O2'S Dropping FAST at WOT!! Loooong Story!!

[FRANKIEz28]

MY o2's start at around 850's and drop to like 740's with no knock or 720's with 2 Knock

Board member ULYCYC has helped me every step of the way Thank you ED!!
To get to the point, Were stumped
This is what we have done so far tis is not in any particular order:

1) Added Xylene to clean injectors
2) Fuel Filter
3) Checked for any Kinked fuel lines
4) A/C Delco o2 sensor with new one I thought it was lazy, ULYCYC was right, it wasn't!
5) Checked fuel pressure at WOT and holds 6) Changed alternater (thanks Steve) because LOW Amprage at pump thought it was fixed now it gets high 13's in voltage to the pump at WOT and does the same thing
7) Swapped ECM with known good one
8) Switched the Adjustable FPR with a stock FPR & stock chip and no change
9) Chips: Kenny Belle/Thrasher/Joe lubrant

Raised fuel up to 45 line off with stock chip and 5 PSI of boost and the o2's still started at 850/840's and dropped to low 750's to 720's on top of 3 gear

The car is stock eccept for the Walbro 340 fuel pump,FPR,Hooker Exhaust,K&N,Joe Lubrant chip,gauges.

I noticed my Fuel Pressure drops some when I shut te car off.
Could this be because I didn't use the hose in place of the PULSATER??
IT's been like this for a year with the fuel pressure at 42/43 and the o2's 800's with no problems.


I am going to take the tank down and see if the SOCK is clogged or callapsed, If not I will change the fuel pump as a last resort.

Thanks Guys

P.S. Rich I will be putting the tape in the post office on monday, sorry for the delay!

FRANKIEz

 

[TurboJim]

You may want to contact your favorite chip burner and have him add % in FAPE. Seems to work well for me. Dont add a lot as too much will make it tough to climb hills on the ride home

 

[dconnor]

Re-using the pulsator with a Walbro pump could very well have caused the problem, may have a leak at that fitting when the fuel pressure demands shoot up at WOT.

Doug C.

 

[FRANKIEz28]

Thanks Guys!

I thought about that pulsater not working with the 340 but never botherd to replace it with the hose it came with because it worked fine till now

Can the pulsater leak that bad to give me those low o2 readings im seeing on the scanmaster?

Anybody else ever had a simular problem that im having because of the pulsater??

Thanks Again Guys
FRANKIEz

 

[Buicksx2]

Frankie,

Let us know what you find with the fuel pump. I remember year ago before there was tuning tools like Scanmaster, Tlink, DS etc that my car would bog at mid track, turned out it was the fuel pump. I changed it and it was fine. How old is your pump? Is it hot wired? Got a volt booster? just throwing out some ideas here.

Sounds like a fuel pump problems from what you described.

Keep us posted and thanks for the tape and shoot me your address and I will replenish your VHS supply.

Hope to see you guys on the 6th at Etown.

 

[FRANKIEz28]

Ed (ULYCYC) and I tried everything before we rule the fuel pump as the culprit.

Anybody know where can I get the 340 Walbro for a resonable price, It's been awhile since I bought one.

Hey Rich me Steve (TTA850) and ED (ULYCYC) just watched the tape, Great Run and the crowd thought so too!

FRANKIEz

 

[Buicksx2]

Originally posted by FRANKIEz28

Hey Rich me Steve (TTA850) and ED (ULYCYC) just watched the tape, Great Run and the crowd thought so too!


>>>> Frankie,

Thanks so much, cant wait to get the tape this week.

 

[TurboJim]

Well, if fuel pressure holds at WOT, then volume must be high enuf to maintin the pressure so I doubt its a fuel pump issue, but I guess you cant try. PTE sells the 340 for $129

http//www.precisionte.com/cgi-local/store/commerce.cgi?search_request_button=YES&keywords=WALBRO

 

[Otto J]

possibel exhaust leak somewhere tricking O2s?
do you have any egt?
if so what is the temp at wot? does it drop also?
OJP

 

[ULYCYC]

This is a strange one. No exhaust leaks, Rock solid fuel pressure at 60 or 65 @ 45 base. with boost set anywhere between 5 and 16lbs and no knock. O2 readings drop steady to 720 @100mph in 3 gear 4900rpm's This will happen with what ever chip we put in. This is tested with a Pro 3" face OTC fuel pressure tester so the readings are correct. Motor is a fresh rebuild all stock.

 

[GNSCOTT]

I agree,if it was the pump his FP would be dropping. Sounds like everything is ok up to the injectors, so are you running out of injector?? what levels are you running at?? Have you tried swapping in a known good set of injectors, or have you had yours flowed. Running anything through to clean injectors might not always do the trick. If all that checks out, its not your fuel system, and then i'd start looking elsewhere. I'm far from being a Guru, but that is where I would go from there.

 

[ULYCYC]

Good point. I will loan him my spare set of Blue tops and a chip and see if it's an injector problem.

 

[GNSCOTT]

Damn..we need more Ed's out there...way to go!!

 

[FRANKIEz28]

Originally posted by GNSCOTT
Damn..we need more Ed's out there...way to go!!

You can say that again"
Thanks A bunch Guys for all the replys!

FRANKIEz

 

[FRANKIEz28]

It's fixed!, well not exactly

Originally posted by GNSCOTT
I agree,if it was the pump his FP would be dropping. Sounds like everything is ok up to the injectors, so are you running out of injector?? what levels are you running at?? Have you tried swapping in a known good set of injectors, or have you had yours flowed. Running anything through to clean injectors might not always do the trick. If all that checks out, its not your fuel system, and then i'd start looking elsewhere. I'm far from being a Guru, but that is where I would go from there.

Scott you were right it was the injectors. I put in the blue tops and headed over to Gateway with ULYCYC and TTA850. I took the car for some runs and the o2's (850-796) held and in some frames on the Scanmaster they actually rose in the top of 3rd gear all with 16psi & no knock. On the last run I blew the turbo seal
Oh well at least I fixed my fuel problem!

Thanks Scott and board members for all the replys

P.S. Also Thanks to ED & STEVE

 

[GNSCOTT]

Glad i could help