How do I Test the fuel pressure damper?

BrettandSam · **Posted:** Sun Jan 16, 2022 9:04 pm

Hi all May I get some help please.
1986 normally aspirated 944. Going through one of those starts then stops phase. I’ve changed due relay etc. just looking at the fuel pressure damper on front of fuel rail. If I remove the vacuumed hose and suck on it, it responds but slowly the vacuum I’ve created releases. should it hold that vacuum until I release it??
thanks in advance.
bremar.

stratfordshark · **Posted:** Mon Jan 17, 2022 6:51 pm

Should hold vacuum. If diaphragm failed then you should also be able to suck fuel from vacuum port, so use clear hose on MityVac to spot this.

mikesred 2 · **Posted:** Tue Jul 05, 2022 12:59 pm

did you get sorted?

Wh1t3Kn1ght · **Posted:** Wed Jul 06, 2022 5:48 pm

BrettandSam wrote:

Hi all May I get some help please.
1986 normally aspirated 944. Going through one of those starts then stops phase. I’ve changed due relay etc. just looking at the fuel pressure damper on front of fuel rail. If I remove the vacuumed hose and suck on it, it responds but slowly the vacuum I’ve created releases. should it hold that vacuum until I release it??
thanks in advance.
bremar.

Have you checked fuel pressure and performed a leak down test etc?

As others said pretty easy to spot if the FPR or damper is busted as you will get fuel in the vacuum line.

Not sure that a dodgy damper would cause an issue as I've known some people delete the damper, more likely the FPR or fuel pump?

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How do I Test the fuel pressure damper?

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