ok.. i'll catch hell for this but oh well.

[destro360]

i've searched and searched.. no luck. my 87 5.7 full size jimmy has started a new issue.. runs smooth with out any real noticeable problems, until now. runs fine but off idle either backfires or dies.. feathering the throttle helps to keep it from dying but feels like a serious lack of power and the whole backfiring and dying thing really makes me mad.,. the timing is good tune is somewhat fresh and no vacuum leaks that i can find. so what next? i'm sure alot of chevy guys see this, i just dont know hwere to start? i've done all the simple check out with no luck.. if someone could atleast lead me to a decent thread covering this??

p.s. no codes in the system and fires right up everytime. new throttle position sensor and recently changed the intake gasket...

 

[Burbdood 74]

How old is the fuel filter and fuel pump? Look down into the throttle body while it's running and see if it's getting a good flow of fuel because it sounds like it's a fuel issue to me.

 

[ryoken]

Egr

 

[British Slave]

Using new intake gasket as a clue,............ timing.

 

[destro360]

Using new intake gasket as a clue,............
timing.

intake was done with valve job aprox 2 years ago with no issues until now... the fuel filter could be an issue, thats one of those things i never replace until it fails but seriously timing is good at zero with the connector unplugged on the fire wall and there is not a single code in the system.....

 

[destro360]

the egr passeges were clogged in the intake when i had it off the motor but i clened them all out.. i have no since checked to see if the egr itself was functioning properly or not...

 

[Stomis]

Yeah timing is 4* BTDO on these motors just fyi.

I would start with the fuel filter. Theres definatly a chance with the egr. Also fuel pump, or fuel pressure regulator.

 

[destro360]

Yeah timing is 4* BTDO on these motors just fyi.

I would start with the fuel filter. Theres definatly a chance with the egr. Also fuel pump, or fuel pressure regulator.

i dont know what you drive or what set up you got but mine is an 87 and the tag in the engine bay clearly reads "0 degrees btdc"

 

[chevyuser74]

timing on the tbi motors is set at 0, computer can move it 32 degrees, so yes u can set it to 4 for 36 degrees that ppl like.

 

[chevyuser74]

i am going to agree with ryoken on this one my gut says egr issue as well. also the throttle body gasket likes to go on these as well, 2.00$ and 5 mins to change.

 

[ryoken]

most "off idle" issues I've ever seen ended up being a bad EGR...

 

[destro360]

i am going to agree with ryoken on this one my gut says egr issue as well. also the throttle body gasket likes to go on these as well, 2.00$ and 5 mins to change.

the throttle body gasket was changed about 2 years ago... it may have loosened up some though, i'll have to check on that. the egr i'll have to check out too but i'm gonna have to borrow a vacuum pump all i have is a gauge right now. everyone else i've talked to insists that it has to be vacuum related but as far as i can tell the lines are good etc.

its annoying though because at speed it runs fine you can floor it with no issue its just pulling away from a stop it will backfire and half the time die.

one thing i'm curious about is i dont have a belt running the air injection pump.. i didnt think this would be an issue but???

 

[destro360]

thnx for the input so far gentlemen.... if time allows i'll do some checking tomorrow and see what i find? i'm trying to get this bug worked out as i plan to drop a new motor in and would like to start with a clean slate rather then abunch of small bugs that just carry over to the next engine..

 

[dsmd58]

def keep us posted!

 

[British Slave]

i dont know what you drive or what set up you got but mine is an 87 and the tag in the engine bay clearly reads "0 degrees btdc"

You are correct. Mine is also an 87 with 350 and TBI. The sticker says 0 degrees for manual and automatic.

 

[Stomis]

Idk I checked all data. Says 4* for everything but California emissions trucks.

Which is a big lol cause when i was typing that I said "I wonder if hes from cali"

 

[British Slave]

Not California.

 

[British Slave]

Still not California