 AAR year result on 1.7 FI | cold start suction means OK? |
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| Tdskip |
 Jan 11 2019, 01:25 PM
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#1
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Advanced Member  Group: Members Posts: 3,678 Joined: 1-December 17 From: soCal Member No.: 21,666 Region Association: None 
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First of all thank you for all your help and patience as I work through these issues on the ‘73 1.7 FI car.
I’m having idle and loss of power issues that I’m trying to get sorted out. Brand new MPS from Jeff 40 PSI fuel pressure at the pump outlet Just did a cold start test on the AAR by immediately pulling the hose that goes to the rubber install and I had suction there. That suggests that my AAR is OK and I should keep moving on to other components, correct?  |
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Replies(1 - 6)
| BillC |
Jan 11 2019, 02:14 PM
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#2
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Senior Member Group: Members Posts: 534 Joined: 24-April 15 From: Silver Spring, MD Member No.: 18,667 Region Association: MidAtlantic Region
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I think your fuel pressure is too high. Have you checked the fuel pressure at the rail? The fuel rail should be about 28 psi.
And, yes, you should have suction at the inlet to the AAR at startup. The suction should diminish over time as the AAR closes. If the AAR doesn't close, you'll have a very high idle once the engine warms up. |
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| Tdskip |
Jan 11 2019, 02:16 PM
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#3
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Advanced Member Group: Members Posts: 3,678 Joined: 1-December 17 From: soCal Member No.: 21,666 Region Association: None
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Hi there, and happy Friday to you.
I have not checked it at the rail - oops |
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| BeatNavy |
Jan 11 2019, 02:23 PM
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#4
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Certified Professional Scapegoat Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region
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Bill's right - ~28/29 psi +/- at the rail. On the 1/2 side fuel rail there should be a stub. Either it's blocked off with a very small bolt or it has a fuel line routing over to the cold start valve. That's a good place to attach a fuel pressure gauge -- just disconnect the CSV as needed.
AAR should slowly close off in a few minutes, assuming the heating element is working. I think I timed mine at 7 or 8 minutes once, just because I wanted to know. |
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| Tdskip |
Jan 11 2019, 03:15 PM
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#5
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Advanced Member Group: Members Posts: 3,678 Joined: 1-December 17 From: soCal Member No.: 21,666 Region Association: None
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May be tomorrow before I can get my hands back on that but will test at the rail and report back.
Maybe I goofed on the pump number and installed a higher pressure one than I was supposed to....this one came with the car. |
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| 914_teener |
Jan 11 2019, 03:42 PM
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#6
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914 Guru Group: Members Posts: 5,193 Joined: 31-August 08 From: So. Cal Member No.: 9,489 Region Association: Southern California |
Tom,
You can remove the AAR and bench test it by looking at it visually. 12v and just ground to the body of the AAR and the valve should slowly close. Easy peasy. |
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| JawjaPorsche |
Jan 11 2019, 03:51 PM
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#7
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Advanced Member Group: Members Posts: 3,463 Joined: 23-July 11 From: Clayton, Georgia Member No.: 13,351 Region Association: South East States |
Idle issues usually is a vacuum leak somewhere.
I had a hard time sorting mine out. I noticed your hoses look new so we can cancel that off the list. Things to replace: Manifold gaskets. Injector seals Air intake gasket Oil fill gasket Good luck! |
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