Engine Dies While Driving - MAF Code, Not the MAF
04-02-2020, 04:06 PM
#42
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O, that rounded corner is normal on that rising edge !!...you can see mine in thread #29..just one of those questions I could never get an answer to !!
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C5 Diag (04-14-2020)
04-12-2020, 08:59 AM
#44
Drifting
Of those two traces the top MAF signal trace looks like a normal MAF signal. The lower trace is not a good signal. I believe that the C5 MAF signal should approximate a square wave. The duty cycle should be ~50% and the duty cycle of the lower trace is not 50%. You sure you did not mix up the vehicles. Since the ECU expects the signal to be a square wave the calculated airflow will be off. You should try tapping the MAF and wiggling the harness while monitoring the signal to see if it changes or becomes erratic.
04-14-2020, 07:53 PM
#46
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Of those two traces the top MAF signal trace looks like a normal MAF signal. The lower trace is not a good signal. I believe that the C5 MAF signal should approximate a square wave. The duty cycle should be ~50% and the duty cycle of the lower trace is not 50%. You sure you did not mix up the vehicles. Since the ECU expects the signal to be a square wave the calculated airflow will be off. You should try tapping the MAF and wiggling the harness while monitoring the signal to see if it changes or becomes erratic.
05-25-2020, 03:20 PM
#47
Team Owner
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Last edited by ddecart; 05-25-2020 at 03:32 PM.
05-25-2020, 03:41 PM
#48
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Thread Starter
Now that our 3rd winter is finally past us, there’s been more driving, more looking at scopes, and I’m no closer to a solution.
When the engine stumbles, the signals at the MAF sensor (back-probed) look fine. The MAF signal voltage doesn’t miss a beat. The frequency changes as the car stumbles and tries to catch its breath, but no surprise there. I think we can conclude that the MAF itself isn’t the problem. MAF wiring? Possibly.
Going back to 69’s post on the conditions for setting the P0101 code:
Conditions certainly match. Cruise control on at ~55 in 4th gear meets that criteria for running the DTC.
But MAF vs Speed Density….
The car won’t run with the MAF disconnected. I’m thinking that’s a clue here.
Looking at the vacuum system closely, the fuel purge valve switch is disconnected from the little stub of a hose that it’s supposed to connect to
Plugged that "hose to nowhere" back in, but haven’t driven it yet. It previously stumbled a little when returning to idle, so a bit of a vacuum leak isn’t a surprise. Hardly should be enough to manifest itself with the issues it's been having with stumbling and stalling. Heck, my ’01 had a cavernous crack in the PCV line and was generally fine except for a cold idle.
Otherwise, there is nothing apparently wrong vacuum-wise. Everything is connected and the hoses are in good shape. The entire PCV hose and valve (that runs from the right front of the intake, rearward, behind the intake manifold, and to a port on the left valve cover) was replaced after this started happening.
Electrically, I chased the main harness back from the MAF, behind the engine (with my borescope) and out the other side. The corrugated tubing is in better shape than I would expect in a 20+ year old car. No signs of rubbing or anything. When I’ve been underneath at the ECM in the past, there was nothing notably wrong down there, either.
The problem is that I have absolutely no record of what, if any, tune was ever done to this thing. I'd love to dump a stock tune back into it (if it's not stock already) and see. It's certainly plausible.
When the engine stumbles, the signals at the MAF sensor (back-probed) look fine. The MAF signal voltage doesn’t miss a beat. The frequency changes as the car stumbles and tries to catch its breath, but no surprise there. I think we can conclude that the MAF itself isn’t the problem. MAF wiring? Possibly.
Going back to 69’s post on the conditions for setting the P0101 code:
Conditions for Running the DTC
• DTCs P0102, P0103, P0107, P0108, P1120, P1220, P1221 not set.
• The engine speed is greater than 50 RPM but less than 2800 RPM.
• The TP sensor angle is less than 50% when engine vacuum (BARO-MAP) is greater than 65 kPa.
• The change in TP sensor angle is less than 3%.
• The ignition voltage is greater than 10.0 volts but less than 16.0 volts.
• All above conditions stable for 2 seconds
Conditions for Setting the DTC
• The MAF frequency is 50% greater than the speed density calculation.
• All conditions met for 10.0 seconds.
• DTCs P0102, P0103, P0107, P0108, P1120, P1220, P1221 not set.
• The engine speed is greater than 50 RPM but less than 2800 RPM.
