Intermittent Speedometer, Speedo Problem
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From: 9th Plane of Hell
Originally Posted by Sleeper2000,Oct 12 2008, 04:27 PM
It was then that I made the assumption that there is a grounding issue in my ECU.
I've replaced my A01 ECU with an A02. After finally getting it programmed for the car, I have the Gremlins worse than ever...
To re-cap:
[QUOTE]The worst problem is the erratic Speedometer display.
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Joined: Apr 2008
Posts: 78
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From: 9th Plane of Hell
SOLVED!
Well - I solved my speedo issue (et al) Easter Weekend. I have waited over a month to see if the gremlins were going to come back and bite me in the @$$. So far, the only issue I have is a wacky IACV. And I think the IACV itself is bad - but that's another thread - and I'm not done trouble-shooting it, yet.
OK - my symptoms were:
Wacky speedo. (The speedo error "responded" to engine RPM.)
Unusable cruise control.
Intermittent temp gauge.
Intermittent A/C.
Steps I took:
Tested / Toubleshot engine bay harness (including grounds).
Tested / Toubleshot dash harness (including grounds).
Replaced cluster.
Replaced ECU.
Had exorcism performed.
Performed VooDoo rituals (killed 6 white roosters).
Sang Chicken Noodle Soup song to car.
Nothing panned out. So, I got to thinking... all of the issues that I could quantify came down to ground issues. The only ground for the wiring harness is on the back of the engine. I had checked that connection several times (when changing clutches - since that's the only time you can get to it.)
However (and this is the thinking part), the path for the ground to actually get there is rather convoluted. Battery to firewall (body ground). Body to front sub-frame. Front sub-frame to engine (another ground strap). Engine to wiring harness.
And the up-shot to all this is... The negative terminal of the battery is less than 16" away from the ground terminal for the wiring harness. WTF!
So, I made myself an 18" ground strap out of #6 ultra-fine stranded OFC wire. Since I didn't have a pressing need for clutch replacement, I removed both engine mounts and dropped the engine down to gain access to the back of the head. I Installed my strap, connected the other end to the firewall under the screw for the battery ground, and presto - a successful exorcism.
Additional benefits are more power on tap, and better fuel economy.
Just thought I'd share.
And to all the guys that were saying "check your grounds" you were right... kinda. All my ground lugs were tight. But, something else wasn't right.
Sleeper
PS: I was going to post a photo of the ground strap - but, I assume my "guest" status precludes that...
Well - I solved my speedo issue (et al) Easter Weekend. I have waited over a month to see if the gremlins were going to come back and bite me in the @$$. So far, the only issue I have is a wacky IACV. And I think the IACV itself is bad - but that's another thread - and I'm not done trouble-shooting it, yet.
OK - my symptoms were:
Wacky speedo. (The speedo error "responded" to engine RPM.)
Unusable cruise control.
Intermittent temp gauge.
Intermittent A/C.
Steps I took:
Tested / Toubleshot engine bay harness (including grounds).
Tested / Toubleshot dash harness (including grounds).
Replaced cluster.
Replaced ECU.
Had exorcism performed.
Performed VooDoo rituals (killed 6 white roosters).
Sang Chicken Noodle Soup song to car.
Nothing panned out. So, I got to thinking... all of the issues that I could quantify came down to ground issues. The only ground for the wiring harness is on the back of the engine. I had checked that connection several times (when changing clutches - since that's the only time you can get to it.)
However (and this is the thinking part), the path for the ground to actually get there is rather convoluted. Battery to firewall (body ground). Body to front sub-frame. Front sub-frame to engine (another ground strap). Engine to wiring harness.
And the up-shot to all this is... The negative terminal of the battery is less than 16" away from the ground terminal for the wiring harness. WTF!
So, I made myself an 18" ground strap out of #6 ultra-fine stranded OFC wire. Since I didn't have a pressing need for clutch replacement, I removed both engine mounts and dropped the engine down to gain access to the back of the head. I Installed my strap, connected the other end to the firewall under the screw for the battery ground, and presto - a successful exorcism.
Additional benefits are more power on tap, and better fuel economy.
Just thought I'd share.
And to all the guys that were saying "check your grounds" you were right... kinda. All my ground lugs were tight. But, something else wasn't right.
Sleeper
PS: I was going to post a photo of the ground strap - but, I assume my "guest" status precludes that...
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