Supra Forums banner
1 - 17 of 17 Posts

·
Registered
Joined
·
202 Posts
Discussion Starter · #1 ·
Went down to the dyno today and got sad results. I'm running stock 440’s with MAFT and when we tune to safe A/F levels (11.4 to 11.8), I'm hitting fuel cut at 9 psi...?! When we try to tune out the fuel cut we're getting scary numbers like 13.5 AFR @ 4500 rpm!! We even tried lowering the injector size to 420cc (BASE = 0) and still fuel cuts like crazy... For the heck of it even tried limiting the Hz: Normal, 1500, 1450, 1400... Nope, just nothing works. :( Once we even hit fuel cut at 1200 Hz!? What the hell?! I heard that once our cars switch to open loop we should be seeing some really rich numbers like in the 9's and 10's but I'm nowhere near those numbers.

What can it be? What do you think is wrong? My base settings are: AUX = 0, BASE = 2, IDLE = 0, MID = 1, WOT = 2. And my fine tune settings are: 3000 = 3, 4000 = 3, 5500 = 0, 6500 = 0. I didn't even get to tune the 5500 and 6500 rpm range because I keep hitting fuel cut before 4500 rpm, very sad... I heard that with the MAFT people are able to run 14.5 psi comfortably with stock fuel system because once on WOT, our cars run so rich that people need to SUBTRACT a lot fuel. Well, I'm nowhere close... I'm having to ADD fuel 'cuz it's so lean and once I do, I'm hitting fuel cut at something stupid like 9 to 10 psi, lol. Geez, this is frustrating, please help. Thanks,

For reference my mods are: Upgraded IC and hard pipes, ball & spring type MBC set to 14 psi, full 3" turbo-back exhaust, MHG, SSQV BOV, MAFT & S-AFC II (not being used, will use to fine tune after MAFT is properly set).

p.s. I haven’t changed the fuel pump but I’ve changed the filter 2 years ago. Other than that, my fuel system is totally OEM. Thanks,

Jason L.
 

·
Premium Member
Joined
·
4,409 Posts
check your tps via the tsrm, could be that its not seeing enough throttle signal to go into closed loop. Ide say boost leak but that would make it run rich, although i may be overlooking something because its maf.

PS hz doesnt tell the whole story as far as fuel cut is concerned. ITs a combination of many things.
 

·
Registered
Joined
·
202 Posts
Discussion Starter · #3 ·
You mean to go to "open loop", right? I know that the ECU is seeing WOT from the TPS because I can monitor that thru my S-AFC II. I see 100%. Thanks though, good thought.

Anyone else?
 

·
Newbe....I know nothing!
Joined
·
1,853 Posts
20pwns said:
You mean to go to "open loop", right? I know that the ECU is seeing WOT from the TPS because I can monitor that thru my S-AFC II. I see 100%. Thanks though, good thought.

Anyone else?

As long as the floor mat is not stufed under the gas pedel. :rofl:

Jeremy
 

·
Registered
Joined
·
202 Posts
Discussion Starter · #5 ·
Turbo Drifter said:
As long as the floor mat is not stufed under the gas pedel. :rofl:

Jeremy
LOL, that was hella funny Jeremy. We're like, "Wut the hell?! Why are we only seeing 66% throttle? Oh shit, the mat, the MAT!" :lol: I just wish that WAS the problem, damn... Hey man, I took a picture of that banjo bolt, you wanna see it? I'll post it here. I've also gone ahead and ordered the bolt from Toyota. It's only $5.50 after taxes so for that price I'll stick the OEM one in there to be 100% sure, right? Thanks,

Jason L.
 

·
Registered
Joined
·
202 Posts
Discussion Starter · #6 ·
Here is the bolt:












And here is where it was found:



Does your bolt look like this? Or is mine looking restrictive? Mechanic shop that rebuilt my engine might have put in the wrong bolt... :( Can someone double check?

Jason L.
 

·
Registered
Joined
·
202 Posts
Discussion Starter · #8 ·
Oh shit... So, is this banjo bolt a significant source of fuel? According to the diagram it looks like the fuel comes from the tank, goes thru the bolt, up to the fuel pulsation damper and into the rail, or is it the other way around?
 

·
Registered
Joined
·
67 Posts
Yep, it's part of the high pressure line. You can either drill that one out or pick one up from Toyota.

