HELP! Truck not building boost past 20psi. - Ford Powerstroke Diesel Forum
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post #1 of 3 Old 06-28-2009, 08:39 AM Thread Starter
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HELP! Truck not building boost past 20psi.

I was running RCD's track only tune when I raced a Camaro last night and it didn't feel like it was running right. It normally pulls hard all the way past 100 but once I hit 70 it didn't pull hard and it felt like it didn't want to shift. I loaded the street version and it felt fine at first but when I was driving home it wouldn't go past 20lbs of boost. Now it feels like it is not wanting to shift either. I don't know what is wrong but I was thinking the coverter at first but it builds boost fine up to 20psi then it doesn't go past that and it delays before finally shifting. This is also what one of the members on stated as well. The EGT's don't go over 800. The tranny temps were aroun 174 or so, the ECT's were around 194, and the oil was 94-96 on the livewire. If anybody has had any similar issues please help me out. Also it normally bellows out smoke with both tunes but now I don't see any.
Thanks in advance.
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post #2 of 3 Old 06-29-2009, 10:24 PM
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Did you scan for any DTC's?

2008 F-350 6.4 Power Stroke 4X4
CC LWB SRW Auto 3.73's
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post #3 of 3 Old 06-30-2009, 06:21 AM
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Me thinks your HPFP is a bit flaky. Scan for codes, you may find a P0087 (fuel rail pressure low). Mine would do exactly what you are talking about, then it got worse to the point that it wouldn't go over 35mph. The shifting is screwed up because the you don't have any power. The boost is screwed up because you don't have the fuel to burn to make the exhaust to make the intake charge.

Tuners have been known to cause a weak HPFP to go out. It would have gone out anyway, but it would have taken longer.

Eli Benson - EMT, Ambulance Mechanic
'08 F350 Dually KR - Spartan'd
'07 F250 CC SB 4x4 XLT - SCT /w Innovative Tunes
4 '09 & '10 E350 6.0l ambulances
1 '08 Duramax 6.6 (LMM) van ambulance
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