Update: ignition coil #2 p0302

[$outhCentral]

Can someone please tell me how to uninstall the fuel feeds pipe on my 2004 gmc envoy 4.2 i6 im trying to clean my fuel injectors thank u

 

[IllogicTC]

I've moved your thread to an appropriate subforum, and changed your thread title to help people understand what you're looking to do.

I can provide a rough list on what needs to be done.

0.) (Prep) Disconnect your positive battery cable
1.) Remove intake resonator. This includes removing all vacuum lines, and disconnecting the clip holding the wire loom toward the back.
2.) Remove the throttle body, this includes disconnecting the wiring and vacuum hose. Now is a good time to clean it, since when the battery goes back on the PCM will expect a clean TB.
3.) Remove the intake manifold. This includes removing any vacuum lines. You should now be able to see your fuel rail.
4.) Remove the four bolts securing the fuel rail to the engine. Note that you'll want to follow proper procedure on dealing with fuel lines as this is obviously connected to them via the fuel pressure regulator (the cylinder on the front of the rail, may have the other end of the hose from the resonator still on it). I haven't any clue on how to do that as I have never had my hands in a fuel system. I believe there may be some other connector toward the back of the rail too, for the injectors.

You may or may not need to have a replacement intake gasket on hand when you do this, I can't remember. Throttle body cleaner is a must, since the PCM will expect a clean one (it can relearn a dirty one, just takes quite a while and will run like garbage the whooole time). A torque wrench is a necessity to replace all bolts at their proper torque values.

Fuel injector rail bolts: 89 inch pounds
Intake manifold bolts: 12 foot pounds
Throttle Control Module bolts: 89 inch pounds

Can't find and can't recall off-hand what the resonator should be, just tight but not crazy.

Don't go off these instructions alone. This is just a rough draft of what you're looking at. Maybe I have it all right or maybe I'm missing something, wait for someone to check my work.

 

[$outhCentral]

I've moved your thread to an appropriate subforum, and changed your thread title to help people understand what you're looking to do.

I can provide a rough list on what needs to be done.

0.) (Prep) Disconnect your positive battery cable
1.) Remove intake resonator. This includes removing all vacuum lines, and disconnecting the clip holding the wire loom toward the back.
2.) Remove the throttle body, this includes disconnecting the wiring and vacuum hose. Now is a good time to clean it, since when the battery goes back on the PCM will expect a clean TB.
3.) Remove the intake manifold. This includes removing any vacuum lines. You should now be able to see your fuel rail.
4.) Remove the four bolts securing the fuel rail to the engine. Note that you'll want to follow proper procedure on dealing with fuel lines as this is obviously connected to them via the fuel pressure regulator (the cylinder on the front of the rail, may have the other end of the hose from the resonator still on it). I haven't any clue on how to do that as I have never had my hands in a fuel system. I believe there may be some other connector toward the back of the rail too, for the injectors.

You may or may not need to have a replacement intake gasket on hand when you do this, I can't remember. Throttle body cleaner is a must, since the PCM will expect a clean one (it can relearn a dirty one, just takes quite a while and will run like garbage the whooole time). A torque wrench is a necessity to replace all bolts at their proper torque values.

Fuel injector rail bolts: 89 inch pounds
Intake manifold bolts: 12 foot pounds
Throttle Control Module bolts: 89 inch pounds

Can't find and can't recall off-hand what the resonator should be, just tight but not crazy.

Don't go off these instructions alone. This is just a rough draft of what you're looking at. Maybe I have it all right or maybe I'm missing something, wait for someone to check my work.

Thank you very much IllogicTC YOUR information is very helpf ill make sure i buy a torque wrench since i dont have one thanks again

 

[IllogicTC]

Thank you very much IllogicTC YOUR information is very helpf ill make sure i buy a torque wrench since i dont have one thanks again

If you get the "click" type (where you set the desired torque on the handle, and the head clicks when it's done) you may need a 1/4" size (they can handle the inch-pounds) and at least a 3/8" size (it can handle low-midrange foot-pound torque specs). I myself only have a 1/2" adapter type (FOR NOW!), so I'd be stuck on this project too, but if I needed to tighten a lug nut you better bet I'll get it to 103 foot pounds

Just an FYI also: 12 foot pounds is 144 inch pounds, just like 12 inches to a foot for length and so on... So if you can find a 1/4" drive socket torque wrench that goes up to say 150 inch-pounds, one wrench can get you by for this project.

Harbor Freight has a 1/4" drive socket torque wrench adjustable from 20 to 200 inch pounds, so that'd cover your needs for just over $20. I can't promise it'll last forever, because Harbor Freight, but it should handle what you need without having to get multiple wrenches.

