Idle speed 328

One thing to consider…
If you set the IDLE RPM to be 1000 with the AC off, it will drop too low (spec-wise) with the AC on. Remember, these are not computer-controlled engines where the idle will be automatically adjusted based on load… If you never use the AC, then set the idle with ac off at 1000. If you DO use AC, set it at 1000 with the AC on and compressor engaged (which means the idle with the ac compressor off will rise several hundred RPM).

 

i kept mine at 650 rpm idle. Still pulled without any strain. The odd day if AC required, turned the switch off at stop...:good for a minute with residual and than on once got going.

 

Bad idea. The FI does not work well at that low an RPM. There are good reasons the idle is supposed to be 1000-1100.

Zero advantage to run lower.

 

Have a 77 cRb not
Fi.

 

Odd

The question was about a 328 yet you gave info for a completely different car.


Not a really good choice on your part

 

Sorry, did not have my reading glasses on and I did not make out the 2 in 328. Realized it afterwards.

 

I'm learning about these cars too. I assume the 'electric switch' in your pic is an idle speed valve? I've adjusted some of the solenoid types by loosening and turning the solenoid but not sure that 'electric switch' can be adjusted. I did notice that my idle speed went up when I switched to synthetic oil. I adjusted the idle speed down by turning the stop screw on the throttle lever side (the vertical slot screw surrounded by the black plastic surround - I think). Idle speed came down to about a 1000 (on the tach assuming it's relatively accurate) when warm (slightly lower until warmed up and occasionally needing a little throttle for a few seconds) and seems relatively stable. Someone let me know if I did not do the right thing.

 

When it returns to idle only after applying some load you have to check your vacuum relief valve. You can check this by removing the valve and closing the two hoses. If it idles good then the valve is the cause. The valve prevents excessive overrun conditions.

 

it should be just under a 1000rpm, 900 to 950

sticky or faulty aux air valve, the one under coolant expansion tank, if the air valve does not close when car warms up after startup and driving it will idle high above 1000 rpm towards 1400 rpm...

you can test this by blocking the airpipe connected to the valve if the idle speed drops then its defnitely the auxilary air valve.. .

also lubricated the accelerator cable left of that electric switch and check your throttle linkage if not sticky, new copper slip compound works best..

flootmats ?? hopefully not ...lol

cheers
Johnny

 

That black thing on the right is called a Throttle Position Sensor, and there is no adjustment of the idle with that switch. Idle adjustment is done at the fuel-air metering device (that looks like a big melon, right hand side, under the air filter box).

At 1400 RPM, your idle is high. What did you do to it before this?

 

Umm are you sure about this? I would think the last thing to do would be twiddle the adjustment on the metering device. Everything else would need to be checked first.

Its probably worth the easy check of the connectors on the AAV and WUR to ensure they are not corroded (the WUR connector is directly under a water-inducing engine cover louvre on the 328) and block hoses on the AAV and the "bypass valve" (top-hat shaped thing) as Jeka suggested above.

Also maybe check control pressure changes correctly with temperature using a gauge if nothing else found.

The switch inside the housing should click when the throttle is closed, not a critical adjustment.

 

+1 I did not mention to check the electrical connectors on the warm-up regulator and aux air valve.

dont mess with the air-fuel metering device unless you know what you are doing, trust me...

 

That is true. For CIS one would check the multiple things on the system including system pressure, control pressure, vac leaks, AAV, before tuning the idle. But, if you want to adjust the idle, the place to adjust it is at the metering device.

 

The same way you can check the vacuum relief valve, so you don't have to remove it

 

Hey Johan, howzit going there in Netherlands ? I'm visiting in August.

cheers
Johan G aka Johnny

 

Hi Johnny,

It is nice over here and August is a good time to visit because te temperatures will be nice! Are you coming for holiday?

Cheers,
Johan

 

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Yes, I'm staying in Germany for a week close to Belgium and Netherland which I want to visit and then off to Poland for another two weeks.

 

yes Menno, the warm-up regulator like Andy indicated...

 

What valve is that?