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: 15,482 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. |
JeffBowlsby |
Dec 27 2014, 10:43 PM
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#2
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914 Wiring Harnesses Group: Members Posts: 8,519 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
Rather than throwing parts at it, the only clue is that is goes lean with every interruption. What could cause that?
Have you monitored fuel pressure and is it constant? You have replaced all the parts, but what if the fuel pump circuits are intermittent? Have you cleaned your grounds lately? The fuel pump ground on a 74 is under the relay plate. How clean do all the electrical contacts look? Tried DeOxit on every connection? How about the coil, they can fail intermittently. How about the spark plugs? |
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