same intake. I will have to see if there is any way to verify it has no water in it... and or buy another intake [emoji51]

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[Matthew Jeschke]

Backfire! SOLVED I think died of COVID

Best news is, it did run on uh cylinders haha

See my 6.0L build post.

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[SnowDrifter]

Backfire! SOLVED I think died of COVID

Best news is, it did run on uh cylinders haha

See my 6.0L build post.

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I could think of better placed to put your blow off valve

 

[Matthew Jeschke]

I could think of better placed to put your blow off valve

Haha sure thing. I think this would make a gd project farm youtube video / test for jb weld.

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[89Suburban]

Matt you got good spirits for being kicked in the nuts trying to do the right thing, sucks bro. Feeling for ya. No good deeds go unpunished.

 

[Matthew Jeschke]

Matt you got good spirits for being kicked in the nuts trying to do the right thing, sucks bro. Feeling for ya. No good deeds go unpunished.

haha that's a nice way of looking at it thx

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[sonic_the_hedgeh]

So was there anything wrong with the fuel injectors that made you decide to clean them that way or were you just doing maintenance? Sorry about the outcome either way.

Never tried that diy method. I have just used seafoam or regular injector cleaner spray.
That would suck. I would not expect to screw the engine by cleaning injectors.

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