Reduced power after Coil/Spark changes
 

Hi


2007 X5 3.0 over 250K KM

Was having misfires on Cylinder 1 & 2 (Codes P0302, P0301) every other week; it was becoming worse and got a Reduced Power error so decided to change Spark Plugs and Coils.
Changed them (BOSH Coils, BOSCH Spark Plugs), old sparks where full black. No Oil in plugs.

Started the engine, no issues, idling fine, no smoke, all looked normal so I let it running for 10 min. Decided to take it for a spin around the block, but barely made it to the corner as soon as I rev it up past 3K rpm got a Engine Light and Engine Reduced Power message (+ AWD/ASC errors) - had to limp back home....


Read codes, cleared them, restarted the engine, idles just ok but got same error Reduced Power immediately (not even moved). Can't rev it up (of course)

Read the codes again and I'm getting these errors now:

-2CEC
-2CED
-2D09

These seem to point to Intake Manifold? Nothing was touched there......

No misfire errors.....but engine feels like IS misfiring....

Any leads/suggestions?

It feels like the DME can't read the proper throttle position.

Best guess is that a connector or cable related to TPS was disturbed while changing the coils.

What scanner solution are you using? I would pull up the two TPS values realtime and see how they react to RPM. (also of course check the connector and cables to the tps).

PS: had a similar problem on my wife's m54 (01 e53) when the engine tried to ingest the o-ring from the MAF and jammed the actual throttle plate so maybe poke a look in there make sure nothing crazy happened like my case.

Thanks - will take a look then.

Although Im going to say this probably isnt your primary issue....Dont assume plugs and coils are 'not a question'


What SPECIFIC "bosch" plugs did you use? OE or one of their 'performance' versions?


Also, WHERE did you buy these? Tons of 3rd world counterfeits being sold online. Coils are notorious ....


Again, dont think this was the issue proir to replacement (:) ) but just a heads up

Plugs/coils won't be related to the errors for the TPS. Definitely need to track down what's going on there

Thanks, bought them from a trusted provider and they appeared to be fine -- it does not mean I will remove them from list of potential culprits-- or that they are exempt to be a bogus batch. I normally buy OEM or BMW original parts; not a fan of saving on parts specially if there is the risk of wasting $$ AND doing it twice....

The misfiring issues started a couple of weeks back but were quite sporadic but when I got the reduced power message decided to replace them immediately.

The point is that the new Coils/Sparks do not appear to have resolved the Reduced Power error - so I'm wondering if I jumped to replace the Coils/Sparks and there is another issue that I overlooked....

(Note they were at least +7 years old, maybe even the original ones....so that will make them 14yrs old....so due anyway)...

The current errors suggest stuck throttle or TPS problem have you looked at that yet?

Remind me which motor.

on my To-Do list for Tonight

3.0si

N52N

I did a starter replace on 328xi. Very similar. Not difficult to get down to the throttle body. (entire intake comes off to get to starter)