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longhorn
10-30-2010, 10:07 PM
I have a 2000 Chev 1 ton with a 454.
It runs good and has lots of power but ....................

It backfires very loudly everytime you slow down.
Its getting worse, I try not to let it do it by slowing down slowly or gearing down but today if I just barley let off it backfires.

It backfires hard and loud it almost blows the box right off it.

Anyone got any ideas on what I should check?

4skin
10-31-2010, 04:24 AM
its a chevy
sounds like unburnt fuel lighting in exhaust
posibly iac hanging up
havent played with one of those tbi setups for a while
pull idle air control solinoid of and clean it with fuel injection cleaner
or your washer fluid is low

JackRabbit
10-31-2010, 04:58 AM
if its a 2000 it should have the flat horrizontal style distributor cap and lots of times what happens is the spark cross fires when they get worn out. replace cap should fix it

longhorn
10-31-2010, 10:52 AM
Thanks guys ...............
I checked the waher fluid, and it was all good so it must be one of the others.

kootenaycat
10-31-2010, 12:05 PM
I would check for exhaust leaks at or near manifolds, or if it has an air pump see if the thermactor air divertor valve is working. Sounds like it's sucking in air on decel which will cause unburnt fuel in exhaust to light off.

offroadordrift
10-31-2010, 12:31 PM
why fix it. i bet it sounds bad ass

longhorn
10-31-2010, 12:45 PM
why fix it. i bet it sounds bad ass

Its getting so bad people in town run and hide when they see me coming.
Cops are going to start shooting back.

longhorn
10-31-2010, 12:46 PM
I would check for exhaust leaks at or near manifolds, or if it has an air pump see if the thermactor air divertor valve is working. Sounds like it's sucking in air on decel which will cause unburnt fuel in exhaust to light off.

Makes sense.
Is got a exhaust leak

longhorn
10-31-2010, 12:48 PM
its a chevy
sounds like unburnt fuel lighting in exhaust
posibly iac hanging up
havent played with one of those tbi setups for a while
pull idle air control solinoid of and clean it with fuel injection cleaner
or your washer fluid is low

And the air control solonoid is where?
In the line between the throttle body and the air cleaner?

Kingblazer84
10-31-2010, 03:11 PM
IAC is located on the tbi throttle body should have a 4 prong plug on it. once pulled out have a look and if its covered in carbon and crap clean it off with some brake clean let it dry then reinstall it see if that fixes it if not i would recommend just buying a new one and putting it in and trying it. At the same time i would pull a plug and have a look and make sure they arnt fowled as well.

longhorn
10-31-2010, 06:00 PM
IAC is located on the tbi throttle body should have a 4 prong plug on it. once pulled out have a look and if its covered in carbon and crap clean it off with some brake clean let it dry then reinstall it see if that fixes it if not i would recommend just buying a new one and putting it in and trying it. At the same time i would pull a plug and have a look and make sure they arnt fowled as well.

They tryed to sell me that thing inbetween the throttle body and the aircleaner.
It was almost $400 bucks?

OK I finally found the right thing and cleaned it.
It was sooted right up.
I looked on Ebay and they are $20 bucks , Lordco want $130 .
Anyone got any idea how much they should cost?

Kingblazer84
10-31-2010, 07:30 PM
well we do live in canada so prob 130$ i think is what they go for considering it is a sensor... do you have or know someone with a discount? get it cheaper that way haha..

FU Toolbag
10-31-2010, 07:43 PM
my cab/chassis one used to do that all the time. Found out that the muffler clamp was loose cause it regularly blew the muffler clean off. It was on some nice and flexy hangers so it usually whent back on my itself. Buddy saw this and almost crashed he was laughing so hard. I fixrd it by going to propane and chucking the aforementioned parts.

longhorn
10-31-2010, 07:49 PM
my cab/chassis one used to do that all the time. Found out that the muffler clamp was loose cause it regularly blew the muffler clean off. It was on some nice and flexy hangers so it usually whent back on my itself. Buddy saw this and almost crashed he was laughing so hard. I fixrd it by going to propane and chucking the aforementioned parts.

So what was causing it?

In The Zone
11-01-2010, 08:37 PM
exhaust leak

longhorn
11-01-2010, 09:30 PM
Someones put a crappy pair of noisey bottles on it?
Maybe I should take it to a muffler shop and get them to go over everything.
Its a good work truck but it about to get parked and Ill use my old 90 Ford diesel.

bigrig81
11-02-2010, 12:25 AM
When you get 'er figured post it up cuz I'm curious now! hope it's a cheap fix!

:D

FU Toolbag
11-02-2010, 04:59 AM
So what was causing it?

I have no idea. Like I said, i pulled all the injection stuff and whent proplane.