Flat/Dead Spot at about 1500- 2500rpm

[4KING MP]

Hi Fanatics

I have a problem with my car and it's starting to bug me. 

So I bought an amazing E92 325i ///M in Jan and I've been loving the experience. E92 coupes are the best 

So...in January/February I did an Ecu Chip Tuning by Eurospeed and the car was running strong and was very smooth...until I decided to do a plug service and oil change.

I contacted BMW and they quoted me 1800 for plugs and I was like what the hell...so I did some research and I ended up buying Bosch Plugs (Platinum ) from Gowagen...

Took my car to an RMS approved service dealer and they did the service for me.

When I fetched the car took it for a spin,ran well and I was happy. Following morning when I started it...it had an ugly start up but stabilised until I drove off and I experienced what seemed like a flat spot during acceleration but only on gears 1 and 2 and at low rev ranges. However this wasn't consistent but now and then you could feel it. Soon probably after a week or few days it cleared and the car was running super strong and loved it.

Then about two weeks back I then took my car for some further mods at PowerPipes. They did a decat system, new Down pipes and free flow system . SHE SOUNDS LIKE A GODDESS HAVING AN ORGASM 

However when they were done took her for a spin and she was perfect.until I had to drive home. Got to a robot and she was idling sexy then when it hit green I tried to gun her down and pull and there was that flat spot again 

I thought OK it will go way after a few days but nothing. It's still there. Took it to my tuner and he did a diagnostic test and it only picked up cats as being faulty. So I was advice to go back to PowerPipes and fit mini cats of which I did yet still nothing changed.

Now I'm stuck with this issue and I don't know what to do 

Please help if you have any idea what could be wrong?no faults appear in the cluster and for the most part she runs well it's just those occasional dead spots at low revs....and it's irritating sounds like my cars a skorokoro...please help and advice 

Thanks

 

[Kish2604]

did you put the right plugs in? How sure are you that they match the oem plugs? You obviously need a set of cat foolers to get the sensors happy again before you can diagnose further... Also one of the sensors could have been damaged during the install?

 

[4KING MP]

did you put the right plugs in? How sure are you that they match the oem plugs? You obviously need a set of cat foolers to get the sensors happy again before you can diagnose further... Also one of the sensors could have been damaged during the install?

Hi Kish

Well when I purchased the plugs I assumed they would be the right plugs ...I think probably that should be my starting point then...is there any place where I can get solid oem Plugs except from BMW or I'm doomed for the 1800?also which sensors do you reckon could be damaged during the install...should the computer box pic it up or at least the diagnostic tests?

 

[Kish2604]

Verify what plugs went in against what came out or check real oem for part numbers, I am thinking the heat range on the replacement is wrong and explains the the cold start lumpiness the next day.

Wrt the O2 sensors, a proper diagnostic set up like inpa or gt1 will be able to check the voltages the sensors are reading and if either of them are out of kilter, alternatively the cat foolers might also help...

Adaptions will need to be reset as you have changed material items involved in the operation of the car, that is spark plugs and fiddled with O2 sensor possibly changing their position in the air stream in the exhaust.

 

[Philip Foglar]

Check www.realoem.com to see what plugs your car needs. Typically most places should have either these NGK or Bosch plugs for less than what the agents charge, but you can also see what G-Drive.co.za has. What oil did they put in the car when serviced?

 

[Ralf*]

you could by process of ellimination,
if you still have the old plugs lying around, even though they may be old, at least they were still working up to that point, it seems all your problems, although intermittent, only started after the plug change that you did.

if after replacing with your old plugs, the trouble stops....then thats your answer, it could be that one of the plugs has a defect, (cracked ceramics etc) and only shows up at certain combinations of temp/compression/boost etc causing the plug to break down....then you know that you need to replace the plugs again.

The CAT sensor/probe, could have received an electric surge, or the probe head is damaged, or the wiring received a "knick".
Why not do software to "delete" the CAT probes all-toegether

 

[Philip Foglar]

Yep, if you still have the old plugs I would put them back in and see if that changes anything!

 

[AshG108]

Hi 4KING- MP,

i met you at Powerepipes the other day when your buddy was there with you getting his Vivo Backbox & tips.

nice car and your sounds nothing like a skoroskoro.

as the above, start with your plugs, sounds like the plugs are the issue

Good luck with coming right dude.