Jumpy timing on 3.0
03-12-2010, 08:36 PM
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Jumpy timing on 3.0
Okay, I'm going crazy trying to figure out what's wrong with my 4runner. It's very weak and when I try to set the timing with a timing light, it's not steady. It fluctuates about an inch back and forth. I have checked compression, and each cylinder is reading around 170psi. The timing belt was supposedly changed by the previous owner. Also when timed to 8 degrees btdc it runs horrible. I have to turn the distributor clockwise, so that the timing mark is way off for it to run okay. Also the exhaust has an odd odor and when I put my hand over the tail pipe, I hardly feel any air coming out. I took the truck to an exhaust place to have the cat checked and they told me it was 25% clogged but that would not cause the problem that I'm having. I have been looking over vacuum lines and they all seem in good shape. the diagnosis is not giving me any trouble codes. Please Help!
03-12-2010, 09:14 PM
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It has. The manual says the idle should be 800 rpm. I have been messing around with the Idle adjustment, also. It's just hard to get it right when the timing is so jumpy. Would the timing being off, cause it to not have pressure out of the exhaust? or does the 3.0 not have that much pressure coming out to begin with. My 22RE has plenty of air coming out. I just don't know the 3.0 that well.
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03-13-2010, 01:12 AM
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If you put the jumper in and the timing does not settle to a consistant mark (which should also be accompanied by a noticible change in idle speed), the throttle position sensor may be faulty or out of adjustment.
03-13-2010, 01:19 AM
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To clarify, inserting the jumper in the diagnostic check connector causes the ECU to fall back to various 'default' settings, but it cannot do so if the throttle position sensor is not also telling the ECU that the throttle is at idle position. The TPS does that via the IDL/E2 terminals, which should read less than 2.3K ohm when the throttle is closed.
If the jumper is inserted properly in the diagnostic connector, and the throttle position sensor reports to the ECU that it is in the proper position, the timing should drop to the baseline and should not jump around.
If the jumper is inserted properly in the diagnostic connector, and the throttle position sensor reports to the ECU that it is in the proper position, the timing should drop to the baseline and should not jump around.
03-13-2010, 10:41 AM
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got some trivia for you...
As far as I know, and I'm pretty sure I'm right... Jumping the terminals makes the computer go back to sea level settings...
Un-jumped and the altitude settings set by the computer affects the timing...
Jumping the terminals bypasses the automatic altitude adjusting the computer does automatically.
As far as I know, and I'm pretty sure I'm right... Jumping the terminals makes the computer go back to sea level settings...
Un-jumped and the altitude settings set by the computer affects the timing...
Jumping the terminals bypasses the automatic altitude adjusting the computer does automatically.
03-13-2010, 06:53 PM
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Okay, I checked the resistance between terminals on the TPS, and with my ohm meter set to 20kohms they all read around 5.7ohms, which I know is not right. I switched TPS with another one I have on another truck, and it made no change. Whenever I set the timing to the the right marks, It runs bad, and kinda sputters. I'm almost positive I have no vacuum leaks. I'm still stumped.
03-14-2010, 12:53 PM
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Well went out and bought a new TPS. I installed and adjusted. There is no change, but I did notice the TPS was installed backwards.....At least I think it was backwards. Can anyone tell me which way the plug is supposed to face. I now have the plug coming in from the drivers side, the plug was entering from the passenger side. Thanks
04-10-2010, 10:24 AM
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04-12-2010, 01:51 AM
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It's a 94 4runner, with about 110,000miles on it. I still haven't figured out what it is. Next weekend I think I'm going to pull off the intake manifold to see if it's clogged or something.
04-12-2010, 04:56 AM
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I dont remember the code for the knock sensor, but on mine it was a combination of a bad knock sensor wire and a bad distributor(along with 300K+ miles and all the other issues). Sometimes it would run like crap, other days it would run like a top. It always had a funny odor in the exhaust. My Chiltons and haynes manuals had some information on diagnosing the various sensors and how to set them.
