Will Increasing Fuel Pressure Increase O2 Readings

[mmarlett]

Sorry.

Pictures attached.

 

[trbojo]

i'm going to make a quick guess based on your last post..one of two things...either the tank got smacked underneath, or, a vaccum is being pulled on the tank somehow through the evap system....i can actually make a tank suck inward with an obd2 test on newer cars....check the evap canister, solenoid, VACCUM lines, check valve, GAS CAP..........

 

[trbojo]

i would still throw a new pump in though too.....

 

[Ttype6]

Well, the kids and wife went to grandmas tonight; so under the car I went to drop the tank.

Please see attached pictures of my Walbro pump. These are pictures of the pump after being pulled from the tank. How does it look? Anything obvious that does not look correct?

I inspected all fuel lines going into the tank; all look good.

I inspected the wires going into the tank; all look good.

I inspected the fuel lines and rubber hose in the tank; all look good.

I inspected the fuel filter sock and filter screen at the bottom of the pump; all look good.

However, I believe this part may be important. I was surprised at how flat the sock screen was when I pulled it out. I then measured from the bottom of the fuel pump screen as it is installed on the pump to the top of the fuel pump unit lid that seals with the top of the fuel tank. It measured 8 1/8". Hmmm. I then meaured on the gas tank from the top seal to the bottom of the fuel tank, 8 1/8". According to my multiple measurements and visual inspection, I believe this screen was compressed againt the bottom on the fuel tank. This seems way to tight to allow adequate fuel to the pump under increased boost (the problem I keep having). There are to small plastic pieces in the pump filter sock to keep the sock seprated, but they seem they would not help in this situation. Since I cannot make this measurement with the pump istalled, it is hard to confirm.

Tell me I am crazy and this should not be the reason.

Now, how to preoceed???

Thanks!
Matt

What model Walbro?
When was it purchased?
Do you have a dent in the bottom of your tank?

 

[mmarlett]

Purchased from a well known turbo Buick vendor on 1/26/2010.

The receipt has the decsription - 834GMHP

The fuel tank is in great condition with no dents.

Please see attached pics.

Ttype6,

Do you still have a known working unit to sell?

Thanks
Matt

 

[trbojo]

here's one more weird thing i thought of...check very carefully for a CONDOM in the tank!!! dead serious, i had a friend with a town car, car would shut off out of nowhere...long story short, there was a condom in the tank...it would get sucked up on the pick up when fuel got below a certain level...make sure you check out that evap system if you get the pump in and still have the issue...

 

[trbojo]

also, did you look very carefully at the electrical terminals for in tank connections to see if they're spread/corroded/burnt??

 

[trbojo]

then again, this sounds more like pump or regulator, given the fact you couldn't increase it past 60 psi...if you had the proper adapters, you could hook fp gauge right out of filter and dead head pump for a few secs to see what max psi is...

 

[Ttype6]

Ttype6,

Do you still have a known working unit to sell?

Yes. I'll send it to you so you can put it in. If it fixes your problem,then you can send me some money. This is the new design,I'm finding it hard to believe that it's bad. I'll send you my whole pump and sender assembly.

What numbers are on the pump?

 

[Ttype6]

.if you had the proper adapters, you could hook fp gauge right out of filter and dead head pump for a few secs to see what max psi is...

Vise grips on the rubber portion of the return line is an effective way to do this. This should have been a test that we had him do before he removed the tank,but I also find it hard to believe the regulator is bad. If the pump doesn't fix it,this will be something to try.

 

[Ttype6]

I just measured my setup as you described. The reason I thought to do this is because I dented my tank years ago and hammered it out as best I could and still believe there to be less clearance than there was originally. This setup flowed well and my screen is not flat. In fact it's quite rounded with plenty of clearance, It measures in at exactly 8" with a nice puffy screen.

 

[mmarlett]

Thanks again for the insight!

I did check all wires, harnesses and connections for signs of stress or corrosion. Everthing looks good. The hot wire kit was installed at the same time in put in the new fuel pump, spring of 2010. Since then the car has been in the garage and seen only 3-4,000 miles. Therefore, all still looks brand new. The stock wire harness that connects the hot wire kit back at the fuel tank and its wires and connections to the top of the fuel tank also look good.

Also, no condoms. What could be the story behind that one...

The pump number reads - F20000169 with 23309-1 written below that (picture attached).

Ttype6,

I will take you up on your pump offer. I will send you a PM with me details. Fortuantelly the pumps are not too expesnsive, its the the time and aggrevation!

