Thursday, August 25, 2011

She starts hesitating and hitching/surging

At the very same time I installed the gears, the 4Runner started hesitating when accelerating. It was like I was pushing and fully releasing the gas pedal, but very quickly.

It was also running less well than before the gears. Now when a truck with 4.10s and 33s seems more powerful than after installing 4.88s...

There were other indicators something was wrong:
  1. The 4Runner would not go as fast down the highway as before the gears/lift. I expect this to some degree since there's a lot more air being pushed with the lift. But the truck feels like it's driving into a headwind as speeds go up, and 75-80 is harder than it should be. This thing ripped with 225/75R15s and 4.10s, which calculate out to the same as 33s and 4.88s - something's up.
  2. Further proof the 4.88s/33s are nearly the same as 225/15s - the speedo was accurate with the 225/4.10 combo, way low with 4.10/33s, and is now about 2mph high at 70 with 4.88s/33s. If anything, I now have a slight advantage.
  3. It doesn't go up hills any faster or more easily than with the 4.10s
  4. I could go up some hills at about 60 in Drive with 4.10s. The nearly 20% jump from 4.10s to 4.88s should mean I can run the same hill in OD (20% steeper than D). No way right now.
At first the hesitation was was only present when it was cold, first thing in the morning. But it gradually  started to do it when it was warm as well.

Since it's easy, I decided to check for codes. The word is that, even if the Check Engine light is not on, you may have codes.

I'd never checked codes on this truck, so it was a learning process. Here's a couple tidbits I learned. :)

22RE's generate codes as Flash, flash, flash...pause...flash...pause,pause,pause...repeats (or next code).
It turns out 22RTE's generate some additional codes. A 14 is 14 flashes, not Flash...pause...flash,flash,flash,flash... it threw me for a second when it got past 9, then kept going... LOL

A quick check of the ECU codes showed two in memory.
  • 14 - Turbo overpressure (hit the fuel cut - and it had with the old cam after the dyno shop finished adjusting it)
  • 7 - TPS no bueno
I'll doublecheck it with an ohmeter tomorrow since they're not cheap.

Here's LC Engineering's thorough setup/verify/adjust procedure - you CANNOT just remove the old one and install the new one.

I'm checking on the right place to get a TPS now. I prefer OE parts, but they're sooo much more expensive. Time to ask my hookup at the local dealer if he can really hook me up! :)

I'll be surprised if it fixes the power issue, but we'll see.

I think it's amazing that these issues started at the same time I added gears. LOL

I'll report back on the outcome!

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