North American Turbocoupe Organization



having an odd boost issue
dd88T/C Offline
Senior Member
#1
this may seem typical, and yes ive done my searches and tried everything i came across. so heres the deal. car runs great when normal daily driving. absolutely superb in every manner. heres the problem tho. at WOT, i hit about 10 psi, and it sticks there for a second, hiccups, and then picks up to full boost and will carry pretty well til 4.5k rpm. all of this hiccuping happens between 3k rpm and 3.5k, then it sorts out and goes. im only running it on 15psi as of yet.

things ive done are: check for leaks in the plumbing, disconnect knock sensor, check fuel pressure, tighten down t bolts and clean up the vacuum tree (all lines there are tight as well), tighten clamp from boost valve to waste gate, change oil/filter

what im going to do soon: cap, rotor, plugs, wires, vc gasket.

i pulled codes but they were all from the continuous memory which was from before this motor went into it. cleared that and drove it home just now. before i did the above, the car would only make about 10psi and continuously break up and hiccup. the knock sensor helped a lot and im pretty sure fixing all my leaks and loose spots did as well since i picked up 5 psi and it carries more consistently.

anyone have any ideas of where i can go with this? fuel pressure is at 39psi with the line off, and like i said she runs great when normal driving. the ignition components were new, but the car sat for a year as well. im just looking for ideas at the moment. im lost on this one. go figure. thanks in advance.

-dan
'88 tc daily driver
.48 t3, stinger fmic, boblog, ebay twin piston BOV, 3" stinger dp, 3" exhaust shop straight pipe to the axle, ported/knifed lower, gutted upper, 3" intake tube & k/n filter, kirban fpr (42 psi), walboro 255, gillis @ 22 psi, pony wheels
shelf:
sn95 tb, rr, zeitronix zt2 wideband, magnaflow muffler/turndown, MAF swap, tune
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lonstar7 Offline
Posting Freak
#2
[QUOTE]Originally posted by dd88T/C:tighten clamp from boost valve to waste gate, change oil/filter

what im going to do soon: cap, rotor, plugs, wires, vc gasket.


New plugs, wires, dizzy cap and rotor definitely helped out with the stumbling problem I was having at above 10psi boost, check your timing too.
Lonestar7

1988 Black/Red TC, 5 Speed, 92,400miles (on 4/14/2012). KYB Shocks And Struts, 140MPH Speedo, CHE Rear Control Arms, Otherwise Stock.

2005 Volkswagon Golf GLS 1.9L TDI Turbo Diesel, 5 Speed Manual, InMotion Stage II Chip Tuning

1998 Dodge Ram 2500 4X4, 5.9L Cummings Turbo Diesel, 5 Speed Manual

1988 Firebird Formula 350, 350ci Tuned Port Injection, 700R4 Auto
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Pete D Offline
Administrator
#3
After you tune it up, run the fuel system diagnostics:
http://www.turbotbird.com/techinfo/Fuel_...ostics.htm
Pete Dunham


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dd88T/C Offline
Senior Member
#4
when i pulled the codes earlier, there were not fuel system problems. its got the high output walboro, the kirban, and brown tops that dont seem to be leaking. im going to check them when i get the vc gasket on and see what may be the problem. im thinkin of running injector cleaner thru them as well.
'88 tc daily driver
.48 t3, stinger fmic, boblog, ebay twin piston BOV, 3" stinger dp, 3" exhaust shop straight pipe to the axle, ported/knifed lower, gutted upper, 3" intake tube & k/n filter, kirban fpr (42 psi), walboro 255, gillis @ 22 psi, pony wheels
shelf:
sn95 tb, rr, zeitronix zt2 wideband, magnaflow muffler/turndown, MAF swap, tune
Reply

dd88T/C Offline
Senior Member
#5
stinger seems to think its running way rich at boost onset and then it leans itself out and cleans up. i dont have the wb02 on it yet to see this so in this instance i guess im reading plugs. anyway, if the plugs read rich after i do a pull, how should i lean it out for now? more boost? advance timing a couple degrees? im shooting in the dark here.
'88 tc daily driver
.48 t3, stinger fmic, boblog, ebay twin piston BOV, 3" stinger dp, 3" exhaust shop straight pipe to the axle, ported/knifed lower, gutted upper, 3" intake tube & k/n filter, kirban fpr (42 psi), walboro 255, gillis @ 22 psi, pony wheels
shelf:
sn95 tb, rr, zeitronix zt2 wideband, magnaflow muffler/turndown, MAF swap, tune
Reply

86 XR7 5spd Offline
Senior Member
#6
have ya done the tune-up yet ?

that should always be the FIRST thing done on an old engine B4 doing WOT work, turbo engines Especially

otherwise: tail-chasing, like yur doing
David T
T5 / ported E3 / .63 / 35# / K&N
2.5" exhaust w/ cherry bomb
30+ mpg! 8.2 0-60, 16.4@88 1/4 (gTech)
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xcrunnerbd Offline
Posting Freak
#7
Along with the tune-up - make sure you have your TPS adjusted and get your hands on the VAM test info, unless you have a spare one to test with.
Project 13 sec. / 30mpg in '88 TC 5Speed : 15.91@89mph / 32+ mpg

On The Car: KN cone, 2-stage Gillis@ 15psi wired to fuel switch, Kirban AFPR @ 39psi, Walbro 255 HP FP, 130A 3G Alt., Full 3" Stinger Exhaust incl. cat. no muffler,

Shelf: .48 T3, ported E6, BPV
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dd88T/C Offline
Senior Member
#8
i got the info on the vam test. i was wondering if that was the problem as well. the plugs, wires, cap, and rotor were replaced on this motor before it sat for a year. they are in fairly good shape but i have them coming anyway. the tps is adjusted.
'88 tc daily driver
.48 t3, stinger fmic, boblog, ebay twin piston BOV, 3" stinger dp, 3" exhaust shop straight pipe to the axle, ported/knifed lower, gutted upper, 3" intake tube & k/n filter, kirban fpr (42 psi), walboro 255, gillis @ 22 psi, pony wheels
shelf:
sn95 tb, rr, zeitronix zt2 wideband, magnaflow muffler/turndown, MAF swap, tune
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