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1987 B2000 2.0 engine - emission problems?


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crojack
New User

Apr 11, 2012, 10:55 PM

Post #1 of 5 (4944 views)
1987 B2000 2.0 engine - emission problems? Sign In

Hi everyone, thanks for the great forum and hope you can help.
I recently got this Mazda truck and for the most part it's a great little truck. The issue I'm having is this.

On the front of the air cleaner, there are three hoses going into a manifold thing which contains three reed valves respectively.
Not long after I got the truck I noticed the middle hose was not connected to the manifold, and did not have a clamp on it.
I bought a hose clamp, slid the hose onto the spigot coming off the manifold and tightened down the hose clamp, easy peasy.
A few days or so after that, I looked under the hood again and noticed that there was a big hole blown in the same hose, the middle one. Weird, I thought, but must just be an old hose.
Tracked down a new hose and installed.
Immediately the truck ran with very little power and a pretty loud whirring noise was coming from under the hood. So, after a few days of head scratching I unhooked the hose and the truck regained power and no more whirring noise and the wonderful exhaust smell started to fill up the cabin again.

So, my question is, what is stopped up in the engine/exhaust system to cause this problem? Do you think it;s in the manifold thing, or I was also told that it could be a clogged up cat convertor.
Any ideas, even where to start? I bought a nice Clymer for it so I do have diagrams.

Also, I talked to a shop near my work that had lots of good reviews, but he said he only ahd one guy that worked on old carb engines and the emissions can be a pain, etc. etc. which just sounded like more and more dollar signs to me.

Thanks in advance!


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Apr 12, 2012, 3:15 AM

Post #2 of 5 (4901 views)
Re: 1987 B2000 2.0 engine - emission problems? Sign In

"Manifold thing" doesn't tell us too much. You're going to either have to post a picture or explain it much better.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Apr 12, 2012, 5:00 AM

Post #3 of 5 (4894 views)
Re: 1987 B2000 2.0 engine - emission problems? Sign In

He/she is probably meaning the pulse air injection reaction system.

If you have a restriction in the exhaust, it is going to melt the hoses going to the reed valve assembly on the air cleaner and probably bake the reed valve too. It's designed to pull fresh air (oxygen) from the air cleaner into the exhaust stream for the catalytic converter. The natural pulses in the exhaust manifold create a vacuum. If you have a restriction in the exhaust, the hot exhaust gasses are going to back up and cook the air injection hoses and valves.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Apr 12, 2012, 5:01 AM)


crojack
New User

Apr 12, 2012, 7:36 AM

Post #4 of 5 (4876 views)
Re: 1987 B2000 2.0 engine - emission problems? Sign In

It's a he, haha.

This is good info, I wasn't sure if the reed valve assembly brought un-burnt gases back from the exhaust and into the engine as some sort of emissions reclamation system, or if it sent fresh air down into the exhaust.

It sounds like the path of air should go from the air cleaner, through the reed valve assembly, through the hoses, and into the exhaust system?

So, the cat could be clogged up and sending exhaust gases back up through the tube? I guess I need to pull the cat and see if that is it? Is there anything else back there that could be clogged up?



The manifold thing is seen in the top of the pic, hooked onto the air cleaner near the "13-104G" I couldn't find a pic of the hose routing.




Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Apr 12, 2012, 5:18 PM

Post #5 of 5 (4838 views)
Re: 1987 B2000 2.0 engine - emission problems? Sign In


Quote
It sounds like the path of air should go from the air cleaner, through the reed valve assembly, through the hoses, and into the exhaust system?

That's correct.


Quote
So, the cat could be clogged up and sending exhaust gases back up through the tube? I guess I need to pull the cat and see if that is it? Is there anything else back there that could be clogged up?

Anything in the exhaust causing a restriction from a clogged cat, collapsed muffler, or potato in the tail pipe can cause exhaust gasses to burn up the pulse air injection reaction system.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.






 
 
 






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