 

[eXplicit]

Not sure if it was already said, but before doing anything, you should let the engine drain your fuel line up to the fuel rail by pulling the fuel pump fuse while it's running. That way you're not dealing with a bunch of gas up front.

 

[$outhCentral]

Not sure if it was already said, but before doing anything, you should let the engine drain your fuel line up to the fuel rail by pulling the fuel pump fuse while it's running. That way you're not dealing with a bunch of gas up front.

Awww damn it i didn't do that u see im a do it your self kinda guy to save money and my mechanic experience its just well basics brakes oil change plugs the simple stuff so there for i didnt do that first step and everything is disassemble except the fuel rail now im do you think i should assemble everything back together to do first step or would it be ok to keep on going?

 

[eXplicit]

Awww damn it i didn't do that u see im a do it your self kinda guy to save money and my mechanic experience its just well basics brakes oil change plugs the simple stuff so there for i didnt do that first step and everything is disassemble except the fuel rail now im do you think i should assemble everything back together to do first step or would it be ok to keep on going?

No, whatever falls will eventually evaporate. I wouldn't worry about it now.

 

[IllogicTC]

No, whatever falls will eventually evaporate. I wouldn't worry about it now.

Having a small bucket and some rags on hand couldn't hurt if you've got some

 

[$outhCentral]

Having a small bucket and some rags on hand couldn't hurt if you've got some

Hey guys here is an update i did everything i need it to do and once i assembled back together the misfire is still there but much less now and i also notice that before the check engine
lightwould flash and then stay on and now it just flashes and goes out and then it will flash again ans trn of it was alot of work but now im getting a little frustrated tomorrow i will go buy the ac delco spark plugs see ic that is any help , anymore ideas guys i really need some thank you

 

[jimmyjam]

have you connected a scanner to your car yet? There may be a P030x code (x denoting which cylinder is misfiring). may possibly be a coil pack going bad

 

[$outhCentral]

have you connected a scanner to your car yet? There may be a P030x code (x denoting which cylinder is misfiring). may possibly be a coil pack going bad

Thank you jimmyjam well i took it to pepboy since they scan it for free and the codewad p0302 and said faulty coil#2 so i replace it with a new one but its not a ac delco it was a pepboys brand and since i wad told that somehow these engine seem to know when its not the brand they usually have but later on today i will take it back and have them scan it again to see whats the problem

 

[Gevans17]

Thank you jimmyjam well i took it to pepboy since they scan it for free and the codewad p0302 and said faulty coil#2 so i replace it with a new one but its not a ac delco it was a pepboys brand and since i wad told that somehow these engine seem to know when its not the brand they usually have but later on today i will take it back and have them scan it again to see whats the problem

I have 2 Trailblazers running great with BWD coils from Advance Auto.

 

[$outhCentral]

I have 2 Trailblazers running great with BWD coils from Advance Auto.

Thaks for all the help gmtnation crew but i took it to pep boys again and now the code reed faulty coil number six now i really dont know whats going on they wr all good except number 2 i changed it with a new one and now its number 6 pls guys i need more help what should i do now buy a new ing coil for number 6 or what shoul i try in order to fixs this problem and ill definitely look into the bwd coils thank you

 

[Gevans17]

Thaks for all the help gmtnation crew but i took it to pep boys again and now the code reed faulty coil number six now i really dont know whats going on they wr all good except number 2 i changed it with a new one and now its number 6 pls guys i need more help what should i do now buy a new ing coil for number 6 or what shoul i try in order to fixs this problem and ill definitely look into the bwd coils thank you

Sounds like pepboys is throwing parts at it. Didn't know there was a code for "bad coil".

 

[RedEnvoyDenali]

Logic tells me that you can just swap the #2 for the #6 and take it back to Pep Boys and the trouble will follow the coil. If you had a bad coil and a weak one perhaps you have 4 more since one would think they are same age.

Good luck with the search.

 

[dla442]

That seemed like a lot of work with fuel rail for a misfire that a scanner could have caught. Typically I think the #4 coil is the bugger. Also when you reinstalled the coils from the fuel rail job, maybe something went wrong. If you had two coils bad your i6 would have ran like crap if at all. The PCM will throw a general p030 code at first then after a while it determines what cylinder p0304, 0306 etc. The last number denotes the cylinder. Maybe pep boys just guessed or the bad coil wasn't really replaced because the firing order was backwards when getting to the coil. A bad injector usually can be cleaned by attatching a 3m cleaner directly to the fuel system and the engine runs off the 3m canister and when it's done,the engine stops. Never heard of removing the top on engine to clean injectors. Anywho front of engine towards fan is #1 and the back by firewall is #6. My #4 is the chronic one I think as it's been replaced 3 times over the life of ownership. Plenty of posts on this one.