• The TP sensor angle is less than 50% when engine vacuum (BARO-MAP) is greater than 65 kPa.
• The change in TP sensor angle is less than 3%.
• The ignition voltage is greater than 10.0 volts but less than 16.0 volts.
• All above conditions stable for 2 seconds
Conditions for Setting the DTC
• The MAF frequency is 50% greater than the speed density calculation.
• All conditions met for 10.0 seconds.
Conditions certainly match. Cruise control on at ~55 in 4th gear meets that criteria for running the DTC.
But MAF vs Speed Density….
The car won’t run with the MAF disconnected. I’m thinking that’s a clue here.
Looking at the vacuum system closely, the fuel purge valve switch is disconnected from the little stub of a hose that it’s supposed to connect to
Found another thread: http://forums.corvetteforum.com/c5-t...s-part-do.html
Shows the 'elbow to nowhere'
Shows the 'elbow to nowhere'
Otherwise, there is nothing apparently wrong vacuum-wise. Everything is connected and the hoses are in good shape. The entire PCV hose and valve (that runs from the right front of the intake, rearward, behind the intake manifold, and to a port on the left valve cover) was replaced after this started happening.
Electrically, I chased the main harness back from the MAF, behind the engine (with my borescope) and out the other side. The corrugated tubing is in better shape than I would expect in a 20+ year old car. No signs of rubbing or anything. When I’ve been underneath at the ECM in the past, there was nothing notably wrong down there, either.
I hate to chime in here without really really reading all that stuff above and taking it all in but I think you guys are looking in the wrong place here. I'll try to be brief. Go ahead and tell me if I'm jumping to conclusions without all the data being collected here.
The op has a complete shutdown problem and I don't think this is mechanical or electrical at all. It sounds to me like somebody was wrenching around in the tune and they have the ve table off far enough that the math checks that are being done which are supposed to make certain that the airflow and fueling stay Within a certain range of parameters during transient moments, are no longer within those parameters. At that point the PCM will shut the car down. I think you got to get HP tuners involved here and this car needs a very basic tune.
now it's been a little while since I've played with a tune because I just haven't had time to mess with this stuff recently but, I'm pretty sure there are a couple of tables which if they are not within a certain percentage of error, it'll just shut the PCM down. It knows there's impending doom or at least it thinks there might be and it says yo yo yo we're stopping.
The op has a complete shutdown problem and I don't think this is mechanical or electrical at all. It sounds to me like somebody was wrenching around in the tune and they have the ve table off far enough that the math checks that are being done which are supposed to make certain that the airflow and fueling stay Within a certain range of parameters during transient moments, are no longer within those parameters. At that point the PCM will shut the car down. I think you got to get HP tuners involved here and this car needs a very basic tune.
now it's been a little while since I've played with a tune because I just haven't had time to mess with this stuff recently but, I'm pretty sure there are a couple of tables which if they are not within a certain percentage of error, it'll just shut the PCM down. It knows there's impending doom or at least it thinks there might be and it says yo yo yo we're stopping.
The problem is that I have absolutely no record of what, if any, tune was ever done to this thing. I'd love to dump a stock tune back into it (if it's not stock already) and see. It's certainly plausible.
05-25-2020, 04:31 PM
#49
Team Owner
Thread Starter
Just went for a drive, no change.
Although, in the most recent few drives, with the cruise set at ~55 in 4th gear, the engine will stall and then catch itself a couple of seconds later. Cruise is set, so it resumes to 55, then after a few seconds it does the same thing. Drove a mile or so with it cycling like that. When I slowed to a stop, it flat out died though.
So I pulled the IAT connector and drove the couple miles home, also at 55 with cruise on. it would still stumble on occasion. Perhaps 10% as much as with the IAT plugged in. And when it did, it was severe enough as to be noticeable, but very brief in duration and corrected itself almost immediately.
Although, in the most recent few drives, with the cruise set at ~55 in 4th gear, the engine will stall and then catch itself a couple of seconds later. Cruise is set, so it resumes to 55, then after a few seconds it does the same thing. Drove a mile or so with it cycling like that. When I slowed to a stop, it flat out died though.
So I pulled the IAT connector and drove the couple miles home, also at 55 with cruise on. it would still stumble on occasion. Perhaps 10% as much as with the IAT plugged in. And when it did, it was severe enough as to be noticeable, but very brief in duration and corrected itself almost immediately.
