Map Sensors
- Thread starter MAK
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Re: Map Sensors
Okay....now that the correct map sensor was replaced.......that thing is a beast! It has so much boost I am scared to go WOT. When I made it kick down at highway speed it went above +20 psi instantly so I quickly let off. The gauges are so inconsistent with their readings which scares me as well. The pillar gauge is showing -28 vac at idle and at around 3/4 throttle it is showing +20 psi of boost. When the cluster boost gauge is showing 0 psi the pillar gauge is at +10 psi.
I can't wait to get it dialed in and take care of the torque converter.
DaveP - the additional map sensor on the firewall had the hard line going to the bottom/rear of the intake - definitely for the boost gauge. 2 map sensors - lucky me. I still wonder if the additional firewall map sensor should be a 3 bar. I wish I had an extra one to see what the difference in readings would be.
Okay....now that the correct map sensor was replaced.......that thing is a beast! It has so much boost I am scared to go WOT. When I made it kick down at highway speed it went above +20 psi instantly so I quickly let off. The gauges are so inconsistent with their readings which scares me as well. The pillar gauge is showing -28 vac at idle and at around 3/4 throttle it is showing +20 psi of boost. When the cluster boost gauge is showing 0 psi the pillar gauge is at +10 psi.
I can't wait to get it dialed in and take care of the torque converter.
DaveP - the additional map sensor on the firewall had the hard line going to the bottom/rear of the intake - definitely for the boost gauge. 2 map sensors - lucky me. I still wonder if the additional firewall map sensor should be a 3 bar. I wish I had an extra one to see what the difference in readings would be.
Eric Sy GN
Donating Member
Re: Map Sensors
The boost target set in the chip is 14psi, so be careful. If it's really hitting 20psi, I wouldn't get on it until we figure that out.
Also, if you were switching chips back and forth, make sure you disconnected power to the ECM for at least 30 seconds for the new chip. The Velosyty chip configures the ram differently than other chips.
Regards,
Eric
The boost target set in the chip is 14psi, so be careful. If it's really hitting 20psi, I wouldn't get on it until we figure that out.
Also, if you were switching chips back and forth, make sure you disconnected power to the ECM for at least 30 seconds for the new chip. The Velosyty chip configures the ram differently than other chips.
Regards,
Eric
Re: Map Sensors
Like I said in the PM, I have doubts to the accuracy on the boost gauge because of the differences. Hopefully I can get Datamaster soon and log the actual boost. The battery was disconnected for over 5 minutes so that is covered. I will certainly take it easy until I get that boost figured out.
Like I said in the PM, I have doubts to the accuracy on the boost gauge because of the differences. Hopefully I can get Datamaster soon and log the actual boost. The battery was disconnected for over 5 minutes so that is covered. I will certainly take it easy until I get that boost figured out.
Eric Sy GN
Donating Member
Re: Map Sensors
Ok, sounds good.
Eric
Ok, sounds good.
Eric
DaveP
Active member
Re: Map Sensors
Well I learned something. I never knew there were electric aftermarket boost/vacuum gauges. Now I do. My premonition that the "extra MAP" could be for a boost gauge was correct.
Now. It looks like you're getting erroneous readings from your pillar gauge. The goal of aftermarket equipment is to improve things. Like the accuracy of information rendered. This goal is not being met. You don't know what the actual boost pressure in your engine is. This is not a good situation to be in during development and tuning. Go purchase a mechanical gauge and install it in the pillar. Should cost about $75, tops. Engines cost a lot more than that.
Well I learned something. I never knew there were electric aftermarket boost/vacuum gauges. Now I do. My premonition that the "extra MAP" could be for a boost gauge was correct.
Now. It looks like you're getting erroneous readings from your pillar gauge. The goal of aftermarket equipment is to improve things. Like the accuracy of information rendered. This goal is not being met. You don't know what the actual boost pressure in your engine is. This is not a good situation to be in during development and tuning. Go purchase a mechanical gauge and install it in the pillar. Should cost about $75, tops. Engines cost a lot more than that.
Re: Map Sensors
To resolve this mystery once and for all, would the reading on my Autometer Pro Comp Ultra Light gauge be affected by which map sensor it is connected to (2 bar or 3 bar)? It is mechanical so I am guessing not. As of now, the engine has a 3 bar and the Pro Comp gauge is running off of a 2 bar.
I did put out the wrong info earlier - the additional map sensor on the firewall has the hard line going to a tee in the vacuum line coming off the front of the intake, not the rear as I stated before. I meant to change that but forgot.
To resolve this mystery once and for all, would the reading on my Autometer Pro Comp Ultra Light gauge be affected by which map sensor it is connected to (2 bar or 3 bar)? It is mechanical so I am guessing not. As of now, the engine has a 3 bar and the Pro Comp gauge is running off of a 2 bar.
I did put out the wrong info earlier - the additional map sensor on the firewall has the hard line going to a tee in the vacuum line coming off the front of the intake, not the rear as I stated before. I meant to change that but forgot.
Darin
New member
Re: Map Sensors
Yes. It matters which map sensor is connected where.
