Fuel Pump WTF (part 2)

[ChrisF]

OK guys here it is:

Just finished installing my Walbro 340 and hotwire kit. Everything plugged in nicely, the pump fits well, and per the manufacturer's instruction, eliminated the pulsator and restrictive portion of the steel tubing on the bulkhead, and used the high pressure hose supplied. Everything looked okay, I was very careful about the orientation of the new "sock" so it isn't pinched or bunched up, and all lines seemed to be in great shape.

The car ran good under all conditions until I added this kit.
The pump should be MORE than enough fuel.

The car now feels like its running out of fuel. At the top of 1st gear it stumbles and nearly stalls. From 55+ mph if I go WOT it feels like its got no pull.

Tlink shows my 02's in the 800's until this point, and then they drop to DOUBLE DIGITS

I am currently running 100 octane, and excepting the above, I have NO knock.

The only other change is an RJC plate, but I would think that it isn't related.

Any ideas folks??

TIA
Chris

 

[UNGN]

On the 55+ mph no pull, is the car not downshifting into drive? is the converter unlocking? In drive, it should pull pretty good at 60 mph.

The O2's might drop like that if the MAF is bad. Not enough fuel with a known good fuel system points to the MAF. What does TL say the MAF is doing during all this (though this maybe a chicken/egg thing)


The other thing it might be is a bad fuel line, but I think that is less likely as puddles of gas would be obvious (Then again, I didn't notice when this happened to me until the 3rd or 4th pass at the track and heard gas sizzling as it dripped and boiled on the exhaust pipes )

 

[ChrisF]

UNGN-

Lines all look good...

The 55+ mph pull the trans downshifts, but the car has no "seat of the pants" feel, and its definetely slower than it was.

The MAF seems to be functioning per t-link.

If you have t-link I could send you the file...

TIA

Chris

 

[Sleeper87]

Again this sounds like what is going on on my TurboT
Sleeper87

 

[ChrisF]

I'm thinking it's a pinched line somewhere.....any common places for a line to get pinched?

Can anyone reccomend where to get an "extension" hose for my fuel psi gauge? It goes on the schader valve but the hose is only about 2 feet long, I want to tape it to the windsheild so I can verify I am running out of fuel.

Anyone else know what would cause the 02's to hit the floor like that?

Chris

 

[ChrisF]

Anyone? No one has anything on this one?

 

[azgn]

if any lines are pinched, the first place to check is on the top of the tank...the 3 rubber pigtails that go to the pump....you might look for leaks there also

 

[pracingrev1140]

Originally posted by ChrisF
I'm thinking it's a pinched line somewhere.....any common places for a line to get pinched?

Can anyone reccomend where to get an "extension" hose for my fuel psi gauge? It goes on the schader valve but the hose is only about 2 feet long, I want to tape it to the windsheild so I can verify I am running out of fuel.

Anyone else know what would cause the 02's to hit the floor like that?

Chris

hi chris i had a oil gauge line lying around you know the white plastic type i had to use the brass ends that come with the kit and screwed it on to my fuel gauge hose and then screwed the fuel gauge on to the other end of the white plastic line be syre to use teflon tape on all treads RR

 

[ChrisF]

Thanks, it's worth a try....I'm going to hit the local welder's supply and see if they sell an extension of sorts......it's raining here anyway, so no good testing to be done regardles...

 

[pracingrev1140]

hey man you can go the local parts store and buy the line and the ends i think

 

[ChrisF]

I will get the gauge issue sorted so I have solid testing data....

I can't think of anything else that would cause the O2's to hit the floor like that.....

Anyone intersted I can send them the T-link file...

 

[TurboBuickSix]

Any luck? Keep us posted!!

 

[c&cgn]

I have heard of guys pinching a line when putting the tank back up after doing the Fuel pump. I would drop the tank again and look at the lines. I suspect one of them is pinched. It doesn't matter whether it is a feed line or return line, either can cause a backup of fuel.

 

[turbolimited]

pump hanging down too low in the tank? maybe its crushing the sock against the bottom of the tank and preventing the pump from sucking any fuel. Just one of many possibilities. You changed the filter too right? Good luck.

 

[Racetronix]

The newer style fuel socks supplied in the Racetronix kits have plastic ribs inside that prevent them from being crushed unlike the factory ones that can. The new white fuel socks (no bleach required ) filter down to 30 microns as oppose to 60-70 for a factory tube style fuel sock. This is required to protect the gears in the Walbro pumps from excessive wear which would increase clearances and degrade pump efficiency.

Jack
Racetronix

 

[ChrisF]

UPDATE

OK- got the fuel pressure gauge taped to the windshield, and at idle it is 40 psi on the mark. It is set to 42 psi line off.

The fuel pressure does not increase a lot until I really get into it, and it maxes out at 60-62 psi....boost is set to 20 psi for 100 octane.

I know there is a formula for how much the psi should increase proportional to boost, I do not recall what it is. It is at this point the pressure goes no higher, and the car "runs out of steam" and if I don't lift the gas, it stumbles, and O2's hit the floor.

I haven't had a good opportunity to drop the tank and inspect the lines as crappy weather and a flu bug for the past few days has prevented it. I was hoping these fuel psi #'s might lend some insight to the problem.

Again, Thanks all in advance.

Chris

 

[ChrisF]

Oops, I forgot, the fuel filter IS brand new also.

Thought: Would turning up the fuel psi help? It already throws a "rich exhaust" code once in a while, especially if it hasn't been driven in a while...

 

[Racetronix]

Chris,

A Buick is generally 1:1 on the FP ratio.
2" vacuum or 1lb boost for every 1 PSI FP
Check the signal to the regulator and make sure it is tracking manifold pressure. 2 PSI change from vacuum line on/off does not sound right unless you have a crazy cam with very little vacuum.
If your manifold vacuum @ idle is about 12" then fuel pressure should drop apx 6PSI.

Jack
Racetronix

 

[ChrisF]

Sounds good, Jack, I should be able to test it tomorrow...

What about the top end pressure? Do we still think I have a pinched line?

Remember: all things are equal except the pump change and the power plate. It was a lil lean on the top end before this which I why I bought the kit, but you would never know it by feel, I only saw it on T-link..

To anyone reading this:

Jack's kit(s) are top quality and so is his attention to customer service. I RECOMMEND him to all of you looking to upgrade. I just have a car that wants to be a PITA!

 

[Racetronix]

If the fuel system has enough volume then the pressure should track 1:1. If it tracks ok under light to medium load but not on the top end then chances are you have a volume related issue. There is the odd chance that your regulator is defective. These tests should help isolate the problem.

I have seen certain Buick regulators which have diaphragms that puncture easily or pressure plates which strip especially if one constantly fiddles with the adjustment screw.

Jack
Racetronix