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79 Toyota carburator sensors question


foreverkeeps's Avatar
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02-14-03, 06:06 AM   #1  
79 Toyota carburator sensors question

Brother is rebuilding 79 Toyota Corolla carburator again. Changed fuel pump, too. He thinks something is still not reading right and causing abnormal symtoms. He does not have vacuum testers,etc. We have not hooked it up to a computer, etc, to test sensors. He says there are LOTS of sensors and he has no idea if one is bad and if so which one. He says some sensors are cheap, dollars.

I am asking if anyone has any suggests on which sensor(s) might cause the most havoc, and if anyone suggests replacing certain ones since testing is not available. IOW, does one go bad more frequently than others?

 
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02-14-03, 10:34 AM   #2  
Joe_F
Whoa Nelley, throwing parts at the problem is a sure fire way to spend a lot more than this thing will ever be worth.

I suggest that if you do not understand how the sensors work, how to test them and what not, the FIRST thing you pick up is a service manual to guide you as to what to check.

You may also seek to bail out and order a rebuilt carburetor for this vehicle. "FC Carburetor" based in Chicago makes excellent foreign rebuilds. This would be the way I would go if the vehicle is even worth fixing and I didn't have the know-how to do it on my own.

 
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02-14-03, 01:04 PM   #3  
We have the service manual and know as much as it tells. Rebuilt carbs on this car are $300. Can't pay that.

 
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02-14-03, 02:57 PM   #4  
These carbs are nightmares to rebuild thoroughly as the kits never include all the worn out rubber parts,etc. Been there and done that...will never do it again. I would install only a quality rebuilt in the future. Now what kinds of symptoms do you have? If this car has a manual transmission and the carb is original there is a good chance the bushings on the throttle shaft are shot and will cause erratic idle, etc.

 
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02-14-03, 03:34 PM   #5  
Joe_F
You do not have the TOYOTA service manual as they would go into how to rebuild the carburetor---Toyota likely still has the rebuild parts available .

It takes skill and knowledge to rebuild this properly. These carburetors are worthless when they get old and tired. Lots of trouble with them .

A rebuilt is the way to go unless you have the skills, knowledge, patience, and service literature to do it right. If the vehicle is not worth 300 bucks in parts (all the materials to do it yourself will be about 200 bucks between the manual, gaskets, etc), the vehicle is not worth repairing.

 
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02-14-03, 07:01 PM   #6  
You're right. We have the Haynes repair manual. The carburator wasn't a problem. It's the sensors all around it. Does that make sense? (I mean, it's obvious I'm not doing the work, just listening to what I'm told). I know the carburator is already rebuilt and running. As is the fuel pump and a new water pump is going on.
I was just hoping for sensor info, if there is any specific sensor info to be had.

Hope to get it back soon! This $1.79 per gallon is killing me!

 
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02-14-03, 07:03 PM   #7  
Steve, I think he just did the bushings too. And we do have some erratic idling. Had the throttle get stuck wide open last fall, no apparent reason.

 
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02-14-03, 07:05 PM   #8  
BTW, it's a 5 speed, about 170k miles. Carburator has been rebuilt before by someone else.. and they didn't do it right. Brother is fixing their mistakes.

 
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02-14-03, 07:08 PM   #9  
Main problem has been a lot of black carbon in one of the barrels. One side not firing right. Mixture too rich. He's changed that. (Y'all guys will have to 'cuse me if I mess up on my quoting and terminology, K?)

 
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02-14-03, 08:47 PM   #10  
Joe_F
There could be a multitude of problems as to how it runs rough/gets black smoke. It could have a misfire, burned valve, etc.

As for manuals, there is a LARGE difference between the Toyota manual and the Haynes. That is why there is a price difference!

 
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02-14-03, 11:10 PM   #11  
Factory manual or no it would take weeks to rebuild the carb by going to Toyota to order parts from the thugs behind the counter!
Go with a rebuilt.

Anyway, have the plugs,wires,cap,rotor and coil been changed? If your engine has EGR valve, check its operation. Have you done a compression check?

 
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02-15-03, 07:52 AM   #12  
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Stevo:

I have ordered COMPLETE carburetors from Toyota in the past (before most dealers had modern systems like now) and it took less than a week .

The problem with Toyota on their kits is that they do not have a "complete" kit like you would get for a domestic application. Domestic applications such as GM, Ford, Chrysler, etc, actually list a complete kit in the parts books, and the aftermarket companies model their kits off of those.

Toyota offers gasket packs, and the needles and seats separate, etc. It makes it tougher to compile the needed kits on the aftermarket side!

On something this old, the parts person may have to go back to the microfiche. It's pretty easy to use .

Toyota may also publish a "Quick Reference Guide" which will make the parts person's job a bit easier .

 
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