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Someone else with MAP issues.


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I am posting this here because it was sent to me in a PM, and though I answered the best I could, I felt it would benefit the original poster to have this posted in the forum instead.

Ion user_popup.png

  • Car Model/Year: 1994 ETC

Sent 15 February 2010 - 09:21 PM

Hi there...

I've been having intermittent stalling issues with my 94 eldo for literally years and have thrown thousands at the problem and have to date, still not solved it! I just got it back from a local shop where I deposited another $1200.00. After a week, MAP errors return. I've replaced it (MAP) many times through the years and just about all other sensors 'cept O2's and had many other things replaced in the fuel system. Has your last MAP replacement done the trick for you? Have you learned of any other fixes that might directly and finally solve the intermittent stalling issues?

-Don

CarlaValentine user_popup.png

Sent 15 February 2010 - 10:28 PM

It took me a while to figure out what was wrong. I had a stalling problem. No codes were showing up for the MAP sensor. I changed the spark plugs, wires, cleaned the ignition control module, checked all my vacuum lines...nothing worked. Then I finally started getting a MAP sensor code.

I had to put a new one in, and that solved my problems. The thing is though, when I had the manifold cover off to check/change the MAP sensor, I also noticed there was a bare spot in the wiring that goes to it. I sealed the bare spot with thermal electrical tape. (plain old electrical tape won't work. it gets too hot under there. It also is not oil resistant.) I have had no problems since.

I would suggest you check over the wiring really well where the MAP sensor connection is.

What codes are you getting on the diagnostics?

There is also a way to monitor the MAP sensor to see if it's working correctly using the onboard diagnostics. If you don't know how to do it, let me know. I can tell you how. It's pretty simple.

Ion user_popup.png

  • Car Model/Year: 1994 ETC

Sent Yesterday, 11:44 PM

Hi and thanks for your reply!

I don't know if you're aware, but I have a '94 Eldorado, with the original PCM's, resulting in the original codes. I'll give you the most relevant ones I keep getting:

P095 = engine stall.

P032 = opem MAP sensor signal

I've had this of and on problem for many years and would love to finally learn why no local mechanics can figure it out. 4 have tried and failed and cost me literally thousands of dollars. I know darn well, the car isn't worth what I've put into it trying to track this down!

I paid a local shop another $100.00 to test the MAP. They said while idling, it was fluctuating between 1 and 2. I don't recall the unit of measure stated, but they said they readings should remain at 1 and not fluctuate. This is the same shop I just paid $1200.00 to fix my intermittent stalling issue. After a few hundred miles, the exact same problem returned! They replaced lower and upper intake manifold gaskets, poured some sort of oil and fuel resistent goo into a wire harness housing that, according to them had deteriorated because fuel had saturated the original one. Inside the deteriorated one they showed me how exposed wires were present, potentially causing shorts, so this made sense to me, however, didn't solve the problem. They just quoted me $450.00 to replace the MAP!!! I know they cost around $50.00 and I've replaced one myself in the past. WTF? Is this legalized rape? I told them I'd pickup the car and do it myself. I'll be

sure to check the wiring for any possible shorts.

I would be interested in learning how / if I can use my 1994 Eldo's OBD to monitor the MAP's performance and what are considered normal parameters. Do you know what that would be?

Thanks in advance!

-Don

CarlaValentine user_popup.png

  • Car Model/Year: 1994 Eldorado 154K Miles
  • Engine: Northstar 4.6L V8 (LD8/L37)

Sent Today, 12:03 AM

I most certainly do.

Here's how you monitor the MAP sensor.

Run the OBD just as you would to check your codes (hold the "OFF" and "WARMER" buttons down on the climate control until everything lights up). After all codes have been displayed, you will see "PCM?" show up on the driver information center.

Once it does, you want to push the "up" button (not the warmer button) on the climate control. You should then see "PCM DATA" show up on the display.

