 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
| r_towle |
Apr 1 2024, 07:01 PM
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#2
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Custom Member Group: Members Posts: 24,585 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States 
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I agree with Superhawk above
Send this link to the mechanic https://members.rennlist.com/pbanders/ AND Remove and tape over all other vacuum hose connections to the intake plenum. If it runs ok with JUST the MPs hooked up for vacuum, start replacing one system at a time. I would suspect the AAR because they corrode open. Ensure the fuel pressure is good on both sides of the regulator |
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Posts in this topic
enf2232 vacuum issue, won't run Apr 1 2024, 12:56 PM
ctc911ctc 1) All High Pressure hoses (the ones on the plenum... Apr 1 2024, 01:23 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 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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