how much should my fp change with line off?

How would you verify if it is the maf? Would'nt the car still try to make more than 7psi; my car will not builld anything more than 7psi. Line off fuel pressure is usually 38psi. It doesnt really go up much at all when i remove tha vaccum line. I am not sure of the actual chips brand but I do know that on the back of the chip it says, First line: August 28#
Second line: 20* 17# 93oct

On the top of the chip it has a yellow smily face sticker. Like this :) .
As for the fuel pump, what brand and model should I with? I've already had bad luck with a walbro 255 that died on me after only 3 months use :mad:!! Im about to go outside now and check the turbo now.
 
Is the SES light lit? Start the and tap on the maf (lightly) with a screwdriver and see if the engine stumbles or stalls, that would indicate a possible bad maf. I thought the Walbros were OK now? meaning they fixed the problem with them?
 
christians87 said:
How would you verify if it is the maf? Would'nt the car still try to make more than 7psi; my car will not builld anything more than 7psi. Line off fuel pressure is usually 38psi. It doesnt really go up much at all when i remove tha vaccum line. I am not sure of the actual chips brand but I do know that on the back of the chip it says, First line: August 28#
Second line: 20* 17# 93oct

On the top of the chip it has a yellow smily face sticker. Like this :) .
As for the fuel pump, what brand and model should I with? I've already had bad luck with a walbro 255 that died on me after only 3 months use :mad:!! Im about to go outside now and check the turbo now.
Click to expand...

If the car is breaking up, stumbling, etc... it won't build boost as the exhaust flow isn't there while the car is doing so....

One more time.... the fuel pressure issue MUST be verified... it may be a bit of a pain to get a hose, etc, but you will be better off in the long run, as after you do it, you will always have a way to verify THE MOST CRUCIAL part of the TR equation.... adequate fuel delivery... Little or no pressure rise when you remove the hose leads me to STRONGLY suspect this is where your problem lies.....

Too much info on the Walbro issue.... it gives me a headache... search here and make your decision... I would probably use the Walbro GSS340 from Racetronix if it were me... but I'm betting that any of the new Walbro's from Gbody, FullThrottle, etc should be ok now.... shoot them an email and see if they are again confident in the product now.... I can't remember who put smiley faces on their chips... Red's maybe? It's probably time to upgrade there as well.... chips have come a LONG way in the last couple/few years.... even my 'state of the art' :wink: Thrasher is going bye-bye real soon... for a TurboTweak... :)
 
The fuel pressure issue has been on my car for about 2 to 3 months now but I am going to order one of those pumps tonight. Im kind of favoring towards it being a maf. I checked out the compressor wheel today and none of the fins are bent. As for shaft play, I would say its about normal for a turbo with 77k miles on it. It does have just a little up and down play but it doesn't touch the housing anywhere..
Once I got the car back together i drove it around the block. Back in the garage i got these numbers off of the scanmaster.
o2 all over at idle
af 04
L8 29
bat 13.7
Int 121-132
bL 126
mph 00
clt 173
ats 71
r 775
tps .44
iac 112
cc 05 then climbs to 251 and starts over
mal 23

Im not sure what trouble code that is. While driving it around i slowly started to get into it and i noticed that the car would start to break down every time it reached 0 psi boost. Once it started breaking down it would start the compressor surge and the scan master would read way rich. While all this is happening there is 0 knock.
 
87GN_70GS said:
Put air pressure on the regulator and verify that it goes up accordingly.
Click to expand...

