M3 E30 ITB Synch

[nbp_uy]

Hi, hope everyone is fine.

I have been reading this forum two years from now, helping me with a lot of issues on my 318i and hopefully now with a M3.

The car was parked and saw little use in about 3 years (less than 3k miles).

Since I got it, been doing basic maintenance that was neglected like fluids, filters, bands, sparks, rotor, coil, etc..

And other mayor like new new cats, intake gaskets and all hooses.

Finally got to the part to regulate idle, now sits about 900, no gas smell, runs well, getting 9lts/100km on mix use (highway and city).

Got myself a carbtune to synch each throttle body since someone messed up (also the CO screw), because the car had an air leak and the best solution was to move everything to compensate that leak.

Car warm, TPS disconnected and in a loop, the readings on cyl 1 an 2 were too high compared to 3 and 4.

Now CO screw is closed so the air bypass between the ITB, thats the best combo I got with the car idling right, not stalling or so.

This is the best result I got:



Now I ask you guys, what should I try? balancing the throttle bodys? do a valve adjustement?

Any idea on this matter?

Thanks a lot[/img]

[nbp_uy]

Forgot to say, according to manual specs they should be around 22 - 24 cm HG.

When I first plugged the carbtune pro, 1/2 were high as 24's and 3/4 low as 8 or no reading.

[nbp_uy]

Hi, first of all thanks for the quick reply.

As I said and you recommend will check the butterflys first. Do you have any link to a DIY?

To my knowledge the AFM screw hasn´t been messed up with, I didn't touch it but could be 100% sure if PO or mechanic did it.

It's there any way to check a correct position for the AFM?, reading I found that the air screws between the TB for some are just a full turn out (from fully closed).

Maybe I didnt explain myself, my idle its right at 900 not hesitating. If I unscrew the CO, the idle rises.

Thanks

[BMG]

http://home.insightbb.com/~todd.kenyon/throttle.htm

[nbp_uy]

Thanks!

[bigbird76]

I used that guide on my m3 and then used the carbtune and it was spot on, I got all four the same, It takes a while to get thme exact but just have patinece and small adjustments, New plastic caps probably going to be required too after you have adjusted them.

Good luck

Leigh

[BMG]

There's lot of guides and chat on this on M3 forums and also M5 forums as the TB's are basically just 2 more of the same on the 6 cylinder E34s

[nbp_uy]

Thanks, sorry for the late reply was on vacations.
Yes I saw those post, will print them, study and try to do my best DIY later.

Thanks!