[ConradConrad]

2008 E90 93K miles completely stock since 55K(only a JB4 prior)

I recently replaced my spark plugs. I was only able to replace 4 in the beginning because Advanced auto parts sent me two of the wrong ones.

I installed the 4 bosch replacement plugs and the car ran great, just a little hesitation still left from the two old plugs.

I received the two remainig plugs and installed them three days later. Immediately after putting everything together and taking the car for a spin I could tell it was lagging. After it warmed up I got on it a little to see if it was something that would improve and threw a half engine light.

Shut car off and back on nothing but same throttle lag sensation. If I put the car in DS or get on the throttle it will throw the half engine light, if I drive like a granny nothing.

Checked vacuum lines, which I have replaced before due to some information on another thread, http://www.e90post.com/forums/showthread.php?t=546560
and found one to have a small split. Same issue continues.

BT cable states 30FF each instance. No other codes.

I have read to check chargepipe and Diverter valves first. I assume charge pipe I should take completely out and inspect the pipe itself? Anything else? DV the same? Also I read the DV can be loose causing a leak, how do I tighten them as they look like a simple twist in. Should there be any play where they attach to the charge pipe?

Also I read someone chased a boost leak for months and turned out to be faulty DVs, would that $ BOV mod where I put chair ends over the chargepipe DV openings a good way to test a issue at the DV attachment?

Should those be the first places to look ? Also huge coincidence it happened immediately after the plug change? No SES or misfire codes or anything

Thanks

[N44183]

Check the boost solenoids-I found one would barely hold a vacuum. I bypassed the bad one until the new one arrives. I am running both vac tanks and both waste gates from one solenoid (the good one) and the 30FC and 30FC codes are gone. Not sure how safe it is but I have not had an overboost issue.

[ConradConrad]

Originally Posted by N44183

Check the boost solenoids-I found one would barely hold a vacuum. I bypassed the bad one until the new one arrives. I am running both vac tanks and both waste gates from one solenoid (the good one) and the 30FC and 30FC codes are gone. Not sure how safe it is but I have not had an overboost issue.

Hey thanks for the response, did you only have 30FC codes and not 30FF? Also how were you able to check/test the boost solenoid?

[N44183]

Had both codes. I believe I used a vac pump (miti vac from vatozone) and pretty sure I hooked it to the hose that goes to the canister. I found a how to online somewhere. It may have been the one that goes to the wastegates though. Whichever one holds vac, it should not bleed down much if any at all. One solenoid bled down very rapidly where the other was very slow.

Was getting aforementioned codes and the half engine light like clockwork on any sustained highway pull.