VANOS in mind

[gusagar]

Hi guys!

As some of you know, I have a '97 328i and have two years trying to solve a low end (<1500 rpm) engine hesitation. With the A/C off and no hills, this phenomena stays for three seconds or less and it's not a heavy problem but if the A/C is on and ther is a hill the lack of power is really very uncomfortable.

I have changed almost all power related parts, spark plugs, gas filter, air filter, fuel pump, had cleaned the injectors, changed the ign coil resistors (1K), and the problem remains.

I'm suspecting the problem can be VANOS related, it's the only one part I never tryed. As I understand the VANOS mechanical control has an electrical solenoid driven by the engine ECU and an oil pressure operated piston, so one of this two things can be the cause for the problem, I HOPE SO.

I'll appreciate any comment or experience with similar power loss problems that prevents me to buy a new VANOS valve only to discover that this wasn't the problem.

Thanks in advance

GUSTAVO

 

[frolf]

gusgar,


"VANOS unit failure"

was on European Car's 22 "other known problem areas" list when they did their e36 buyers guide.

 

[GodfatherBMW]

If your vanos solenoid was bad it would set a check engine light. Your vehicles vanos only effects the intake camshaft. Possible bad mass air meter or idle control valve. The idle control valve works up till 4000 rpm.

 

[gusagar]

If your vanos solenoid was bad it would set a check engine light. Your vehicles vanos only effects the intake camshaft. Possible bad mass air meter or idle control valve. The idle control valve works up till 4000 rpm.

Godfather:

I never heard about a idle valve operating up to 4000. Are you sure?. My idle is very smooth, so, don't must think I the valve is good?.

Please broaden your theory, I'm very interested, and BTW the idle valve is very cheap

Thanks in advance

GUS

 

[gusagar]

And something more:

The check engine is off and a time ago I interchanged the mass air meter with a friend's 328i and nothing happened.

 

[JGM3E3632]

the vanos unit can be bad, even when there is no check engine light. The units usually make noise at 4000+ rpm when they are going out. If it was a vanos soleniod there would be a check engine light. Have you ever had your DME reprogrammed? Has the DME ever gotten wet?