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Discussion Starter #1
Hi to all and hope someone hear can help me.....
I have a 1991 Samurai JL with the 1.3 TBI engine w/91000 miles on it. I purchase it with a bad miss under load. I had the ecm rebuilt and that solved that but I am having another problem. When I drive down the road, the exhaust smell gassy and there is black soot inside my tailpipe. I replaced the cap, rotor, plugs, and wires, I have very good spark in all cylinders, but still the same results. Compression was 100-110 on all cylinders. If I advance or retard the timing, I get the same results.....timing marks are on as far as I could tell. The check engine lights works and is NOT on. Hope someone can steer me in the right direction. Thanks
 

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Discussion Starter #2
Another thing I forgot to mention is that at warm idle, I can manualy open the EGR and it does not change the idle. I removed the EGR and tested it and it held vacuum. I also tested the modulator? that activates the EGR and this was good also. I did not find the holes to be plugged with carbon. My exhaust consist of headers with muffler and tailpipe...no cataletic converter.
 

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Have you ck the map sensor? This could be your problem. The ecm will read it is working fine but mechanically is not. Hope this helps.
 

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is your O2 sensor good? a bad one (or one that is not there) can make your fuel mixture to rich giving you lots of carbon. another sing that you are running to rich is if your spark plugs are black or wet looking.
 

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Discussion Starter #6
I put NGK BPR5ES plugs in and the one I took out were.....2 AC Delco R43XLS plugs and 2 Autolite Platinum AP64 plugs. I put new thermostat in and tested the water temp sensor, air temp sensor, and the BVSV sensor last night...all read consistent to what service manual said. I bought a new universal Bosch O2 sensor today but have not put it on yet.
I pinch the return line from the fuel regulator nad the engine idle dropped noticably so I figured this is functioning close to what it should. Yhanks for the replies.
 

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I like NGK, also Nippondenso(ND). While my work life was with Toyota, the Suzuki is very similar.
I found that AC Delco, Autolight, and Champion didn't last very long(either fouled out or sometimes the porcelain cracked). I found Bosch, and especially the "platinum" worked poorly from the very start, at least in most Asian vehicles .
One thing to keep in mind is the fuel pressure for a vehicle at idle is much lower then one under load. My Samurai is carbed, and i don't have specs for efi-but I'd imagine your fuel psi at idle is around 18-20 psi, as opposed to 30-40psi under load. While I'm not enthusastic about fuel pump being the culprit, you can't cross it off, yet. And a fuel pump going bad would not set off the check engine light.
The mass air flow sensor was a good rec. by the other reader, too. The tough part is that you have black soot, whixh would mean an awefully rich condition. Fuelpumps, mass air flow sensors, usually don't push extra gas.

Usually when an O2 sensor is bad the vehicle's ecm will default to preset values to keep the vehicle running(i.e. safe) It will usually favor a rich mix as opposed to a lean one. This would explain the soot, butt this would almost surely set off the check engine light for a rich condition. But outside of bad ignition components it's a resonable guess
 

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I have the same year sami and mine does not have an airflow sensor. Mine has a map sensor wich read air differently. On the mass air sensor the computer is reading how much air is going throuht the intake and telling the rest of the components what to do. In a map sensor the sensor is reading air pressure and adjusting air acordingly. I had a Mitsu Starion that did the same thing. I changed injectors and pump and the car ran the same. Well my friend told me to change the map sensor and that solved my problems. You dont loose anything by just inspecting the sensor. Good luck.
 

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Discussion Starter #10
I am still having problems with this one.......it about kills you to drive it for the exhaust fumes are horrible. Could a weak fuel pump cause a rich charge by starving the engine of fuel and the charge not being good enough to have proper combustion? It has 30 inch tires but seems to lack power compared to my other 91.
 

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Discussion Starter #11
I put a new o2 sensor in and I still get the same results and I swapped the map sensor off my good running one and there was no change. Is there an easy quik way to check the fuel pump without getting a pressure tester?
 

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It's is definately running rich.

Here is a silly question.
Do you have your exhuast running straight out the back?
If so, the reason Suzuki bent the original pipe to point it off the side (corner) of the vehicle is because its box shape is as aerodynamic as a brick. And if the exhaust is let out behind the vehicle it is sucked right into the back of the truck and into the passenger compartment. :eek:
 

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Discussion Starter #13
yes it is right at the back of the bumper, but even so, it is terrible smelling. It about makes you sick even with the top off. RockAuto has a part "fuel injector o ring" not sure if this could cause this condition or not. Another thought is that the O2 sensor is way underneath the unit......while the factory location on a factory manifold is right up by the engine. The O2 sensor has to reach a certain temp before it operates right and being at the far end of headers might not be hot enough.
 

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By all means, see what you can do to lean out the mixture. But please adjust the location of the exhaust exit. Even a 'right smellin' exhaust will make you sick on the trail if it goes straight out the back. When I went to a 2" exhaust on the trail rig it ended up looking like this...

 

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rich running

Have you ckd the fuel pressure regulator? If the regulator is shoot it will run rich. IF that is not the problem remove the injector and ck the spray pattern. The pattern should be in a cone and misty not a drip or piss like stream. Good luck. To bad you dont live close by otherwise I would give you a hand. :p
 

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i would just like to say that if you manually push the diaphram on the egr it should definately effect the idle if not stall the engine...this make me think disfunctional egr...it may not be in the exhaust manifold but could be in the intake manifold or head it could be carboned up. take the egr off and stick a peice of bailing wire through it and see if theres a clog somewhere if it doesnt effect it...if no clog then its a bad egr
 

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Discussion Starter #17
Looz nutz, I replaced the fuel pressure regulator for it had fuel coming out on the vacuum side but it did not change it. I get 28 miles per gallon so this is just driving me nuts. I compared the spray pattern of the injector to the other sami that runs good and they look the same.

87samurai dunn, When I manually push the diaghram of the egr in, nothing at all happens, the engine does not stumble or anything. I do not have a cat on this engine so I do not think I can get enough backpressure to actuate the egr in the 1st place. Would there be a bad enough of a plug-up in the intake to effect the fuel charge?

Thankyou all for your help.
 

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Discussion Starter #18
I should add what I have all done.....
new plugs
new wires
new cap and rotor
new fuel pressure regulator
new fuel filter
had ECM rebuilt
checked timing
reset timing
swapped out all sensors with the good running one including map and idle position sensor.

now for the good stuff.....threw a wrench half way into orbit, screamed every cuss word I could think of until my neighbor asked if I was ok, just about wound up single...LOL
 

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i would think it would still actuate even with minimal backpressure because mine worked with just strait header without a muffler even!!! so i would pull it and check for a clog...if not then ur still only out a buck for a gasket and then you know its clean...but it could take a little bit of power out but not really make it smoke much...you are running a header so thats gonna burn at about 1200 degrees and burn up most fuel coming thru... its gotta be in carbueration
 

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Discussion Starter #20
it doesnt smoke all the time, it gives off a puff of darker smoke if you gun the engine.....if you hold your hand behind the tailpipe while it idles, you get little black wet specks shot on your hand. I had a friend smell the exhaust while it idled and the I gunned it right when he was smelling it.....black specks all over his face. LOL too funny.
Another thing i did was adjust the valves and there was not change there either. I do notice that the upper radiator hose is alot warmer than the bottom one at all times, yet I get good heat through the heater and defrost and I checked radiator and it is not plugged.
Are there any channels under the throttle body that could get plugged to make this condition with the richness? but still run good? I only notice a lack of power at 50mph on up and worse if going into the wind.
 
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