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Fuel cut or boost leak?

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97gsx_zeclipse

15+ Year Contributor
220
0
May 4, 2007
San Diego, California
I was driving and accelerated on the freeway and when it hit full boost, the car felt like it slammed on its brakes and then shot a 5 foot flame out the back. Usually I run 16 psi but since I put on the type s and after I hooked up the lower nipple this happened three times already, and boosts up to 18 psi on stock fuel pump and injectors. Now from waht my friends are telling me, that it can be either fuel cut or boost leak. I quickly changed things back to stock boost and disconnected the lower nipple of the type s just in case untill I figure out whats going on. So what do you guys think it can be and what should I do? Thanks
 
Fuel cut is a direct result of boost leaks.

My advice: do a boost leak test and fix your leaks.
 
turbosax2 is right fix the leaks. and yes you hit fuel cut. anything 16psi and above will make you hit fuel cut. it's like hitting a brick wall isn't it. fix the leaks and adjust boost accordingly until you can afford some fuel upgrades and management
 
I would agree, check your intercooler pipes for leaks, if you have stock pipes they are notorious for leaking over time if not kept up properly. I'm assuming you have a manual boost controller, if you do make sure when you set it to tighten it up well. A friend of mine had a similar problem with his 86 daytona. Hopefully that helps you.
 
As said before, boost leaks will lead to fuel cut. If you are on your factory T25 turbo, keep it under 16 psi. If it runs more boost due to an exhaust or intercooler pipes, get a boost controller and turn the boost down.
 
It was wierd, the guy behind me almost hit me when my car bucked hard like that. I got another idea why it might of happened. It might of not happened from a boost leak. I don't know, you be the judge. My friend put a bleeder valve on the turbo waste gate line and thats where I tapped for the lower nipple of the bov. Could that be the problem?
 
I was wondering if you ever fixed your problem. I have the same cutting out on my t-25, but it happens right when the turbo spools and spikes to 17ish psi before settling to 15. It seems that it only happens when I step on it from low rpms. Could this still be fuel cut?
 
I was wondering if you ever fixed your problem. I have the same cutting out on my t-25, but it happens right when the turbo spools and spikes to 17ish psi before settling to 15. It seems that it only happens when I step on it from low rpms. Could this still be fuel cut?
GUYS! You're not supposed to run 100 million psi on a STOCK GST OR GSX!!! It's like running in 100 degree weather with no water! If you want to up your boost pressure then do it right!
 
Anything over 15psi your going to want at least a 190, but i would go with a 255 wally.you know once and done kinda thing. gotta have the fuel upgrades over 15psi. if you dont you might look like this.:beatentodeath:
 
Anything over 15psi your going to want at least a 190, but i would go with a 255 wally.you know once and done kinda thing. gotta have the fuel upgrades over 15psi. if you dont you might look like this.:beatentodeath:

A 255lph pump usually needs a FPR to go with it.....

You should go ahead and disconnect the bleeder valve that is hooked up to the lower nipple of your BOV as it isnt necessary. As mentioned, turn the boost down to no more than 15-16 psi on the stock turbo/fuel. You should go ahead a do your fuel pump rewire now as well. A cheap fuel pump upgrade that is a simple bolt on is the EVO8 190 pump. Just start making plans on your turbo upgrade, as trying to make more power from the T-25 is pointless.
 
I have a Walboro 255 pump and an AFPR for fuel mods so far. Should i still be concerned about there being enough fuel? I'm not trying to boost the hell out of the turbo. I have it set @ 15 psi. which is what i've herd is safe on a t-25? I'd love to up grade, but spending money on turbos is hard to do when your a poor college student. I know the turbo sucks, but i'd like to get as much as i can out of it.
 
I have a Walboro 255 pump and an AFPR for fuel mods so far. Should i still be concerned about there being enough fuel? I'm not trying to boost the hell out of the turbo. I have it set @ 15 psi. which is what i've herd is safe on a t-25? I'd love to up grade, but spending money on turbos is hard to do when your a poor college student. I know the turbo sucks, but i'd like to get as much as i can out of it.


You wouldnt need to worry about having enough fuel for the T-25 @15 psi with a 255/AFPR as that setup is more than safe. Anything over 15-16psi on that turbo is pointless, as the turbo is just inefficient at higher boost and rpm levels.

Here's a good link, scroll down about halfway and there's a chart that is a good baseline for turbo/fuel recommendations....
Road Race Engineering's Eclipse Fuel Delivery Upgrades

You could probably pick up a 14b in decent condition for a cheap turbo upgrade. It really makes a world of difference over the T-25, and it also holds boost to redline. But looking at your parts wishlist, it doesnt seem like you want to go MHI when you upgrade, so it might not be cost effective on a tight budget.
 
Thanks for the quick reply. Any ideas on why im misfiring when the turbo spools up? It only happens from about 2500-3000 rpm, right when the turbo spools and spikes. It seems that it only happens when im low in the rpm range and have to wait for the turbo to spool. It cuts out several times in a row, and then pulls hard through the rest of the power band. Any information would be appreicated. How's that 14b working for you?
 
Wires are a good place to start. Check your plugs, too. It's cheap enough to change them out. If you put in new ones, use NGK BPR6ES gapped at .028. If that doesn't work, it could also be a bit of knock as your turbo hits, which is evident at 17psi, but not at 15psi after you level out. Log a run and look for timing being pulled.
 
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