My Expy acceleration video

[toms89]

I uploaded a video I just shot tonight. I was holding camera so sorry about the quality and focus.

I was going up a slight incline and was initially on the side of the road so I hesitated for a moment until I was sure she was pointed straight.

http://www.youtube.com/watch?v=I8-khaHr52I&feature=mfu_in_order&list=UL


The boring details:

The motor has been going dead lean on the shifts. Still not sure why this is happening but believe the tranny is hitting some kind of limit which signals the ecu to cut fuel. I loaded my new tune re-enableing torque reduction (limits power on shift) hoping it would keep the ecu from cutting fuel. This did help as it was far less noticable but it is still cutting fuel . After it cuts fuel it takes some time to recover....not obvious on video but it can easily be felt.

Watch the needle on the wide band gauge on the shift. The 5:00 position is 19 to 1 air/fuel and that is as far as the gauge reads. At full throttle it should remain at the 10:00 position as this is 11.5 to 1.

 

[panda24619]

UGH! love that sound dude! gives me a woody everytime! yeah thats weird that the gauge dose that. is it cause there is no fuel going into the engine during a shift or is just something the gauge dose?

 

[toms89]

UGH! love that sound dude! gives me a woody everytime! yeah thats weird that the gauge dose that. is it cause there is no fuel going into the engine during a shift or is just something the gauge dose?

The gauge is accurate...the ecu is cutting fuel?! Datalogging confirmed it just not sure why yet.

 

[nvycrmn]

i want one!

 

[Soldier777]

tom incredibly sexy... once I burn through my motor I am coming to your house or I will fly you down to help me with this swap.lol

 

[alaskanexpy]

your low on washer fluid....lol


omg i'm so jealous! i wish my expy was that fast!

 

[toms89]

your low on washer fluid....lol

Actually I am not. Damn light just goes off every time I drive. Just has not been high on my priority list to fix.


Thanks guys for the nice comments!

Just wish I could track down my fuel cut issue...its gonna drive me nuts... I know, I know ...as my wife would say "Short trip".

 

[nvycrmn]

well let us know, cuz i am def going to start looking into the swap since i cannot find the s/c that i want. might as well do the swap and go from there!

 

[tallsville]

nvy dont forget to stop in colton and pick up the engine block on your way home.

 

[BakerEdition]

run video

Tom...sounds like the fender gaskets are leaking and the canooten valve may be getting stuck.. Its impressive to watch that speedo climb...now drop it off the jack and lets see what it does....*****...Seriously man..its sounds sweet....

 

[toms89]

Tom...sounds like the fender gaskets are leaking and the canooten valve may be getting stuck.. Its impressive to watch that speedo climb...now drop it off the jack and lets see what it does....*****...Seriously man..its sounds sweet....

Have not thought of that. Will have to check my fender gaskets and canooten valve.

Yeah could not believe how dark the video came out.. Not great with cameras. I will attempt a daylight shot sometime and try and get street view also. Looks faster if you have a point of reference. Would prefer to do after issue is taken care of dont like pushing it when I know it has a problem. Fortunately it appears to be cutting fuel completely which avoids lean related detonation... But for some reason..shutting off the fuel tends to slow it down?!?

 

[panda24619]

the only thing i can see with why its shutting it down is like in a man trans. let foot of clutch shift foot back on. i dont remember but did lightning come mans?

 

[toms89]

the only thing i can see with why its shutting it down is like in a man trans. let foot of clutch shift foot back on. i dont remember but did lightning come mans?

Lightnings came with 4r100 also.. modified version. The odd thing is with lower boost this did not happen. The harder its running the more pronounced it becomes and for longer period of time. I agree it is like the ecu is "getting off the gas" to shift but this is not normal. It will also shift nice and firm at lesser throttle positions and less boost.

 

[panda24619]

thats really weird. go on a lightning forum and ask them whats up with that.

 

[toms89]

thats really weird. go on a lightning forum and ask them whats up with that.

I have and posted video....no answers yet..

 

[Berg]

nice truck man!

 

[JUST4FUN]

i seems like your hitting the rev limiter 5300rpm if you put it in neutral and rev the ball sac off it it will cut out at like 5300 same as in gear need to get/find some way to eleminate this

 

[toms89]

i seems like your hitting the rev limiter 5300rpm if you put it in neutral and rev the ball sac off it it will cut out at like 5300 same as in gear need to get/find some way to eleminate this

Thats one of the 1st things I checked. The rev limit is set at 6,000 in the tune. There is actually a seperate neutral rev limit but I have it set at 6,000 also. I set shift rpm @ just under 5,400. I raised it over stock due to cam powerband. It could use a bit higher shift point but trying to be conservative.

I have tried several things in the tune with no luck yet but you gave me an idea. I can turn off fuel cut in the tune, only its in the rev limit area?! Might try this and see if it works. I have been focused on finding the cause I did not consider if I could eliminate the symptom..

 

[JUST4FUN]

the symptom is the coputer is shuting the fuel supplie off at lets say 5400rpm
but it will not restart untill it goes below 5100rpm

 

[ExpeditionDrew]

wow that is sick....about a 5.5sec 0-60 time....