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  #21  
Old 12-29-2019, 05:29 PM
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rws31 rws31 is offline
232 I6
 
Join Date: Dec 10, 2016
Location: Florida
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Quote:
Originally Posted by Dave Jeeper
The plugs were fine for about 4 or 5 months and there was no carbon. Shortly after replacing the vacuum canister a few weeks ago is when it started fouling. It took about a week after the charcoal canister before it started throwing carbon out the tailpipe when idling. The carbon was visible on the sidewalk but not visible in the gas coming out of the exhaust


If your looking for carbon build up on the plugs to see how your fuel ratio is doing, your not looking for the right things.

Search the net, for a competent site not Joe Bob's Youtube sight on spark plugs, and see what your plugs are doing.

Put a new set in and drive it normally for a day or so. Pull them out and look at them. They will tell you what you have going on.
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  #22  
Old 01-01-2020, 08:08 PM
Dave Jeeper Dave Jeeper is offline
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Join Date: Sep 08, 2019
Location: Denver, CO
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I installed a new o2 sensor and the engine is running leaner now and is not throwing codes on the Howell TBI GM computer.


I played with timing, no spark knock at up to 30 degrees btdc (high altitude is 17 +-2) base timing. I have set the base timing to 21.5 btdc.



Power is still poor with or without the new EGR attached to vacuum.


I am suspecting compression issues and will do compression and leak down tests when I have time.
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  #23  
Old 01-09-2020, 09:19 PM
Dave Jeeper Dave Jeeper is offline
232 I6
 
Join Date: Sep 08, 2019
Location: Denver, CO
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I checked engine compression and all is good (tested with cold engine at 60 degrees F, varied between 120 and 130, with one cylinder at 117, taking 10 turns of the engine to pump up to max pressure on each cylinder) . I re-gapped the plugs from .052 down to .040" (I have HEI) and the vehicle is idling and running very smooth with base timing at 20.5 degrees BTDC. No longer getting carbon out of the exhaust after replacing the O2 sensor.



Acceleration up a mild hill is 0 to 55 in about 20 seconds. This is without air conditioning, can't imagine how slow it would be with the AC on. The transmission does not slip at all when accelerating (monitoring the tach). The air intake is functioning correctly and there is a new cat/muffler/tailpipe. The vehicle is running quietly and smoothly now. TBI, HEI, EGR and charcoal canister seem to be functioning correctly now. I do not believe that there are any vacuum leaks at this point.



I reconfirmed that the gearing is 3.31 (3 1/3 turns of the driveshaft per two turns of one wheel with the other wheel on the ground). I have new 31" tires and a 4" lift.


If anyone has any ideas on lack of power I am open to hearing them. I have not checked fuel pressure yet to the TBI, but had cleaned the tank and installed a new pickup about 400 miles ago when I got the vehicle running again.



Not sure why the power is so low, I haven't driven any other SJ's so I can't compare it to other wagoneers. My 1997 XJ is much faster.

Last edited by Dave Jeeper : 01-10-2020 at 08:48 AM.
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  #24  
Old 01-10-2020, 06:33 AM
wiley-moeracing wiley-moeracing is offline
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Location: arizona
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Compression at 220 per cylinder? more like 120 maybe?
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  #25  
Old 01-10-2020, 08:49 AM
Dave Jeeper Dave Jeeper is offline
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Thanks, I edited out the typos on my last post regarding compression numbers.
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  #26  
Old 01-10-2020, 09:46 AM
wiley-moeracing wiley-moeracing is offline
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Join Date: Feb 15, 2010
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You still should be better than 20 seconds to hit 60? are you getting full throttle on the tbi? Hell a loaded 18 wheeler will do that! 120 psi is a little low but will run ok, you may need to find a good shop/mechanic to help, your missing something somewhere.
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  #27  
Old 01-10-2020, 11:05 AM
Dave Jeeper Dave Jeeper is offline
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20 seconds to 55 mph up a slight hill. It seems to have less power in the lower half of second gear. The tranny is not slipping. It is possible that the throttle could open a tiny bit more if the carpet was not in the way. The Howell throttle body might require a little more down travel on the gas pedal to fully open the throttle compared to the original 2150 carb. I will check if there is slack in the cable, perhaps some careful bending can improve throttle opening.



I replaced the single exhaust cat, muffler and tailpipe with oem diameter aftermarket equipment. The cat looked to be free flowing, only a screen in there, no ceramic. Will using a larger diameter or dual exhaust give significant power gains? I also have the passenger thermostatic exhaust valve on the downpipe. Will tying that in the open position help with better power? The valve moves freely by hand and returns to the closed position via the spring with the engine off and when cold.
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  #28  
Old 01-10-2020, 03:18 PM
Dave Jeeper Dave Jeeper is offline
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Join Date: Sep 08, 2019
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Thanks to wiley-moeracing for solving my power problem!!!


The throttle plates on my Howell throttle body were not opening fully, probably 10 or 12 degrees shy of vertical. The throttle cable from the pedal to the arm on the throttle body was not able to pull far enough. First I tried bending the arm on the gas pedal that pulls on the cable, but this didn't work enough. Then I tried opening up the holes in the support plate for the cable on the engine and moving the cable housing/support further away from the throttle body. It worked, throttle plates fully open.


Much more power and I lowered my timing from 20.5 to 18.5 degrees BTDC (High Altitude spec is 17 or 17.5 +/-2). Engine is now running smooth, idling great and I have more power. I will have to see how it runs with air conditioning in the summer going up the mountains here in Colorado. I don't think that I will need to regear unless I were going to tow a trailer.


The lead foot is now optional, thanks for your help!
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  #29  
Old 01-10-2020, 05:55 PM
wiley-moeracing wiley-moeracing is offline
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Good to hear! Sometimes its a little thing that gets missed.
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  #30  
Old 01-10-2020, 08:47 PM
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PlasticBoob PlasticBoob is offline
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So what's the 0 to 55 now? 19?


Always good to see people come back and actually post the solution to their issues.
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