 L-Jet Injectors Aren't Getting Ground, L-Jet Injectors |
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| nmkimosabe |
 Mar 21 2026, 09:44 AM
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#1
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Member  Group: Members Posts: 59 Joined: 16-March 25 From: Santa Fe, NM Member No.: 28,660 Region Association: Rocky Mountains  |
After a thorough investigation, it appears that the injectors are not getting ground to fire properly on my 1974 1.8L. Maybe it's an air flow sensor issue but not sure. All the other wiring seems to be okay. I would appreciate any thoughts from the knowledgeable folks on this forum. Thank you.
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| JeffBowlsby |
Mar 21 2026, 09:58 AM
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#2
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914 Wiring Harnesses & Beekeeper Group: Members Posts: 9,319 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None 
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Check the schematic for these circuits. LJet injectors do not ground directly, they go through the resistor pack (look for broken wires) and then to the double relay.
Attached thumbnail(s) 
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| nmkimosabe |
Mar 21 2026, 04:25 PM
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#3
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Member Group: Members Posts: 59 Joined: 16-March 25 From: Santa Fe, NM Member No.: 28,660 Region Association: Rocky Mountains |
QUOTE(JeffBowlsby @ Mar 21 2026, 08:58 AM)  Check the schematic for these circuits. LJet injectors do not ground directly, they go through the resistor pack (look for broken wires) and then to the double relay. @JeffBowlsby Thanks Jeff for taking the time to send the schematic and your thoughts. I've read many of your articles since I bought this car last Spring. I will print this out and review with my mechanic on Monday and get back to you. We've checked all the wiring, AFM plug and flap, vacuum lines, dual relay, dwell, coil but can't seem to get the injectors to ground and per your article they don't. It has normal fuel pressure and will start briefly at times but won't continue running. I will order a new resistor pack as mine might be the problem. Thanks Jeff. |
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| Superhawk996 |
Mar 22 2026, 11:16 AM
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#4
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914 Guru Group: Members Posts: 7,973 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch
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QUOTE(nmkimosabe @ Mar 21 2026, 06:25 PM) I will order a new resistor pack as mine might be the problem. Thanks Jeff. Not trying to start a whole (IMG:style_emoticons/default/stromberg.gif) show but your mechanic should not be guessing and throwing parts at it blindly. If your injectors are not grounding that ought to be addressed. The injectors are switched ground via the ECU. The resistor pack is on the +12v side. The resistor pack has nothing to do with grounding. Has your mechanic verified power to ECU (pin 10) and grounds to the ECU (pins 5,16,17,35) ? |
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| nmkimosabe |
Mar 22 2026, 12:55 PM
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#5
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Member Group: Members Posts: 59 Joined: 16-March 25 From: Santa Fe, NM Member No.: 28,660 Region Association: Rocky Mountains |
QUOTE(Superhawk996 @ Mar 22 2026, 10:16 AM) QUOTE(nmkimosabe @ Mar 21 2026, 06:25 PM) I will order a new resistor pack as mine might be the problem. Thanks Jeff. Not trying to start a whole (IMG:style_emoticons/default/stromberg.gif) show but your mechanic should not be guessing and throwing parts at it blindly. If your injectors are not grounding that ought to be addressed. The injectors are switched ground via the ECU. The resistor pack is on the +12v side. The resistor pack has nothing to do with grounding. Has your mechanic verified power to ECU (pin 10) and grounds to the ECU (pins 5,16,17,35) ? @Superhawk996 I honestly don't know but will ask him about your suggestions on Monday and let you know. I appreciaate your feedback! |
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Posts in this topic
nmkimosabe L-Jet Injectors Aren't Getting Ground Mar 21 2026, 09:44 AM
nmkimosabe
Check the schematic for these circuits. LJet inj... Mar 22 2026, 10:42 AM fiacra Jeff is the expert here so I'd start with what... Mar 21 2026, 12:15 PM
nmkimosabe
Jeff is the expert here so I'd start with wha... Mar 21 2026, 04:19 PM Superhawk996 Just beware - lots of mechanics are basically lear... Mar 22 2026, 01:24 PM nmkimosabe
Just beware - lots of mechanics are basically lea... Mar 22 2026, 02:11 PM nmkimosabe Here's an update on my 914 and unfortunately, ... Mar 31 2026, 05:07 PM Superhawk996 . I had the car towed to my mechanic who spent 2 d... Mar 31 2026, 07:45 PM nmkimosabe
. I had the car towed to my mechanic who spent 2 ... Apr 1 2026, 09:14 AM Superhawk996
A) I believe it is getting spark, and fuel but j... Apr 1 2026, 12:11 PM JeffBowlsby L-Jet is one of the early EFI systems, common in t... Mar 31 2026, 05:41 PM nmkimosabe
L-Jet is one of the early EFI systems, common in ... Mar 31 2026, 06:44 PM Rob-O I’m with Superhawk. Make a plan and methodicall... Apr 1 2026, 11:39 AM nmkimosabe
I’m with Superhawk. Make a plan and methodical... Apr 1 2026, 12:13 PM Superhawk996
Yes I can use a voltmeter and I have a list of t... Apr 1 2026, 12:48 PM StarBear Also check the o-ring on the oil filler cap. A fai... Apr 1 2026, 12:28 PM nmkimosabe
Also check the o-ring on the oil filler cap. A fa... Apr 1 2026, 02:42 PM Maltese Falcon Check your main grounds around the engine bay/ and... Apr 1 2026, 12:31 PM nmkimosabe
Check your main grounds around the engine bay/ an... Apr 1 2026, 04:07 PM nmkimosabe Well 2 weeks and learning a lot about L-jet inject... Apr 7 2026, 02:38 PM TRP great job at debugging the issue! I have so m... Apr 7 2026, 03:00 PM Rob-O The head sensor isn’t terribly difficult. Take ... Apr 8 2026, 04:16 AM nmkimosabe
The head sensor isn’t terribly difficult. Take... Apr 8 2026, 08:24 AM Rob-O For gaskets it depends. The injectors could be le... Apr 9 2026, 06:25 AM Geezer914 If it's running like crap, it may be a vacuum ... Apr 9 2026, 09:12 AM nmkimosabe Can someone please tell me if I should use a crush... Apr 11 2026, 02:22 PM fiacra
Can someone please tell me if I should use a crus... Apr 11 2026, 04:03 PM nmkimosabe
[quote name='nmkimosabe' post='3252868' date='Apr... Apr 11 2026, 07:35 PM nmkimosabe
Can someone please tell me if I should use a cru... Apr 12 2026, 08:43 AM fiacra @[url=http://www.914world.com/bbs2/index.php?showu... Apr 12 2026, 11:39 AM nmkimosabe @fiacra
My part # appears to be 032.096.041 which... Apr 12 2026, 01:06 PM fiacra
[b]@[url=http://www.914world.com/bbs2/index.php?s... Apr 12 2026, 03:06 PM nmkimosabe
[b]@[url=http://www.914world.com/bbs2/index.php?... Apr 12 2026, 03:55 PM Superhawk996 RE: L-Jet Injectors Aren't Getting Ground Apr 12 2026, 02:30 PM Rob-O They’re available from Porsche again, I believe. Apr 12 2026, 03:36 PM |
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