TomP

I searched the tech articles, but couldn't find any info, so hopefully I can get a hand? (I'm more of a multiport kinda guy, but I'm troubleshooting a TBI non-f-body car now.)

I have the multiport fuel pressure gauge, which hooks into that Schraeder valve (big tire-valve thing) on the fuel rail. There's no such animal for TBI, and the GM book just says to "attach fuel pressure gauge."

Where do I attach the gauge if there's no tap? Do I have to open fuel lines and use a T-fitting? If so, how do I ensure against leaks when I'm done testing?

One more question- would my old carbuerated-style fuel pressure gauge be more suited for this? Or is there an adapter I can buy to make the multiport (high pressure) gauge work with a regular T-fitting?

Thanks guys! I (and my friend) appreciate it!


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
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rsilver

I remember someone writing about this but I could not find it. I would sure like to know the answer to this too. Since i am doing a swap in a few weeks I would like to know how to do this too.............bob

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91 camaro RS L03 convert,
t-5, ultimate TBI mods,TBI spacer,SLP 1 5/8 headers,
3"cat back, 3.42 torsen posi,alston SFC's,Global West LCA relocation brackets, edelbrock STB

Pukka

I did come across a T-fitting for GM TBI vehicles once, but it was packaged with the fuel pressure guage which I didn't need(I already had one). If you ask around a auto parts store I'm sure you could find one.

The fitting should go between the fuel line and the throttle body. If your guage can reade between 0 - 20 accurately then it should do.

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92 Camaro RS LO3, 5-spd, T-tops
Performance:
SLP 1 3/4" Headers (Coated by Paul Barry Motorsports), Flowmaster Catback Exhaust, Fastchip Performance PROM, Centerforce Dual Friction Clutch, Xact 8mm wires, Open Air Element w/K&N Filter, Z28 Grille w/aftmkt fog lamps
Electronics:
Alpine 8030 Alarm System, Valentine One Radar Detector (How did I ever drive without one?), Pioneer DEH 7450 Head Unit w/6-pack CD changer, Pioneer DEQ 7600 Sound Processor, 2 Kenwood KAC-846 Amps powering 2 12" Pro Red subs, 2 Pioneer 6x9 and 2 MTX 4x6 speakers.
NEXT UP: TBI mods, Edelbrock performer intake

TomP

Thanks for the placement info! Do these lines use pressure fittings, or are they held on with normal hose clamps? Maybe I could make my own Tee...

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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

Tab92bird

I *believe* you need a seperate system to test tbi than mpfi. At autozone we sell two different guages, both of which say on the package that they don't work on the opp. system. I do know for sure, however, that you must have a t-fitting (as Pukka mentioned); there is no schrader valve on tbi systems.

Hope this helps.
Brandon

TomP

Well, I checked out the TBI test gauge at Pep Boys. The kit is the same exact gauge I bought for my multiport engine, with the T-tap included- and $20 more!! The T-tap was one helluva thing... it's threaded on both ends, and the tap part has the Schraeder valve for connecting the fuel pressure gauge. So it looks like I wouldn't have to pull my pressure gauge apart to use it.

Does anyone have the thread pitch handy for the TBI fuel hoses? I'd still like to try & make my own T-tap...


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
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TomP

Does anyone know? I thought a ton of people would've given me answers here! Are the fuel lines the same threading as MPFI or TPI engines, at least? I don't see why GM would've changed the routing & size of the rubber fuel hoses from the tank to the engine, but maybe they did...


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
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Dyno Don

iTrader: (7)

Yes, the thread sizes are the same.
I just went to a pick-a-part yard cut the ends off of the hoses and made up a tee fitting in between with a schrader valve.
Then put it in between the rubber hose that feeds the TBI.

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Chronologically challenged. But still kicking!
'92 CAMARO RS
305 TBI 5/spd (now TPI)
B4C Alt.
'69 camaro-BB/Lenco,1050 dominators, /Pump Gas/no drugs 8.97-150+/3200lbs.
SoCal Thirdgen F-Bodies

TomP

Yeah!! Thanks Dyno Don, that's exactly what I wanted to hear! Thanks!


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!