91 Samurai w/rich sootie exhaust - Page 3

Looz nutz · 08-30-2009, 11:28 PM

Have you ckd the thermal switch? The switch that tells the computer what temp the coolant is. If it is not working properly the computer will not inject the proper amount of fuel. Perform and Ohm test as per your work manual. I if perhaps change the thermostat. There is a passage way from the exhuast through the head that gives the Egr valve the gas frome the exhuast. When I did my head gasket I cleaned it out cause it had a whole bunch of carbon.

zook77 · 11-23-2009, 11:12 AM

Did you sort out what the problem was that was giving you such a rich mix and the sootie exhuast? I am having almost exactly the same things you listed and wondered what you found out?
Thanks

Baratacus · 11-23-2009, 01:14 PM

I'd check your air fuel mixture to be sure that it is runing rich. A lot of people mistake a rich condition and a lean condition. Running too lean causes your exhaust to smell like fuel because you have unburnt fuel in the exhaust. Running too rich, your fuel burns ineficiently, but it does burn. It will produce a lot of carbon monoxide as a biproduct but you won't be able to smell that. (its the scentless killer) Soot can be a result of either too rich or too lean a mixture, but the lack of vacuum pressure and smell of unburnt fuel in the exhaust leads me to believe there is a vacuum leak somewhere causing a Too-lean condition.

Operating with the EGR stuck closed is not going to make you run rich, but it will make you run hot and you will produce excessive NOx. Running too lean will also make you run too hot and produce excessive NOx. Things that can cause a too lean condition are clogged injectors, spark gap too large, clogged fuel lines or vapor return lines, low pressure from the fuel pump, vacuum leaks, faulty readings from the map, o2, or temp sensors...

on the up-side... at least it's not the stock carb giving you trouble... I'd take the Fuel injection over that little nightmare any day!

zook77 · 11-23-2009, 01:24 PM

Hey Baratacus, you helped me with the oil in my air filter!! Set the valves this weekend and just need to take it for a test ride to see how it does.

My sammie is an '87 with the stock carb...... The symptoms seemed exactly what Weasel was experiencing!! My exhaust is very sootie and my fuel consumption is really bad...like 15mpg!! I think I have a minor fuel leak, not sure where from but could be from the pump. When I touch my finger on the discharge pipe on the side of the pump there seems to be a bit of fuel on my finger, so think it may be from there. I have new spark plugs that I am going to put in tonight. Also the smell from the exhaust is really bad, a horrible smell.

captron · 11-23-2009, 03:42 PM

There has to be something wrong with the gas flow as I just took my 1987 stock Samurai on a 275 mile round trip from San Diego to Los Angeles and got over 32 mpg

Baratacus · 11-23-2009, 10:22 PM

Quote:

Originally Posted by zook77

Hey Baratacus, you helped me with the oil in my air filter!! Set the valves this weekend and just need to take it for a test ride to see how it does.

My sammie is an '87 with the stock carb...... The symptoms seemed exactly what Weasel was experiencing!! My exhaust is very sootie and my fuel consumption is really bad...like 15mpg!! I think I have a minor fuel leak, not sure where from but could be from the pump. When I touch my finger on the discharge pipe on the side of the pump there seems to be a bit of fuel on my finger, so think it may be from there. I have new spark plugs that I am going to put in tonight. Also the smell from the exhaust is really bad, a horrible smell.

always glad to help out.
If you have a fuel supply issue then it would cause your fuel mixture to be too lean, causing the unburned fuel in your exhaust to smell of gasoline. If the Stink that you are refereing to is more of a Sulfer or "rotten egg" smell, then your catalytic converter could be failing. If the cat is starting to back up, it will cause a loss of power, excessive backpressure, and really hot manifold

james123 · 11-24-2009, 07:39 AM

nice information got from your post thanks for sharing the information....

zook77 · 11-24-2009, 08:40 AM

The smell is more like a fuel smell and not sulfer. I took the spark plugs out and replcaed them and at least two of them show that they are burning hot, which I read can mean a too lean mixture, just like you suggested. Going to spend the weekend doing all the test and see what I find.

Thanks again for your help, Baratacus!!