From there, you want to push the "up" button again. You should then see "PD01" display with a number before it. This is the setting to monitor your throttle position sensor. Pushing the "up" button again will display "PD02" with a number before it (if not, then push the down button instead. I may have it backwards, but either way it will scroll through all the different DATA displays as you push up or down). PD02 is the monitor for your MAP sensor. Without the car running, but with the key on, the number should read between 85-105. This measurement is in KiloPascals (kPa, barometric pressure). If the number reads BELOW 85, then there is a problem in either the wiring to the MAP sensor, or with the sensor itself.

Prior to replacing mine, my reading was 10 kPa.

After replacing it and fixing the bare wires, it reads perfect at 99 kPa.

I hope this helps you.

I am going to see about adding this conversation to the boards, as I know everyone on here prefers that questions get posted there rather than private messages.

Also, there may be other advice that someone else could offer you to help out with your problem.

If I can be of any more help at all, don't be afraid to ask.

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Carla and I chatted about this -- I love the new conversation system for personal messages, but there is not a great automatic way to convert from the conversation system to a new topic. So she copied the conversation so far into this topic (good).

Generally if you have questions about your Cadillac you are best off posting them to the forum. Private conversations are good for specifics sometimes like when you need to get someone's address. But posting issues in the public forum allows multiple inputs, which is where our Cadillac Community shines.

Bruce

2016 Cadillac ATS-V gray/black

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GM does have a bulletin about some goofy 1994 PCM's floating around. The bad PCM's set false MAP codes.

False PO71:

THE NORTHSTAR'S PCM HAS BEEN REDESIGNED TO CORRECT THIS INTERNAL CIRCUIT "NOISE" CONDITION. TO DIAGNOSE AND REPAIR THE ABOVE CONDITIONS, PERFORM THE FOLLOWING PROCEDURES:

1. IF THE VEHICLE HAS MULTIPLE DIAGNOSTIC TROUBLE CODES AND DTC PO71, DIAGNOSE AND REPAIR THE **OTHER** DIAGNOSTIC TROUBLE CODES FIRST.

2. IF THERE WAS A BACKFIRE OR STALL, DIAGNOSE THAT CONDITION AS OUTLINED IN SECTION 6E-B OF THE SERVICE MANUAL.

3. IF THE VEHICLE IS A 1993 AND HAD A LOSS OF POWER AFTER AN EXTENDED HIGHWAY DRIVE, PERFORM THE PROCEDURES OUTLINED IN CORPORATE BULLETIN 216306 (GM OF CANADA 93-6-118; CADILLAC T-93-49 IN GROUP 6E).

4. IF THE VEHICLE IS A 1993, PERFORM THE PROCEDURES OUTLINED IN CORPORATE BULLETIN 316005 (GM OF CANADA 93-6-118; CADILLAC T-93-101 IN GROUP 6E).

5. IF THE VEHICLE HAS A HARSH CHUGGLE DURING HIGHWAY DRIVING, SURGE, MISS OR HESITATION ACCOMPANIED BY A HISTORY DTC PO71, INSPECT THE SERVICE PART NUMBER ON THE PCM. IF IT IS ONE OF THE PRESENT SERVICE PART NUMBERS LISTED BELOW, REPLACE THE PCM USING ONE OF THE APPROPRIATE **NEW** SERVICE PART NUMBERS LISTED BELOW.

6. IF THE PCM HAS THE NEW SERVICE PART NUMBER, FOLLOW THE APPROPRIATE SERVICE INFORMATION MANUAL PROCEDURES FOR DTC PO71 AND INSPECT THE MAP SENSOR CONNECTIONS AND CIRCUITRY.

PARTS INFORMATION:

PRESENT NEW DTC PO71 DESCRIPTION APPLICATIONS SERVICE P/N SERVICE P/N ----------- ------------ ----------- ------------- POWERTRAIN CONTROL MODULE 1993 V WITHOUT V4J 16159277 16207768 POWERTRAIN CONTROL MODULE 1993 V,E,K WITH V4J 16180517 16197429 POWERTRAIN CONTROL MODULE 1994 E/K + KSP 16196402 16197429

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