Hi again,

My 1980 20R California edition is starting to frustrate me.

Well, not so much the engine it's self, the lack of experienced "professional" mechanics in my area that can troubleshoot, tweek, adjust or repair a carbureted engine.

It starts up OK, from that point on things go down hill. The carb is dumping fuel in the right (passenger) port causing idle to be high. The bullseye shows a good gas level (between the tabs). It spits, sputters, hesitates on take-off. I can reach 55 mph (loses ummph after that) and I can hear/feel it miss-fire/sputter. It seems to "catch" and speedup. By catch I mean the sputtering stops for a fraction of a second while at steady speeds and I lurch foward.

At idle the revs are very high and cannot be adjusted down, plus it's mis-firing.

This is the second carb (previous owner, 70+ years young, replaced the original carb with a rebuild). When I bought the motorhome I had the above symptoms, discussed it with the previous owner who volunteered to exchange the carb at the same place bought this one.

I installed the replaced rebuilt carb and did my best to hook up the vacuum hoses by the chart on the hood. all the hose's appear to be new, not rotted or cracked. I am still dumping fuel with all the same symptoms.

I did most of the checks (Haynes manual) and tried to replace a few emission parts (MC valve and Thermo sensor). The dealer says "no longer available". Still I can't determine what is causing my difficulty.

While crawling over this thing I noticed:
- no O2 sensor, or I'm not looking in the right places. I did find a temp sensor after the cat, if this is bad could it cause false readings?. Haynes says "Fed, fuel injected 4 cyl models" in parenthases i'm assuming they're saying that only these models have O2 sensors?.
- exhaust pipe from the manifold flange splits into two 1 1/4"(?) pipes then combine again at the flange that connects to the cat. Is this normal or did someone in its history re-do the pipes?
- is there a ecm type control (in their infantcy) in these old vehicles?
- would the cat being bad/plugged be causing my erratic operation?
- I was thinking of trying yet another carb, from a different remanufacter... waste of time/money?

Thoughts and inputs greatly appreciated. My smog deadline coming up end of July.

I hope no one mind's if I recommend other Toyota motorhome owners with their mechanical questions to this forum. Most 4x4er's usually know their vehicles inside and out.

Thanks, I feel better just to have a listening ear.

I actually have a 1977 celica gt that I bought new from the dealer with the 20R engine. Ive heard of the problems your having, I actually rebuilt the celica at 100,000 miles and installed the EFI and turbocharger from a 1987 4Runner. Along with the 22R head the old 20R motor still runs strong with 295,000 miles. (It can also outrun V8 Mustangs if you ask it nice).

How do you know what the carb is "dumping" fuel in the passenger side? What do the plugs look like? When was the last tuneup?

~90% of carbed 22r's have o2's. AFAIK, 0 20r engines had o2's.

Only thinking about what you said about the problem, its sounds like the AAP diaphram has a hole in it. I'm pretty sure those carbs have them also. The 1st spark plug should look more sooty than the others.

You could also have a vac leak in the vac advance. That would cause some jumpyness.

Josh

He can probably see it dumping fuel when looking into the throats...........

Anyway,

I don't not-never-know chit about Toyota carbs, so please correct me if I am wrong....But I'm thinking one barrel is primary and the other is secondary. One runs all the time and the other kicks in under load.....If so, it is a vac secondary 2 bbl, right?

If that is the case, then your secondary bbl is getting the signal to flow fuel when it shouldn't....and that is what you are seeing in that one bbl that is dumping raw fuel at idle. And that is what is causing all your problems.

If all the above is true, then the problem is most likely related to incorrect vac hose connections. 80's carbed California stuff is a snake's nest of hoses. You can bet one or more is connected wrong.

good luck....and please tell us what you discover.

A 77 Celica 20R w/ Turbo and Fuel Injection? That's badass! I had no idea that was possible. How hard was that to do? I'd love to fuel inject / turbo my 22R. More info please...

I haven't seen a 20R for a while, but I will give it a shot. There isn't much that can go wrong on these carbs that can make them dump too much fuel. The first thing that comes to mind is to check/replace the thermostat. If I remember right the 20R carb uses a coolant warmed choke, so if the engine doesn't warm up the choke won't open. I would pull the spark plugs and see what they look like, and do a compression check at the same time. From what you descibe it sounds like you have a vac leak somewhere though. Checking plugs will tell you if you are running rich or lean, so that is a good place to start. I don't think volume carb rebuilders do a very good job, carb rebuilding is not very difficult, but does require a certain attention to detail. That being said, usually the carb is the last thing to malfunction on these vehicles, so I would do a tune up first and go from there. Don't start throwing parts at it, that is very exspensive and rarely fixes anything. The O2 sensor should be located on the ex. manifold for all the cali's I've seen. Your truck was probably sold as a cab and chassis, which I believe were not subject to as strict emissions, so it might not have a O2 sensor on it. Contrary to what Josh says, I think 90% of carbed trucks don't have an O2 sensor. All (late model) carbed trucks do have a simple egt located in or around the cat which turns off the exhaust afterburning system to keep the cat from overheating. That is probably what you found. The exhaust pipes are normal, I think. THere is an emission computer, it is usually located on the drivers side kickpanel. I don't know if a plugged cat will cause your problems. I think your money is better spent getting a carb rebuild kit and doing it yourself. Also get a new insulator plate from the dealer, should be about $20 with new gaskets. But don't condem the carb yet. Check all your vaccuum lines and ignition system thoroughly first. Check and make sure the vac advance on the distributor works as Josh said. If you would like I might be able to get you some vac hose schematics in a few days. Good luck,
Blue82

