Where is your MAP sensor? did you hook it back up? i believe its on an intake runner clam shell somewhere.
Considering DD'ing 350k mile LB7?
- Thread starter fl0w3n
- Start date
Okay so after googling, no. I still have it attached to the Cali y bridge.
There’s three Baro sensors on a Cali lb7 and I thought you only needed one, the one under the main engine to body harness connections on the passenger side.
I didn’t realize the other one on the intake side was actually a MAP sensor. I won’t see the truck for another two weeks, but I don’t recall a spot to tie the MAP sensor into the Federal Y bridge?
Edit: okay now I’m real confused... I’m googling picture of LB7 MAPs and I’m realizing two things - my y bridge intake looks different than other federal intakes... and I don’t have a map sensor location.
If you look back at post 175 you can see how my y bridge is still angled up, while I’m seeing other federal y bridges turn flat to point level at the passenger side. There’s also only an intake heater port on mine, nothing else.
What’s going on?
https://www.duramaxdiesels.com/forum/showpost.php?p=1138310&postcount=175
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My federal Y bridge hooked straight up in place of a CA one, no new tubes required. I wonder if you have an aftermarket y bridge?
Edit: looked at your photo. I think you have a van y-bridge.
Edit: looked at your photo. I think you have a van y-bridge.
You have a 01 federal y bridge. 02-04 federal use a different style that includes the map sensor at the 45* bend that then has the boot attachment point horizontal, not pointing up at a 45* angle.
I did a little research on where your map sensor is before I asked the question and it seems there are two spots. One is on the intake clam shell on the pass side and other may be on the driver side. I guess the Cali emission used a vac hose that then had the map sensor off to the side somewhere. Not 100% sure there.
The sensor under the big bail connectors is strictly a baro sensor. All it does it feel barometric pressure.
I did a little research on where your map sensor is before I asked the question and it seems there are two spots. One is on the intake clam shell on the pass side and other may be on the driver side. I guess the Cali emission used a vac hose that then had the map sensor off to the side somewhere. Not 100% sure there.
The sensor under the big bail connectors is strictly a baro sensor. All it does it feel barometric pressure.
Damnit, that sucks. But that makes sense why I wasn’t finding the intake boot using 02 as model year.
I recall a sensor on the Cali two piece Y bridge that had a little plastic tube out the bottom. I don’t remember where the tube connected to though. It may have even been disconnected or easily fell off when I was taking the truck apart, which led me to thinking it was just another baro sensor.
Aah, OK. I basically only come across 2003-2007 trucks, explains why I've never see that version before.
The CA y bridge had a nipple that a hose to the MAP sensor hooked to. The MAP sensor mounted off one of the stupid brackets on the top of the top piece of the y bridge. The 2002+ federal y bridge has a hole for the MAP sensor. You just get a MAP sensor seal for the CA sensor (the same seal is used on the LS MAP, so you can find them at the junkyard for free usually). Or you can drill and tap, add a hose nipple, and use the same setup as CA for the sensor. Not sure where the stock sensor was on a 2001.
Edit: it sure looks like the boost sensor just pokes into the passenger side intake clamshell. See attached picture.
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He has a weird one as its a 2002 cali emission. i cant find crap on MAP location for it. least nothing definitive but thats just using google search.
the only reason i know about the 01 federal y bridge is that when i bought my twin kit from Trent, it was originally built on his 01 lb7 and he had the short y bridge. So the cold side pipe needed cutting and welding to fit to my 02 long y bridge.
the only reason i know about the 01 federal y bridge is that when i bought my twin kit from Trent, it was originally built on his 01 lb7 and he had the short y bridge. So the cold side pipe needed cutting and welding to fit to my 02 long y bridge.
So I did a little research and it looks like the 01 had the MAP sensor on the passenger side intake runner.
Looks like I got myself into a pickle
I think my best bet is trying to find an 02-04 Federal y bridge and swapping that in. But that means taking the fricken wiring harness and portions of the fuel system back apart.
Damnit.
Looks like I got myself into a pickle
I think my best bet is trying to find an 02-04 Federal y bridge and swapping that in. But that means taking the fricken wiring harness and portions of the fuel system back apart.
Damnit.
and i would suggest finding a cold side pipe that matches that y-bridge unless the one you have will work.
I think the one I have will work with an 02-04 Federal bridge. But it will not work with this 01.
I just spoke with ProFab because their Y bridge doesn’t come pre-tapped for MAP.
Rick said that it doesn’t matter the location of the sensor as long as it’s in the pressurized portion. So I think I’m just going to drill an 1/8” hole and figure out how to secure the map to it.
Rick said that it doesn’t matter the location of the sensor as long as it’s in the pressurized portion. So I think I’m just going to drill an 1/8” hole and figure out how to secure the map to it.
you need to put the rubber grommet on the end of the sensor. its the same sensor as the 02-04 minus the rubber grommet that seals it to the inside of the bridge. without it, you will get a boost leak and possibly inaccruate readings at the MAP. its larger than 1/8" by far.
y-bridge, intake clam shell, or cold side pipe all work for what you need.
if yours used a nipple off the intake clam shell to a vac line, just hook it back up that way unless you ditched the clam shell that came on the truck. its not going to be bolted into the actual intake clam shell. if you did reuse it, at min you will need a plug on that nipple or you will have a boost leak.
When you say clamshell, what are you referring to?
Other than swapping to the 01 Y bridge and 01 intercooler cold side, the intake is stock.
1/8” did sound small to me too.
Mine did have the nipple and vac line, because I remember seeing the vac line off the sensor in my parts stash. But I don’t recall where it hooked into and I won’t see the truck for another week so I can’t check to see.
Intake clam shell. its the part the y-bridge connects too, feeds air into them and then connects to the heads.
The clamshell is the intake manifold.
IMO just put a hose barb on the y-bridge and mount the sensor remotely somewhere, like the original CA setup. Less chance of sealing issues trying to drill exactly the right size hole to fit the MAP and the rubber boot.
I’ll have to check when I’m near the truck again. I guess I was assuming that the stock location on my 02 Cali was the y bridge, but then that wouldn’t make sense if I really did see the vacuum tube.
So if I did see the vacuum tube, it’s hooked up to the clamshell and then I don’t have any issues. Just remount like stock.
So if I did see the vacuum tube, it’s hooked up to the clamshell and then I don’t have any issues. Just remount like stock.
correct. but as both dave and i said, its not real clear where factory mounting was. when you get back, look around it and go from there.
