'83 928s starting help
04-07-2016, 09:40 PM
#32
Track Day
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That is exactly correct. It idles at 2,000. Much higher than it should, but idles beautifully. And, when I press the gas, it revs just fine as well. All the way up to red line if I want it to. So, all the ignition components are just fine.... That is why I am so confused.
04-08-2016, 02:18 PM
#33
Official Bay Area Patriot
Fuse 24 Assassin
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Fuse 24 Assassin
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Here is something worth trying. Disconnect the battery and disconnect your O2 sensor, but reconnect the AFM. Reconnect your battery and start the car (or try to). Let us know if it runs. I am wondering if maybe the loop signal for the O2 may be causing some sort of running issue when the L-Jet's ECU is trying to read both sensors. Like the more modern 928s with LH, the L-Jet has a default fuel and ignition map loaded into the prom when the O2 is disconnected, causing the car to run in open loop.
Mark had also made a good point to check the temperature sensor. I think I saw you replaced that sensor already. Not sure if you checked for any breakages in the wiring, or corrosion on the actual harness contacts connecting to the sensor's pins. A bad Temp II can cause all sorts of funkiness with these cars.
IMO I saw your cheap shot at me on page 2. Back off; I have more years troubleshooting L-Jet than you have discovering your body as you entered manhood.
Mark had also made a good point to check the temperature sensor. I think I saw you replaced that sensor already. Not sure if you checked for any breakages in the wiring, or corrosion on the actual harness contacts connecting to the sensor's pins. A bad Temp II can cause all sorts of funkiness with these cars.
IMO I saw your cheap shot at me on page 2. Back off; I have more years troubleshooting L-Jet than you have discovering your body as you entered manhood.
04-08-2016, 03:19 PM
#34
Rennlist Member
Here is something worth trying. Disconnect the battery and disconnect your O2 sensor, but reconnect the AFM. Reconnect your battery and start the car (or try to). Let us know if it runs. I am wondering if maybe the loop signal for the O2 may be causing some sort of running issue when the L-Jet's ECU is trying to read both sensors. Like the more modern 928s with LH, the L-Jet has a default fuel and ignition map loaded into the prom when the O2 is disconnected, causing the car to run in open loop.
Mark had also made a good point to check the temperature sensor. I think I saw you replaced that sensor already. Not sure if you checked for any breakages in the wiring, or corrosion on the actual harness contacts connecting to the sensor's pins. A bad Temp II can cause all sorts of funkiness with these cars.
IMO I saw your cheap shot at me on page 2. Back off; I have more years troubleshooting L-Jet than you have discovering your body as you entered manhood.
Mark had also made a good point to check the temperature sensor. I think I saw you replaced that sensor already. Not sure if you checked for any breakages in the wiring, or corrosion on the actual harness contacts connecting to the sensor's pins. A bad Temp II can cause all sorts of funkiness with these cars.
IMO I saw your cheap shot at me on page 2. Back off; I have more years troubleshooting L-Jet than you have discovering your body as you entered manhood.
IMO! you should know better!!
also, im still thinking temp II... did you connect it correctly? the other temp sensor looks very similar and if you get them confused, you will melt the tempII sensor and this problem arises. because it runs with a screwdriver in the AFM , it sounds like its the TEMP II
04-08-2016, 03:25 PM
#35
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It is able to run with it propped open, so what you're saying makes sense. And, from what I've read, the temp II goes out pretty often. How would I check it? It is the plug right on the front of the engine, in the water cooling system, correct? And, would it just be and OHM meter on each pin of it? Sorry about the AFM vs MAF, there are just so many part names.
i dont understand how it runs with the AFM out of the car. you mean disconnnected or the AFM pulled out of the "U" inlet?
bottom line, you can run the car by sticking a screwdriver in the AFM while its installed, right? this means its not getting fuel normally, which is a clear indication of tempII not working. lets verify that and then we can move on to the next possiblity.
put a ohm meter on the temp II posts . both to ground and tell us what you get.
04-08-2016, 08:39 PM
#36
Track Day
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Here is something worth trying. Disconnect the battery and disconnect your O2 sensor, but reconnect the AFM. Reconnect your battery and start the car (or try to). Let us know if it runs. I am wondering if maybe the loop signal for the O2 may be causing some sort of running issue when the L-Jet's ECU is trying to read both sensors. Like the more modern 928s with LH, the L-Jet has a default fuel and ignition map loaded into the prom when the O2 is disconnected, causing the car to run in open loop.
