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Bad fuel pump ?

Certainly looks weak,no appreciable rise with boost and ridiculously high inj duty cycle at 13 psi of boost.

The chip is doing it's job though to compensate judging by the WB and narrowband. I see pretty rich WB under boost but that may be the alky skewing that number too.

If you can't gain control of it using the regulator and there is good voltage back at the pump then looks like the pump is giving up the ghost.
 
I added 4.7% wot overall before that run, that and the alky got it rich but safe (and low boost), it's just real odd that it was fine before i changed the exhause housing on the turbo and the alt, which was new not rebuilt from Kirban's. Since the fuel gauge jumps right up with boost then drop's like a rock it may have a sock issue, also from i gather a single pump will handle mid to high 10's which is all i'm looking for... when you say gain control with the regulator you mean crank up the base psi ?
 
WS6 said:
Yes, it looks a little low to me,even with the vacuum line on it.
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Changed the fuel filter and raised the base psi to 50, still drops in boost, i have a new 340 Walbro, will that suffice or should i get a double pumper and save some work down the road? from the looks of things i only want to do this once...
 
It's a HUGE PIA to change the fuel pump, but I would imagine if your Walbro is new than that should be more than enough.

I'm not an expert on fuel pumps and properly sizing them, but I race with a guy who runs the walbro into the upper 10's and he has no trouble. I run the walbro into the mid 11's.

It's more of what I've seen work and not work that I go on, but I have also seen better and bigger pumps run on 12 sec cars too.




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WS6 said:
It's a HUGE PIA to change the fuel pump, but I would imagine if your Walbro is new than that should be more than enough.

I'm not an expert on fuel pumps and properly sizing them, but I race with a guy who runs the walbro into the upper 10's and he has no trouble. I run the walbro into the mid 11's.

It's more of what I've seen work and not work that I go on, but I have also seen better and bigger pumps run on 12 sec cars too.




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It's more of what I've seen work and not work that I go on, but I have also seen better and bigger pumps run on 12 sec cars too.
Hmm.. guess i'll have to pray on this a min... the 340m may be on the edge for what i'm looking for, 10.6-10.8
 
I know you can install the pump, It would be good if you had some help when droping and installing the fuel tank in place. Heck you might even want to install a access door for the new pump, since that TTA is for racing. I like my Walbro 340 with the hotwire kit, been in over a year and no problems!
 
Jason is probably better suited to answer this question than me.

I run the pump he suggested.



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TTA984 said:
Huh, I hope its not a Corvette pump!
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Nah...it's just he is more "plugged in " to the aftermarket pump tech and talk than I am. Boosted or not he knows what works and what doesn't.

After all....I can't know everything...can I ???? :boxed:
 
WS6 said:
Nah...it's just he is more "plugged in " to the aftermarket pump tech and talk than I am. Boosted or not he knows what works and what doesn't.

After all....I can't know everything...can I ???? :boxed:
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No pun intended, Jason knows his stuff, I am sure what he recomended is good.:clap:
 
No pun intended (since it's 5am) but it just dawned on me, Alky change's the whole equation, i think that would make the 340 work to the low or mid 10's...:coffee:
 
It's been my experience that tuning with methanol as fuel supplement is risky because the stoich is much lower. It lowers the average of the 2 fuels combined.

I prefer to tune with fuel and supress knock with alky. Methanol lowers IATs and adds octane and that's how I've come to use it.

Since you're still running the 5.x chip you maybe better off running race gas and spraying "some" alky to cool the charge...the upside is detonation resistance,therby lowering the stoich required, the downside is ruined O2 sensors and expense of the race gas.

Maybe the answer is to run the the 340 and see how fast the car is and if it's running out of fuel then maybe a set-up like ratfink runs with a booster pump.


Lets see if Jason will come up for air soon.




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WS6 said:
I prefer to tune with fuel and supress knock with alky. .
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Me too.

I still run NON-progressive kit with alcohol and have yet to try meth. But I tune the turbo to run up to whatever boost number based on ambient air temp, then start bumping the alky ON when I start turning up the boost. I can raise and lower boost from inside the car. I kinda watch the scanmaster/ fuel pressure /afr and keep 100+ unleaded in it when I'm doing WOT runs. It also helps to have another pair of eyes when doing this....I need a logger.
 
A properly functioning Walbro 340 is more than adequate for what you are looking for (mid 10's with meth). I'd trust a 340 to 600 wheel with a good power source. 650 with meth. You either have a bad Walbro, an improperly installed Walbro, OR your FP regulator is faulty. How new is your regulator?

Don't put a double pumper on your car. It isn't needed.

BTW, I do actually have a Z06 fuel pump on the shelf I am going to install in my TTA this winter. OEM quality>aftermarket everyday of the week and twice on Sunday's. The stock Z06 pump is 99% identical to the Walbro 340's output and has very similar inlets and outlets.
 
I bought the regulator at the meet in Hebren last yr from G-body (kirban brand i think ) and i did replace the the feed and return off the rail with S.S right before it started acting up so i guess i will swap the reg. first in case trash got in it...BTW the 340m does work with the stock size fuel line right? Also let us know how that Z06 pump works out for you...
 
robert lee said:
I bought the regulator at the meet in Hebren last yr from G-body (kirban brand i think ) and i did replace the the feed and return off the rail with S.S right before it started acting up so i guess i will swap the reg. first in case trash got in it...BTW the 340m does work with the stock size fuel line right? Also let us know how that Z06 pump works out for you...
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340 is fine with the stock fuel size. It is what I run without issue.

Check your install and make sure it is free flowing. My bet is on the pump, but weirder things have happened.

Jason
 
if u look on turbo buick people say the walbro is shyt! Ive ran the same pump from 13 sec to 10.97 no problem in over 5 yrs
 
Verdict is in, bad pump, took the FPR off and apart and nothing wrong with it, also jumped the FP relay and hooked a line to the fuel rail to drain the gas and that was only so-so volume... so much for Bowling Green KY:(
 
Don't know how i got it out this way but i did , by MYSELF, and guess what: it was one of the old 0000169 walpro's.. been in there almost 7 yrs. that guy standing in front in the last pic did give tech advice...
 
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