C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

MAP Sensor on 91 [Question]

Thread Tools
 
Search this Thread
 
Old Apr 11, 2002 | 12:02 PM
  #1  
-=Jeff=-'s Avatar
-=Jeff=-
Thread Starter
Race Director
25 Year Member
All Eyes On Me
Photogenic
Community Favorite
 
Joined: Mar 1999
Posts: 12,597
Likes: 237
From: Bartlett Illinois
Default MAP Sensor on 91 [Question]

how do you know if it is bad or not? what symptoms will the car have if this sensor goes bad?

Thanks



[Modified by Marcho Polo, 10:04 AM 4/11/2002]
Reply
Old Apr 11, 2002 | 01:04 PM
  #2  
gcrouse's Avatar
gcrouse
Melting Slicks
10 Year Member
 
Joined: May 2000
Posts: 2,148
Likes: 1
From: Chandler AZ
Default Re: MAP Sensor on 91 [Question] (-=Jeff=-)

If it's completely toast your engine won't even run. The MAP sensor measures engine load, and that plus rpm are primary inputs to the ECM to look up spark/fuel maps. If it's sort of working, or if the vac hose is leaking, etc, it might barely run, hunting up and down for idle, stall when you open the throttle.

If you have a hand vacuum pump/bleeder and a multimeter you could test it.
Reply
Old Apr 11, 2002 | 01:13 PM
  #3  
ZylaRace's Avatar
ZylaRace
Drifting
10 Year Member
 
Joined: Mar 1999
Posts: 1,931
Likes: 1
From: Norcross GA
Default Re: MAP Sensor on 91 [Question] (gcrouse)

A bad MAP can totally hose the engine operation. It is the main ECM input to control fuel output.
Totally bad, and you will get a TCode.
Reply
Old Apr 11, 2002 | 06:42 PM
  #4  
devilfish's Avatar
devilfish
Melting Slicks
15 Year Member
 
Joined: Oct 2000
Posts: 3,010
Likes: 1
From: Sweden/Stockholm
Default Re: MAP Sensor on 91 [Question] (ZylaRace)

the engine will run without the MAP. Mine did.. :) But you will get a "service engine soon" light.
Reply
Old Apr 11, 2002 | 08:31 PM
  #5  
VAHROOM's Avatar
VAHROOM
Burning Brakes
20 Year Member
 
Joined: Apr 2000
Posts: 980
Likes: 2
From: Chandler AZ
Default Re: MAP Sensor on 91 [Question] (devilfish)

While it is true that the engine will run. It will go to the "limp home mode". As we all know limp is bad. (Or so I hear)

Will a MAP on the way out cause poor performance?


[Modified by 90_roadster, 6:32 PM 4/11/2002]
Reply
Old Apr 21, 2002 | 04:53 PM
  #6  
VAHROOM's Avatar
VAHROOM
Burning Brakes
20 Year Member
 
Joined: Apr 2000
Posts: 980
Likes: 2
From: Chandler AZ
Default Re: MAP Sensor on 91 [Question] (90_roadster)

Well will it?
Reply
Old Apr 21, 2002 | 07:23 PM
  #7  
-=Jeff=-'s Avatar
-=Jeff=-
Thread Starter
Race Director
25 Year Member
All Eyes On Me
Photogenic
Community Favorite
 
Joined: Mar 1999
Posts: 12,597
Likes: 237
From: Bartlett Illinois
Default Re: MAP Sensor on 91 [Question] (90_roadster)

While it is true that the engine will run. It will go to the "limp home mode". As we all know limp is bad. (Or so I hear)

Will a MAP on the way out cause poor performance?


[Modified by 90_roadster, 6:32 PM 4/11/2002]
I don't know.. but my trouble was my VE tables in my PROM.. stock tables and my set-up don't like each other :)
Reply
Old Apr 21, 2002 | 07:53 PM
  #8  
VAHROOM's Avatar
VAHROOM
Burning Brakes
20 Year Member
 
Joined: Apr 2000
Posts: 980
Likes: 2
From: Chandler AZ
Default Re: MAP Sensor on 91 [Question] (-=Jeff=-)

Hahahaha thanks Jeff. That was my way of getting it back to the top.

I am glad you found the root cause of your problem.
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

 Michael S. Palmer
story-1

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-2

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-3

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-4

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-5

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-6

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-7

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-8

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-9

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
Old Apr 21, 2002 | 11:12 PM
  #9  
Sam Lam's Avatar
Sam Lam
Melting Slicks
20 Year Member
 
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
Default Re: MAP Sensor on 91 [Question] (-=Jeff=-)

Jeff: It gets darn expensive replacing sensors when you think they "may" be going bad. There is another altenative that is not quite as expensive as just buying a new one and see what happens. Mid America Direct sells sensor testors for about $12 to $15 depending on what sensor you suspect. These along with a good Volt/Ohm meter will "tell the real story". I just bought a set of testers for my '89 for about $85 total. I had a very rough idle and the sensor testors led me to a new IAC motor/valve and my problem was solved!
Regards, Sam
Reply

Get notified of new replies

To MAP Sensor on 91 [Question]





All times are GMT -4. The time now is 05:01 PM.

story-0
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-1
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-2
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-3
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-4
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-5
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-6
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-7
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-8
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-9
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE