RUSH2112

I found the MAP Sensor and went to remove it per the Haynes book instructions which state:

1) Remove elecritcal connector from sensor
2) Remove vacuum connector from sensor
3) Remove bolts that hold sensor to the firewall.
4) Replace sensor using above steps.

After locating my MAP sensor on the firewall and disconnecting the electrical connector, I found that I had NO VACUMM LINE connected to the MAP sensor. I spent alot of time looking for a loose or dangling vaccum line, but couldnt find one.
This might just be my whole problem. So either:

A) The vacuum line is hanging down somewhere OR
B) It fell off completely.....

So my question is, where does the vacuum line connect TO from the MAP sensor????
Please, someone help me.

roundman

should be a larger vacuum hose, like 3/8" ID and it connects underneath the upper intake manifold at the back side to a large hose nipple screwed into the back side of the upper intake. it's hard to see but you should be able to feel it with your fingers under there.

mdvaldosta

Your map sensor doesnt have a vacuum line unless you've got a pre '89 Speed density 5.0, on mass air cars the MAP sensor is actually a BAP sensor and reads the outside air pressure

brundz

damn...the motor in my car is from a 93, it has an aftermarket intake wtih no mass air...but it does have the map on the firewall but maybe thats just suppose to be a map sensor and the stupid kid before me just wanted an intake...this is confusing?

brundz

will the car run with a bad map sensor?

dman302

If your running an SD computer with no maf then the MAP sensor on the firewall must have a vac line leading from the manifold to the port on the MAP. If your running MAF set up then you want the MAP vac port venting to the atmosphere and any line on the manifold designated for the MAP to be capped off. If your running an MAF style ECU and no MAF sensor then you have a different bag of problems.

brundz

aright that makes sense. theres a vacuum line going to the map and theres no maf on the aftermarket intake so i'm assuming its running as a map car. throttle body looks alot different then ones i've seen pictured. the tps sits on the top of the throttle body with the iac to the right side. the tps has a hole in the top of it that i'm assuming shouldn't be there. anybody have a picture of this type of throttle body for reference or a picture of what various tps sensors look like?

dman302

Maf sensor would be situated on the air inlet pipe if present...it is a plug in sensor (box) aprox 3x3 inches...not located on the intake. Some info or pics of your current car yr and or setup would be of assistance. TPS usually has no holes in it...but again hard to call without visual.

brundz

ok. i'm at work right now so i cant get pics on the internet. it definetly doesn't have a maf. its just a chrome intake tube with a cone filter on the end. it goes straight to the throttle body. the motor was swapped in but this is what i was told about it. its a 93 5.0 ho motor. the car is an 88 that was a 4 cyl. there is a map sensor on the firewall with a vacuum line going to it so i dont think its a maf car. the tps sensor sits on the top of the throttle body and it has a hole on the top of it. and the iac is to the right of the throttle body. sorry i cant post pictures to help you identify

dman302

Yr of motor won't be an issue...they are all just 5.0 engines. What you need to confirm is that the computer being used (sounds like the car is set up for speed density) is a speed density computer...if you can get the numbers or pic of the ECU (passenger side kick panel) then you can be sure your working right from that starting point. A MAF style computer will definately have issues without a MAF reading being sent to it so check that first when you get home...the ECU will have a label on it indicating the part number (ex MAF computers begin A9- for our mustangs.