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Feels like BoostLeak/Fuel Cut cant figure out

DSM_PWR

Proven Member
2,459
18
Oct 12, 2007
Austin, Texas
OK so i have done Boost Leaks tests with soapy water and have found no boost leaks...
I have 680cc with the safc about -8/-12 across the hi throttle board with the wideband reading 11:1-11:5

Im usually hitting around 22lbs-24lbs of boost with 50/50 mix of e85 and 93... but one day as im on the highway my car feels like it "hit a brick wall" at 17-19lbs. I cant figure out why its doing this and driving me crazy:cry:
 

DSM_PWR

Proven Member
2,459
18
Oct 12, 2007
Austin, Texas
Well ive:

*Boost leak test
*Checked all the vacuum lines

I turned the boost down to about 15-17lbs and i can redline foot to floor just fine.
Which makes me think its fuel cut.
But i usually hit 24lbs...

There is however one possibilty i will do today. I use to have the boost guage on the cigarrette lighter with thick vacuum hose.
I changed it to the side A pillar and with nylon

Could the boost guage not be accurate? and im really hitting something like 30+psi? it doesnt seem to pull any harder than before so im stumped
 

joyfil2001

Proven Member
838
1
Dec 17, 2007
Toms River, New_Jersey
the 2g ecu is mapped to 25 psi, so if your gauge is slightly off and you hit 25+ your going to hit fuel cut. also, when you say you did a boost leak test what did you use to test it? did you use a compressor, foot pump etc.? how much boost did you hold while doing the test? and, did it drop off slowly? because believe it or not it can still be a boost leak. i had alot of problems before i finally did a CORRECT boost leak test.
 

webconnect

Proven Member
499
0
Dec 22, 2007
San Antonio, Texas
Something I did not think of at our recent meet was for you to use my boost gauge for a comparison. Because I was rewiring it anyways and it was out. Maybe you could use someone else's or I'd let you use mine again if we meetup.
 

joyfil2001

Proven Member
838
1
Dec 17, 2007
Toms River, New_Jersey
Something I did not think of at our recent meet was for you to use my boost gauge for a comparison. Because I was rewiring it anyways and it was out. Maybe you could use someone else's or I'd let you use mine again if we meetup.

thats actually a good idea. i also questioned my boost gauge at one point. the good thing with the autometer ones is that it is easy to find someone who has one, and simple to swap them for testing.
 

DSM_PWR

Proven Member
2,459
18
Oct 12, 2007
Austin, Texas
I dont question my guage its the vacuum hose. when i had it on the cig lighter hole, it was with pretty think vacuum hose.
{----} <---about that wide inside diameter.

Now i switched to the nylon stuff they give you when you buy a guage which is tiny in diamter
 

DSM_PWR

Proven Member
2,459
18
Oct 12, 2007
Austin, Texas
ok so i still cant find the problem and its even gotten a bit worse. Now i cant even go WOT on 15lbs, no matter what boost im at, the car cuts off at 5500rpm. And i have absolutely no boost leaks (trust me, ive checked).

Also, my wideband reads really lean around 14:1-17:1 through WOT which leads me to believe my injectors are going out? anyone have a different thougth? maybe fuel filter??

During cruising mode it stays steady at 14:7 and i get same gas mileage...
 
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