Testing the air rail? (smog check repairs)

[Carpe Discus]

I've been pulling apart my 2F to try to figure out why my smog check fails with high CO. A common cause I am told is not enough air injected by the smog pump, so I checked the intake to the pump (sucks good) and output to the air rail (blows good). Not that this is to spec or anything, but nothing obvious.

I pulled the air rail to check it out. It's rusty of course, but I can't see any holes. I can blow through it, but with effort. Is the valve on the front of the air rail supposed to be somewhat difficult to blow through? We're not talking "blow up a skinny balloon" kind of hard, but it's definitely not free flowing.

Barring these things, what are some other possible causes of high CO? I've already replaced the air filter and plugs (not that fresh plugs should help high CO, but you never know).

I've been unfortunately been driving this around with expired plates, so I'd definitely appreciate your help before I get a huge ticket.

 

[2mbb]

The valve is a check valve. You should be able to blow through in one direction (towards the air rail) but not the other. From what I remember, the flow direction did have some resistance on both my old ones and the new ones I installed.

The emissions manual shows an SST to measure the air pump outlet pressure. It's a pressure gauge witha restriction oriface(5.5mm). Unfortunately, there is no specified pressure, just that the SST gauge should read in the green.

Check your emissions read out for the oxygen (O2) level. If you have residual O2 (greater than 1%), then it may not be the air pump but rather the catalytic converter. The emissions manual says that high CO is the fault of either the air injection system or the catalytic converter. If there is low or no O2, then not enough aire it getting in--this could be the air pump or faulty air bypass circuit. If you have residual O2, then the catalytic converter may not be doing it's job...

If you don't have one already, I highly recommend you purchase the emissions manual RM36043. It is still avaiable from Toyota. It has procedures to test all the emissions related equipment. Chances are, even if you take it someplace to be fixed, they will need this manual (my dealer had to borrow my manual when I had emissions problems a few years back--even then they couldn't fix the problem).

When I was failing emissions, I evenutally replaced both my air pump and catalytic convertor to get it to pass. I took apart my air pump and found one of the vains was broken--however, I don't know which solved the problem, the new pump or the new cat, but I've passed CA emissions two more times--so what ever I did fixed the problem.

Good Luck

 

[NocalFJ60]

The check valve is hard to get to and is at the bottom of the air rail down under the brake booster. It is hard to change in place but I manage to do it. The check valve is so air can blow down to the cat but does not let exhuast up the air rail.

You only failing on high CO reading? Post your numbers if you can. I would look at the carb first if you just have high CO. Has it ever been rebuilt? Where is the fuel level in the window on the front?

 

[Carpe Discus]

First, thanks for giving the location for that valve; I'd have been hard pressed to find it on my own and will still likely have trouble.

15 mph:
RPM: 1645
%CO2 meas.: 13.1
%O2 meas: 0.0
HC PPM meas.:50 (Max 189, GP 370)
CO% meas.: 2.61 (Max 1.33, GP 2.83)
NO PPM meas.: 39 (Max 1448. GP 2669)

25 mph:
RPM: 1645 [what's with this--everyone else is higher!]
%CO2 meas.: 12.8
%O2 meas: 0.0
HC PPM meas.: 44 (Max 113, GP 288)
CO% meas.: 3.08 (Max 1.13, GP 2.63)
NO PPM meas.: 29 (Max 1308. GP 2469)

I've since this test gotten the CO% down around 2%, under gross polluter but still failing (replaced air filter). The no O2 leads me to believe I'm not getting enough air injection. There is air to immediately before the air rail, though I don't know if it's sufficient (seems like it's strong). I don't have any reason to suspect the smog pump (no PS leaking, haven't found any fan fragments anywhere yet). Of course, I haven't actually pulled it and taken it apart.

The carb has been reportedly rebuilt about 3 years ago. Is that recent enough? It was rebuild several times in the last 5 years chasing a whistle that turned out to be unrelated. Don't know if the carb's at fault if I've got no O2. The fuel level in the front of the carb is usually in the middle. I couldn't see it last time at all but it had been sitting for some time with no air cleaner (I'm assuming this will cause it to evaporate).

I will be ordering emissions manuals no doubt, but the lead time is apparently pretty long and of course, I'd like to actually drive this thing soon.

 

[NocalFJ60]

When did you change your oil last? If the oil is saturated with fuel it can cause a high CO.

Check the air intake and make sure the valve is closing when the engine warms up so you are not always getting hot air from the manifold instead of cool air from hose on fender. If you pull off intake hose on the air cleaner you will see the valve. It should close with the engine hot and open once it warms up. You could even unplug the hose and cap it off since you live in a warm area.

