Gauges resetting with every start
10-18-2009, 04:21 PM
#11
1st Gear Member
Thread Starter
Join Date: Sep 2008
Location: Florida
Posts: 128
Thanks for the info Cliffy, I just checked my #21 fuse and though it wasn't blown, after I put it back in and started the car the gauges did not reset like they had been doing. I started it several more times and they didn't reset once, so possibly the fuse just had a bad connection? It looked a little black around where it inserts into the box (the fuse did, not the box) but it definitely wasn't blown.
I'm curious to see if the problem persists.
If it comes down to needing a new battery, does anyone have and recommendations?
I'm curious to see if the problem persists.
If it comes down to needing a new battery, does anyone have and recommendations?
10-18-2009, 05:56 PM
#12
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
Thanks for the info Cliffy, I just checked my #21 fuse and though it wasn't blown, after I put it back in and started the car the gauges did not reset like they had been doing. I started it several more times and they didn't reset once, so possibly the fuse just had a bad connection? It looked a little black around where it inserts into the box (the fuse did, not the box) but it definitely wasn't blown.
I'm curious to see if the problem persists.
If it comes down to needing a new battery, does anyone have and recommendations?
I'm curious to see if the problem persists.
If it comes down to needing a new battery, does anyone have and recommendations?
If the battery starts the car well it is probably OK--this is a handy thing to own. I got mine years ago from J.C. Whitney for $9.99. HF often has them on sale for $16 or even 1/2 price. Placing the 100A load on the battery for 20-30 seconds will tell you real fast how it's doing...
10-18-2009, 06:56 PM
#13
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
I forgot to say that you might want to replace that fuse--the fusible metal work hardens over time due to vibration. This hardening can cause microscopic cracks that will arc and fail intermittently, and sometimes "get better" just from removing and reinserting the fuse.
10-18-2009, 08:32 PM
#14
1st Gear Member
Thread Starter
Join Date: Sep 2008
Location: Florida
Posts: 128
I would have if I had any extras. I'll pick up some tomorrow.
You're a pretty smart guy Cliff, just curious but where'd you acquire all this knowledge? Electrical engineer maybe?
And by the way, thank you for your help.
You're a pretty smart guy Cliff, just curious but where'd you acquire all this knowledge? Electrical engineer maybe?
And by the way, thank you for your help.
01-18-2010, 09:16 PM
#17
Join Date: Dec 2008
Location: TX
Posts: 39
Check fuse #21 (5A) under the dash. It powers the instrument cluster and the PCM's memory, the car will start and run fine if it's blown however the cluster will reset each time you start as you describe.
It's being blown will also reset the KAM (Keep Alive Memory) each time you shut the car off for more than 5 minutes. This leaves the PCM pretty much in a permanent learning mode (idle air, fuel trims, etc.) each time you drive it. This mostly affects precise tuning of AFR and fuel economy--you'd also fail emissions testing in those states that look for the OBD2 "system ready/tests complete" flag.
It's being blown will also reset the KAM (Keep Alive Memory) each time you shut the car off for more than 5 minutes. This leaves the PCM pretty much in a permanent learning mode (idle air, fuel trims, etc.) each time you drive it. This mostly affects precise tuning of AFR and fuel economy--you'd also fail emissions testing in those states that look for the OBD2 "system ready/tests complete" flag.
Thanks a lot
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