engine missfires as soon as i hit boost

[dirtsdsm]

i was driving from work yesterday and i got to a hill and my car went into to boost i got what seem to be a bad miss fire . as soon as i hit flat land i tried it again as soon as the car starts to build 1lb of boost it sounds like a subaru. under vac it runs just fine . please help me out

 

[JonathanNL]

Usually an ignition problem. When I had it, it turned out to be the spark plug wires which we're arcing. After replacing those the problems went away.

I would check: spark plugs, then wires, then the coil-pack. Hope that helps any.

 

[dirtsdsm]

checked plugs and they looked good. i could not see the wires arching anywhere.

 

[dsmdeliveryboy]

If it is as soon as you get into boost its a boost leak or your plugs might need changed/gapped.

 

[dirtsdsm]

the problem was my crank timing pully bolt came lose. when it did that the pully slipped probably 1/8 a turn. threw all timing off. i didn't think it was timing because all the timing marks lined up perfect.

 

[Absit]

Your plugs "looked good", what plugs are they and what are they gapped to (measure the gap yourself, don't look at the box)?

 

[dsmgsx98]

yeah i had this same problem a week or so ago but it was when the car was cold it would miss fire like that.. I say change plugs BPR7ES gap to 0.28, its a good cheap place to start $8 at the auto parts store!!

changed my plugs and it fix my problem, the other plugs i pulled out had 5k on them plugs can be decieving sometimes!

 

[XiKeiyaZI]

yeah i had this same problem a week or so ago but it was when the car was cold it would miss fire like that.. I say change plugs BPR7ES gap to 28, its a good cheap place to start $8 at the auto parts store!!

changed my plugs and it fix my problem, the other plugs i pulled out had 5k on them plugs can be decieving sometimes!

From my understanding, the BPR7ES's are a step colder burning plugs, used normally in high boost applications. I would recommend BPR6ES's gapped to 0.28 over the BPR7ES's at stock levels.

Besides checking the plugs, you should do as the rest have stated and perform a boost leak test, go ahead and check your coil packs and go the extra mile and test your plug wires. If nothing else, check for pre-turbo exhaust leaks and do a compression test for good measure. If you really want to be cautious - Check your timing.

 

[dsmgsx98]

COME ON BRO you have a post count of 1200 and you are telling ppl that BPR7ES aren't stock plugs?!?!?! BPR6ES is a step colder than a stock plug !!!

 

[1990AWD]

COME ON BRO you have a post count of 1200 and you are telling ppl that BPR7ES aren't stock plugs?!?!?! BPR6ES is a step colder than a stock plug and i ran them with my 20g setup on 24psi gapped to 0.26!!

BPR6ES is what my owners manual says for recommended spark plugs. If that isn't the stock plug then I don't know what is.

NGK rates them by the number. BPR7ES is one step colder than the 6's and BPR8ES is another step colder an so on and so forth.

 

[dsmgsx98]

, sorry bro got confused 7's are a step colder

 

[GRAVEDIGGER]

COME ON BRO you have a post count of 1200 and you are telling ppl that BPR7ES aren't stock plugs?!?!?! BPR6ES is a step colder than a stock plug and i ran them with my 20g setup on 24psi gapped to 0.26!!

Maybe you should understand what you are saying before you call someone out on the matter.

For the record:
BPR6ES is the stock heat range
BPR7ES is one step COLDER
BPR8ES is two steps COLDER
BPR9ES is three steps COLDER

number goes up, plug gets colder

 

[dsmgsx98]

i said sorry bro

 

[gst96spyderman]

this thread is 5 months old...

 

[AlaskanDsm]

the problem was my crank timing pully bolt came lose. when it did that the pully slipped probably 1/8 a turn. threw all timing off. i didn't think it was timing because all the timing marks lined up perfect.

Haven't heard or read about this happening yet outside of the pulley separating. I would this this would cause timing to be off enough to bent or at least tap some valves... Correct?