When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I've been searching and googling for several days and can't finding the correct solution. The temperature gauge, tachometer, and the fuel gauge drops to zero and then picks back up. This started the day that the car was tuned on the dyno. When the gauges start dropping out the service vehicle light comes on at the same time.
Stuff like that will happen when the voltage drops too low. If this happens while you are running (not starting), then you should check your alternator and main wiring for loose/corroded connections.
Stuff like that will happen when the voltage drops too low. If this happens while you are running (not starting), then you should check your alternator and main wiring for loose/corroded connections.
Main wiring from the alternator or like the bcm or pcm? Did you see the video?
I have heard "whiskered" technicians claim "90% of electrical problems are a bad ground". I am starting to believe them.
On a side note, there are many videos and articles about grounding the crap out of everything...I've gone as far as to put extra grounds in many of my cars.. block to fender well, block to battery, manifold to fender well, manifold to block. The delicate electronics are driven by voltage differences which are impacted by resistance (bad connections). If you have any bad or intermittent connections, stuff won't work correctly.
I am old and gray and have been working on electronics since the electron was invented.
It is true that bad grounds can cause many problems. But I avoid that expression because it often leads to people adding additional unnecessary grounds to circuits instead of tracking down the real source of a problem. Check the ground as part of the diagnostic procedure but if it's good then move on to something else. Adding more grounds isn't going to solve anything.
I defer to your experience and expertise and I think we mostly agree .
To strengthen the "ground argument", grounds are among the few exposed connections in late model cars. A small resistance behind a reference ground is a game changer. With operating ranges of a few volts (especially sensors) where tenths of a volt matter a bunch, good clean reference grounds are critical. As far as older cars, how many of us have seen old Nova's and Camaro's with screwed up brake/tail lights? Guess what that problem is?
When repairing a ground, I put one or two drops of LPS1 on the connection to avoid future corrosion.
On another related and possibly controversial topic, I hate the solder that is now in use on most electronics (solder with lead is pretty much illegal). If you find some old stuff at a garage sale, buy it. The new stuff literally has an expiration and re-soldering connections on newer electrical components can bring broken components back to life.
Oh yes, we agree that grounds can be a big problem. My comment was aimed more at people who are less experienced than us. They hear that "a ground is most often the problem" and they get fixated on grounds to the exclusion of other possible causes of a problems. I've seen people adding secondary grounds to circuits which already had adequate grounds just because they figured "if it's an electrical problem, I've heard it must be a ground". Checking fuses and grounds first is a good idea but if both are good then more extensive diagnosing is the next step rather than just adding another ground.
02-07-2019, 09:48 PM
HELP! 3 gauges acting crazy. 
. 