also, my '84 pickup had the 2 pipes coming out of the manifold for some odd reason <img src="/forums/images/graemlins/confused.gif" alt="" />

Moderator, thanks for switching this to the "tech" section. I had thoughts of posting here first but went to "Off topic" because it being a Motorhome.

Thanks much for all the inputs, some of the recomendations I've tried, others are good suggestions to try.

I thought I had it today, I triple checked the timing. I was using a yellow dot someone put on the damper. After I pulled the spark plugs I used the stick in the plug hole to verify TDC and compared with rotor position (using yellow dot). The disto was a few degrees off, So I set the damper notch to 0* TDC and slipped the disto out a little and tweeked the rotor to fire at #1 TDC. Then set at 8deg BTDC.

With the timing correct I was able to adjust the fast idle to stop the gas from squirting in the throat (passenger side is the Primary or secondary?).

Drove it around a little and felt fine until it warmed up. Then the missing and sputtering started up and it stalls at idle. At least I got the idle down from screaming fast.

So it continues. I need to get my tach back from my son though.

Thanks again for the inputs.

Like I described in several other carb threads..........If the butterfly isn't shut far enuff, you suck raw gas thru the cruise jets.

You are doing good-headed in the right direction. <img src="/forums/images/graemlins/kewl.gif" alt="" /> <img src="/forums/images/graemlins/kewl.gif" alt="" /> <img src="/forums/images/graemlins/kewl.gif" alt="" /> <img src="/forums/images/graemlins/kewl.gif" alt="" />

Thanks,

I did a search (newer than 1 year) in 4wheelin, Off-Topic and Archives. Didn't find specific info. Suppose I should go back further. I should also look for a Toyota FAQ section after this note.

The vac hoses I connected is based on the label under the hood. Problem I have with it is the 6 ports on the passenger side of the carb for the hoses.

The label is vague as to which hoses connect above(?) the throttle butterfly in the 2 ports on the "spacer" left (rear) of the idle mixture adjusting screw, and there's also 4 ports below(?) the butterfly (below spacer) on same side of the idle mixture screw.

Then there's 2 ports below butterfly (below spacer) on right (foward) of the idle mixture screw.

The label looks like they are in a straingt line, not specific as to above or below the butterfly.

The other side of my confusion is the direction to turn the idle speed and idle mixture screws during adjustments. Haynes just says to turn them.

I've beed starting with the idle mixture screw 1 1/2 turns open (turned all the way clockwise, then 1 1/2 turns counter clockwise) and jumping between this screw and the Idle speed screw. I assume going open (counter clockwise) each time. Then again I'm going by ear on the RPM's, I guess I'll buy a new tach since my son can't find mine.

I'm ignorant with carb's. Last carbed engine I had was a 1968 Bug, those just replace and be done with it.

The butterfly mentioned above, Choke or throttle? I did read somewhere about adjusting the throttle (?) butterfly using a drill bit as measuring device. No size of bit was mentioned. How do I adjust the butterfly to open, is by the idle mixture screw? Are the cruise jets the smaller tubes lower in the carb? The fuel I had spraying was through the "center tube" within the "ring".



It sure would help me pull the motorhome weight up hills by changing this over to EFI and turbo. I'm sure a lot of drivers behind me would like it too. <img src="/forums/images/graemlins/sleeping.gif" alt="" />

Lots of work involved, and finding a donor vehicle which shouldn't be to hard with all the Toyota around. California would probably prefer I go to a newer engine.
<img src="/forums/images/graemlins/rolleyes.gif" alt="" />
By dumping fuel I was refering to the choked side (primary ?) of the carb. The center tube was spraying fuel into the throat. The plugs (based on haynes back page) looked "normal" however the high speed glazing isn't to far off <img src="/forums/images/graemlins/confused.gif" alt="" />. The threads were slightly wet from the fuel.



lets see,
six vac connections at the passenger side base of carb. Then the CB, FICB, AAP, TP, HAC, the VSV's for the MIC-KEY mouse. Yep, it's a mess <img src="/forums/images/graemlins/smile.gif" alt="" /> Even though I'm running a little crappy, I can still feel the pull of this little engine even for a 3 ton motorhome. Can't wait to get it purring.

Been thinking of the "motorhome cam" to put in, A Delta re-grind or something.

Your a great group. Thanks for all the help. <img src="/forums/images/graemlins/cheers.gif" alt="" />