e30 320i hesitation problems

[almost_goth]

Last week I picked up an import e30 with a nice M body kit for about 2k. After some confusion with the vin number not matching up (a story in and of itself) we did a little research and found that the car was not an '86 325e but rather a 320i. Ok, so my car is more unique and interesting than I though. Other than the usual trunk leak (found the source and will fix tomarrow) and some minor interior stuff the car is in good shape and runs pretty well. The problem I'm having is a bit of hesitation at about 5k rpm. I've been a little wary of probing the high revs until I've had a chance to do a more thorough inspection of the guts of the car, so I don't want to start reving it up to 6k just to say I can. I'm thinking the problem might be from not getting fuel fast enough as it goes back to being ok if I let of the throttle.

So beyond helping me with my hesitation problem, what can you guys tell me about the m20b20 that I should be aware of? I don't need to or want to hear about how the 2.0 sucks and I should get a stroker.

I'll post pics of the car soon.

[mikeedler]

the 2.0 sucks!!! J/K. it is the same motor basically as the 2.5s it has a different bore and stroke. the throttle body is smaller, I think the same as the ETA models, and the exhaust manifolds on the earlier models are smaller. I have owned a couple 2.0s over here, and cant really say anything good about them, they suck down the same amount of fuel, and feel like they are missing the power they should have. everything from the 2.5s fit directly on it(well almost everything) interranll parts not included, and it is not worth putting the 2.5 throttle body, or exhaust on it cause you will not feel a difference( i know cause ive done it)

[almost_goth]

In all truth I wish it did have more power but it still shovels pretty well compared to my old e21 320i. For now I just want to keep the car running and in good shape. It came with a pretty nice performance exhaust and at most I'll probably get a cone filter and chip, can't picture getting much more than those two items for this motor. I'm planning on getting a shark in the next few years and yanking the motor as part of a project (666csi - aluminum 402 v8) so if I need more power then I might go the m30 route.

Do you know how the 2.0 is for reliability compared to the 2.5? Does it wear differently from the smaller pistons/dif. head? It's only got 150k on the clock now and the oil's clean so I'm just curious.

Thanks.

[PeterCip]

hey, when was the last time you checked your plug gaps? if they are too far apart you wil get that feeling near the peak or your torque band. some people gap them further than recommended to get a smoother idle.
the plugs youre running might be to hot for the car too. I use w5dc plugs and they work great on my turbo. you may not want to go that cold. try stock or one step colder on your car.
-p

[BavarianBimmer]

In all truth I wish it did have more power but it still shovels pretty well compared to my old e21 320i. For now I just want to keep the car running and in good shape. It came with a pretty nice performance exhaust and at most I'll probably get a cone filter and chip, can't picture getting much more than those two items for this motor. I'm planning on getting a shark in the next few years and yanking the motor as part of a project (666csi - aluminum 402 v8) so if I need more power then I might go the m30 route.

Do you know how the 2.0 is for reliability compared to the 2.5? Does it wear differently from the smaller pistons/dif. head? It's only got 150k on the clock now and the oil's clean so I'm just curious.

Thanks.

reliability is objective , but logically (and it's proven) the M20b25 is more reliable as the M20b20 -> more power and torque is less wear

it'l like Mike already said compare the 2.0 with the 2.5 and you feel that the 2.0 miss power costs are the same on both engines such as maintenace, fuel , etc.....

[almost_goth]

Do you know the correct gap for the plugs? The PO thought the car was an eta rather than a 2.0 so he's probably got the wrong gap in there anyways.

Hell, anyone know where I can get an owners manual and/or repair manual for this thing in English? The Bently and Chilton books for the e30 are only for the US models. If they made on in English for left hand drive models that would be preferable.

[Court M3]

Haynes manual number 815. Had the same problem finding tech info on the M20b23

I have one that I found in while stationed in Japan. Covers the M20b20 to the 87 M20b25 Will send you the info later.

[mikeedler]

here in germany most of the 2.0 motors are gone---dead. for some reason the 2.5s seam to last longer, and the only real difference is the oil cooler. I cant really see that as the reason the 2.5 lasts longer, but they do. alot of 2.0s ive seen here seem to blow the head gasket alot sooner in life than the 2.5s.

[PeterCip]

I want to say that the gap should be .025.. maybe that is what I used and the real number is .028. I had a big prob with spark "blow Out" at my peak torque.

someone verify .028 for me? this is off the top of my head.
-p

use the recommended plugs for the car or a step colder. don't even think about putting platinums in there. they will only casue more problems

[Court M3]

Manual recommends Champion N9YC or equivalent
Electrode gap .024-.028

[BavarianBimmer]

Manual recommends Champion N9YC or equivalent
Electrode gap .024-.028

it's strange but i've got problems with the champions on my ex 320i (cracked head on 200k kms)
esp. cold acceleration between 2- 3k rpm
I swear with the Bosch sparks