05-26-2020, 04:49 PM
#50
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Thread Starter
Here is everything I know about the current configuration of the engine. I'm thinking maybe finding someone with HP Tuners wouldn't be a bad idea.
No idea if this is where the tune was done or not.
I have Melrose headers with R/T high flow cats and X pipe followed with B&B Bullets. The Melrose setup uses all four O2's in their original configuration. I've never had any codes or problems. I did have the rear O2's tuned out when I got a tune a week after the install.
I had my car dyno'd and tuned when I installed my headers, high flow cats and X-pipe. The tuner mentioned at the time that my injectors were running at 85% and for my next round of mods I should consider injectors. When I installed my ported LS6 intake and ported/polished throttle body I installed the SVO 30 injectors and he retuned the car free. According to him, I'm good now for a serious heads/cam job.
05-31-2020, 08:13 PM
#51
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I took both cars out for a drive and recorded a bunch of data with my ALDL scanner. Same road, same conditions, same speed, same gear, etc... 4th gear, cruise set @ 55mph.
The '98 was, of course, struggling to stay running. The data is interesting though.....
MAF:
'98: ~35 g/sec
'01: ~20 g/sec
IAT:
~90F for both
MAP:
~25kpa for both
Same MAP, same IAT, different MAF
So I calculated the speed density mass airflow at those conditions. Not exact, but pretty close. I had to assume the volumetric efficiency, and played with the volumetric efficiency in order to minimize the error between the speed density MAF and the MAF-MAF.
VE
'01: ~63% (part throttle, part load, not unreasonable)
'98: ~115%
While the '98 has a ported LS6 intake and a polished throttle, I have a hard time believing that under the exact same conditions that it's flowing that much more air and doing so that efficiently.
If the MAP pressure reading was drastically different, I'd say there's an obvious issue, but it's almost identical in both cars.
Does anyone know if a "tune" has a calibration parameter that is adjustable for turning the MAF frequency into a flow rate?
The '98 was, of course, struggling to stay running. The data is interesting though.....
MAF:
'98: ~35 g/sec
'01: ~20 g/sec
IAT:
~90F for both
MAP:
~25kpa for both
Same MAP, same IAT, different MAF
So I calculated the speed density mass airflow at those conditions. Not exact, but pretty close. I had to assume the volumetric efficiency, and played with the volumetric efficiency in order to minimize the error between the speed density MAF and the MAF-MAF.
VE
'01: ~63% (part throttle, part load, not unreasonable)
'98: ~115%
While the '98 has a ported LS6 intake and a polished throttle, I have a hard time believing that under the exact same conditions that it's flowing that much more air and doing so that efficiently.
If the MAP pressure reading was drastically different, I'd say there's an obvious issue, but it's almost identical in both cars.
Does anyone know if a "tune" has a calibration parameter that is adjustable for turning the MAF frequency into a flow rate?
05-31-2020, 09:44 PM
#52
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Normally VE testing is done at WOT and 80% is always the magic number for a NA engine...if you watch the video and get me the parameters needed I can plug your numbers into my DECS program and see if your engine is “breathing” properly !!...the temp reading should be your IAT temp and not outside air temp !!...also a good idea to check your O2 voltages if VE is low...low mV (less than 450 Mv) numbers (lean) indicate a bad MAF (under reporting)
Last edited by C5 Diag; 05-31-2020 at 10:17 PM.
06-01-2020, 05:05 PM
#53
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Thread Starter
Normally VE testing is done at WOT and 80% is always the magic number for a NA engine...if you watch the video and get me the parameters needed I can plug your numbers into my DECS program and see if your engine is “breathing” properly !!...the temp reading should be your IAT temp and not outside air temp !!...also a good idea to check your O2 voltages if VE is low...low mV (less than 450 Mv) numbers (lean) indicate a bad MAF (under reporting)
https://youtu.be/zG_l3YcV0gU
https://youtu.be/zG_l3YcV0gU
Since VE is one of the parameters in the speed density calculation, it's easy enough to just guess something reasonable and fit the speed density calc to the MAF data. Given that the conditions were the same for both cars, and the calculated VE was drastically different, I'm going to go ahead and assume that the VE in the car without the problem is probably reasonable, and the one in the car with the problem isn't.
Given that the P0101 sets under those driving conditions when the MAF and Speed Density are in disagreement, I'm not surprised that I see a disagreement in calculations. The question to me is WHY?
It's implausible that the '98 is different than the '01 by that much with the slight mods that were done.