Did you rebuild the carb yourself? I don't think looking at the O2 coming out the pipe has much to do with the air rail. The air injection is made to help burn unburnt fuel to bring down HC. The O2 will increase the leaner you run. You might want to order a carb kit and rebuild it yourself for $30.

Just stick with it. I am going to be trying to get mine to pass once I get it running here soon.

 

[Carpe Discus]

Oil last changed less than 3k miles ago--it's got a couple of leaks so it's more of an ongoing thing in between full changes. I didn't know oil could get fuel-saturated, interesting.

The valve on the snorkel to the air cleaner (which is what you are talking about, I think) is currently open (air intake from cold air intake, not from manifold intake). This is while the air cleaner is off the truck, which is interesting--I guess it's supposed to be getting hot air until warmed up? If this is not correct, it still doesn't seem relevant to the smog discussion if it's always getting cold air.

I did not rebuild the carb myself. I may try that or sending it to JimC. I will also try checking out the check valve you mention under the brake booster. I'm a bit confused on the location you mention "at the bottom of the air rail down under the brake booster", but I'll probably find it. by "bottom" do you mean "towards the firewall"? The brake booster, in my mind, is at the top end of the air rail but maybe I'm mixed up.

 

[jefferson-mo]

Carpe............where you located?

I'm near Balboa & 805.............going through the EXACT same thing.........my tags expired in Dec, had a Red Sticker until Feb.........now I'm using the Red Sticker from my Crown Vic! It expires this Friday though..........the only good thing about not enough cops in this city is that they got better things to do than worry about my tags..........

I need to go through my Carb....3rd time........I'm gettin good at it...

my readings are :

15 mph: 1517 RPM
cO2 12.1
O2 0.0
HC 142
CO 4.21 (!!)
NO 73

25 mph: 2374 rpm
CO2 12.3
HC 50
CO 3.87
NO 54

( I just noticed this test was from January so the last time I tried it was better but still not close enough)

My smog guy even let me re-route the air hoses to skip the air diverter and blow straight to the cat but it still didn't help...........he sez it's like there's an internal fuel leak just dumping ito the motor.........

new spark plugs......new air filter..fresh oil change........fuel below center in the window............new smog pump

I would love to go through this with someone else.........maybe if you got time this Saturday we could get together..........there's a lot of Cruisers in this town but I haven't met anyone else to go wheelin with............

PM me or give me a call........I'm a parts dude @ Pearson Ford

 

[Carpe Discus]

Carpe............where you located?

I'm near Balboa & 805.............

Heh, I'm near Balboa and Clairemont Dr. I don't get much wrenching (not to mention wheeling!) time weekends, I'm usually doing family stuff during the day and do repairs late at night.

My registration expired in May. The month sticker is practically unreadable, which helps. I really am not a fan of driving expired, though.

You're saying you rebuilt the carb three times?

 

[2mbb]

I will be ordering emissions manuals no doubt, but the lead time is apparently pretty long and of course, I'd like to actually drive this thing soon.

I'm not sure why the lead time should be long. Typically, Spector Off Road has these manuals in stock (if you want to pay their prices), or you can call the Toyota Material Distribution center directly and order the manual with a credit card. Here's a link with the telephone number:

https://forum.ih8mud.com/showthread.php?t=97103&highlight=service+manual

 

[jefferson-mo]

Yeah but THIS time(hehe)

I 'll go slower and double check everything. It's acting like an internal fuel leak so maybe a o-ring got chafed or something.............

Also maybe I re-routed the air hose to the wrong check valve....I'll hafta check that again............I've GOTTA get this thing smogged so I can get tags and start my engine swap and not have to worry about smogging it for 2 years while I sort it out

Del Taco is our(me & the boy) regular Saturday breakfast stop..........what color is yours?

Mine's Tan:




See ya 'round

 

[jefferson-mo]

OK now I know I'm an idiot............

on my Crown Vic I had to move the air hose to blow straight into the cats to get it to pass smog...............which I thought I did on the Cruiser.............but

I ran the hose straight from the pump to the FRONT air check valve which is the air rail on the engine...............duh.......not the REAR one which obviously goes down to the cat.............

explains why it made no difference in the smog test or the exhaust smell

 

[Carpe Discus]

Boy, in anyone has successfully removed either check valve from the air rail or the pipe to the cat (under brake booster) let me know! Those things are TIGHT!

The location of the one in the back doesn't help either.

 

[NocalFJ60]

Thinking back I remember how I got the check valve off. I cheated... I pulled the hose off the air rail and loosen the clamp holding the air rail to the exhaust. Then I cut the air rail close to the exhaust with a saw and pulled the air rail out and got the valve off it. Replaced the valve and put it back in and attached the hose. Then drove to the exhuast shop down the street and got it welded back together.