20V BT with velocity stacks, stock ECU questions

bwh13
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20V BT with velocity stacks, stock ECU questions

Postby bwh13 » Sat Feb 15, 2014 11:12 am

I installed the Technotoy Tuning stacks on my BT and am getting some odd running issues. I have an Auto ECU, 5 speed in an AE82. Running on streets it would not take more throttle above 3k for a while, then it would. First run on the freeway it ran fine, but after running around for 30 minutes on surface streets, on freeway at 60-65 if I give it more gas it acts like it's running out of fuel. Got off freeway, turned it off, started back up and it runs fine on streets. Is there something I need to do to run the stacks with the stock ECU to make it run well?

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jondee86
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Re: 20V BT with velocity stacks, stock ECU questions

Postby jondee86 » Sat Feb 15, 2014 3:41 pm

If you had the full factory airbox and filter installed, and then you
replaced that with open stacks, you have most likely upset the ECU
by reducing the intake resistance. You now are getting a bit more
air into the engine, and the manifold vacuum most likely dropped a
fraction. On top of which you have removed the factory stacks which
Toyota spent countless hours developing to give the best engine
response.

However, the ECU has some learning capability, so do a ECU reset
(disconnect the battery for 10 minutes) and then just keep driving
the car for a few days. If you are lucky the ECU will adjust to the
new conditions and run better after a few hours on the road.

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

bwh13
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Re: 20V BT with velocity stacks, stock ECU questions

Postby bwh13 » Sun Feb 16, 2014 8:41 am

I did install a new battery so it was disconnected for at least 15 minutes. I thought it would have learned while driving around for the 45 minutes but maybe not. I'll try it again and see if it gets better.

OK drove around for anther hour or so, it won't take more than 1/4 throttle without sputtering and spitting back thru stacks. More throttle doesn't do anything. It feels like it's running out of gas, won't rev much above 4k.

It seemed to run fine the other day, but I did just fill up the tank and added some octane booster just before this started happening. Maybe the octane booster is messing with the oxygen sensor signal output or something.

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jondee86
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Re: 20V BT with velocity stacks, stock ECU questions

Postby jondee86 » Sun Feb 16, 2014 9:19 pm

Kind of hard to troubleshoot a running car if you never had the exact
same thing happen... and I never had a 20V. But just changing to stacks
should not make your car run as bad as you say. So there must be some
other problem involved. Maybe you trapped a wire when you were working
on the engine ? Forgot to connect up a plug somewhere or left a hose off ?

I'd be guessing that the timing is off for some reason, so if all the obvious
stuff is good, you will have to do the standard diagnostics...

- Pull any trouble codes
- Check the cam timing (belt might have jumped)
- Check the ignition timing
- Check the fuel pressure (pump might be weak or filter clogged)
- Check your spark plugs are clean

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

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Crownvicman289
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Re: 20V BT with velocity stacks, stock ECU questions

Postby Crownvicman289 » Mon Feb 17, 2014 10:02 pm

Mine was always a bit lean too. WOT operation was fine, but part throttle sucked. I'd had a bone stock silvertop before that was wonderfully responsive, but a lot of guys report these issues with stacks on a stock ECU. Best answer is to get a Megaqsuirt or put the stock box back on.

bwh13
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Re: 20V BT with velocity stacks, stock ECU questions

Postby bwh13 » Tue Feb 18, 2014 6:34 am

It seemed to run fine when I first put the stacks on a few weeks ago. I didn't make any changes other than add a catch can, and filled up the tank added octane booster. To eliminate a variable I took the catch can out of the PCV loop. Seemed to run the same.

One thing I did note is that when the issue started up a couple of times, I would take a hard turn to get off the main street, and it would seem to run OK for a few minutes, then the issue would come back.
After thinking about this I wonder if the in-tank filter may be getting clogged or something- and the hard turns is moving whatever it is away from the pickup for a bit. Wish the fuel pump was accessible from up top, I'd pull it out in a minute and check it.

phanist
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Re: 20V BT with velocity stacks, stock ECU questions

Postby phanist » Sun Feb 23, 2014 2:23 pm

man I'm having the same problem.. except that my 20v bt with open stack was running fine till i decide to swap out to another bt itv set that i have laying around. so i clean that extra itv set i have and install them and now I'm having the same problem as you.. it start up and idle but once i take it out for a drive and hit about 3.5k rpm it hesitate and feel as if fuel is clog and not coming in. i try new fuel pump . same result.

note to jondee86 above

i did change out from 70mm stack to 30mm stack... maybe i did upset the stock ecu.... and now the ecu it acting up....
so i change everything back to what i have on before this problem come... but still nothing help.......ttt

i also did fill up a full tank of 92 octane at chevron .........
hope you find a solution.

i will take a look at the vacuum line routing later today... maybe i wrongly connect them...and upset the vacuum system and cause this...
if it help i will post...
good luck

phanist
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Re: 20V BT with velocity stacks, stock ECU questions

Postby phanist » Sun Feb 23, 2014 9:43 pm

oK

take a look at this video
http://www.youtube.com/watch?v=tLcVH8DRuEc

i have that similar problem ... i have one that eval line routed incorrect and my BT act like it short of fuel after 3--4k rpm....
re-route is now running fine.. i run stock BT Mt ecu...

hope that help

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