Problems with 99 Yukon

[buckeye026]

ok here it is. I have a 1999 Yukon with 147k miles. I have recently replaced the plugs, plug wires, fuel pump, fuel filter, put a flow master exhaust on it, new cats, o2 sensers and an airaid intake system on it. a couple days ago i fired it up and check engin light started flashing at me, I read the codes and its multi cylinder misfire and fuel system to rich. The truck is backfireing really bad and not running well at all. does anyone have any idea what it could be? I am lost here.

 

[imtbear69]

Sounds like it could be a ECM prob or you may have a fowled plug even though you just put it it still might have fowled if you didnt get the gap right

 

[99Yukon_Z71]

Did you change the cap and rotor by any chance. But according to your symptoms and codes, sounds like it probably is your CPI fuel injection system. They are very common to go out on our 1996-2000 Vortec 5.7L engines. The poppets are probably sticking open and dumping fuel. How is your gas mileage? Part number is 63886 and its made by Borg Warner.

 

[buckeye026]

the gas milage is extremly bad.

 

[fyremanpat]

maybe try cleaning the MAF

 

[99Yukon_Z71]

But if you do clean the MAF make sure it is with MAF cleaner spray!! You DO NOT want to use carb cleaner or anything esle as any residue on the filament can cause driveability problems or even damage the MAF. Remember to NEVER touch the filament!!! But I doubt the MAF is your problem. Keep us informed!

 

[buckeye026]

I just ordered a ECM and The CPI Injector system. The truck sounds like its carburated and the carb is is dumping fuel. So I hope this fixes it.

 

[buckeye026]

well I changed out the spyder injectors it cleared everything up. I also had to change out the intake because it looked like the injectors caught fire. they were all fused together. and the intake was melted on the inside.

 

[ravingmadman]

Whoa. Sounds like you narrowly avoided a full-on engine fire. Go buy a lottery ticket!!!

 

[TheBeast99]

hmmm, all these things are something i might want to consider this summer - i'm gonna work on solving my warm hesitant starting issue.

 

[Redman7]

I have the poppet on number 1 stuck shut. I was going to have the whole injection system cleaned by a shop near me. Any opinions on this vs. replacement. My thinking is, if I'm going to remove that cover to get to the spider, I'm going to switch over to the mfi system and that costs $300 more than cleaning. Just thinking out loud here.

 

[destroyer1362]

hmmm, all these things are something i might want to consider this summer - i'm gonna work on solving my warm hesitant starting issue.

I hear ya I got the same problem

 

[fire730]

Ditch the popppets!!! Get the upgraded spider.

Don't even waste your money cleaning them. Best thing I did to my Tahoe.

 

[drowndindreams]

Whoa. Sounds like you narrowly avoided a full-on engine fire. Go buy a lottery ticket!!!

lol +1!

 

[TheBeast99]

I hear ya I got the same problem

it kinda sucks tho. i was hoping this'd be the first problem i could tackle myself on my Yukon, but i get the feeling it's about my skills as a newbie and i should do some other general maintence first to get a good hand on it lol

 

[buckeye026]

it was acually easy to fix. I just pulled the hood to make it easy for me to get into the engine. but i did go with the upgraded spyder.

 

[stykthyn]

it kinda sucks tho. i was hoping this'd be the first problem i could tackle myself on my Yukon, but i get the feeling it's about my skills as a newbie and i should do some other general maintence first to get a good hand on it lol

imagine how hard this would have been a few years ago without the internet at your side. Jump in there and take care of it. You will be done and driving around before you know it.

 

[TheBeast99]

i will, once i order a repair manual or two. just haven't gotten around to it yet. after this month's bills are done i will.

i just thought of this though - how would dirty fuel injection or stuck poppets affect only warm starting for me? cuz i don't have anything else wrong with the engine, be it at idle, WOT, around town, etc...