I was hoping you could answer a question that has been debated here before, but no one has responded with a solid answer...

Do 01-02 Lightnings dump boost during shifts?

Lately I have noticed something going on during shifts in addition to the torque reduction. I did a search on the subject and found that some people think that boost is in fact dumped during shifts on the 01s and 02s, but again they were not 100% sure.

I figured that if anyone knows for sure it would be you.

Thanks in advance!
Sammy

 

I'm going to say yes. On 01-02s, I've noticed a definite "pause" on the 1-2 shift, that's not torque reduction or limiter related. No brand of chip I've seen eliminates it, the only fix is to disconnect the dump soleniod either via the plug, or a bypass kit.

 

This is an idea, maybe ill try it sometime or someone else could figure something out. Why dont we figure out what signal is sent through those wires that some of us unplug, and say attach a light to it or some type or meter, and then go take the truck for a run. Then we would be able to see exactly what happens, if it dumps or not.

 

Sal, thanks for the quick response!

SpankDog, that sound like a good idea. I have a Fluke meter that will record voltage peaks. This could be connected to the wires and secured somehow under the hood during the testing. But like you said, we just have to figure out which wires to connect to. I will take a look tomorrow, but if there are only a couple of wires it should be pretty easy to figure out!

 

I was just trying this out tonight. I had the boost bypass, but wanted to remove it to test a few things. Well anyway with an autometer boost guage I was reading ~10 lbs on a stock pullied truck and at the 1-2 shift I lost maybe ~.5 lbs. I don't think it is dumping boost at the shift. The truck is running much smoother at the shift and the hesitation I had seems to be gone after I cleaned out the throttle body.

I have a question that maybe someone could try to help me understand. I had new keys made for the truck and they had to flash the computer. Now anytime my bypass is disconnected the check engine light comes on. Never did this before the flash, but now it will anytime the bypass is disconnected. Its not that big of a deal cause its easily reset, but kind of odd. Anyway when I was putting the throttlebody back on, I forgot to reconnect the TPS sensor. When I test drove the truck it was shifting really hard, but no check engine light. I had the same thing happen when I forgot to connect the MAF sensor up so I figured it to be something I forgot to plug in. My question is -- Why doesn't the MAF sensor or TPS sensor being unplugged set off a check engine light, but the boost bypass being disconnected does? Also why is the tranny shifting so hard when these are disconnected?

-Brad
01 L

 

My truck does the same thing, I have an 02 with a chip and boost bypass and after the 1-2 shift there is deffinatly a lag or pause, if anybody has any ideas let the rest of us know.

Larry.

 

I was even thinkin of just running some wires into the cab from under the hood, who really cares what it looks like, its just for a test. Maybe bring a passenger along so they can keep an eye on the voltage. Back in my honda days I remember guys hooking a light to the VTEC so they can see when they are ugh in vtec, maybe we can have a boost dump light, but then again i dont think anyone wants to see that light.

 

The tranny is shifting hard because when the compueter sees the other things not responding it goes into limp mode, whcih sets EPC Line Pressure 55 to MAX and ups your line pressure to protect the cluthces until you get the other problems resolved.

I haven't got a clue about the other stuff,,

G

 

Wanted to bring this thread back TTT to see if anyone else had any input...

 

Now the 2nd to 3rd shift has much reduced torque multiplication lag time. Also no MIL light yet



Spike

 

since installing a 4# pounder on my 2000 i get boost dump,was never a problem before i installed the larger pulley,disconnected the solinoid and no problems since

 

svt360, am I correct to assume that your boost was being dumped because you were hitting your rev limit due to the higher shift points on your chip?