Be sure to slap your mechanic in the face.
 

·
Registered
Joined
·
202 Posts
Discussion Starter · #10 · (Edited)
In case some of you are wondering what made me look into that bolt, here is the full story:
After I got my car back from the shop I started smelling a lot of fuel in the cabin. Under the hood I found a fuel pressure regulator with a small hole on the top where fuel was shooting out!! When I took the car back and complained about how they overlooked such thing they said, "It wasn't like that when it left here, it must've happened after." And then they told me to go find the replacement part for it. From then on I was on a wild goose chase for days until I found a diagram of the fuel system in the EPC (thanks Cygnus) and I realized that there was no such part for my vehicle; it was supposed to be a damn banjo bolt!!! I was just pissed. When I went back and told them that the damn part never belonged in my car, guess what they told me, "Nope, we put everything back to the way it was. Some other mechanic before us must've put it in there, not us." I was really, really disgusted and mad but saw that there was no point in arguing with these monkeys; they'll never own up and accept the fact that "they" screwed up. So, I asked them to find the right part (the banjo bolt) and put it in, and they did. Or so I thought until today when I went to the dyno and saw that my car was just absolutely freakin' lean!!! The bolt didn't cross my mind at first. I just thought that we were doing something wrong with the tuning but after hours of trying we (the tuner and I) started thinking about other possibilities such as an old fuel filter, fuel pump, etc. and that's when it hit me, the fu*kin’ bolt!!! Could it be?!! I came home from an unsuccessful tune and quickly looked into the bolt. And what do you know... Those fu*kers managed to screw me over again. I'll find out for sure tomorrow when I get the correct part from Toyota but I'm convinced now that the hole down the middle of that bolt is ridiculously small. So, that's my story, thanks for listening. What do you guys think?

BTW, the name of the shop is called ATEB, in Burnaby. There, I finally said it. I didn't want to badmouth a business unless I have good reason to but I think this is a good enough reason. So, what ever you do DON'T TAKE YOUR CAR THERE!!!!
 

·
Newbe....I know nothing!
Joined
·
1,853 Posts
Dude thats your problem right there, that bolt was it I'm 90% sure. There is no way that will flow the amount of fuel you need. Each time we would try and change somthing it would do nothing, the same time and time again. That is what lead me to belive there was somthing in the fuel supply i.e. fuel filter, fuel pump..........somthing.

I'm glad it looks like it will be an easy fix.

Jeremy
 

·
86.5 Turbo
Joined
·
1,571 Posts
iirc the bolt on my fuel system had a lot larger hole through it. Even the one I have here for the oil line is no where near that small. I have noticed the same problem with anything just short of wot my af's are really lean. this is another thing that i can see with my af gauage, the light show will be in the red not all green. btw how do the half dyno graphs look?
 

·
Newbe....I know nothing!
Joined
·
1,853 Posts
I also know what that banjo bolt they put in there is off. I though it looked familer when we where looking at it.

Its the oil feed banjo off a Mitsu turbo, the small hole works as a restrictor for the oil supply on those turbos.

:sadance:

Jeremy
 

·
Premium Member
Joined
·
4,409 Posts
whoa.

yea i meant open loop sorry
would make sense as to why youde have to add fuel + hitting fco early.
Sucks, but at least you found it
 

·
Registered
Joined
·
259 Posts
consider yourself lucky on two parts

a) simple solution
b) no detonation (hopefully)

did you ever get that idle fixed?
 

·
Registered
Joined
·
2,649 Posts
Yes, we fixed the idle a while back - same shop neglected to bolt the EGR fitting to the rear of the intake plenum, so it was leaking badly back there. We just dug through my bits box and found a couple bolts that fit, then snugged it up - still without a gasket though, likely should fix that with some FIPG and park it for a day while it cures...
 

·
Registered
Joined
·
71 Posts
20pwns said:

BTW, the name of the shop is called ATEB, in Burnaby. There, I finally said it. I didn't want to badmouth a business unless I have good reason to but I think this is a good enough reason. So, what ever you do DON'T TAKE YOUR CAR THERE!!!!



I'm glad you tolled us the name. I'll be sure to never go there. I remeber you saying something bad about them before but wouldn't give out their name. :)
 
1 - 17 of 17 Posts
Top