MAP Sensor On A 88 L98
Thread Starter
Drifting
Joined: Jun 2001
Posts: 1,697
Likes: 454
From: Mass Mass
MAP Sensor On A 88 L98
I turned up the boost and I think I blew this thing out, the readings use to change, now it just reads 2.33 volts all the time.
Problem is I can't find the darn thing!!!! :confused:
I've been all over the engine and the service manual, and I can't find it, or find any illustration of it in the manual.
Can anyone out there point me in the right direction......
thanks
Problem is I can't find the darn thing!!!! :confused:
I've been all over the engine and the service manual, and I can't find it, or find any illustration of it in the manual.
Can anyone out there point me in the right direction......
thanks
Thread Starter
Drifting
Joined: Jun 2001
Posts: 1,697
Likes: 454
From: Mass Mass
Re: MAP Sensor On A 88 L98 (BobMachus)
I would tend to agree (seeing I can't find it) but what is the scan tool reading?
Before the supercharger it would read one value (say 2.33 volts) but different every day.
After I installed the supercharger it would change with mph.
Repair manual says it is for altitude correction.
Yes it started out as a carroll kit, but I've modified it since.
[Modified by SuperL98, 8:24 AM 7/7/2002]
Before the supercharger it would read one value (say 2.33 volts) but different every day.
After I installed the supercharger it would change with mph.
Repair manual says it is for altitude correction.
Yes it started out as a carroll kit, but I've modified it since.
[Modified by SuperL98, 8:24 AM 7/7/2002]
Melting Slicks
Joined: May 2000
Posts: 2,148
Likes: 1
From: Chandler AZ
Re: MAP Sensor On A 88 L98 (SuperL98)
From your sig picture, that kinda looks like a MAF sensor in the middle of your intake plumbing (between the two U-bends). I assume you're get varying MAF readings from the scan tool? I could believe a MAP to measure barometric pressure for altitude correction, and yes it would read one value, different each day. Ya know it looks like maybe there's air blowing against the sensing diaphragm- like that MAP is in the airstream- so higher mph causes increased pressure against it?
[Modified by gcrouse, 11:31 AM 7/8/2002]
[Modified by gcrouse, 11:31 AM 7/8/2002]
Pro
Joined: Dec 2001
Posts: 634
Likes: 0
From: Oregon
Re: MAP Sensor On A 88 L98 (SuperL98)
I turned up the boost and I think I blew this thing out, the readings use to change, now it just reads 2.33 volts all the time.
Problem is I can't find the darn thing!!!! :confused:
I've been all over the engine and the service manual, and I can't find it, or find any illustration of it in the manual.
Can anyone out there point me in the right direction......
thanks
Problem is I can't find the darn thing!!!! :confused:
I've been all over the engine and the service manual, and I can't find it, or find any illustration of it in the manual.
Can anyone out there point me in the right direction......
thanks
Drifting
Joined: Oct 1999
Posts: 1,722
Likes: 0
From: Gloucester Va
Re: MAP Sensor On A 88 L98 (884fun)
Unless you added a MAP sensor your car does not have one. You are most likely seeing MAF volts. If you pumped up the boost you most likely killed the sensor wire in the MAF. My friend TT callaway has this problem. Pull that black thing off that's in the middle of the intake and see if the wire looks OK. NOTE: This does not mean it is though.
Thread Starter
Drifting
Joined: Jun 2001
Posts: 1,697
Likes: 454
From: Mass Mass
Re: MAP Sensor On A 88 L98 (88_vette)
No, I log the MAF readout also (in grams/sec) and that still looks fine.
Car runs great, all the other sensor outputs look like they always did.
So it's not a problem, It's just an odd thing.
I had some odd idea that the above plot was actually the boost pressure in the intake.
I've had the top of the engine apart a bunch of times and have followed all the vacuum tubes, none go to any vacuum sensor I can see.
The sensor on the bottom of the intake plenum is the MAT sensor (I've relocated that to the supercharger ducting).
Still don't know what this is reading and why it would have changed?
I'll keep looking....
Car runs great, all the other sensor outputs look like they always did.
So it's not a problem, It's just an odd thing.
I had some odd idea that the above plot was actually the boost pressure in the intake.
I've had the top of the engine apart a bunch of times and have followed all the vacuum tubes, none go to any vacuum sensor I can see.
The sensor on the bottom of the intake plenum is the MAT sensor (I've relocated that to the supercharger ducting).
Still don't know what this is reading and why it would have changed?
I'll keep looking....
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Drifting
Joined: Oct 1999
Posts: 1,722
Likes: 0
From: Gloucester Va
Re: MAP Sensor On A 88 L98 (SuperL98)
What kind of scan software are you using? It really shouldn't show a MAP anything for your year car. Either way I wouldn't try to fix it if it's not broke. Plus you shouldn't have that MAP reading, so I wouldn't put much worry into it.
Melting Slicks
Joined: May 2000
Posts: 2,148
Likes: 1
From: Chandler AZ
Re: MAP Sensor On A 88 L98 (88_vette)
I agree- your scan tool was probably designed to work for both MAF/MAP engines; leaving the operator to read the correct one. Your ECM is probably just spitting out bogus numbers from an unused memory location. You might try asking in the ECM Tuning forum; Jeff probably knows...
