missfires at idle, and under heavy acceleration, also just recently will take longer then usual to start after car is warm (will start perfectly fine at cold start) . Missfire is not consistent and begin after changing spark plugs and installing jb4 tuner. I took it to the mechanic and they cleaned the fuel system, then the missfire continued and they concluded that the spark plug gaps were off, so i bought the recommended spark plugs again (pre-gapped), and changed them all out. The missfire is inconsistent and lightly makes car stutter during idle.Problem still remains
Last edited by 335islapshift1; 03-15-2018 at 09:57 PM. Reason: Missing info
First, delete the tune.
Then drive the car ~50 miles, and read the codes with a BMW specific professional scan tool.
Tell us what the codes are.
How many miles on the car? Have the injectors ever been replaced? Have the intake passages ever been blasted with walnut shells, to clean them? (No, that is NOT a joke.)
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
After installing a JB4 that raises cylinder pressure through increased boost, make sure you plugs are good and gapped no greater that stock and consider gapping them a little less. Your coils are the next weak link. Mine were fine at stock boost but gave misfires with the JB4. I replaced with S55 coils. 08 535xit. The coils showed issues only at the higher boost level. No problem at idle. My plugs were fresh and stock gap.
Not sure about the idle problems. Vanos solenoids can cause issues at idle, an intermittent stumble. You can try cleaning them or replace them. Mine were replaced around 45k miles due to a stumble. I cleaned them at 115k miles as preventative maintenance.
while its been in my possession, no it's never been blasted with walnut shells. Injectors were cleaned, not replaced. The only thing leading me to believe that its not the injectors is the fact that the car ran perfectly before the the previous spark plug change.. I feel like its very possible that its the jb4. So by delete, do you mean completely remove the jb4?
What about the ignition coils? Still have the original Bosch POS coils?
ASE and BMW Master Certified Technician
White 94RX..... ATLANTA ???? What, you got tired of bubbas?
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
Replied the same in the other thread you created.
Step 1, Read codes. It will tell you which cylinder.
a. you didn't seat your coils correctly back on
b. you need new ignition coils, and the 'tune' brought out the problem. coils are notoriously common on that car. New brand name coils for proper result, don't cheap out.
if you have 30bb code or similar, you need a dme.
Last edited by 328 Power 04; 03-16-2018 at 09:23 PM.
-Abel
- E36 328is ~210-220whp: Lots of Mods.
- 2000 Z3: Many Mods.
- 2003 VW Jetta TDI Manual 47-50mpg
- 1999 S52 Estoril M Coupe
- 2014 328d Wagon, self-tuned, 270hp/430ft-lbs
- 2019 M2 Competition, self-tuned, 504whp
- 2016 Mini Cooper S
When I said "delete the tune", I'm assuming this is a flash which can be returned to stock, and then "reflashed" at will, when the issue is discovered and attended to. My intent is to remove that variable from the equation, and concentrate on the misfires without the new tune being the focal point. I do admit to being very leery about such tunes, since they defeat much of the diagnostics available, especially when coupled with other related mods.
I also believe that the coils, or their connections, are a very likely suspect. Note that the plugs to this generation of coils MUST be assisted in place. Allowing the clip to pull the plug into place is NOT sufficient. Carefully note the gap behind the plug after it is plugged into the coil.
Still, the coils themselves don't usually cause IDLE issues, then clear up....which is what I think we're looking at here?
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
Walnut blasting is also a great thing to do on these direct injection motors. I could not believe the amount of goo I scraped out of the intake ports in the head and the carbon I blasted out. It really opened up the passage and the car seemed to me to run better afterwards. I don’t think this is the OP’s idle problem though.
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