 

[RedEnvoyDenali]

Logic tells me that you can just swap the #2 for the #6 and take it back to Pep Boys and the trouble will follow the coil. If you had a bad coil and a weak one perhaps you have 4 more since one would think they are same age.

Good luck with the search.

My apologies. This method would work for the coils, but although it would work for injectors as well, it is not very practical considering the work required to get at the injectors. I agree an injector cleaner should have been the first step, probably the least costly for both time and money. However the good news is you now know how to change injectors. LOL You may never need this knowledge again or perhaps you can pass it on to someone else. Just the way this site rolls.

 

[$outhCentral]

My apologies. This method would work for the coils, but although it would work for injectors as well, it is not very practical considering the work required to get at the injectors. I agree an injector cleaner should have been the first step, probably the least costly for both time and money. However the good news is you now know how to change injectors. LOL You may never need this knowledge again or perhaps you can pass it on to someone else. Just the way this site rolls.

LOL!!! Thank you for helping guys well im now taking my envoy to pepboys to be scanned again, and I did changed the coil #2 to #6 so now im gonna see what the scanner reeds

 

[MAY03LT]

i was told that somehow these engine seem to know when its not the brand they usually have

There is some truth to this - using plugs other then the recommended 41-103s can cause random misfires and wipe out the coils (regardless of coil manufacturer).

Sounds like pepboys is throwing parts at it. Didn't know there was a code for "bad coil".

I'm sure they scoped the coil(s) before condemning them. On second thought, I don't think so.

This method would work for the coils, but although it would work for injectors as well, it is not very practical considering the work required to get at the injectors.

Yeah, way too time consuming. There is a way to test the injectors but it's not DIY - a bi-directional scan tool is needed.

 

[$outhCentral]

There is some truth to this - using plugs other then the recommended 41-103s can cause random misfires and wipe out the coils (regardless of coil manufacturer).



I'm sure they scoped the coil(s) before condemning them. On second thought, I don't think so.



Yeah, way too time consuming. There is a way to test the injectors but it's not DIY - a bi-directional scan tool is needed.

Thank you guys for your posts well I took my truck to pep boys scanned it and it reed that ignition #6 has a miss fire I don't get it the first time it said img #2 miss fire so I replaced it with a new one took it back to get scanned and said #6 miss fire I took of #2 the new one installed it on #6 took it back to pep boys and it reed #6 miss fire now IM getting I bit more frustrated because not only that it pop out two more codes p0122 p0223 OLD HELP

 

[MAY03LT]

Thank you guys for your posts well I took my truck to pep boys scanned it and it reed that ignition #6 has a miss fire I don't get it the first time it said img #2 miss fire so I replaced it with a new one took it back to get scanned and said #6 miss fire I took of #2 the new one installed it on #6 took it back to pep boys and it reed #6 miss fire

They shouldn't only go by codes for finding a misfire. A higher end scan tool can show real-time misfire counters as well as misfire history.

Don't they have a law or something in cali where they can't turn off the check engine light unless a repair was done? I would want to be 1000% sure that the codes were cleared.

now IM getting I bit more frustrated because not only that it pop out two more codes p0122 p0223 OLD HELP

Did you ever get a reduced engine power light with the engine running? Those codes should have turned the REP light on. Since there has been a lot of work done to the engine recently, it could also be because at some point the key was on with the throttle body unplugged.

 

[$outhCentral]

They shouldn't only go by codes for finding a misfire. A higher end scan tool can show real-time misfire counters as well as misfire history.

Don't they have a law or something in cali where they can't turn off the check engine light unless a repair was done? I would want to be 1000% sure that the codes were cleared.



Did you ever get a reduced engine power light with the engine running? Those codes should have turned the REP light on. Since there has been a lot of work done to the engine recently, it could also be because at some point the key was on with the throttle body unplugged.

Thank you MAY03LT I believe pep boys can scanned your car but not give you the diagnostic and no I don't think they are allowed to clear the check engine light unless they repair it themselves, reduce engine power light has not come on but also what I have notice (only when the engine is cold) is a loud hissing sound and I remember the forts code did say ignition coil #2 miss fire or vac leak ummm so now IM thinking IM going to,try and find that hissing sound

 

[IllogicTC]

Only when the engine is cold? Could be the SAIS system. On the passenger side of the engine you'll find a valve attached to the cylinder head, the air intake tube runs roughly above it or next to it on its way to the resonator. Could be coming from there as part of normal operation.

