North American Turbocoupe Organization



replaced fuel pump, car still bogs - car runs lean too
r3lic76 Offline
Member
#1
well i replaced the fuel pump and put on a BBK 255 (same as walbro 255) and it isn't the high pressure one

at around 10psi on my T3, the car starts to bog....kinda feels like maybee the knock sensor is retarding timing or something

running car test shows codes 25, 41, and 73 (and possibly 21 but it only gave that once)

41 is "system lean", 25 is "ks sensor not detected" and 73 is "insufficient TP output change during test"

what do those codes mean?

could it be my spark plugs? i just changed them and i didn't set any gaps
88 Turbocoupe - T3 conversion - bbk255 - kirban FPR - open 3" dp - ported lower intake
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r3lic76 Offline
Member
#2
ok i suppose "ks sensor not detected" is because i didn't tap on the car to activate the knock sensor

what does TP output change mean?
88 Turbocoupe - T3 conversion - bbk255 - kirban FPR - open 3" dp - ported lower intake
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r3lic76 Offline
Member
#3
because my car is running lean, im thinking i need a new FPR because I have a T3 turbo, 3" DP, ported lower intake

another thing, im running with an open 3" downtube (its the short 3" dp from sac mustang)....this shouldn't cause a lean condition because if the O2 sensor was picking up extra air, the car runs rich

i put in copper spark plugs but didn't set a gap, didn't someone say that their car bogged because of this?

thanks
88 Turbocoupe - T3 conversion - bbk255 - kirban FPR - open 3" dp - ported lower intake
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natmac3 Offline
Administrator
#4
First off, gap the plugs to spec, although I don't think that's the problem.

I'd bet money that all you need is a new TPS, becasue the code's showing insufficient TP voltage change during the test, and if it was malfunctioning, the EEC wouldn't be able to properly add fuel, so the EEC is seeing less voltage than it should at a given throttle opening, and dumping less fuel than it should, hence the leaning, KS hearing a ping and cutting timing, there's your bogging... There's my .02

Check the TPS with a voltmeter and get back to me...
1987tc
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Kev Offline
Posting Freak
#5
Good call natmac.
Kev
1988 TC 5spd
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Pete D Offline
Administrator
#6
If you didn't quicky open and ckose the throttle to near WOT during the test, then you get the code 73. Test the TPS per the article in the Tech Section before replacing it.

It sounds like you need to run the fuel system diagnositcs. I can send them to you in a few days when I get home. Send me an e-mail if you want them.

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NATO Member. it's not a vice, it's an obsession
"The nice thing about each new day is nobody ever used it before" Barnaby Jones
88 TC X 2, 86 SVO, mods list at
http://www.turbotbird.com/showroom/pd_88tc.htm
Pete Dunham


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Ales Offline
Junior Member
#7
I would definitely like to have this diagnostics too, I think my fuel pressure regulator its not working right [Image: frown.gif], i will drop you an email.
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r3lic76 Offline
Member
#8
yea you already sent them to me a week or two ago Pete, thanks but I dont have a fuel pressure regulator (it's $40 for a new one)
88 Turbocoupe - T3 conversion - bbk255 - kirban FPR - open 3" dp - ported lower intake
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r3lic76 Offline
Member
#9
err i mean i dont have a fuel pressure guage
88 Turbocoupe - T3 conversion - bbk255 - kirban FPR - open 3" dp - ported lower intake
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Jeff K Offline
Administrator
#10
You REALLY need to get a fuel pressure gauge to diagnose the problem!

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 00 Windstar (wifes vehicle)
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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