Continuity Test Results, Help to interpret Continuity Test Results |
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Continuity Test Results, Help to interpret Continuity Test Results |
MFejsa |
Jan 14 2022, 05:37 AM
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#1
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Newbie Group: Members Posts: 40 Joined: 25-April 20 From: Saudi Arabia Member No.: 24,178 Region Association: None |
Need help to interpret results of continuity test results (see attached) and explain what to do next to get my car running right.
Porsche 914 2.0L 1974 (I believe was originally a 1.7L) My car starts, runs and drives but idles rough and wont rev past 4,000rpm. It hesitates on acceleration. I have changed virtually all components / parts from rebuilt MPS, tested TPS and works, ignition switch, fuel pump, air & cylinder head temp sensor, swapped out ECU to one that was tested to work, and the list goes on. I am posting my continuity test results with the hope that some may have experienced or had the same results and knows what to look into more deeply or can diagnose. The test results concluded the following: 1. When testing the ECU power source from main power relay I could not get the 1V voltage difference from the voltage measured at the battery terminal. No difference and remained the same. Voltage at the battery was 12.79 throughout 2. when testing the voltage at start signal from ignition switch the voltage dropped to 9.7V and was not greater than 12V. However, should be greater than 12V. So, can anyone help, please. I haven't been able to get the car run and drive right since being restored and have run out of options. Regards Michael Attached thumbnail(s) |
Van B |
Jan 14 2022, 09:59 AM
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#2
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Senior Member Group: Members Posts: 1,582 Joined: 20-October 21 From: Maryland Member No.: 26,011 Region Association: None |
Wait, are we gonna talk about that 9.7v?
What was your voltage at the battery? If you’re getting 12v at the battery and only 9.7v between that pin and a ground, I recommend looking into that first. If you’re only getting 9.7v at the battery too, then you need to make sure you’re meeting required voltage. All kinds of weird gremlins can appear when insufficient voltage is in the circuit. |
MFejsa |
Jan 14 2022, 10:26 AM
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#3
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Newbie Group: Members Posts: 40 Joined: 25-April 20 From: Saudi Arabia Member No.: 24,178 Region Association: None |
Im getting more that 12v at the battery but 9.7V at the pin and ground
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914Mels |
Jan 14 2022, 11:16 AM
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#4
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Member Group: Members Posts: 357 Joined: 20-June 11 From: Santee Member No.: 13,221 Region Association: Southern California |
Im getting more that 12v at the battery but 9.7V at the pin and ground Looks like you have a voltage drop at the relay plate in the engine compartment. You said you replaced the ignition switch already. Pin 18 gets its power from the ignition switch thru the relay plate. I'd pull the plate and clean all the contacts and the wire ends. I'd also get a vacuum gauge and check what your engine vacuum is. This can tell you a lot about engine condition. read up on the different types of readings and this will point you in a direction to follow. Is your rough idle traceable to one cylinder dropping out or do all seem about the same? Pull plug wires one at a time to see if one cylinder is weaker than the others. Valve adjustment is critical so don't overlook this even though it is a pain in the butt to do. Good luck. |
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