Trust MAP or boost gauge when looking for pressure?
10-15-2013, 05:23 PM
#23
9 Second Club
I went to the dyno yesterday and the tuner said the map sensor was only showing 7lbs on the laptop. My autometer gauge says 14lbs though and has ever sense I installed the SC. The gauge is hooked up directly to the intake manifold and with my pulleys / engine mods it should be right at 14lbs.
I'm real curious to see what number is right, the car is making 600HP. I was expecting a little more with 14lbs. I know its just an LT1 but I was lookig for around 650-700, what do you guys think?
Another consideration was the IAT was high... 165. I'm not running meth just yet (next step of the project) and the intercooler is a little small. Not sure if the intercooler is restricting the air because the gauge says its still 14lbs after it, sure is heating it up though. The intercooler looks like the vertical procharger 2 core with the 3" inlet and outlets on the same side, bought is used and might be a knockoff.
The next step is to get a bigger A2a intercooler with some meth to help with the IAT. Is there anything I can do at he moment to determine whats what?
Thanks guys.
I'm real curious to see what number is right, the car is making 600HP. I was expecting a little more with 14lbs. I know its just an LT1 but I was lookig for around 650-700, what do you guys think?
Another consideration was the IAT was high... 165. I'm not running meth just yet (next step of the project) and the intercooler is a little small. Not sure if the intercooler is restricting the air because the gauge says its still 14lbs after it, sure is heating it up though. The intercooler looks like the vertical procharger 2 core with the 3" inlet and outlets on the same side, bought is used and might be a knockoff.
The next step is to get a bigger A2a intercooler with some meth to help with the IAT. Is there anything I can do at he moment to determine whats what?
Thanks guys.
I guess this wasnt done ?
10-15-2013, 07:11 PM
#24
I spoke to the tuner and he assured me that the map was performing correctly on his computer and it is the 2 bar tune and all. Tomorrow I'll check the Kpa again on another scanner. He told me to go buy another boost gauge and see what it does so I did and its the same as my current one. So at least this narrows it down completely to the MAP. The tuner said the map could just be bad and next time I see him I'll bring a new one. At this point the tune is dead on either way, might be able to tweak something a little more with a proper MAP though.
I pulled the map off and it read 306 again on the Kpa with the motor off, when I turned it on it showed 177 to 180 it was not installed at this time. I didnt check it when the car was running though.
I pulled the map off and it read 306 again on the Kpa with the motor off, when I turned it on it showed 177 to 180 it was not installed at this time. I didnt check it when the car was running though.
10-16-2013, 02:32 AM
#25
9 Second Club
Can you detail exactly what you mean by map and MAP ?
"map" would suggest the tune file on the ecu
"MAP" is Manifold Absolute Pressure" ie a pressure reading, not a physical component as you seem to be implying.
MAP Sensor is the actual sensor.
He does not have your map sensor and wiring installed on his computer, so to say a map is working correctly in that context is just nonsense.
Key on, engine off the MAP sensor reading should be circa 100kpa. ie atmospheric. This may fluctuate very slightly depending on weather etc.
Obviously you can only take readings when the sensor is wired/connected to the ecu and the ecu is live.
Given there is clearly doubt about either the scaling of the sensor, the wiring or indeed the actual tuning map. To continue running the car hard because you feel it is "dead on" is rather dangerous.
Until you have physically proven the sensor is working correctly. ie outputs a linear voltage with respect to pressure applied to it, and is consistent in doing so. You risk engine damage by continuing to drive.
You must do this to ensure the sensor is not faulty, or indeed you dont have a wiring fault.
It all goes back to simple basic checks before tuning. If your MAP sensor was not reading circa 100kpa at key on, engine off, no tuning should ever even have taken place until it was resolved.
Likewise at idle, camshaft dependant of course, you'd expect it to be in the 35-65kpa region. Any deviation from either of those should be ringing alarm bells
"map" would suggest the tune file on the ecu
"MAP" is Manifold Absolute Pressure" ie a pressure reading, not a physical component as you seem to be implying.
MAP Sensor is the actual sensor.
He does not have your map sensor and wiring installed on his computer, so to say a map is working correctly in that context is just nonsense.
