Thrasher and cutting out, Fuel pres?

[larry33kc]

I have a thrasher for stock inj. and I know it said to put the FP at 45# line off which I did, but it cuts out at WOT, so I turned it up, and it ran better but was still cutting out so now I am at 58# line off, it has only cut out at WOT a couple times but still does it, do I crank the pressure up more or do something else?

I am confused also because my boost was turned down from before, it was at 22# with the KB chip I turned it down for the Thrasher, its at 16# at WOT which is lower than it should be I think, And I would like to put more boost in if I can.

Also I did notice that my IAC #'s went from 19 to 39 what give's there, why would these #'s change and would that effect my WOT problem.

I dont know what to do this is driving me crazy, I think that 58# is alot of fuel but I have heard that the Thrasher chips use alot also.

If I can't solve this problem I think that I will put my KB HI/LO Pro chip back in and turn the boost back up to 22#, I just like having the anti-theft option.

TIA, Please help, All the junk on my car is in my SIG

 

[jetmech]

You shouldn't have to go over 50# psi ever on fuel press. Is that kb boost a pump a hotwire kit or a different pump. Do you have a new hi volume fuel pump. You should be able to run 16 # of boost w/ a thrasher 92 chip w/ 45 psi of f/p. What plugs are you running. what octane are you running. How old is your fuel filter. The thrasher chip works very well for a stock setup.Some thing else is wrong w/ the car. Can you watch f/p rise w/ boost .Get us more info on the fuel pump, or maybe the regulator is bad, can you borrow one to test.

 

[TT/Ameasap]

check plugs ( should have a real tight .035 gap) my car runs better with this gap setting. Second, replace fuel filter ( it only takes a little bit of crap to clog this sucker) HTH

 

[blackbuick87]

Do you have a scantool? What are your O2's when it cuts out? You need to turn that FP back down before you fill your crankcase with oil.

You need to mount a FP gauge so you can check to see if your FP rises with boost. It should go 1psi for every 1psi boost

Also Leave the wastegate alone but try switching back to the KB chip and see if it does change. The chips should have nothing to do with this problem you are having

 

[larry33kc]

Thanks for the reply's, First the KB Boost a Pump is supposed to increase the amount of fuel out of the tank so it is like running a 340 walbro, But I still have the stock pump.

My plugs are the ac43's which is what I should be running right?, They are gaped at 35 also.

I am runnig 107 octane low lead AV gas

I do need to change the fuel filter havent done that this year.

I can watch the fuel pressure on the gauge go up.

I have changed back to my KB chip and it seams to run fine with it, my IAC's go back to normal with the KB chip also.

I do have T Link but the batt's are dead and I have to get my inverter fixed, it just died on me so I couldnt check it at WOT.

So what else do I do after I change the fuel filter TIA

 

[JFH]

I have the KB boost a pump in my car. It is somewhat like a hot wire. But it doesn't get it volts straight from the alternator. If you splice the unit in at the trunk harness for the fuel pump your properly reading only 12 volts . You then can adjust the unit to give you up to 5 volts more then the input and it will keep that voltage even if your car drops down to nine volts. Works I've checked it. But even if you get a constant 14v to the stock (original pump?) doesn't mean your flowing like a 340 pump.
Also notice that your running 107 av gas. I'm not a gas expert but from my navy aviation days 107 av gas is not the same as 107 car gas. Aviation gas is designed to burn at high alt..There was a thread on it says not to use it . Try exyleen instead or alky.

John Hordych

 

[UNGN]

Originally posted by larry33kc
Thanks for the reply's, First the KB Boost a Pump is supposed to increase the amount of fuel out of the tank so it is like running a 340 walbro, But I still have the stock pump.

Don't believe every thing you read. I've got $100 that says it will be NO WHERE CLOSE, especially at 58 psi (where you set your base FP) + 22 psi boost = 80 psi.

For doing that with the fuel pressure, you get a double:



Get a real fuel pump and really hot wire it. Turn the FP back to 45 psi. Throw away your FP adjusting allen wrench and your KB catalog.

 

[Chuck Leeper]

FP AND SUCH

The first thing you'll be changing if you don't get the scan tool up and running, is the crank!!
Next: the comment on 58+22 for max FP at boost is right on and WILL put those stock injectors into "coronary arrest". I test alot of them here and see MANY inj's that just shut off, go wacko w/ bad patterns,flow all different volumes, etc.

The stock pump was marginal when new.. that was the reason folks "invented" such as the voltbooster, boost a pump, etc.
Follow what the folks here are telling you and :
Get the scan tool up and running .
New 340 in the tank. HOT WIRE it!
New filter. [AC]
Clean and flow the stock inj's or step up to more inj and tune from there.
Do the gnttype "spring cleaning".

Get ready to ROCK!

 

[Berman]

KB stuff is mostly junk. Get rid of that boost-a-pump and get a real fuel pump and a hotwire kit. $50 says this fixes your problem.

 

[JFH]

boost a pump

I won't say that the BAP is junk! Just an expensive form of hotwire. If I set the output of the BAP to 15v I'll have a constant 15V even if I have all my accessories on and the charging system drops below 13v i'll still have 15v going to the pump. I can even raise the output to the pump to 17v and it will still hold. I've tested the output and it holds the voltage you set it at. A up graded pump and a hotwire is a must, but I think the BAP is just a little bit better than a straight hotwire kit.

Just my opinion
Thanks
John Hordych

 

[larry33kc]

Thanks guys I am going to save the funds and get a pump and hotwire, till then I think that I will put the KB Hi-Lo Pro chip back in and turn the boost back up to 22#'s which it ran just fine I think my O2's were 790-810 with that set up.

I have ran xylene and it didnt let me run as much boost as the AV gas has (19-20 xylene vs 22+ with AV gas) Plus the AV gas is only $2.25 a gal.

I am trying to save the $'s for alky just cant swing it right now ( maybe if I sell the kids LOL)

And I will be changing my fuel filter

TIA