06-02-2020, 08:31 PM
#54
OK. Read some of this. A couple of things. I am thinking you are not looking at VE at all. The reason I say this is when you disconnect the MAF the car dies. It should still be able to run with it disconnected. My guess is the tuner only tuned the car for MAF. Really fast and easy to tune MAF, takes time to tune VE so quick and easy to tune, but if MAF fails... My guess is the "High RPM Disable" for the MAF was set to 0 RPM, disabling VE so when you disconnect it the car dies. Just a guess, could not know for sure without reading the tune file. Also, the car does not go into speed density mode with the IAT connector disconnected, but it more than likely changed fueling tables. MAF codes have to be failed for it to go into speed density.
Wonder if the problem isn't the PCM itself. You changed a lot of parts out and sometimes it is the PCM throwing out a bad signal.
Wonder if the problem isn't the PCM itself. You changed a lot of parts out and sometimes it is the PCM throwing out a bad signal.
Last edited by RedRiderZR1; 06-02-2020 at 08:38 PM.
06-05-2020, 08:38 AM
#55
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Thread Starter
OK. Read some of this. A couple of things. I am thinking you are not looking at VE at all. The reason I say this is when you disconnect the MAF the car dies. It should still be able to run with it disconnected. My guess is the tuner only tuned the car for MAF. Really fast and easy to tune MAF, takes time to tune VE so quick and easy to tune, but if MAF fails... My guess is the "High RPM Disable" for the MAF was set to 0 RPM, disabling VE so when you disconnect it the car dies. Just a guess, could not know for sure without reading the tune file. Also, the car does not go into speed density mode with the IAT connector disconnected, but it more than likely changed fueling tables. MAF codes have to be failed for it to go into speed density.
Wonder if the problem isn't the PCM itself. You changed a lot of parts out and sometimes it is the PCM throwing out a bad signal.
Wonder if the problem isn't the PCM itself. You changed a lot of parts out and sometimes it is the PCM throwing out a bad signal.
I've been wondering if the ECM has been flaking out, but the conditions are pretty repeatable. It seems to be when the check for the P0101 would take place.... i.e. the speed density and MAF disagreeing.
I presume a local tuner would be able to see what's in there and make any necessary changes. Aside from whatever needs to be done for the headers/O2, I'm inclined to put the thing back to a stock cal as a starting point. Better to have less power and a driveable car.
The tune was done ~10 years ago in Florida. Is there anything to be learned from talking to the tuner at this point? Better to find a competent local shop? I wish these ECMs weren't so friggin expensive. It'd be an easy swap if they were.
06-05-2020, 04:31 PM
#56
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DDECART
If it were me, I would take it to a GOOD tuner and allow him to Data Log the PCM. That will tell him a wealth of knowledge. One of the thing that you will need to know is if the PCM is tuned and if it is, Is it LOCKED or OPEN. If its locked there will not be anything that he can do with it other than flashing in another tune STOCK or CUSTOM.
Find a good tuner in the Michigan area and see what he has to say. That will give you some more knowledge as to where you need to go to possibly resolving the issue. I believe that the data logging will tell you what you need to know. Maybe someone in this post can recommend a good tuner. There is also the opportunity to get the PCM CAN tuned if you know what mods have been done to the engine. . Those tunes are much less expensive (approx. $100-$150) If you need a good PCM, try VETTENUTS Salvage. He has quality OEM used parts. You can get that PCM CAN Tuned close enough to make the engine happy.
Let me know what you think.
Bill
If it were me, I would take it to a GOOD tuner and allow him to Data Log the PCM. That will tell him a wealth of knowledge. One of the thing that you will need to know is if the PCM is tuned and if it is, Is it LOCKED or OPEN. If its locked there will not be anything that he can do with it other than flashing in another tune STOCK or CUSTOM.
Find a good tuner in the Michigan area and see what he has to say. That will give you some more knowledge as to where you need to go to possibly resolving the issue. I believe that the data logging will tell you what you need to know. Maybe someone in this post can recommend a good tuner. There is also the opportunity to get the PCM CAN tuned if you know what mods have been done to the engine. . Those tunes are much less expensive (approx. $100-$150) If you need a good PCM, try VETTENUTS Salvage. He has quality OEM used parts. You can get that PCM CAN Tuned close enough to make the engine happy.
Let me know what you think.
Bill
06-05-2020, 06:18 PM
#57
That makes sense. It should run without the MAF, so that's been puzzling me... until I found out that it had a tune, so all bets are off at that point.