Key on, engine off the MAP sensor reading should be circa 100kpa. ie atmospheric. This may fluctuate very slightly depending on weather etc.
Obviously you can only take readings when the sensor is wired/connected to the ecu and the ecu is live.
Given there is clearly doubt about either the scaling of the sensor, the wiring or indeed the actual tuning map. To continue running the car hard because you feel it is "dead on" is rather dangerous.
Until you have physically proven the sensor is working correctly. ie outputs a linear voltage with respect to pressure applied to it, and is consistent in doing so. You risk engine damage by continuing to drive.
You must do this to ensure the sensor is not faulty, or indeed you dont have a wiring fault.
It all goes back to simple basic checks before tuning. If your MAP sensor was not reading circa 100kpa at key on, engine off, no tuning should ever even have taken place until it was resolved.
Likewise at idle, camshaft dependant of course, you'd expect it to be in the 35-65kpa region. Any deviation from either of those should be ringing alarm bells
10-16-2013, 08:10 AM
#28
9 Second Club
100% true. I did clearly say dependant on camshaft. And again, you know the vacuum it is pulling. It will still be circa 100kpa at key on, engine off.
Clearly the OP's in this case is miles off, and the car should never have been tuned like that unless you were 100% happy doing so knowing a sensor is reading/calibrated wrong.
10-16-2013, 08:45 AM
#30
9 Second Club
10-16-2013, 10:38 AM
#31
Can you detail exactly what you mean by map and MAP ?
"map" would suggest the tune file on the ecu
"MAP" is Manifold Absolute Pressure" ie a pressure reading, not a physical component as you seem to be implying.
MAP Sensor is the actual sensor.
He does not have your map sensor and wiring installed on his computer, so to say a map is working correctly in that context is just nonsense.
Key on, engine off the MAP sensor reading should be circa 100kpa. ie atmospheric. This may fluctuate very slightly depending on weather etc.
Obviously you can only take readings when the sensor is wired/connected to the ecu and the ecu is live.
Given there is clearly doubt about either the scaling of the sensor, the wiring or indeed the actual tuning map. To continue running the car hard because you feel it is "dead on" is rather dangerous.
Until you have physically proven the sensor is working correctly. ie outputs a linear voltage with respect to pressure applied to it, and is consistent in doing so. You risk engine damage by continuing to drive.
You must do this to ensure the sensor is not faulty, or indeed you dont have a wiring fault.
It all goes back to simple basic checks before tuning. If your MAP sensor was not reading circa 100kpa at key on, engine off, no tuning should ever even have taken place until it was resolved.
Likewise at idle, camshaft dependant of course, you'd expect it to be in the 35-65kpa region. Any deviation from either of those should be ringing alarm bells
"map" would suggest the tune file on the ecu
"MAP" is Manifold Absolute Pressure" ie a pressure reading, not a physical component as you seem to be implying.
MAP Sensor is the actual sensor.
He does not have your map sensor and wiring installed on his computer, so to say a map is working correctly in that context is just nonsense.
Key on, engine off the MAP sensor reading should be circa 100kpa. ie atmospheric. This may fluctuate very slightly depending on weather etc.
Obviously you can only take readings when the sensor is wired/connected to the ecu and the ecu is live.
Given there is clearly doubt about either the scaling of the sensor, the wiring or indeed the actual tuning map. To continue running the car hard because you feel it is "dead on" is rather dangerous.
Until you have physically proven the sensor is working correctly. ie outputs a linear voltage with respect to pressure applied to it, and is consistent in doing so. You risk engine damage by continuing to drive.
You must do this to ensure the sensor is not faulty, or indeed you dont have a wiring fault.
It all goes back to simple basic checks before tuning. If your MAP sensor was not reading circa 100kpa at key on, engine off, no tuning should ever even have taken place until it was resolved.
Likewise at idle, camshaft dependant of course, you'd expect it to be in the 35-65kpa region. Any deviation from either of those should be ringing alarm bells
Like I said though, I will need to get it on another scanner, my tuner said the MAP sensor was reading correctly before, durring and after the tuning session. It was just strange that it only picked up 7lbs.
I'm going to order a new GM 2 Bar MAP sensor today and go put the car on a new scanner to check out the Kpa again and when the new sensor comes in I'll do the same. All of the wiring looks good so I'll get back to you guys after I put it on the other scanner.
