Intermittent Problem with Betty's car, I am at my wit's end on this one. |
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Intermittent Problem with Betty's car, I am at my wit's end on this one. |
ClayPerrine |
Dec 22 2014, 07:17 PM
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#1
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Life's been good to me so far..... Group: Admin Posts: 15,503 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille |
About 2 weeks ago, Betty came home and said her 74, 1.8L Ljet 914 was intermittently cutting out. I took it out to test drive it, and sure enough, it will randomly cut out. Sometimes mildly, sometimes it feels like the engine shuts off completely, then turns back on.
So I started troubleshooting. Nope, grounds for the injectors are fine. Put the LM-1 in the tailpipe and had her drive it. Every time it cuts out, the LM-1 shows it going lean. I put an L-Jet tester I have on it and ran through all the tests and it shows as working fine. I had it running in the garage, and I went through a "wiggle test", wiggling every wire and connection on the engine. Nothing I do can replicate the issue in the garage. So I started throwing parts at it. To date I have replaced: The air flow meter. The fuel injection wiring harness. The double relay. The dropping resistors. The fuel pump. The ECU. The CHT. The whole distributor with a different pertronix, and tried points too. Nothing I have done to date helps. So I am hoping the collective knowledge of this place will help. I have checked all the simple stuff already. This is going to be hard to fix, whatever it is. I am now to the (IMG:style_emoticons/default/WTF.gif) stage, and looking for suggestions. |
ClayPerrine |
Dec 28 2014, 06:04 PM
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#2
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Life's been good to me so far..... Group: Admin Posts: 15,503 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille |
Ok.. I have determined what is causing it.
It's the alternator. (IMG:style_emoticons/default/WTF.gif) While I was out test driving it earlier, in my head I heard my father saying "What was the last thing you f***ed with?" My dad almost never used profanity, so when he did, it made an impression. I remembered that just before this started, I replaced the alternator with a fresh bosch rebuilt one. So I pulled over and disconnected the alternator wires from the relay board without turning the car off. Took off again, and it didn't cut out at all. (IMG:style_emoticons/default/WTF.gif) Stopped and hooked the alternator back up and it started to cut out again. (IMG:style_emoticons/default/WTF.gif) Tomorrow after work I am going to replace the alternator with one I just had rebuilt by a local re-builder. Then I will go through everything I messed with just to be sure nothing else is broken, messed up or otherwise out of whack. I still don't know why the alternator would cause the injection to cut out. (IMG:style_emoticons/default/confused24.gif) Maybe some kind of voltage spike or blown diode sending reverse voltage to the ECU? |
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