I've been wondering if the ECM has been flaking out, but the conditions are pretty repeatable. It seems to be when the check for the P0101 would take place.... i.e. the speed density and MAF disagreeing.
I presume a local tuner would be able to see what's in there and make any necessary changes. Aside from whatever needs to be done for the headers/O2, I'm inclined to put the thing back to a stock cal as a starting point. Better to have less power and a driveable car.
The tune was done ~10 years ago in Florida. Is there anything to be learned from talking to the tuner at this point? Better to find a competent local shop? I wish these ECMs weren't so friggin expensive. It'd be an easy swap if they were.
I've been wondering if the ECM has been flaking out, but the conditions are pretty repeatable. It seems to be when the check for the P0101 would take place.... i.e. the speed density and MAF disagreeing.
I presume a local tuner would be able to see what's in there and make any necessary changes. Aside from whatever needs to be done for the headers/O2, I'm inclined to put the thing back to a stock cal as a starting point. Better to have less power and a driveable car.
The tune was done ~10 years ago in Florida. Is there anything to be learned from talking to the tuner at this point? Better to find a competent local shop? I wish these ECMs weren't so friggin expensive. It'd be an easy swap if they were.
Well, what sucks is that the car won't run without the MAF, If it could you can then disconnect the MAF and let it fail. It would run in only VE mode. If the problem went away you would know it is the MAF giving you problems as the P0101 code would imply. As mentioned by others, It should go to a tuner that can scan the sensors on the car and "see" what is happening when the car stumbles. Also would be able to look at the tune and see what would be needed to change. As my post from before said, they should look to see why the VE mode of the car does not work like that setting I mentioned before set to zero or something below idle so the car will not run in VE mode at all. That kills Limp Mode and is not helping you figure out this issue. You should have that fixed anyway since there is no reason for your car to have it disabled. It can only help you especially now with your MAF errors.
Someone with a tuning package can scan the car for you. You can also check the MAF and other diagnostics with A GM TECH 2. If not a tuner nearby, check your regional forums for someone with either of those that can help you out. The tuning package would be able to look at your tune though. Possibly also ask in your regional forums if someone knows of a good tuner nearby you.
As for the tune currently in it. Going back to stock and making the changes for your mods needed might be the way to go. But if the car was running fine before this issue than by just getting the tune "fixed" to where it can run in VE mode again and be tuned (checked) for VE it should be fine. Just figuring out what is going on with the MAF would be the issue.
Right now your car is no way running in Speed Density or even can with VE disabled.
06-05-2020, 06:28 PM
#58
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St. Jude Donor '08
IMPORTANT NOTE! IF,, You do decide to get the car tuned professionally (it is not cheap) I would start out with a good known base line: New Plugs, new / clean air filter, new wires, clean MAF, Clean Throttle body, and new fresh O2 Sensors and NO unmetered air leaks!. That way, if the car ever has an issue, you can replace the wear items and get back to the best it can be. If you tune on old stuff, and then say,, replace the O2 sensors, the tune may be effected.
Just my 2 cents.
Bill
Just my 2 cents.
Bill
06-08-2020, 08:13 AM
#59
Team Owner
Thread Starter
DDECART
If it were me, I would take it to a GOOD tuner and allow him to Data Log the PCM. That will tell him a wealth of knowledge. One of the thing that you will need to know is if the PCM is tuned and if it is, Is it LOCKED or OPEN. If its locked there will not be anything that he can do with it other than flashing in another tune STOCK or CUSTOM.
Find a good tuner in the Michigan area and see what he has to say. That will give you some more knowledge as to where you need to go to possibly resolving the issue. I believe that the data logging will tell you what you need to know. Maybe someone in this post can recommend a good tuner. There is also the opportunity to get the PCM CAN tuned if you know what mods have been done to the engine. . Those tunes are much less expensive (approx. $100-$150) If you need a good PCM, try VETTENUTS Salvage. He has quality OEM used parts. You can get that PCM CAN Tuned close enough to make the engine happy.
Let me know what you think.
Bill
If it were me, I would take it to a GOOD tuner and allow him to Data Log the PCM. That will tell him a wealth of knowledge. One of the thing that you will need to know is if the PCM is tuned and if it is, Is it LOCKED or OPEN. If its locked there will not be anything that he can do with it other than flashing in another tune STOCK or CUSTOM.
