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Post by justyrick on Mar 22, 2010 16:42:10 GMT -5
Well the car passed all the smog aspects except for NOx, so it failed. Usually high NOx is a clogged EGR, but no EGR. I think I am going to take the intake manifold off and see what I can find. Any advise would be greatly appreciated. Thanks in advance
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Post by RedRooJusty on Mar 23, 2010 13:17:54 GMT -5
**justyrick** The high NOx emissions are a sign of either manifold Vac leak or just running too rich. In the FCU control uses the O2 sensor feedback to the tell the Load solenoid (inside the Carburetor) to enrich or lean the mixture. The closed loop fuel enrichment control(using the Load Solenoid) would throw a fault code is it was not operating. There is still the "static" idle mixture that can be adjusted, but San Diego measures smog under load conditions. Then there is the float/jet adjustment within the carb, as I gather from others that these carbs are very sensitive to this. Before digging in to the Carb, I suggest the "fingers-and-toes" checkout like checking all the vac lines end-to-end for leaks (dry-rot, cracking), pay special attention to the brake booster line. Check intake manifold has every nut and bolt tight, check that the carb mounting hardware is tight. I am confident that taking some time and attention to detail will pay off for you. Please let us know what you find. -RRJ
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Post by RedRooJusty on Mar 23, 2010 13:28:07 GMT -5
For troubleshooting AFR under load I use the O2 sensor as my feedback. Tap a test wire to the sensor and read the voltage produced under load (like accelerating onto the freeway in top gear WOT), the voltage should read stable almost instantly under load. Linear voltage output (Vlin) zero to 5 Volt, with AFR = 9 + (2 * Vlin). Stoichiometric AFR should put you in at 14.4~14.7, with 14.6 ideal (or 2.80vdc to the voltmeter). -just additional troubleshooting info if the finger-and-toes check out. -RRJ
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Danimal
Getting my two Justys back together after a Justy hiatus.
Posts: 589
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Post by Danimal on Mar 26, 2010 11:01:29 GMT -5
**Danimal**, as always you are right-on. HA! Not always. It looks as if the 87' distributor wiring goes to ... 87′ of wiring‽‽Danimal
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Post by justyrick on Mar 29, 2010 19:26:17 GMT -5
I thought I would leave an update. All vacuum lines are good and all electrical is good. I believe the carb is dumping fuel and running rich and the O2 sensor does not know what to do. Therefore, it puts out a check engine code. I think it needs a new carb. The car runs great just not the best fuel economy. Any advise would be greatly appreciated.
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Post by justyrick on Apr 10, 2010 22:56:17 GMT -5
Well I got a used carb from an 89 Justy and the problem still exists. The check engine light still comes on, just a lot later. Regarding the fuel mixture screw, how many turns out should I turn it? I want to make it as lean as possible> Thanks all
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SeattleJusty
No, a boxer will not fit in a Justy.
Posts: 1,587
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Post by SeattleJusty on Apr 11, 2010 9:59:27 GMT -5
Well I got a used carb from an 89 Justy and the problem still exists. The check engine light still comes on, just a lot later. Regarding the fuel mixture screw, how many turns out should I turn it? I want to make it as lean as possible> Thanks all Two things - I believe the '87, '88 and '89 all have slightly different if not color coded wiring plugs on the carburetor/looms. Could using the incorrect carburetor be causing a problem or check engine light?
- "Regarding the fuel mixture screw, how many turns out should I turn it? I want to make it as lean as possible"
This seems patently ill advised. Number one, did you actually drill out the protective plug that prevents you from tampering with the idle screw? They do put that there for a reason. Number two, you don't want it "as lean as possible". You want stoichiometric. If you lean it out you will possibly overheat your engine and could burn a hole right through the tops of your pistons.
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Apr 11, 2010 11:58:07 GMT -5
Two things - I believe the '87, '88 and '89 all have slightly different if not color coded wiring plugs on the carburetor/looms. Could using the incorrect carburetor be causing a problem or check engine light?
- "Regarding the fuel mixture screw, how many turns out should I turn it? I want to make it as lean as possible"
This seems patently ill advised. Number one, did you actually drill out the protective plug that prevents you from tampering with the idle screw? They do put that there for a reason. Number two, you don't want it "as lean as possible". You want stoichiometric. If you lean it out you will possibly overheat your engine and could burn a hole right through the tops of your pistons.
+1 on both counts Not only do the different years have different wiring, but the '89 carb is physically different than the '87 and '88. Realistically, the idle screw on a carburetor should only be adjusted a tiny bit if at all. If it seems like there is a problem with the carb that could be alleviated with an idle mixture screw adjustment, then it means there is something else wrong with the carb that needs to be dealt with instead and messing with the idle mixture will only screw things up worse. I would suspect that there is something going on with your duty solenoid circuit. Either the solenoid is failing or the electrical/signal connections have issues. Instead of giving up on the Justy you might consider a professionally rebuilt carb or a carb from a Loyale. The Loyales might not have the integrated Duty Solenoid. I think Doug (dmnordin) put one on his Justy so maybe he could enlighten us on that.
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SeattleJusty
No, a boxer will not fit in a Justy.
Posts: 1,587
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Post by SeattleJusty on Apr 11, 2010 18:54:30 GMT -5
Yeah Ferox. Perhaps this is exacerbated by a tired oxygen sensor. Should be replaced by now anyhow if it hasn't been already.
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