CALLING ALL ELECTICAL GENIUSES

Tom Kelly

Active Member
Thanks for your input. Many responses have focused on grounding so I will focus on that next. I had ruled that out due to the fact that it works consistently on first start and when key on without starting but now I am hearing from multiple members that cold/hot can affect electrical flow. I will try to find a more secure ground and also to help the battery ground to the body better and try again. Thanks to everyone who has tried to help. I have always found that Buick guys are the best. That's why I stick to them.
I did a quick check of grounds under the hood. The auxiliary ground coming out of the negative connection looks to be original as it is firmly attached to the inner fender. The main ground snakes into the abyss. If someone can tell me where it terminates I can look there as well. I did another check looking at the gauges. At idle, the battery reads about 14.1 on the voltmeter (about 13.7 on the scanmaster). Does this give me any comfort that at least the battery is properly grounded? If so I can save time by focusing on the ground for the gauge. Thanks
 

mikestertwo

Well-Known Member
The gauges just have harnesses which fan out to 12v, ground and sending units. I’m not sure what u mean by inverter in this scenario. Must be being dense.
I'm not familiar with that particular manufacturer of gauges. The website shows a separate inverter to run the display on the gauges. I guess that is inaccurate. So all you have is the gauge, sending unit and wiring harness....understood.
 

Tom Kelly

Active Member
I'm not familiar with that particular manufacturer of gauges. The website shows a separate inverter to run the display on the gauges. I guess that is inaccurate. So all you have is the gauge, sending unit and wiring harness....understood.
To be honest the gauges were installed already when I got the car. It's possible that there is an inverter somewhere in there and I never noticed. I see that on the website they list an inverter as coming with the gauge. And the digital gauge does light up so there might be an inverter.
 

mikestertwo

Well-Known Member
To be honest the gauges were installed already when I got the car. It's possible that there is an inverter somewhere in there and I never noticed. I see that on the website they list an inverter as coming with the gauge. And the digital gauge does light up so there might be an inverter.
From reading the tech on those gauges the inverter is used for back-lighting the gauge. It's not necessary for gauge operation. It's a 12v to 200v inverter to power the florescent back-lighting. Check to see if one is hooked up to your gauge. If there is, disconnect it and see if it makes any difference.
 

Tom Kelly

Active Member
From reading the tech on those gauges the inverter is used for back-lighting the gauge. It's not necessary for gauge operation. It's a 12v to 200v inverter to power the florescent back-lighting. Check to see if one is hooked up to your gauge. If there is, disconnect it and see if it makes any difference.
I will look but I don’t remember seeing it on any of my trips into the wiring. And I don’t have backlighting at all.
 

theamcguy

Member
You know it's temperature related, you know it started after the installation of an AEM A/F gauge, changed to an LT-1 MAF with translator and added a powerlogger. First when you get the error confirm the what the voltage reading is at the 5V wire the gauge is reading. Next buy a can of that compressed air that you use to clean computers (that stuff comes out cold) then start spraying each connection or senor in the chain until, the gauge reads normal, then you'll know where to look. Most of these problems point to a corroded connection.
 

Tom Kelly

Active Member
You know it's temperature related, you know it started after the installation of an AEM A/F gauge, changed to an LT-1 MAF with translator and added a powerlogger. First when you get the error confirm the what the voltage reading is at the 5V wire the gauge is reading. Next buy a can of that compressed air that you use to clean computers (that stuff comes out cold) then start spraying each connection or senor in the chain until, the gauge reads normal, then you'll know where to look. Most of these problems point to a corroded connection.
Yeah. Exactly. The weather here in Connecticut has gone chilly. As soon as it warms up a bit I have two projects.
1. Remove the gauge pod (what a pain) and take a detailed look at all the wires lying therein and test and tune as required.
2. I scored a NOS roof rail weatherstrip (driver side) and installed it the other day. Fit like a glove but the softseal one that I had before was so off the window needs radical adjustment to get back to the NOS shape.
Practicing "Social Distancing" these days. Thank God for our books and Buicks. Always something to do.
 

Tom Kelly

Active Member
Yeah. Exactly. The weather here in Connecticut has gone chilly. As soon as it warms up a bit I have two projects.
1. Remove the gauge pod (what a pain) and take a detailed look at all the wires lying therein and test and tune as required.
2. I scored a NOS roof rail weatherstrip (driver side) and installed it the other day. Fit like a glove but the softseal one that I had before was so off the window needs radical adjustment to get back to the NOS shape.
Practicing "Social Distancing" these days. Thank God for our books and Buicks. Always something to do.
I had another thought on this. The problem does occur after warmup but never occurs with just key on if I don't crank. when I turn the key on the gauge initializes correctly but then when I crank it switches to "sender error" possibly indicating an abnormal condition after warmup. What happens to the starter after it is warm? Could this be a sign of a failing starter?
 

