 vacuum issue, won't run, mechanic needs help |
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| enf2232 |
 Apr 1 2024, 12:56 PM
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#1
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Member  Group: Members Posts: 86 Joined: 13-July 14 From: Toledo, OH Member No.: 17,621 Region Association: None  |
Background: 1.7 liter which has been upgraded with new pistons and cylinders, original fuel injection. Car started and ran, then stalled and would not restart. Covid hit so it sat for a while. Now at mechanics shop where they have replaced the fuel pump (rebuilt original) and the manifold pressure sensor (rebuilt).
Engine has low manifold vacuum, 10-12" and will not start. If they apply 15-18" of vacuum with a vacuum pump it starts right up and will run fine for 20-30 minutes (on pump), then stalls. If they attempt to restart, it backfires and will not restart until cold. Any suggestions on what to check or what next step should be? |
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Replies
| ctc911ctc |
Apr 1 2024, 01:23 PM
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#2
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Senior Member Group: Members Posts: 893 Joined: 9-June 18 From: boston Member No.: 22,206 Region Association: North East States 
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1) All High Pressure hoses (the ones on the plenum) - replace, also check that hose connector (see attached 5&13)
2) if that does not work, remove plenum and check all of the welds, they rust and then leak. I used 2 stage epoxy as a fix for my plenum - not optimum but works! See half way down in this post for schematics by JEFF BOWLSBY, item # 5&13 http://www.914world.com/bbs2/index.php?sho...57345&st=20 This is for a 2.0, though it is a DJet, should be a good place to start. QUOTE(enf2232 @ Apr 1 2024, 12:56 PM)  Background: 1.7 liter which has been upgraded with new pistons and cylinders, original fuel injection. Car started and ran, then stalled and would not restart. Covid hit so it sat for a while. Now at mechanics shop where they have replaced the fuel pump (rebuilt original) and the manifold pressure sensor (rebuilt). Engine has low manifold vacuum, 10-12" and will not start. If they apply 15-18" of vacuum with a vacuum pump it starts right up and will run fine for 20-30 minutes (on pump), then stalls. If they attempt to restart, it backfires and will not restart until cold. Any suggestions on what to check or what next step should be? |
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Posts in this topic
enf2232 vacuum issue, won't run Apr 1 2024, 12:56 PM
76-914 Do as previous post suggested and have mechanic do... Apr 1 2024, 03:09 PM r_towle Start with a compression test.
If you pass that te... Apr 1 2024, 04:46 PM
Superhawk996
Stop throwing parts at it.
:agree:
I’d fir... Apr 1 2024, 05:27 PM emerygt350 Compression first... Apr 1 2024, 05:40 PM Ishley What year? Which ECU? Apr 1 2024, 06:20 PM enf2232 To respond and answer some questions. We are not ... Apr 1 2024, 06:46 PM r_towle I agree with Superhawk above
Send this link to the... Apr 1 2024, 07:01 PM Superhawk996 Here’s the resistance vs ambient curve for the v... Apr 2 2024, 07:05 AM McMark I agree with Superhawk996. Vacuum is higher at idl... Apr 2 2024, 07:11 AM 76-914
I agree with Superhawk996. Vacuum is higher at id... Apr 2 2024, 07:22 AM McMark nope Apr 2 2024, 07:34 AM emerygt350 Thats pretty low manifold pressure but intensely r... Apr 2 2024, 07:48 AM dr914@autoatlanta.com need more info, if your mechanic cannot figure it ... Apr 2 2024, 09:01 AM Dave_Darling Check the ignition system first, then make sure th... Apr 3 2024, 11:40 PM |
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