I'm getting a lot of carbon buildup in the throttle body of my megasquirted Gen 1 2.6.

I'm wondering: does air injection still help me pass smog when I'm running a 'present day' fuel controller? I know air injection helps the cat burn off excess hydrocarbon; but I can set my fuel map to lean the burn out in the ECU.

Should I ditch it? Or fix it [I think it back-flows]? Or replace it with a new one from Mr. Bishi? Any aftermarket switched valves or snags from a boneyard that will work?

--frankb

AIR usually only helps the catalyst get up to operating temp. If you can block off the valve without it being visible to the smog tech he'll never know. The net result to you will be less free oxygen to the catalyst, which, with your modern fuel control will allow the catalyst to do it's job better, since it'll be controlled by the lean/rich switching performed by the computer (provided of course, that your MegaSquirt does this).

$.25 to "fix" the AIR. Take the gland nut off the downpipe, insert one quarter in the hole, and replace the gland nut.

MS has a feedback loop if enabled. Note that leaning the mix to drop HC's will raise the NOx, but the inherent low compression of the turbo motor doesn't make much NOx to start off with.

On the 2.6 the fuel mix at idle using the factory setup is rich to get a smooth running engine. So while the injection does help the converter light off, it was also used to get the HC down at idle.

If your able to hold closed loop at idle I cant see the AIR injection doing you much good. On my Turbo motor it wont pass the sniffer if my air injection system is not working properly.

Kevin

Is this with the carbureted fuel system or was there a fuel injection system for these? And where is the injection coming in? I thought it was directly into the converter. Do they have air injection into the exhaust manifold?


What does it fail for without A.I.R.? Is it HC? I would expect NOx to be much higher with air injection on yours.

I've been curious, did you have to go to the referee for your smog on the black truck? I'd really like to know how all that works and how it went.

On my EFI 2.6 the secondary air (SAS)is supplied at idle when warm, warm up and decelerating. The manual is kind confusing on its chart, I think its wrong. It seems to say the SAS is not functioning warm at idle on page 25-24 in the 88 manual. But in fact it does operate (on my system) and on page 14-14 is says it is operating at idle.

When I failed idle emmisions becasue my SAS was not working I failed for a high CO (1.62) and the HC was high but not failing.

That same chart is used in the carb manual and may be wrong as well. The manual also states that the valve opens to reduce CO and HC.

On the carb motor its used when the motor is cold, on deceleration and at idle for the first 70 seconds (according to the chart).

I'm not sure if the carb is closed loop at idle like the manual infers or not. Looking at the carb I dont think it can do it. Seems to me it can only completly turn off the fuel at idle for deceleration, not modulate it like it does with the main metering system.


My system injects before the converter, just after the turbo.

The ref station was a check to see I had everything for the make and model of the doner car and a test to see that it all worked.

Kevin

Carb ecu is at open loop at idle, and the idle is normally rich, just like Kevin said. I took the SAS off my turbo so long ago I don't remember how that one worked. I chopped the pipe, crimped it flat, and welded up the end, about 2" from the gland nut on the turbo exit housing/downpipe. It's just after the ohtwo sensor, of course...

Never had to pass smog with it, either. Registered it at an accomodation address in a non-inspection county, and I live in that county now.

I ran the turbo D50 for years on just the downpipe, stopping at the cat flange, and can tell you the 2.6t also idles rich, based on the smell. I read somewhere once that the rich idle had a beneficial effect on turbo spool up, because the unburned fuel in the exhaust stream between the port and the turbo lights off on snap wot and adds a pop of energy to the exhaust stream as the turbine accelerates. Sort of a poor man's racing Porsche exhaust flamethrower effect