Tom Kelly

Active Member
I had another thought on this. The problem does occur after warmup but never occurs with just key on if I don't crank. when I turn the key on the gauge initializes correctly but then when I crank it switches to "sender error" possibly indicating an abnormal condition after warmup. What happens to the starter after it is warm? Could this be a sign of a failing starter?
Here is a quote from a website promoting performance starters: Could this be what's happening explaining the problem happens when warm?

Many original equipment starters suffer from "heat soak" problems. This means when they get hot, significant cranking power is lost. Direct-drive starters without gear reduction
tend to heat up quicker during use because they draw more current, plus all components inside are spinning faster. Heat from nearby exhaust pipes (especially headers) can also affect
a starter, contributing to sluggish performance when re-starting a hot engine which may already be suffering from temporary "vapor lock". more details on - https://www.carid.com/articles/high...any_OEM_Starters_Lose_Cranking_Power_When_Hot
 

Tom Kelly

Active Member
How old is your battery?
The gauge supplies 5v and gnd to the sender?
Batter is 2 year old Delco and healthy (12.8 V; 14.1 V charging).
Gauge/controller sends I believe 12v to sender which returns 5v (decreases with boost) tech support says initialization is highly sensitive to the gauge getting 5v signal when cranking.
 

mikestertwo

Well-Known Member
tech support says initialization is highly sensitive to the gauge getting 5v signal when cranking.
If this is true...that's a :poop: design! The gauge should care less what the voltage is until the engine is running. To verify this...I would temporarily put a switch in the power feed line to the gauge. Leave the switch off until you start the engine then turn the switch on to power up the gauge. If it initializes and reads normal under any temperature condition then that could potentially be the problem. Of course having vacuum on the sender when initializing the gauge may throw a wrench in the works but who knows.:unsure:
 

Tom Kelly

Active Member
If this is true...that's a :poop: design! The gauge should care less what the voltage is until the engine is running. To verify this...I would temporarily put a switch in the power feed line to the gauge. Leave the switch off until you start the engine then turn the switch on to power up the gauge. If it initializes and reads normal under any temperature condition then that could potentially be the problem. Of course having vacuum on the sender when initializing the gauge may throw a wrench in the works but who knows.:unsure:
I have tried disconnecting the harness while cranking and then reconnecting it once engine is running and I have tried bleeding vacuum lines before cranking. Neither helped.
 

Chuck Leeper

Toxic old bastard
Staff member
"All pressure gauges that use the 0-30 psi sender may give an incorrect reading at "0". This may be caused by trapped air in the pressure sender. After connecting the wire harness to the sender, wiggle the wires at the sender connector to relieve the pressure.".
 

Tom Kelly

Active Member
"All pressure gauges that use the 0-30 psi sender may give an incorrect reading at "0". This may be caused by trapped air in the pressure sender. After connecting the wire harness to the sender, wiggle the wires at the sender connector to relieve the pressure.".
Yeah. I’ve actually “bled” the hose. Tech support says vacuum or pressure in the lines at startup will not affect initialization. Only the 5v signal.
 

Tom Kelly

Active Member
The longer this goes on the more I think just throw a mech boost gauge on there.
That has of course occurred to me. The only reason I want the boost gauge in the first place is so I can monitor boost during tuning. Each time I turn the controller up I like to see two things. 1. What was the maximum boost achieved and 2. Was there retard? The upgraded scan master tells me a/f ratio and retard on the first screen. The advantage of a digital gauge is that it is easy to see what max boost was without referring to the log. Is there a mechanical boost gauge that allows you to recall highest boost? It's harder to read how high it went with the analog dial, especially when you are watching the road ahead of you and also using the old peripheral vision to look for retard. I don't see that feature in the gauges I have checked out. The scan master also shows vacuum/boot but then you can't monitor retard at the same time. If only the main scan master screen showed boost and retard instead of a/f and retard. I am going to ask Eric if the can master will retain highest boost achieved for a run the way it retains highest retard. If it can then I don't really need the boost gauge in front of me 24/7. Of course if I as more patient I would just refer to the log for max boost but usually I only start looking at the log when I get retard to see where it was in the run. Sometimes it takes a number of runs to get retard at all while raising the boost each time.
 
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