Car will not run

Tiny
SLUFOOT51
  • MEMBER
  • 1991 CHEVROLET CAMARO
  • 5.0L
  • V8
  • 2WD
  • MANUAL
  • 110,000 MILES
Every sensor and fuel pump and new injectors has been replaced? Unplug map sensor it runs fine. Have replaced two to three sensors?
Tuesday, June 25th, 2019 AT 11:26 AM

5 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,882 POSTS
Does the car have good power when the sensor is unplugged? You could have a plugged catalytic converter. lets run the codes to see what comes up. here is a guide to help you:

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

Please run down this guide and report back.
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Wednesday, June 26th, 2019 AT 11:54 AM
Tiny
SLUFOOT51
  • MEMBER
  • 1 POST
Car gives no codes.
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Thursday, June 27th, 2019 AT 10:21 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,882 POSTS
It sounds like the PCM is out I would get a used/rebuilt one and plug it in to see what happens here is the location and instructions below.

NOTE: Service of the ECM should normally consist of ECM or MEM-CAL replacement.

When replacing a production Computer with a service Computer, transfer the broadcast code and production number from the production unit to the service unit. Also during replacement, the PROM, CALPACK, and if equipped, the MEMCAL must be removed from the Computer being replaced and transferred to the new unit. Refer to PROM, CALPACK and MEMCAL in this section for replacement procedures.

CAUTION:
To prevent internal ECM damage, the ignition must be OFF when disconnecting or reconnecting power to the ECM (for example, battery cable, ECM pigtail, ECM fuse, jumper cables, etc.).
To prevent possible Electrostatic Discharge damage to the PROM, CAL-PACK or MEM-CAL, DO NOT touch the component leads, and DO NOT remove the integrated circuit from the carrier.

REMOVAL:

1. Disconnect the negative battery cable.
2. Remove the glove compartment.
3. Disconnect the electrical connectors from the ECM.
4. Remove the ECM mounting hardware.
5. Remove the ECM from the passenger compartment.
6. Remove the access cover.
7. Carefully remove the MEM-CAL.
8. Remove the new ECM from its packaging and check the service number to make sure it is the same as the defective ECM.
9. Remove the access cover.

INSTALLATION:

1. Install the MEM-CAL in the MEM-CAL socket.
CAUTION: Press only on the ends of the MEM-CAL. Small notches in the MEM-CAL must be aligned with the small notches in the MEM-CAL socket. Press on the ends of the MEM-CAL until the retaining clips snap into the ends of the MEM-CAL. DO NOT press on the middle of the MEM-CAL, only on the ends.
2. Install the access cover on the ECM.
3. Install the ECM in the passenger compartment.
4. Connect the electrical connectors to the ECM.
5. Install the glove compartment.
6. Connect the negative battery cable.

FUNCTIONAL CHECK:

1. Turn the ignition ON.
2. Enter diagnostics.
A. Code 12 should flash four times (If no other codes are present). This indicates the MEM-CAL is installed properly and the ECM is functioning.
B. If Trouble Codes 41, 42, 43, or 51 occur, or if the "Service Engine Soon" light is ON constantly with no codes, the MEM-CAL is not fully seated or is defective.
If not fully seated, press firmly on the ends of the MEM-CAL.
If it is necessary to remove the MEM-CAL, follow the previous removal instructions.

NOTE: Before starting the engine, follow the "Idle Learn Procedure" as follows.
1. Install the Tech 1 "Scan" tool or equivalent.
2. Turn the ignition ON, with engine OFF.
3. Select IAC System, then Idle Learn in the Misc. Test mode.
4. Place the transaxle in PARK or NEUTRAL.
5. Proceed with Idle Learn as directed.

Check out the diagrams (Below). Please let us know what happens.
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Thursday, June 27th, 2019 AT 10:25 AM
Tiny
SLUFOOT51
  • MEMBER
  • 1 POST
Car has a new computer installed. Car has vacuum problem. Could it worn lobe on cam?
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Saturday, June 29th, 2019 AT 3:49 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,882 POSTS
Yes it can. also the head gasket can be blown between cylinders. lets do a compression test to see if the engine is okay. here is a guide:

https://www.2carpros.com/articles/how-to-test-engine-compression

Please run down this guide and report back.
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Saturday, June 29th, 2019 AT 3:51 PM

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