Thanks
Matt

 

[TurboDave]

Hmmm. The infamous 169 pumps. Weren't there a bunch of problems with them last year?

 

[mmarlett]

169's huh.

Confirming this would be nice to know.

I have a hard time accepting our vendors, the part manufactuers would supply parts that fail right out of the box.

I have always assumed it was me doing something wrong on installation, etc.

Ttype6 is helping me with a replacement pump.

Might be a week or so before I have an update.

Thanks
Matt

 

[Ttype6]

Weren't there a bunch of problems with them last year?

I believe the ones that were bad where made in 2006. They were redesigned in 2009 and,If you had a bad one from a certain time period,they were replaced free of charge,thanks to Mike at Full Throttle Speed and Style.

 

[mmarlett]

Well...the replacement pump sent to me by Type6 fixed the problem.

Today I did the pump swap and took it the car for a spin. Wonderful!!! Now, for the first time, I can actually see what this car is capable of.

How lucky am I; driving this car lean since the problem pump was purchased and installed new in spring of 10'.

Anyway, how to proceed? I understand that the manufactuer/vendor has been making good on problem Walbro pumps?


Thanks
Matt

 

[mmarlett]

Problem solved.

To conclude this thread, I want to thank all those who have contributed their help in diagnosing and resolving this issue on my Grand National.

Obviously, there are many people on this forum willing to offer thier time and knowledge.

I consider myself a rookie regarding my turbo Buick. The idea that others can guide me through this process is fantastic.

Thanks again!
Matt

 

[NorEaster]

Problem solved.

To conclude this thread, I want to thank all those who have contributed their help in diagnosing and resolving this issue on my Grand National.

Obviously, there are many people on this forum willing to offer thier time and knowledge.

I consider myself a rookie regarding my turbo Buick. The idea that others can guide me through this process is fantastic.

Thanks again!
Matt

Great news! Enjoy your 'new' ride. Does this mean that you are back to default settings on your chip (BLM lock at 128)?

 

[Ttype6]

Does this mean that you are back to default settings on your chip (BLM lock at 128)?

The chip burner makes an educated guess as to what your motor will need at different loads. Then the oxygen sensor adjusts up or down from there during closed loop operation. The block learn,at idle and part throttle,could be anything but 128 and different for each. It's not important what this number is.
At WOT operation the chip is adjustable to allow you to enrichen or enlean the fuel mixture based on what the motor needs. No matter what,this number is always 128 as viewed from the Scanmaster.
Matt's problem was that his fuel pump wasn't supplying enough fuel at WOT,so no matter how long the injectors were commanded to stay open,the motor only got the maximum,and not enough,amount of fuel that the pump could provide to feed the motor. Since this was not enough fuel for the motor's requirements,the motor was lean as indicated by the O2 sensor. Matt can,now,easily see an O2 number of .830 or more because he,now,has a pump that can supply as much as he commands it to. If the default number,for WOT fuel mixture,in the chip supplies enough fuel for the motor,you would leave this adjustment at the default setting. If your motor required more or less fuel,than the default setting,you would move this number up or down from the default number of 128. The guess,only,needs to be in the ball park.

 

[NorEaster]

The chip burner makes an educated guess as to what your motor will need at different loads. Then the oxygen sensor adjusts up or down from there during closed loop operation. The block learn,at idle and part throttle,could be anything but 128 and different for each. It's not important what this number is.
At WOT operation the chip is adjustable to allow you to enrichen or enlean the fuel mixture based on what the motor needs. No matter what,this number is always 128 as viewed from the Scanmaster.
Matt's problem was that his fuel pump wasn't supplying enough fuel at WOT,so no matter how long the injectors were commanded to stay open,the motor only got the maximum,and not enough,amount of fuel that the pump could provide to feed the motor. Since this was not enough fuel for the motor's requirements,the motor was lean as indicated by the O2 sensor. Matt can,now,easily see an O2 number of .830 or more because he,now,has a pump that can supply as much as he commands it to. If the default number,for WOT fuel mixture,in the chip supplies enough fuel for the motor,you would leave this adjustment at the default setting. If your motor required more or less fuel,than the default setting,you would move this number up or down from the default number of 128. The guess,only,needs to be in the ball park.

I understand what is going on here. He and I have the same tt chip, and he was maxed on his WOT BLM lock (and I think it shows what it is locked at on the SM when going WOT). I was asking him if he now his his WOT BLM down to the default chip settings instead of maxing it out.

My fuel pump passed the test, but I am maxed out on the chip, and have added a little bit of base FP (this was the reason for this thread). I am seeing the WOT O2's that are in the .780-.820 mv range.