7mgte stumble HELP

cre · 11-19-2012, 03:19 AM

You're sitting in the front row of Trouble 101, waving your arms and shouting "Oh me! Me, me! Pick me!".

And I still can't imagine any reason on Earth why you'd run a second pump (much less an in line, in series with the stocker) on a stock setup. Shit, people run over 400hp on the stock pump without any issues. So, again, WHY are you running the second pump? Is it plumbed in series (I presume it is which is awful)? Is there a bypass to ensure that neither pump can cause a catastrophic failure or the other due to its own failure? Did you at some point delete the in tank pump completely and install an inline instead (you know that in tank pumps generally last longer and are more consistent as they're better cooled)?

This doesn't sound like an issue with the fuel pressure up VSV to me. Could be a failure of the fuel pump relay and resistor pack... Might try bypassing them to see if that helps. You're not going to be boosting enough to see any significant stumble from a boost leak at that RPM unless you've got a full fledged hole somewhere.

Personally, I'm suspicious of your inline fuel pump, the AFM, fuel pump resistor pack/relay and your spark plug gap may be too tight.

What other mods are you running?

EDIT: Please don't mistake me for having a negative or mean tone in any of this. I'm not a fan of that particular setup but it has its place... The Supra just doesn't have any significant deficiencies in the fuel system so I really can't see the point in adding another point of failure and extra complexity.

11-19-2012, 03:19 AM	#9
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	You're sitting in the front row of Trouble 101, waving your arms and shouting "Oh me! Me, me! Pick me!". And I still can't imagine any reason on Earth why you'd run a second pump (much less an in line, in series with the stocker) on a stock setup. Shit, people run over 400hp on the stock pump without any issues. So, again, WHY are you running the second pump? Is it plumbed in series (I presume it is which is awful)? Is there a bypass to ensure that neither pump can cause a catastrophic failure or the other due to its own failure? Did you at some point delete the in tank pump completely and install an inline instead (you know that in tank pumps generally last longer and are more consistent as they're better cooled)? This doesn't sound like an issue with the fuel pressure up VSV to me. Could be a failure of the fuel pump relay and resistor pack... Might try bypassing them to see if that helps. You're not going to be boosting enough to see any significant stumble from a boost leak at that RPM unless you've got a full fledged hole somewhere. Personally, I'm suspicious of your inline fuel pump, the AFM, fuel pump resistor pack/relay and your spark plug gap may be too tight. What other mods are you running? EDIT: Please don't mistake me for having a negative or mean tone in any of this. I'm not a fan of that particular setup but it has its place... The Supra just doesn't have any significant deficiencies in the fuel system so I really can't see the point in adding another point of failure and extra complexity. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar ---> Last edited by cre; 11-19-2012 at 03:42 AM.