Find a good tuner in the Michigan area and see what he has to say. That will give you some more knowledge as to where you need to go to possibly resolving the issue. I believe that the data logging will tell you what you need to know. Maybe someone in this post can recommend a good tuner. There is also the opportunity to get the PCM CAN tuned if you know what mods have been done to the engine. . Those tunes are much less expensive (approx. $100-$150) If you need a good PCM, try VETTENUTS Salvage. He has quality OEM used parts. You can get that PCM CAN Tuned close enough to make the engine happy.
Let me know what you think.
Bill
Well, what sucks is that the car won't run without the MAF, If it could you can then disconnect the MAF and let it fail. It would run in only VE mode. If the problem went away you would know it is the MAF giving you problems as the P0101 code would imply. As mentioned by others, It should go to a tuner that can scan the sensors on the car and "see" what is happening when the car stumbles. Also would be able to look at the tune and see what would be needed to change. As my post from before said, they should look to see why the VE mode of the car does not work like that setting I mentioned before set to zero or something below idle so the car will not run in VE mode at all. That kills Limp Mode and is not helping you figure out this issue. You should have that fixed anyway since there is no reason for your car to have it disabled. It can only help you especially now with your MAF errors.
Someone with a tuning package can scan the car for you. You can also check the MAF and other diagnostics with A GM TECH 2. If not a tuner nearby, check your regional forums for someone with either of those that can help you out. The tuning package would be able to look at your tune though. Possibly also ask in your regional forums if someone knows of a good tuner nearby you.
As for the tune currently in it. Going back to stock and making the changes for your mods needed might be the way to go. But if the car was running fine before this issue than by just getting the tune "fixed" to where it can run in VE mode again and be tuned (checked) for VE it should be fine. Just figuring out what is going on with the MAF would be the issue.
Right now your car is no way running in Speed Density or even can with VE disabled.
Someone with a tuning package can scan the car for you. You can also check the MAF and other diagnostics with A GM TECH 2. If not a tuner nearby, check your regional forums for someone with either of those that can help you out. The tuning package would be able to look at your tune though. Possibly also ask in your regional forums if someone knows of a good tuner nearby you.
As for the tune currently in it. Going back to stock and making the changes for your mods needed might be the way to go. But if the car was running fine before this issue than by just getting the tune "fixed" to where it can run in VE mode again and be tuned (checked) for VE it should be fine. Just figuring out what is going on with the MAF would be the issue.
Right now your car is no way running in Speed Density or even can with VE disabled.
Thanks guys. A path forward is becoming a bit more clear now.
The objective: HAVE A DRIVEABLE CAR
To get there, it looks like there are two options:
1) tune the current ECM
2) tune a replacement ECM
The issue with (1) is that we don't know what's causing the issues that suddenly appeared. Since the car isn't ever running in SD, and it flat out dies with the IAT plugged in and hiccups when the IAT is unplugged (thus altering the tables for -40 deg) there is apparently something whacky going on in the ECM. I've been back-probing at the MAF, so to be a bit more complete in the diagnosis, I can back-probe at the ECM to double-check that the MAF signal is making it all the way to the ECM. Even if I find a wiring issue, a re-tune doesn't sound like a bad idea.
As far as tuning goes, again the objective is a driveable car. This thing doesn't have ridiculous mods. Headers, exhaust, LS6 intake, polished throttle body. If a mail order tune makes the car run reliably at he expense of a few HP, who cares. So the only downside to tuning a replacement ecm is that it might not be necessary (which is why I need to back-probe the ECM).
Unfortunately, I lost my access to a Tech2 and all of the other GM tools a year or so ago. When I did drive with a Tech2 hooked up, I saw nothing out of the ordinary, but they're not much better than a cheap scanner for live data unless you're porting to a computer. The Tech2 replacement is a module hooked up to a computer. Much better for reading real-time data and flashing. I'll have to make a call or two to see if I can get aaccess to one, but even then, I'm not sure it helps me beyond the "old vs replacement" ECM question.
06-14-2020, 11:55 AM
#60
Team Owner
Thread Starter
Just back-probed the MAF signal at the ECM. The signal is absolutely rock-solid when driving, even when the engine stumbles. So, it's not the MAF wiring, either.
Opinions on the next step?
Retune this controller
Find a new controller and retune that
These damn things are as rare as hens teeth, it seems.
Opinions on the next step?
Retune this controller
Find a new controller and retune that
These damn things are as rare as hens teeth, it seems.