After the smog check station gave me the message that my timing was off and the dealer said it could be all kinds of things causing this and that they had no idea how long it would take to fix it (bastards), I searched here and looked it up in the FSM. It seems like (and I say this because there's some wierd stuff going on here) by rotating the distributor you can easily adjust your timing to the correct value.

The dude at the smog check station had one of these fancy timing lights where you can adjust the strobe, and when he had the strobe aligned with the 10 degree mark, the number on his screen said 15. He said that the number on the screen was supposed to be 10 when the strobe was aligned at the 10 degree mark.

In order to fix this myself, I bought a simple timing light at Kragen, followed the instructions, but I got a reading past the 15 degree mark (probably more like 20 or something). WTF?? Anyway, I adjusted it down to about 15 degrees by doing the distributor rotation, went back to the smog station, and he said I was within the limits.

But something is not right. Either the smog-man doesn't know how to read his meter or somehow, my meter is not flashing at the right time. I tried to adjust my timing down to the 10 degree mark, but now the truck runs like crap, and even worse up in the mountains. It barely started at 8000 ft. Can the timing light I bought be bad and give readings that are 5-10 degrees off? Can something else cause my truck to run good with the timing set at 15-20 degrees BDTC? Or is there something obvious I'm missing here? I adjusted the timing back to 15 again today and I will see how it behaves then. Really, the truck ran better before I started touching anything. Any help is appreciated.

Oh, 94 4runner, V6, 4WD, MT

 

Sound like maybe its not dropping to base timing. Did you cross the connectors on the data link connector when you set the timing? Was the engine fully warmed up? The 4Runner has a timing mark for the 0, 5, 10, and 15 degree settings. There is no need to mess with the advance dial on the light. You dont even need an adjustable light for this engine.

If you did all of the things I mentioned and the timing is still reading high then you need to check the adjustment on your tps.

 

Followed all instructions for the timing check, including warmed up car, shorting the connectors (this seems to make no difference) and making sure the idle is set right. When I did this myself, I used the simple timing light where no adjustments are possible, but the smog guy used one of the advanced lights.

Not dropping to base timing sounds very reasonable for my symptoms. What controls this?

TPS adjustment... Any leads on how to do this?

 

Stupid smog regulations - just put the damn sniffer in the tailpipe and stop screwing with our engines! Manufacturers set up the engine SOLELY to optimize the catalytic converter.

If you jumpered the data port properly and the car was warmed up, it should be at base timing.

At the end of the day, though, the number is pretty irrelevant. You don't even really need a timing light. Install the jumper. As you turn the distributor, you will hear the idle change as the engine becomes more efficient. Find the peak, and then adjust the idle speed down. Rotate the distributor some and make sure you are still at the peak timing, and then clamp it down. Take out the jumper, and then take it for a drive and make sure you're not getting any knock/pinging.

My timing was WAY off when I bought the truck - what a difference setting it right made!

 

It is covered in the FSM. However, I have had good results doing it by ear. With the engine idling at full temp, turn the tps down until you achieve the lowest idle you can. Then, turn it up SLOWY untill you hear the idle kick up, then turn it back just enough to let the idle drop again and tighten it down. As long as the TPS is getting the closed position it should go to base timing.

 

If your RPMs are not changing when you jump the two connectors, that sounds like a TPS problem. Check out THIS thread.

 

One more thing. was your engine light flashing when you jumpered the connector? If it was not then you did not get a good connection on the jumper.

If it was flashing, was it flashing any codes?

 

Thanks for all the info, I think I have several things I can check out now.

I'm pretty confident nothing happens to my idle/timing when I short the connectors.

I didn't check the Check Engine light today when I adjusted it, but I know it was blinking before. Didn't pay enough attention to see if it was a steady blink or not...

Btw, how do people apply vacuum to a line when the FSM tells you to?

 

By using a hand held vacuum pump such as this one.

http://images.marketworks.com/fullVi...ke_bleeder.jpg

They are priced anywhere from 10 to 100 dollars.

 

Ooh, cool, more tools I can buy

 

Sounds like TPS to me. Mine did the same thing - timing waaay advanced then wouldn't come down. New TPS fixed the problem.

 

That was my problem also. The timing could not be set because the TPS was so far off. After adjusting the TPS, the timing was easily set.

Troy

 

OK, checking/adjusting the TPS sensor this weekend. Will post results/updates as soon as they are available.