99 PCM replace/update
06-23-2019, 04:09 PM
#106
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Not really. The thought that CPS location can have a bearing on signal strength has been detailed in Renix by Cruiser (see Tip #7).
Is this applicable to OBDI/OBDII CPSs? Well, we're kinda running out of things to look at. I imagine no one considered this because the vehicle was "professionally tested" and the cam and crank sensors were found to be in sync. But if the CPS doesn't see a shutter window clearly (because it is seeing mostly metal), then it may not be generating high enough voltage. Enough of one so that the all functions are normal, but not high enough for ECU to consider it normal.
Is this applicable to OBDI/OBDII CPSs? Well, we're kinda running out of things to look at. I imagine no one considered this because the vehicle was "professionally tested" and the cam and crank sensors were found to be in sync. But if the CPS doesn't see a shutter window clearly (because it is seeing mostly metal), then it may not be generating high enough voltage. Enough of one so that the all functions are normal, but not high enough for ECU to consider it normal.
06-23-2019, 04:23 PM
#107
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Year: 99
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Not really. The thought that CPS location can have a bearing on signal strength has been detailed in Renix by Cruiser (see Tip #7).
Is this applicable to OBDI/OBDII CPSs? Well, we're kinda running out of things to look at. I imagine no one considered this because the vehicle was "professionally tested" and the cam and crank sensors were found to be in sync. But if the CPS doesn't see a shutter window clearly (because it is seeing mostly metal), then it may not be generating high enough voltage. Enough of one so that the all functions are normal, but not high enough for ECU to consider it normal.
Is this applicable to OBDI/OBDII CPSs? Well, we're kinda running out of things to look at. I imagine no one considered this because the vehicle was "professionally tested" and the cam and crank sensors were found to be in sync. But if the CPS doesn't see a shutter window clearly (because it is seeing mostly metal), then it may not be generating high enough voltage. Enough of one so that the all functions are normal, but not high enough for ECU to consider it normal.
06-23-2019, 04:24 PM
#108
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Whatcha thinking?
Hey, you wanted "out of the box"? This is "out of the box"!
06-23-2019, 04:32 PM
#109
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I know. See my above post why it's that particular pattern.
Yes, that was in regards to xjjeery suggesting thermal sensitivity.
That the sensor is not seeing the shutters clearly. Unfortunately, we (you) can't see that the CPS isn't seeing that. Read the cruiser tip and see how and what the output voltage of CPS is. Then we have to guess. If you take off the CPS and put about 1/16" of washers to move it out a little that may make it see more window. You could drill out the CPS holes to be able to close the air gap, but again, IMO right now it's seeing too much metal.
Hey, you wanted "out of the box"? This is "out of the box"!
Yes, that was in regards to xjjeery suggesting thermal sensitivity.
That the sensor is not seeing the shutters clearly. Unfortunately, we (you) can't see that the CPS isn't seeing that. Read the cruiser tip and see how and what the output voltage of CPS is. Then we have to guess. If you take off the CPS and put about 1/16" of washers to move it out a little that may make it see more window. You could drill out the CPS holes to be able to close the air gap, but again, IMO right now it's seeing too much metal.
Hey, you wanted "out of the box"? This is "out of the box"!
06-23-2019, 04:37 PM
#111
CF Veteran
We could do this a lot more scientifically if you pulled the engine and tranny out so we could bench test this...
06-23-2019, 04:51 PM
#112
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i will Re try Awgs clear the adaptive memory with the headlights and re start and ill get a voltage reading from a key on- and turn the crank until ckps is reading the flex plate. i believe i did this already, but i cant recall what the reading was.
06-24-2019, 12:37 AM
#113
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now that cant happen lol, this is a daily driver.
i will Re try Awgs clear the adaptive memory with the headlights and re start and ill get a voltage reading from a key on- and turn the crank until ckps is reading the flex plate. i believe i did this already, but i cant recall what the reading was.
i will Re try Awgs clear the adaptive memory with the headlights and re start and ill get a voltage reading from a key on- and turn the crank until ckps is reading the flex plate. i believe i did this already, but i cant recall what the reading was.
..even though I doubt it is the problem (as the pros would use a code scanner)...all bets are off until you use a $20 scanner plugged into your OBD2 port to clear codes & CEL..no other method is satisfactory imo
apart from that, from what you have said, you would have eliminated the PCM, open wires, and some connectors, you have changed Crank and Cam sensors...engine timing is all but ruled out
so what does that leave not ruled out ?..imo, the following...flexplate, intermittent shorts, PCM connector
All pretty time consuming to verify...I am sure it is no consolation to you that this can happen to pro mechanics and dealers too (as you have found out)
If you wish for further advice on checking the PCM connector/harness. or for intermitent shorts, I can provide some procedures
06-24-2019, 06:21 AM
#115
CF Veteran
Here's another thought (I have never tried this, but it's cheap and you'll end up with a helpful tool). Get a flexible USB camera and see if you can visualize the position of the CPS over the flexplate reluctors.
06-24-2019, 02:10 PM
#118
CF Veteran
Watch this video to see the waveform of a misreading crank sensor on a Dodge Avenger. (pretty similar, cam and crank signals) You can't tell the story with your DMM.
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06-24-2019, 04:41 PM
#119
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ok, let us clarify a couple more things before we go down the more radical paths
firstly, there is no point wasting any more time till you have confirmed PCM codes cleared with an OBD2 scanner..and that scanner then reads "no codes"
Ignoring the flexplate, even though I think it has to be considered the prime suspect, and concentrating on an "intermitent short or open"
Can you confirm your truck has absolutely no symptoms, misfire etc ?