10-16-2013, 11:21 AM
#32
9 Second Club
How can your tuner say it is working correctly, when you are clearly saying it is only displaying half of actual boost pressure ?
It either reads right or it doesnt.
Or are you saying it is something that has developed after tuning ? If so. It is definitely dangerous to be driving the engine under load
It either reads right or it doesnt.
Or are you saying it is something that has developed after tuning ? If so. It is definitely dangerous to be driving the engine under load
10-16-2013, 03:47 PM
#34
He didn't say it was perfect but the A/F ratio was correct when being tuned. Whether it showed 7lbs or 15lbs it doesn't matter so to say as long as everything else is in working condition... leaves some room for error probably but its kind of like saying 1/4 or 2/8, two different numbers but you get the same results (my words not his). When I go back to see him in the near future we will defiantly get to the bottom of this though.
It is a LT1 car with a 02 PCM.
BTW I did check the Kpa on another scanner and it showed everything normal, the other scanner was showing bogus readings. It showed 101 with the key on so who know whats wrong?
It is a LT1 car with a 02 PCM.
BTW I did check the Kpa on another scanner and it showed everything normal, the other scanner was showing bogus readings. It showed 101 with the key on so who know whats wrong?
10-16-2013, 05:49 PM
#35
9 Second Club
You need to be reading the MAP sensor reading via whatever tuning software was used. If it is correct there, then that is all that matters.
101kpa with key on engine off ( at sea level or close to it ) is perfectly normal.
101kpa with key on engine off ( at sea level or close to it ) is perfectly normal.
10-17-2013, 09:43 AM
#37
Ahh OK, I didn't see the 24x in the signature. If it was tuned with HP Tuners you need to use HP Tuners scanner to verify the MAP pid. Also post up and verify the part # for the 2 bar sensor. Hell posting the tune would eliminate a lot of variables.
Last edited by NicD; 10-17-2013 at 10:17 AM.
PN
10-17-2013, 02:33 PM
#40
There is a lot Id change in that tune.
Your tuner needs to change the injector bank select since the computer still thinks it has the LS1 assignment (bet you have split fuel trims if your tuner had CL on, probably why he turned it to OL to mask the problem)
WOT is commanded AFR at 12.1, I think it would help to be a little richer, plus the VE table doesn't look right IMO.
Like you mentioned this is not the updated tune, but I would for sure have more timing in it. At the moment its not even referencing the high octane tables so timing is be reverted to the "drive" spark table.
Your Map sensor Offset and linear values appear to be right for a standard 2 bar Map sensor and I crossed referenced that part number and it appears to be a 2 bar map
Just to make sure its going into SD, Id uncheck the MAF boxes in DTC's, set the MAF fail to 0 Hz, 0 out the MAF chart (all but the first few Hz cells), and set high RPM disable to 12,000 instead of 4,000
Are you running a return fuel system or not?? IFR says you have a Boost referenced Regulator (1 to 1) but your offset tables says you don't.
Trans settings can't be right for your gearing/tire size/ and WOT RPM, bet it shifts super early in WOT
Your tuner needs to change the injector bank select since the computer still thinks it has the LS1 assignment (bet you have split fuel trims if your tuner had CL on, probably why he turned it to OL to mask the problem)
WOT is commanded AFR at 12.1, I think it would help to be a little richer, plus the VE table doesn't look right IMO.
Like you mentioned this is not the updated tune, but I would for sure have more timing in it. At the moment its not even referencing the high octane tables so timing is be reverted to the "drive" spark table.
Your Map sensor Offset and linear values appear to be right for a standard 2 bar Map sensor and I crossed referenced that part number and it appears to be a 2 bar map
Just to make sure its going into SD, Id uncheck the MAF boxes in DTC's, set the MAF fail to 0 Hz, 0 out the MAF chart (all but the first few Hz cells), and set high RPM disable to 12,000 instead of 4,000
Are you running a return fuel system or not?? IFR says you have a Boost referenced Regulator (1 to 1) but your offset tables says you don't.
Trans settings can't be right for your gearing/tire size/ and WOT RPM, bet it shifts super early in WOT
Last edited by T/A KID; 10-17-2013 at 02:47 PM.