Also when the P/S pump gets cold (I'm talking winter cold, not California's idea of cold ) it sometimes grumbles until it warms up.

 

[$outhCentral]

Only when the engine is cold? Could be the SAIS system. On the passenger side of the engine you'll find a valve attached to the cylinder head, the air intake tube runs roughly above it or next to it on its way to the resonator. Could be coming from there as part of normal operation.

Also when the P/S pump gets cold (I'm talking winter cold, not California's idea of cold ) it sometimes grumbles until it warms up.

View attachment 21352 this is the piece that i found that makes all the hissing so far still working on my envoy still has ruff idle when take of can u guys pls help should i replace this part or clean it cause,it douse have little bit of oil inside

 

[$outhCentral]

View attachment 21352 this is the piece that i found that makes all the hissing so far still working on my envoy still has ruff idle when take of can u guys pls help should i replace this part or clean it cause,it douse have little bit of oil inside

Hi gmtnation crew well I did everything I could do to fix it my self, when I first got my envoy I ran it for like 600 miles and the change engine soon light came on when I took the sparkplugs off I checked the calibration on those and it was 0.050 so I said let me double check before I install the new one I called a local parts store and I was told 0.042 and I also googled it,and the same thing 0.042 so my final disunion was to go ahead and gap them at 0.042 the engine was smooth even better then it was before and notice better MPG,so last night I dicided what the hell I will gap the plugs at 0.050 so last night I took it for a drive and needed some has so I added some Lucas has treatment filled up the tank and it ran,great but then the check engine light came on again is started misfiring again but this time waaaaay much less then before so I guess now IM going to replace the ignition cool #6 in which it had the new one cause I swap them before I took it to get scanned to see if the misfire problem was gonna be #2 but no the scanner said #6 so I said fu«» IM going to buy a new today hopefully it will fix the problem now thank you All gmtnation for giving me ideas and advise on this issue I can't complain I've learned alot

 

[$outhCentral]

Hi everybody GMTNATION CREW . WELL im having trouble with my ignition coil #2 i took it to get scanned and thats the code that pop up so i replace it with a pepboy brand coil and the misfire kept on going didnt change a bit, took it back got it scanned again and this time ingnition #6 pop up hmm so i swapt the coils the new one to number six and the six to number 2 took it back and still misfired #6 i told the guy #6 has a new coil why would the misfire still be there well they couldn't anwser the question cause they would have to charged me anyways i took off the new coil brought it back got a new one installed it on #2 went back to pepboys again and misfire on #2 so now im stuck iin between all of that labor i installed new ac delco sparkpl checked for vacum leaks fi found non so im thinking maybe the fuel injector please help im confuse and dont know what to do now thank you.

 

[strat81]

Hi everybody GMTNATION CREW . WELL im having trouble with my ignition coil #2 i took it to get scanned and thats the code that pop up so i replace it with a pepboy brand coil and the misfire kept on going didnt change a bit, took it back got it scanned again and this time ingnition #6 pop up hmm so i swapt the coils the new one to number six and the six to number 2 took it back and still misfired #6 i told the guy #6 has a new coil why would the misfire still be there well they couldn't anwser the question cause they would have to charged me anyways i took off the new coil brought it back got a new one installed it on #2 went back to pepboys again and misfire on #2 so now im stuck iin between all of that labor i installed new ac delco sparkpl checked for vacum leaks fi found non so im thinking maybe the fuel injector please help im confuse and dont know what to do now thank you.

Try swapping the alleged bad coil with coil 1 or coil 3, see if the code follows the bad coil.

Stick with ACDelco coils if you need replacements. And buy yourself a code reader. You can get a basic one for less than $50. They're just as necessary as a ratchet for working on modern vehicles.

 

[IllogicTC]

I don't think it's the injector or it would have stayed on 2 when you switched the coils, but it followed the coil.

 

[salth2o]

Since there has been a lot of work done to the engine recently, it could also be because at some point the key was on with the throttle body unplugged.

So what is the fix for this if that happened?

 

[BlazingTrails]

Ironically I got a p0302 a few days ago. I reset it to see if it happens again. I do have a spare coil on standby hopefully it will not go any further.....

 

[Mike w]

I don't think I will ever go to pep boys... just my 2 cents.. you should watch May03lt's video about diagnosing a misfire on YouTube that's how I tracked down my random misfire problem.