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Registered
Join Date: Jul 2018
Location: Oregon
Posts: 57
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No spark sometimes no fuel.
I've been trying to get my 951 started for about 4 months since the time it didn't start in June. At first it wasn't sending power to the fuel pump, so I replaced the DME relay and fuel pump fuse. After that it still didn't run the pump. I tried using a jumper for the relay and it did run the pump, but the car didn't start. I checked the plugs and it was getting fuel since they were fouled and smelled, but they didn't spark even with a test light. I checked the ignition coil and it was getting 12 volts to all three terminals. I tested the resistance, and the black terminal + the green terminal tested only 0.1 ohms above spec, at 0.7 ohms. The green terminal + the output to the distributor was more than in spec at about 5800 ohms. Could this keep it from sparking at all? It seems like such a small amount out of spec that you would think it'd at least have a weak spark. Thanks for your help.
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10-15-2020, 08:09 PM
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944 addict
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Are you getting a tach bounce? Is your battery fully charged? How old is the gas? Is the engine block grounded to the rest of the car? These are things I would check in this order. Keep us updated on your progress.
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3 944's, 2 Boxsters and one Caman S, and now one 951 turbo. Really miss the Cayman. Some people try to turn back their "odometers." Not me. I want people to know 'why' I look this way. I've traveled a long way and some of the roads weren't paved. |
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10-16-2020, 08:00 AM
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Location: Oregon
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There is tach bounce, the battery has been on a tender for months, the gas is only a few weeks old, and I don't know how to check the ground. The car has no rust, so I don't think the ground would just come off by itself.
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10-16-2020, 04:44 PM
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In the Fires of Hell.....
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Sounds like a computer issue, but you should really follow the DME test plan for your troubleshooting.
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PCA Instructor: '88 951S - with LBE, Guru chips, 3Bar FPR, 1.3mm shimmed WG, 3120 lbs, 256 RWHP, 15 psig boost |
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10-17-2020, 02:38 AM
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Registered
Join Date: Jul 2018
Location: Oregon
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How would I go about doing that?
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10-17-2020, 01:44 PM
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Super Moderator
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'89 turbo-s (2.7, wolf3d ems, garrett dbb turbo, tial 46mm, etc. fast!) |
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10-18-2020, 07:01 AM
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Registered
Join Date: Jul 2018
Location: Oregon
Posts: 57
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Thanks, I'll check it out.
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10-18-2020, 11:34 AM
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Registered
Join Date: Jul 2018
Location: Oregon
Posts: 57
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It's not a DME relay since I got a new one and tested both of them. It's not a fuel pump because it runs with a jumper on the DME relay. It's not a fuel pump fuse because I've replaced it with a known good one. I know it's not reference or speed sensors because I'm getting tach bounce. Although I'm not sure about the DME control unit, security system, or the ignition system. I think the security system is most plausible though since there is neither spark nor fuel, but I can't find the security module under the passenger side footwell. The plot thickens.
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10-18-2020, 11:43 AM
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Registered
Join Date: Jan 2018
Posts: 344
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Quote:
https://www.pelicanparts.com/techarticles/Porsche_944_Turbo/36-ELEC-Troubleshooting_the_Alarm_System/36-ELEC-Troubleshooting_the_Alarm_System.htm Mike G. Last edited by Mike Goebel; 10-20-2020 at 06:23 AM.. |
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10-20-2020, 06:20 AM
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Porsche 944 NA
1986 Porsche 951
944 Turbo
