Electric problems...help needed.

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ewg302

New Member

May 21, 2005

6

0

1

Florida

Dec 16, 2008

#1

• Dec 16, 2008

• #1

I have a few gremlins....... One is that the factory tach just decides to dead at various times while driving, there doesn't seem to be any rhyme or reason to it. The autometer works fine. My worry is that this is an indication of some type of electrical issue. I have changed out the gauge cluster and still have the issue. Has anyone else had this issue?


The car also suffers from the typical electrical drain from sitting. I have put a battery tender on it to help. I am having a problem with the cars consistency. It runs great one day and backfires and misses the next... is the battery a factor in the cars tune? My battery just went bad, could that have been messing with the ignition system?

Thanks in advance..........

 

94GTCoupe

10 Year Member

May 7, 2006

1,412

92

79

CA

Dec 16, 2008

#2

• Dec 16, 2008

• #2

could try checking your ground wires.
at the batt,engine to body,ect...,replace as needed.would'nt hurt to add a few.
bad grounds can cause lots of problems.

as for the tach,make sure the connections at the back of the cluster are clean and tight.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

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129

Dec 16, 2008

#3

• Dec 16, 2008

• #3

The EEC uses a 5 volt reference, which accomodates ebbs and flows in power output. Otherwise, the threshold for other systems is 10.5V. This simply does not sound like it' part of your issue. Check codes to see if something is logged (regarding the tach and related issues).

For the drain, put a meter in series with your neg battery post and cable, with everything off on the car, and see what your meter reads.

 

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ewg302

New Member

May 21, 2005

6

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1

Florida

Dec 16, 2008

#4

• Dec 16, 2008

• #4

HISSIN50 said:

The EEC uses a 5 volt reference, which accomodates ebbs and flows in power output. Otherwise, the threshold for other systems is 10.5V. This simply does not sound like it' part of your issue. Check codes to see if something is logged (regarding the tach and related issues).

For the drain, put a meter in series with your neg battery post and cable, with everything off on the car, and see what your meter reads.

Click to expand...

Will the computer show codes if the check engine light is not on? I was always under the impression that codes were only associated with the light being on.....

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

31,179

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Dec 17, 2008

#5

• Dec 17, 2008

• #5

ewg302 said:

Will the computer show codes if the check engine light is not on? I was always under the impression that codes were only associated with the light being on.....

Click to expand...

Yep, you can definitely log codes without ever illuminating the CEL. Hard faults (issues that cause the EEC to run in FMEM, etc) will light it up non-stop, but lesser issues can cause an intermittant light or no light at all.

 

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ewg302

New Member

May 21, 2005

6

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1

Florida

Dec 17, 2008

#6

• Dec 17, 2008

• #6

Usually I go to autozone and have them read the codes that turn on the light on all my other cars. Would they be able to find these codes with their scan tool as well? I would love to get these issues straightened out.......

What is does FMEM stand for?

 

hotcobra03

Active Member

Nov 29, 1999

969

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39

poteet,tx

Dec 17, 2008

#7

• Dec 17, 2008

• #7

FMEM

ewg302 said:

Usually I go to autozone and have them read the codes that turn on the light on all my other cars. Would they be able to find these codes with their scan tool as well? I would love to get these issues straightened out.......

What is does FMEM stand for?

Click to expand...

FMEM: Failure Mode Effects Management. Operating strategy that maintains limited vehicle function in the event of a PCM or EEC component failure.

 

E

ewg302

New Member

May 21, 2005

6

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1

Florida

Dec 19, 2008

#8

• Dec 19, 2008

• #8

Well the new battery is in and the alternator seems to be charging fine, the car is still having issues... It must have developed this problem related to the tune. It seems to misfire when you tipin to the throttle after deceling around 2800 rpm. The thing is also backfiring on decel as well.......could it be a stuck injector or bad MAF....They are 60 pound injectors with a 90mm lightning MAF and a mafia.

Thanks for the info so far...I checked the ground it reads the same voltage across the terminals as it does from the battery to the body.