1989 CADILLAC HEARSE MAP SENSOR

  • Tiny
  • carolrae
  • 1989 Cadillac Hearse

Engine Performance problem
1989 Cadillac Hearse V8 All Wheel Drive Automatic 72,000 miles

we did a tune up on my caddy and immediately check engine came on. We had it tested. Said map sensor went out. After 3 weeks to find RIGHT ONE and had to redo map sensor AND redo new harness. The light STILL comes on. We undid the battery for a half hour and put it back together and lite STILL comes on and runs worse than ever. Idol off or timming. Any suggestions? I need help

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Thursday, August 19th, 2010 AT 7:21 AM

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  • Tiny
  • Wrenchtech
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  • 20,286 posts

Do you have a good vacuum supply connected to it?

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Thursday, August 19th, 2010 AT 7:31 AM
  • Tiny
  • carolrae
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Do you mean from the little hose that gets connected to the mapsensor itself underneath? I havent tried it. Do I try it with car running? Im a female and ive been workin right along the man workin on my tuneup. So I do know the hose you might be talkin about. How can I tell? Put paper to it and see if it sucks to it>?

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Thursday, August 19th, 2010 AT 7:37 AM
  • Tiny
  • Wrenchtech
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  • 20,286 posts

That's what a MAP sensor does. It measures he engine vacuum so it has to have a good sealed line to the vacuum supply. You should be using a vacuum gauge to measure it. If that's not the problem, then your going to need a scan tool to read the sensor data in the ECM. You could have a wiring problem.

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Thursday, August 19th, 2010 AT 7:55 AM
  • Tiny
  • carolrae
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Thanx for advice. Immediatly after a tune up the map sensor gave problems. We replaced original one with a whole new senor type and harness cus the 1989 piece was obsolete. So they say cuis it took 3 weeks of searching for part. We will heck the vacume and wires to night. THANK YOU! So much for helpin us out here. Hugs

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Thursday, August 19th, 2010 AT 8:11 AM
  • Tiny
  • cferry1
  • Member

Dear carolrae -

It is possible that my 1990 Cadillac is similar to your 1990 Cadillac Hearst. I am sure these vehicles are becoming somewhat obsolete. I would be interested in talking with you about your vehicle. I may be contacted at email "ferrycha@hotmail. Com"

Thank You
cferry1

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Friday, January 20th, 2012 AT 8:46 AM

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