Clearly you must fix this to pass a registration law to do with CEL light or codes?...not just because you want to ?
In the instance of a intermitent open wire problem,,,, that is known to exist in jeeps, however, concentrating on the connectors, especially female pins
You need a few things..to examine each pin and recess under magnification and strong light for any sign of loose, recessed, corroded or otherwise suspect issue..I have magnifying glasses, and a Jewellers loupe
carefully clean each pin and see if it wiggles, using contact cleaner, i use cut wound guitar strings, various OD
I want to say this is tricky work..in most cases, individual wires within a plug can be backed out of the plug using a special tool...they also can get accidentally loosened, mainly by plugging & unplugging connectors
It helps to have an assistant for the next stage which is to test the harness for intermittent opens, by unplugging it, testing continuity with a test light while flexing the wires
the final issue of testing for shorts is gruesome indeed, as you have to cut the factory wires, one by one, and re-solder when tested
it helps to have good test leads made with alligator clips, and test probes, although safety pins do work fine
even though it doesnt make a lot of sense, I am working on the assumption your crank or cam sensor signal is dropping out every so often...I expect that would cause a misfire though, even if ever so slight ??
firstly, there is no point wasting any more time till you have confirmed PCM codes cleared with an OBD2 scanner..and that scanner then reads "no codes"
Ignoring the flexplate, even though I think it has to be considered the prime suspect, and concentrating on an "intermitent short or open"
Can you confirm your truck has absolutely no symptoms, misfire etc ?
Clearly you must fix this to pass a registration law to do with CEL light or codes?...not just because you want to ?
In the instance of a intermitent open wire problem,,,, that is known to exist in jeeps, however, concentrating on the connectors, especially female pins
You need a few things..to examine each pin and recess under magnification and strong light for any sign of loose, recessed, corroded or otherwise suspect issue..I have magnifying glasses, and a Jewellers loupe
carefully clean each pin and see if it wiggles, using contact cleaner, i use cut wound guitar strings, various OD
I want to say this is tricky work..in most cases, individual wires within a plug can be backed out of the plug using a special tool...they also can get accidentally loosened, mainly by plugging & unplugging connectors
It helps to have an assistant for the next stage which is to test the harness for intermittent opens, by unplugging it, testing continuity with a test light while flexing the wires
the final issue of testing for shorts is gruesome indeed, as you have to cut the factory wires, one by one, and re-solder when tested
it helps to have good test leads made with alligator clips, and test probes, although safety pins do work fine
even though it doesnt make a lot of sense, I am working on the assumption your crank or cam sensor signal is dropping out every so often...I expect that would cause a misfire though, even if ever so slight ??
06-24-2019, 05:13 PM
#120
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ok, let us clarify a couple more things before we go down the more radical paths
firstly, there is no point wasting any more time till you have confirmed PCM codes cleared with an OBD2 scanner..and that scanner then reads "no codes"
Ignoring the flexplate, even though I think it has to be considered the prime suspect, and concentrating on an "intermitent short or open"
Can you confirm your truck has absolutely no symptoms, misfire etc ?
Clearly you must fix this to pass a registration law to do with CEL light or codes?...not just because you want to ?
In the instance of a intermitent open wire problem,,,, that is known to exist in jeeps, however, concentrating on the connectors, especially female pins
You need a few things..to examine each pin and recess under magnification and strong light for any sign of loose, recessed, corroded or otherwise suspect issue..I have magnifying glasses, and a Jewellers loupe
carefully clean each pin and see if it wiggles, using contact cleaner, i use cut wound guitar strings, various OD
I want to say this is tricky work..in most cases, individual wires within a plug can be backed out of the plug using a special tool...they also can get accidentally loosened, mainly by plugging & unplugging connectors
It helps to have an assistant for the next stage which is to test the harness for intermittent opens, by unplugging it, testing continuity with a test light while flexing the wires
the final issue of testing for shorts is gruesome indeed, as you have to cut the factory wires, one by one, and re-solder when tested
it helps to have good test leads made with alligator clips, and test probes, although safety pins do work fine
even though it doesnt make a lot of sense, I am working on the assumption your crank or cam sensor signal is dropping out every so often...I expect that would cause a misfire though, even if ever so slight ??
firstly, there is no point wasting any more time till you have confirmed PCM codes cleared with an OBD2 scanner..and that scanner then reads "no codes"
Ignoring the flexplate, even though I think it has to be considered the prime suspect, and concentrating on an "intermitent short or open"
Can you confirm your truck has absolutely no symptoms, misfire etc ?
Clearly you must fix this to pass a registration law to do with CEL light or codes?...not just because you want to ?
In the instance of a intermitent open wire problem,,,, that is known to exist in jeeps, however, concentrating on the connectors, especially female pins
You need a few things..to examine each pin and recess under magnification and strong light for any sign of loose, recessed, corroded or otherwise suspect issue..I have magnifying glasses, and a Jewellers loupe
carefully clean each pin and see if it wiggles, using contact cleaner, i use cut wound guitar strings, various OD
I want to say this is tricky work..in most cases, individual wires within a plug can be backed out of the plug using a special tool...they also can get accidentally loosened, mainly by plugging & unplugging connectors
It helps to have an assistant for the next stage which is to test the harness for intermittent opens, by unplugging it, testing continuity with a test light while flexing the wires
the final issue of testing for shorts is gruesome indeed, as you have to cut the factory wires, one by one, and re-solder when tested
it helps to have good test leads made with alligator clips, and test probes, although safety pins do work fine
even though it doesnt make a lot of sense, I am working on the assumption your crank or cam sensor signal is dropping out every so often...I expect that would cause a misfire though, even if ever so slight ??