View Full Version : 328 not running properly

03-06-2005, 02:19 AM
All you Tech guys,

Need some suggestions. Early this evening, I filled up on some Sunoco 94. Put 40L in to fill up the tank. After getting my car flashed by Mark D (back in the summer), I've been running strictly on the 94 stuff.

Well, about 15 minutes or 15kms of driving - I get on the hwy and notice the car doesn't seem to be running normal. In 5th gear doing about 120km/hr, my acceleration feels about 80%. I drop it into 4th and it feels worse! Almost like the car was only running on 4-5 cylinders. Slight hesitation and not the usual smooth climb. The exhaust sound was much more muted than normal too. Didn't get that throaty sound of the 328 at +3000rpm like normal.

Well I sort of limped home. Not only was my acceleration reduced, but throttle response is also not normal. The car did rev at it's normal range for the speeds I was doing. Ex. 120km/hr roughly 3000rpm in 5th.

Any suggestions as to what I should check first? Help

Feels like when my old 90 Accord's O2 sensor went. BTW. My CEL light's been on since summer - probably one of the 4 O2 sensors shot again. Never fixed since the car always ran great including my fuel economy.

Plugs were changed about 10K ago w/Bosch +2's.


03-06-2005, 03:45 AM
HI Rico

First things first... talk to Mark and get him to flash your DME back to stock first to eliminate a software problem. When I was running his software for a bit and then flashed back to my conforti software, I noticed my acceleration more linear and complete but I know Marks software is pretty good. As soon as that happens and if your problem still persists, you know it isnt the software and then to the next thing.

If your O2 sensor hasnt been changed, change it..... very important especially the first and second primary sensors since they control fuel /air mixtures. 3 and 4 not so important since they are post cat and are used for emissions mostly.

The plugs you are running are not correct. I cant stress this enough but you have to use OEM plugs. especially the ones you are using bosch 2+ not good. I had platinum 4's in my car for a month and took them out. Bought brand new OEM NGK BK6EQUP which is a 4 prong copper plug and idle was much smooother. OEM plugs are expensive but they work.

If that doesnt work, I bet it is a coil that is not working. Check those areas and Im sure you will find your problem.

03-06-2005, 11:21 AM
sounds like the o2 sensor. on my old e30 i had the same problem unplug the o2 sensors and wola it works lol

03-06-2005, 10:08 PM
Gavin / Crusher.

Thanks for the suggestions. First thing I'm gonna try is filling up with 94 from a different location tonight! Burn some gas and add, hoping the mixture will get diluted, if in fact it is bad gas. I've had this issue happen before, in a motorcycle, and it WAS bad gas.

Gavin - that NGK plug model #, is that for an E36 328i? That's probably my 2nd choice. Elminate all the least expensive things before going to the next option.

Thanks Again,

Any other suggestions folks?

03-07-2005, 12:05 AM
BTW. My CEL light's been on since summer

Ding Ding Ding

Check that code.

03-07-2005, 01:06 AM
yes, the actual number of the NGK plugs are BKR6EQUP... that is from NGK... the dealer has a different number that will be avilable from the dealer. Those are the plugs for your car and my M3.

They are about 20 bucks a plug so its not cheap... you may want to order them from sparkplugs.com since they may be cheaper.

I dont think it is the gas..... my opinion anyways.

03-07-2005, 01:30 AM
Bad gas! Yup. Before opening up the hood and ripping things apart. I decided to go the cheapest route. So, if you've all read my 1st post, the car started running poorly about 15min, or 15-20km after filling up on Sunoco 94 (roughly 50L).

So today I decided to burn some of the good stuff off and top of with more Sunoco (15L only @$.94/L Cdn) but from a different location. Lo and behold - SHE's BACK!! Acceleration, throttle response, smoothness, and the slight throaty exhaust (Stock 328 exhaust) are all BACK. Hope she's stays this way.

Thank you for all that posted suggestions and comments.

I will get the car scanned and see what that damn CEL is all about (light's been on since summer).

Again thanks,

Gavin - thanks for the info on the plugs. I'll keep that for later. $20/plug? Hmm. I think I can do better.......

03-07-2005, 12:23 PM
good that you solved it. there is a member here that filled up at Sunoco one time and he got 50% water in his tank.