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Tech501
Tech501, Auto Service Technician
Category: Car
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Experience:  38 years exp, ASE Mastertech with L1 Advanced Engine performance
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1990 buick Park Avenue: replace the map sencor..looked under the hood

Customer Question

I need to replace the map sencor on my 1990 buick Park Avenue. I have looked under the hood and I can't locate the sencor please tell me where it is
Submitted: 11 years ago.
Category: Car
Expert:  Tech501 replied 11 years ago.
 What engine. Many don't use a MAP. How do you know you need one?
Customer: replied 11 years ago.
Reply to Tech501's Post: 3800 v-6 fwd i bought a new map sencor
Expert:  Tech501 replied 11 years ago.
  This may or may not match your type. If you have the sensor, you should be able to see it once you remove the plastic engine cover.

Manifold Air Pressure (MAP) Sensor


See Figures 4, 5 and 6


The MAP sensor measures changes in the intake manifold pressure which result from engine load and speed changes, and converts this to a voltage output. MAP is the opposite of what you would read with a vacuum gauge. When manifold pressure is high, vacuum is low. The ECM uses the MAP sensor to control fuel delivery and ignition timing. A failure in this circuit should set a trouble code 34. To test the MAP sensor, have the ignition ON with the engine not running. Check voltage from sensor terminal B to A. It should be within the value specified in the chart. Apply 10 inches of vacuum to the sensor with a vacuum pump. There should be a 1.2-2.3 voltage change. If the sensor did not meet either of these requirements, have the system diagnosed and repaired by a qualified technician.


Click image to see an enlarged view
Fig. 4: MAP sensor location on TBI engines



Click image to see an enlarged view
Fig. 5: MAP sensor values (Non-Turbo)



Click image to see an enlarged view
Fig. 6: MAP sensor values (Turbo)






Customer: replied 11 years ago.
Sorry but this doesn't help me. I have looked every where i can I bought a haynes manual and it don't show where the map sencor isi have looked by my air box it is not there. I have removed all the plastic coverings on my engine and firewall. I didn't find it there. I was wondering if my map sencor was by the computer so i looked there. In the Haynes manual it shows a picture of a map sencor and it looks like it is mounted somewhere like a fire wall of inner fender but. on the Picture of the engine it isn't numbered. i need to know a specific location please.
Expert:  Tech501 replied 11 years ago.
 It reads from vacuum so it has to be connected to the intake somehow. Some of them are integrated into a small housing on the passenger end of the intake manifold. Look for a 3 wire plug going into it.
Customer: replied 11 years ago.
sorry but this still doesn't help me. I am looking for an exact location.
Expert:  Tech501 replied 11 years ago.
 I'm sorry but I can't find an accurate picture for you and the engines vary some. This one should be on the passenger side of the manifold and I remember it being encased in a little housing. If your not able to locate this by just matching up the part, maybe you should consider having someone else do the job for you.
Customer: replied 11 years ago.
You are talking about 1996 and newer 3800 engines the map sencor is on the passanger side just above the PCV valve. The map sencor i am looking for is rectangle with a three pronged outlet on the same side as the vacume lead. On a 1990 buick park avenue fwd with a 3800 engine.
Expert:  Tech501 replied 11 years ago.
 Does the car have a Mass Air Flow sensor in the intake?
Customer: replied 11 years ago.
Reply to Tech501's Post: The Mass flow ait sencor in on the driver side of the intake right before the trottle body. after the air box.
Expert:  Tech501 replied 11 years ago.
 If the car has a mass air flow sensor, it doesn't have a MAP sensor. They both do the same job.
Customer: replied 11 years ago.
Reply to Tech501's Post: Then Why could i buy a map sencor at a parts store
Expert:  Tech501 replied 11 years ago.

 [Quote]Then Why could i buy a map sencor at a parts store [/QUOTE]


Because sometimes parts people can't read and sometimes parts books are just too general. BotXXXXX XXXXXne is the car isn't equipped with both.

Customer: replied 11 years ago.
I don't belive you. I will call down to the dealership tommarow and if you are right i will except your answer.
Expert:  Tech501 replied 11 years ago.

 Good idea.  


I'll be looking forward to your accept.

Expert:  jon_050 replied 11 years ago.
 Where did you buy the map sensor?
Customer: replied 11 years ago.
Advanced
Expert:  Tech501 replied 11 years ago.

 That explains the stupid counterman scenerio.


He had a paper route last week.

Tech501, Auto Service Technician
Category: Car
Satisfied Customers: 747
Experience: 38 years exp, ASE Mastertech with L1 Advanced Engine performance
Tech501 and 8 other Car Specialists are ready to help you
Expert:  jon_050 replied 11 years ago.
Click to view enlarged imageThis is a picture of the sensor you likely bought. It's designed for a vacuum hose. If you have the emmissions sticker under hood it will show the map sensor (or lack of) on the vacuum diagram.  
Customer: replied 11 years ago.
I looked and i a wrong about having a mass air flow sencor i have a IAT sencor. And that is the part i am looking for the location of
Expert:  Tech501 replied 11 years ago.

 Wow!, You gotta  be kidding. After all this your looking for an IAT?


I've give you one more try. The IAT will be in the intake before the throttle body. Some are right in the snorkal hose and some are in the air filter box. Most have a 2 wire plug and you can usually just pull the sensor out.

Customer: replied 11 years ago.
No I must have said something wrong but i don't have a Mass air flow sencor i have a map sencor and the one in the picture is the one i am looking for.
Expert:  Tech501 replied 11 years ago.
 I give up, You don't know what your looking for.
Customer: replied 11 years ago.
thanks for trying to help
Customer: replied 11 years ago.
Reply to Tech501's Post: I just excepted cause i was tired of you not beliveing me
Expert:  Tech501 replied 11 years ago.
 It's not that I don't believe you, I just can't get through to you with some basic help. You have the sensor in your hand, if it is a MAP sensor, it will be mounted on the engine in a conspicuous place and shouldn't be that hard to recognize. It HAS to be connected to the intake, so that limits where it can be mounted. If you have a MAF sensor, it will not have a MAP. The pictures I found didn't match your car. I really don't know what else to do to help you. If you have a digital camers, take a photograph of the top of the engine with any covers removed and I'll try to pick it out.

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