alright guys,
as some of you know, my bro picked up that 320is, anyways, once it starts, it runs like a dream. everything is powerfull and response is great but starting it can be troublesome.

from my bro:
-it has a hard time starting when the tank is half or less full....
-he changed plugs
-cleaned distrubuter
-checked and cleaned fuel relay

it will start as soon as you flip the key but then turn off. after that it takes a minute to start and then once running, its fine... any thoughts?

i'm thinking the WUR or the fuel pump, but you veterns here this problem more often then i do and i searched but couldnt find an exact answer!

thanks from my bro

I had just about the same exact problem when I reinstalled my old motor...turned out that it was running too lean (the AFR's were 17:1 to 18:1). I adjusted the fuel mixture accordingly (I transfered my wideband O2 to the stock exhaust) & it fires up very easily now. Altho, for my engine, I'm thinking that the WUR could use a freshening up (the AFR @ idle is a bit rich).
I wouldn't recommend adjusting the fuel mixture unless you know what you're doing (and/or have a way to monitor the AFR)

But if it's directly related to the amount of fuel in tank, it might be a bigger possibility of a fuel pump issue (or the fuel filter)

I was thinking fuel filter. Easier to start with that anyhow.

But if it's directly related to the amount of fuel in tank, it might be a bigger possibility of a fuel pump issue (or the fuel filter)


That was my thoughts as well. My car sometimes has a hard time starting when it has warmed up, still not sure why cause it does it rarely.

Warm start issues are usually heat soak. Too much hot air under the hood for the motor to get enough usable O2 to fire. And I can't IMAGINE where you are getting the hot air from. :stickoutt

Hard starting problems on high pressure mechanical injection systems are usually vapor lock. If your fuel accumulator is going, the diaphram is ripped and allowing pressure to bleed off, it will cause vapor lock during warm starting. My 80 vw rabbit truck(also CIS turbo) used to do that and i just delt with it, never replaced the accumulator.
I just made people think i was drivin a shitbox when id crank for 30 seconds on a warm start before it started