3FE Emissions woes

[CO92FJ80]

They both have smog pumps and thus they both have to an air bypass valve (ABV). In one position it sends the smog pump output to the injection rail, in the other position it sends it elsewhere (back to the air cleaner?). But yeah, this system probably has more affect on CO readings than anything else, and if it isn't working properly there's no way to pass CO.

I see an ASV, but no ABV… do they serve the same purpose/function? Mine is an 80 not a 60, and I’m learning the EGR systems aren’t quite the same.

 

[Rzeppa]

The ABV (air bypass valve) is part of the air injection system, not the EGR (exhaust gas recirculation) system. The ABV takes the output of the smog pump and diverts it back to the air cleaner when not injecting it to the air injection rail. When pumping the clean air into the air injection rail, it mixes with the exhaust gas and converts the CO to CO2 before it can come out the tailpipe. The EGR takes spent exhaust, cools it and sends it back to the intake to dilute the fuel/air mixture to reduce combustion temperatures.

 

[CO92FJ80]

Failed again for CO. Got it down to 54. I’m gonna try to see if the smog pump is actually pushing air out (it seems to be pulling air into it fine). Any more tips anyone has would be very welcomed. It’s gotten a full tune up, replaced thermostat as the top o-ring was bad preventing it from getting to and staying at operating temperature. Now it does get to operating temperature and stays there. Cats are new but are standard cats (not California cats). Ran E-85 and that did wonders, but not enough.

Lastly, does anyone know if the ASV on the 91-92 models is the same as the ABV on the earlier model 3fe engines? I’m definitely getting frustrated with this whole deal. Had I known at the time of purchase that it had an emission exemption, I never would’ve bought it. (Purchased from an active rising sun club member). Sadly, I love the rig and know that if I sold it with current Colorado emissions laws I’d be liable if the new owner couldn’t pass.

 

[CO92FJ80]

The ABV (air bypass valve) is part of the air injection system, not the EGR (exhaust gas recirculation) system. The ABV takes the output of the smog pump and diverts it back to the air cleaner when not injecting it to the air injection rail. When pumping the clean air into the air injection rail, it mixes with the exhaust gas and converts the CO to CO2 before it can come out the tailpipe. The EGR takes spent exhaust, cools it and sends it back to the intake to dilute the fuel/air mixture to reduce combustion temperatures.

Would bypassing the ABV so it was always sending the mixture to air injection rail help or hurt my CO readings? I’m at 54 and need them down to 25. Before E-85 I was at 156.

 

[CO92FJ80]

There are normally 3 FSMs:

• Chassis/Body
• Engine
• Emissions

Does anyone have an emissions FSM? I’d be happy to rent it so I can try and get mine to pass.

 

[Cruisertrash]

Does anyone have an emissions FSM? I’d be happy to rent it so I can try and get mine to pass.

Check the "Resources" tab at the top of the page on the Mud forum

 

[AdamKFarmer]

Jeff- I poked around the 3FE manual I think there isn't an ABV on this.

I see an ASV, but no ABV… do they serve the same purpose/function? Mine is an 80 not a 60, and I’m learning the EGR systems aren’t quite the same.

Have you gone through these checks?

3FE Repair Manual - YUMPU https://www.yumpu.com/en/document/view/8411758/3fe-repair-manual

 

[CO92FJ80]

Check the "Resources" tab at the top of the page on the Mud forum

Found a pdf that may help me. Thank you!

 

[AdamKFarmer]

Found a pdf that may help me. Thank you!

You can DM directly if you want to bounce ideas off me. I had to re smog my 2F and got pretty good at it. I think the 3FE is less complicated.

 

[Rzeppa]

Would bypassing the ABV so it was always sending the mixture to air injection rail help or hurt my CO readings? I’m at 54 and need them down to 25. Before E-85 I was at 156.

Yes, that's what I had to do to get my 60 to pass CO, I just routed the output of the smog pump directly into the air injection rail.

 

[CO92FJ80]

Yes, that's what I had to do to get my 60 to pass CO, I just routed the output of the smog pump directly into the air injection rail.

How much of a difference did that make in your CO readings, before vs after rerouting the pump to the rail?

 

[Rzeppa]

How much of a difference did that make in your CO readings, before vs after rerouting the pump to the rail?

I don't remember the actual numbers but it was pretty dramatic, like cut it in half or something. But what I had done is pull the hose off the front of the rail and with the engine running, verify that there wasn't anything coming out of the hose. Then I unhooked the hose on the output of the pump and verified that the pump was just fine.

 

[AdamKFarmer]

How much of a difference did that make in your CO readings, before vs after rerouting the pump to the rail?

IME in was a pretty large difference as well

 

[CO92FJ80]

I wanted to thank everyone who chimed in on this post. Using the FSM and going through numerous steps of troubleshooting, I figured out my air injection valve was bad. I was able to track a new one down through Cruiser Parts. After that, I was just barely failing on CO. Ran a hose directly from the air pump directly to the air injection valve, and she passed! Thanks to everyone who gave input!

 

[Rzeppa]

Ran a hose directly from the air pump directly to the air injection valve, and she passed!

That's exactly what I had to do on my 60.

 

[Crash]

I wanted to thank everyone who chimed in on this post. Using the FSM and going through numerous steps of troubleshooting, I figured out my air injection valve was bad. I was able to track a new one down through Cruiser Parts. After that, I was just barely failing on CO. Ran a hose directly from the air pump directly to the air injection valve, and she passed! Thanks to everyone who gave input!

How about a picture of your workaround? Thanks.

 

[CO92FJ80]

How about a picture of your workaround? Thanks.

I have it back to stock, but I will post a pic showing what I did.

 

[Crash]

I have it back to stock, but I will post a pic showing what I did.

Thanks. Any and all tricks and workarounds that we can use to get our 3FEs to pass emissions are appreciated.