That doesn't hurt to do, but is in no way a substitute for actually verifying fuel pressure under operating conditions. The mode of most pump failures involves the pump not being able to maintain flow volume/pressure under increased demand situations such as occurs WOT at the top of 3rd gear.... with less flow requirement (such as idling or running the pump in recirc with the engine off) the failing pump may make the pressure/meet the demand no problem. This can be easily seen on the fuel pressure gage as the press. rising normally in 1st/2nd gear, and then rising to a point and then falling off as the demand gets large.... this is exactly what I say on my fp gage as my last 2 pumps failed... all the air pressure on the reg will do is verify the reg is functioning properly... :smile:
 
Today i hooked up a vaccum pump to the regulator and when vaccum was applyed it would lower the fuel pressure. That would mean the regulator i working, right? I wasnt able to put and compressed air to it because I dont have an air compressor. I also tryed tapping on the maf while the engine was running and nothing changed. When I first started the car it was running way worse than it usually does. Its like the problem keeps getting worse. It kept choking down and it wouldnt idle until it warmed up. The problem with the mat sensor was I had just forgottened to plugg it back up when I put the intake back together lol :tongue: . I noticed that when you start to spool the turbo and try to build boost then let off the waste gate doent make the same noise. Insted of the normal distinct turkey gobble noise our cars make it made a lite psssss. Nothing like it usually sounds. I've been thinking if the maf is the problem I would go ahead and upgrade to the ls1 set up. do you think thats a good idea? As for a chip, I have a tt alky chip thats only 3 months old that I normally run. I just put the old one back in untill I get the car back running good.
 
christians87 said:
Today i hooked up a vaccum pump to the regulator and when vaccum was applyed it would lower the fuel pressure. That would mean the regulator i working, right?
Click to expand...

That points towards the regulator and gage working properly.... does the fuel pressure rise properly under boost??? :rolleyes: I rest my case.....
 
Im on it tommorow lol. Im going to try to rig up the ole fuel pressure gauge taped to the windsheild trick. Hopefully that will shed some light on what in the world is wrong with my car.
 
christians87 said:
Im on it tommorow lol. Im going to try to rig up the ole fuel pressure gauge taped to the windsheild trick. Hopefully that will shed some light on what in the world is wrong with my car.
Click to expand...

Thank you!!! :tongue: I was starting to get a little frustrated! :) While your at it, set the scanmaster to monitor the MAF and watch it real close to see if anything funny is going on.... I'm really thinking the maf is whack, and the pump may well be on the way also.... It will be hard to tell what's going on with the maf while the car is stumbling, but ease up to it and try and see if the maf numbers look logical... and the fuel pressure will also be bouncing around when it's stumbling.... watch for a fall off right as/before it hits the stumble.... Keep your chin up, you'll get it figured out.... :wink:
 
You should have a aftermarket fuel pump and a hot wire kit in the tank, I went through the bad aftermarket pumps myself. I have the pump from Racetronix on the car now, it's the old school walbro pump, works like it should...in fact I need to have Eric @ Turbo Tweak take some fuel out of the chip now.

Chuck
 
christians87 said:
Im on it tommorow lol. Im going to try to rig up the ole fuel pressure gauge taped to the windsheild trick. Hopefully that will shed some light on what in the world is wrong with my car.
Click to expand...

Yes, verify that you have proper fuel pressure and it does rise with boost.If it's a stock pump I would change it anyway for peace of mind, keep us posted how it goes.
 
Ok so I feel so stupid lol:p . Today right before I was about to hook up the fuel pressure gauge I noticed that something was looking different about my intercooler. After taking a closer look I realized the hose had blown off. Lol, I know all of you all probly rofl at me and I completely dont blame you; but, to try to make my self not look like such a dumb @$$ im going to describe what it looked like. I bearlyed noticed it, when the hose orginaly blew off it went back to its place and made just a good enough seal to make the car idle and drive good when not under boost. When the turbo would start to spool all the air would just push past the light seal. Im still going to replace the old factory pump with prolly a walbro 340 unit just for peace of mind like you all say. Anywase I just wanted to thank every one for the help on this wild goose chase lol. In the process of takeing off the bumper and grill I desided to repaint my bumper fillers. While cleaning them up to paint they fell apart in my hand. So, where is the best place to get replacement bumper fillers?
 
yep, should have had you check that.... that's happened to alot of us... sometimes it's easy to overlook the basics... glad you found the problem..., but still verify that fuel resssure, even after the new pump.. it's a continuous learning process with these cars ;)
 
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