TurboedMJ Posted April 26 Author Share Posted April 26 Pardon my ignorance, I didn't know the RENIX 4.0l had a cam sensor. Where/how would I test that if it turns out to be relevant? Link to comment Share on other sites More sharing options...
cruiser54 Posted April 26 Share Posted April 26 They don't have a cam sensor That deal inside the dizzy is a sync generator used by the ECU to fire the injectors sequentially. You can unplug it and drive your Renix Jeep and not feel the difference at all. Link to comment Share on other sites More sharing options...
TurboedMJ Posted April 26 Author Share Posted April 26 Oh ok. Thanks. I will try the injector thing tomorrow. Link to comment Share on other sites More sharing options...
ghetdjc320 Posted April 26 Share Posted April 26 Notice the oscilloscope readings below. Blue line is “cam”, orange pulses are crank. This is on an HO though. I’ve always referred to “sync generators” as cam sensors since the cam directly drives this sensor. This allows for sequential vs un-timed batch firing. Link to comment Share on other sites More sharing options...
TurboedMJ Posted Saturday at 08:29 PM Author Share Posted Saturday at 08:29 PM Got 4.7 ohms with my "new" NGK sensor with a stainless steel body and 3 wires, and 6.3 ohms with the sensor that was in it before (ceramic body, 3 wires). So I put the old one back in and haven't tested the other parts yet. The idle is still hunting. Link to comment Share on other sites More sharing options...
TurboedMJ Posted Saturday at 08:50 PM Author Share Posted Saturday at 08:50 PM O2 sensor tested good. Voltage was 0.25v for about 20-30 secs, then started alternating between about 0.5v and 4.8v. the voltage would change about every 2 seconds. Link to comment Share on other sites More sharing options...
TurboedMJ Posted Saturday at 09:06 PM Author Share Posted Saturday at 09:06 PM Did the injector thing, any one injector that I unplugged would make the idle steady out at about 500. It ran much better with any one injector unplugged. What does that mean? What should I do next? Link to comment Share on other sites More sharing options...
cruiser54 Posted Sunday at 12:32 AM Share Posted Sunday at 12:32 AM Have you checked for vacuum leaks between the intake manifold and head? Link to comment Share on other sites More sharing options...
TurboedMJ Posted Sunday at 01:10 AM Author Share Posted Sunday at 01:10 AM No I haven't. I'll do that next. Link to comment Share on other sites More sharing options...
TurboedMJ Posted Sunday at 01:25 AM Author Share Posted Sunday at 01:25 AM I tested this with starting fluid, there was no change in idle. Link to comment Share on other sites More sharing options...
cruiser54 Posted Sunday at 01:28 AM Share Posted Sunday at 01:28 AM Best to use carb cleaner. The starting fluid evaporates too quickly. I wonder if your EGR might be hanging open. Link to comment Share on other sites More sharing options...
ghetdjc320 Posted Sunday at 02:40 AM Share Posted Sunday at 02:40 AM 5 hours ago, TurboedMJ said: Did the injector thing, any one injector that I unplugged would make the idle steady out at about 500. It ran much better with any one injector unplugged. What does that mean? What should I do next? Interesting. I’d also check vacuum leak. Is it possible these injectors are providing too much fuel? Or… I’m wondering if the fuel pump is on the fritz and can’t keep up with the demand for all 6 injectors?? Link to comment Share on other sites More sharing options...
cruiser54 Posted Sunday at 03:46 AM Share Posted Sunday at 03:46 AM vacuum leak means low vacuum to MAP sensor resulting in too much fuel. Link to comment Share on other sites More sharing options...
TurboedMJ Posted Sunday at 03:13 PM Author Share Posted Sunday at 03:13 PM 12 hours ago, ghetdjc320 said: Interesting. I’d also check vacuum leak. Is it possible these injectors are providing too much fuel? Or… I’m wondering if the fuel pump is on the fritz and can’t keep up with the demand for all 6 injectors?? Fuel pressure is good, is it possible that the fuel pressure is good but there is simply not enough volume? Link to comment Share on other sites More sharing options...
cruiser54 Posted Sunday at 03:25 PM Share Posted Sunday at 03:25 PM Which is it? Too much fuel or not enough? Link to comment Share on other sites More sharing options...
TurboedMJ Posted Sunday at 03:34 PM Author Share Posted Sunday at 03:34 PM 14 hours ago, cruiser54 said: Best to use carb cleaner. The starting fluid evaporates too quickly. I wonder if your EGR might be hanging open. The EGR system was deleted on this truck Link to comment Share on other sites More sharing options...
cruiser54 Posted Sunday at 05:49 PM Share Posted Sunday at 05:49 PM Okay. Link to comment Share on other sites More sharing options...
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