tps % dropping middle of first gear. y??
Thread Starter
Joined: Dec 2009
Posts: 2,331
Likes: 29
From: Glennville, GA.
tps % dropping middle of first gear. y?? Hey i installed a comp cam into the wifes tbss over the weekend. Been tunning idle and got it pretty good. But on the fist wot pull i felt it bog down and thin pick up the top of first. Second and third pull perfect.
I installed a fuel pressure gauge and noticed a 5psi drop from 60psi at the same time and thin pick back up right at redline. So i was thinking maybe fuel pump. Thin looking over logs i see that my tps goes from 85% at wot (i know) to around 50% at the same time and back to 85 at redline.
What are your thoughts? Tb going bad or fuel pump? Im about to order a 340lph to install anyways.
I installed a fuel pressure gauge and noticed a 5psi drop from 60psi at the same time and thin pick back up right at redline. So i was thinking maybe fuel pump. Thin looking over logs i see that my tps goes from 85% at wot (i know) to around 50% at the same time and back to 85 at redline.
What are your thoughts? Tb going bad or fuel pump? Im about to order a 340lph to install anyways.
Probably something in torque management tables that you missed. I'm not at all familiar with your specific platform, so there may be some expected airflow issues in a table somewhere that are affected as well, but that is wild speculation. While possible, it is highly unlikely that your possible screwup or a random part failure happened just now. I Would bet on a very minor tuning gremlin.
Thread Starter
Joined: Dec 2009
Posts: 2,331
Likes: 29
From: Glennville, GA.
Yea imma look over all the airflow and tm tables once again. Its only first gear. Im really leaning toward a fuel Pressure problem. Wouldnt the load be higher in first gear? Also tbss guys claim the stock pump is only good to a lil over 400rwhp. Im sure mines over that with this cam change. I just ordered a aem 320lph.
I just hope it keeps up with a 200 hit off the rails. The stock one before cam swap could barely get by with 150 shot.
I just hope it keeps up with a 200 hit off the rails. The stock one before cam swap could barely get by with 150 shot.
The full load can only be the same or LOWER in first gear. It can't be higher. This is why I feel a fuel pump issue is less likely. However, if you don't have a full tank, fuel slosh could possibly cause the pump to starve.
Thread Starter
Joined: Dec 2009
Posts: 2,331
Likes: 29
From: Glennville, GA.
Yea but its never had a fuel starving issue. Looks like all tm was removed a i thought. I added some fuel up top to see how it does. I may change pe to something rich and see if it can maintain.
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Thread Starter
Joined: Dec 2009
Posts: 2,331
Likes: 29
From: Glennville, GA.
ok update. Made a few pulls tonight checking things. Its only 1st gear. Log shows 50% tps. Afr shows commanded 12.5.
With a 60mph kick down to second its 100% tps and runs perfect with commanded 12.5afr. So its got to be something based off 1st gear only like tms. But ive removed everything. Got me stumped!
With a 60mph kick down to second its 100% tps and runs perfect with commanded 12.5afr. So its got to be something based off 1st gear only like tms. But ive removed everything. Got me stumped!
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Verdad Gallardo Thread Starter
Joined: Dec 2009
Posts: 2,331
Likes: 29
From: Glennville, GA.
I tgink i got it down to the base running air flow table. Imma tune raf and adjust acordingly. Im geussing it needs less air in first gear above 2000rpm? Which thw tb is trying to close up to compensate. Does that sound right?
If you can post a log, there is a good chance someone can either spot the problem, or at least tell you what else to log in order to narrow down the problem. My airflow table idea was a wild guess, but a definite possibility, so you may be onto something.