The electronic boost gauge is likely a 3 bar map sensor if the readings go over 15psi, as the limit for a 2 bar map sensor is 14.7psi. FYI, the gauge is NOT mechanical, it's simply a volt meter with graduated pressure/vacuum marking on it, thus making it electronic. If you have a 2 bar map connected to something that is looking for a 3 bar signal, it'll read MUCH higher. 0 psi on a 2 bar map is ~2.5V, 0 psi on a 3 bar map is ~1.7V.
DaveP said it best, the best advice is to rip the electronic out, go buy a new mechanical gauge and run a vac line into the cab for the gauge. If you can't rely on your gauges then they are useless.
Yes. It matters which map sensor is connected where.
The electronic boost gauge is likely a 3 bar map sensor if the readings go over 15psi, as the limit for a 2 bar map sensor is 14.7psi. FYI, the gauge is NOT mechanical, it's simply a volt meter with graduated pressure/vacuum marking on it, thus making it electronic. If you have a 2 bar map connected to something that is looking for a 3 bar signal, it'll read MUCH higher. 0 psi on a 2 bar map is ~2.5V, 0 psi on a 3 bar map is ~1.7V.
DaveP said it best, the best advice is to rip the electronic out, go buy a new mechanical gauge and run a vac line into the cab for the gauge. If you can't rely on your gauges then they are useless.
Throws
Active member
Re: Map Sensors
Pop the gauge out of it's pod. If there's a plastic tubing running to/from it... it's mechanical. If there's no plastic tube but just wires, then you have an electronic gauge (I hesitate to say digital). The electronic ones are either connected to a MAP or to a sender near a vac source.
IMHO: electronic gauges have a place: oil pressure and fuel pressure for starters. You'll never hear anyone say it's a good idea to have pressurized gas/oil enter the passenger compartment. Boost/Vac gauges, on the other hand, are perfect for this application.
Ferret out the one you have and get a decent mech vac/boost... not only will it be more accurate, it'll have a faster response.
-P
Pop the gauge out of it's pod. If there's a plastic tubing running to/from it... it's mechanical. If there's no plastic tube but just wires, then you have an electronic gauge (I hesitate to say digital). The electronic ones are either connected to a MAP or to a sender near a vac source.
IMHO: electronic gauges have a place: oil pressure and fuel pressure for starters. You'll never hear anyone say it's a good idea to have pressurized gas/oil enter the passenger compartment. Boost/Vac gauges, on the other hand, are perfect for this application.
Ferret out the one you have and get a decent mech vac/boost... not only will it be more accurate, it'll have a faster response.
-P
DaveP
Active member
Re: Map Sensors
If your electronic pillar gauge does not read "zero" with key on, engine off, it has the wrong MAP sensor, or it is defective.
If it's reading in vacuum (~5in) it has a 3BAR, and wants a 2BAR.
If it's reading in boost (~10psi) it has a 2BAR, and wants a 3BAR.
4BAR??? I have no idea.
If your electronic pillar gauge does not read "zero" with key on, engine off, it has the wrong MAP sensor, or it is defective.
If it's reading in vacuum (~5in) it has a 3BAR, and wants a 2BAR.
If it's reading in boost (~10psi) it has a 2BAR, and wants a 3BAR.
4BAR??? I have no idea.
Sean Krupa
Moderator
Re: Map Sensors
I have 2- 3bar map sensors on my Ty for over 10 years. Back in the day, my Dad and Ivan hooked up a Trans Temp, Intercooler Temp and a Cyberdyne electronic digital boost gauge along with a 3-bar map sensor for the boost gauge. This was installed to read over the stock boost of 14.7 and have not had any problems with it. Mine is piggybacked on the 3-bar for the ECM but someone probably put yours on the firewall.
I originally wrote, mechanical boost gauge when I meant, electronic. I changed it above.
I have 2- 3bar map sensors on my Ty for over 10 years. Back in the day, my Dad and Ivan hooked up a Trans Temp, Intercooler Temp and a Cyberdyne electronic digital boost gauge along with a 3-bar map sensor for the boost gauge. This was installed to read over the stock boost of 14.7 and have not had any problems with it. Mine is piggybacked on the 3-bar for the ECM but someone probably put yours on the firewall.
I originally wrote, mechanical boost gauge when I meant, electronic. I changed it above.
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Quickstop [UK]
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DaveP
Active member
Re: Map Sensors
If it reads zero, it has the correct MAP. Making progress. Can you borrow, or purchase an inexpensive diagnostic vacuum / pressure gauge? Hook it up temporarily, put it under the wiper blade so you can read it looking through the windshield, and go for a drive and compare to the readings on your pillar gauge.
Then you'll know whether you can trust it or not. It sounds like an expensive gauge. It's probably OK for now, but you should validate it.
If it reads zero, it has the correct MAP. Making progress. Can you borrow, or purchase an inexpensive diagnostic vacuum / pressure gauge? Hook it up temporarily, put it under the wiper blade so you can read it looking through the windshield, and go for a drive and compare to the readings on your pillar gauge.
Then you'll know whether you can trust it or not. It sounds like an expensive gauge. It's probably OK for now, but you should validate it.