Mark had also made a good point to check the temperature sensor. I think I saw you replaced that sensor already. Not sure if you checked for any breakages in the wiring, or corrosion on the actual harness contacts connecting to the sensor's pins. A bad Temp II can cause all sorts of funkiness with these cars.
Mark had also made a good point to check the temperature sensor. I think I saw you replaced that sensor already. Not sure if you checked for any breakages in the wiring, or corrosion on the actual harness contacts connecting to the sensor's pins. A bad Temp II can cause all sorts of funkiness with these cars.
04-08-2016, 08:49 PM
#37
Track Day
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each pin measured to ground should measure 1600 ohms (i think.. something like this) keep in mind there is another temp sensor, the one that goes to the temp guage.. on the Ljet models, they can be confused and misconnected. however, with the temp sensor, plugged into the temp II sensor, it will melt the sensor and the problem will be as you have it.
i dont understand how it runs with the AFM out of the car. you mean disconnnected or the AFM pulled out of the "U" inlet?
bottom line, you can run the car by sticking a screwdriver in the AFM while its installed, right? this means its not getting fuel normally, which is a clear indication of tempII not working. lets verify that and then we can move on to the next possiblity.
put a ohm meter on the temp II posts . both to ground and tell us what you get.
i dont understand how it runs with the AFM out of the car. you mean disconnnected or the AFM pulled out of the "U" inlet?
bottom line, you can run the car by sticking a screwdriver in the AFM while its installed, right? this means its not getting fuel normally, which is a clear indication of tempII not working. lets verify that and then we can move on to the next possiblity.
put a ohm meter on the temp II posts . both to ground and tell us what you get.
This is what I got. Nothing.
04-08-2016, 10:13 PM
#38
Captain Obvious
Super User
Super User
Here is something worth trying. Disconnect the battery and disconnect your O2 sensor, but reconnect the AFM. Reconnect your battery and start the car (or try to). Let us know if it runs. I am wondering if maybe the loop signal for the O2 may be causing some sort of running issue when the L-Jet's ECU is trying to read both sensors. Like the more modern 928s with LH, the L-Jet has a default fuel and ignition map loaded into the prom when the O2 is disconnected, causing the car to run in open loop.
Mark had also made a good point to check the temperature sensor. I think I saw you replaced that sensor already. Not sure if you checked for any breakages in the wiring, or corrosion on the actual harness contacts connecting to the sensor's pins. A bad Temp II can cause all sorts of funkiness with these cars.
IMO I saw your cheap shot at me on page 2. Back off; I have more years troubleshooting L-Jet than you have discovering your body as you entered manhood.
Mark had also made a good point to check the temperature sensor. I think I saw you replaced that sensor already. Not sure if you checked for any breakages in the wiring, or corrosion on the actual harness contacts connecting to the sensor's pins. A bad Temp II can cause all sorts of funkiness with these cars.
IMO I saw your cheap shot at me on page 2. Back off; I have more years troubleshooting L-Jet than you have discovering your body as you entered manhood.
Personal attacks are such an easy target, the mitary thought you well. Now go back yelling and secreaming infront of your kid at the hockey game. Father of the year trophy is waiting for you. All you do is recycle what you find on the net and throw every possiblilty at it to see if something sticks.
04-08-2016, 10:15 PM
#39
Captain Obvious
Super User
Super User
I would bring the engine up to operating temperature, plug in the AFM and see if anything chamges.The extra fuel won't harm anything in a short run like this.
04-08-2016, 11:24 PM
#40
Track Day
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I would also like to note that with the TEMP II sensor unplugged, I got no start at all. But, as soon as the TEMP sensor was re-plugged, it started right on up. I'm not sure what this means, but I'm trying to supply you guys with as much info as I can.
04-09-2016, 10:17 AM
#41
Captain Obvious
Super User
Super User
The O2 sensor plug is located near the fuse panel, and comes in from the outside in the passanger side of the torque tube (transmission) tunnel. Slide under the car and you will see where the sensor is and exactly where the wire comes into the cockpit.
If you do this, might as well check the pin continuity between the AFM connector and the other end of the plug inside the car.
If you do this, might as well check the pin continuity between the AFM connector and the other end of the plug inside the car.
