MAP Sensor? Code 31. Does my car have one? - Toyota Nation Forum : Toyota Car and Truck Forums

94celica94 · 02-07-2005, 08:00 PM

After running for about 30-40 minutes the car will buck at low speeds and stall easily. At idle the engine will die if you turn on the A/C or heat. I did replace the Fuel filter with no difference.

I do not have a check engine light. I did pull codes and the only one it gave me was code 31 - "Manifold Absolute Pressure Sensor Signal"

Autozone and the Toyota parts counter tell me this car does not have one. A mechanic in the Toyota service dept. told me that the celica does have a MAP from 1993 1/2 on up. I have a '94 with a 1.8L.

Do I have a MAP Sensor?
Can they be tested?
Where can I buy one?
Could a bad MAP be the cause of my drivability problem?

TIA.

94celica94 · 02-07-2005, 08:02 PM

Forgot to mention.....I took off the TPS and it tested good at Autozone.

fredk · 02-07-2005, 09:24 PM

easiest way to find out is look at the vacuum diagram on the underside of the hood and see if you have one

silverstreakin · 02-07-2005, 10:37 PM

what engine

94celica94 · 02-07-2005, 11:03 PM

Quote:

Originally Posted by silverstreakin

what engine

7A-FE

Pineapple · 02-08-2005, 08:56 AM

A/C idle up VSV maybe bad or other idling problem. Check idle and timing first. Also check for vaccum leak.
MAP should be on firewall with one vaccum hose to passanger side of intake manifold. Don't think its MAP, car won't even run if MAP is bad. Maybe lose wire. Try clean the MAP vaccum hose with throttle body cleaner.

94celica94 · 02-08-2005, 11:48 PM

Found the MAP and the vac. hose that runs from it to the intake looks good. No cracks, air blows through it fine. Between the vac. hose and the intake was a little diaphragm/valve thing circled in the above pic. It screws into the intake with about a 3/4" wrench. I have the vac. line disconnected to get a better shot in the picture.

What is it?
Can you tell if they are bad?
Do these fail?
I took it off and can blow air through it w/my mouth. Is this normal?
How much do these cost?

fredk · 02-09-2005, 05:41 AM

its a vac delay valve, take it off and put your mouth on it to see whitch way it delays

94celica94 · 02-10-2005, 10:01 PM

I took it off the intake and can blow air through it with my mouth both ways. There is very little resistance to the air I am blowing through. Does that mean it is bad? Would a bad valve set off a code 31? Can I get this at Autozone or is this a dealer part?

fredk · 02-10-2005, 10:37 PM

take the old one to the dealer