85 with flicker on dash and radio . . .?
http://garage.grumpysperformance.co...urrent-flow-grounds-and-more.3504/#post-54625
http://garage.grumpysperformance.co...hooting-tip-for-electronics.11317/#post-51557
https://batee.com/pages/repairing-the-1984-1989-c4-corvette-digital-instrument-panel-cluster-dash
http://garage.grumpysperformance.co...instrument-cluster-has-stopped-working.16375/
Id start by pulling trouble codes and checking fuses
but a loose electrical connections , bad electrical ground connection's on the battery and engine and frame would be very high on my list of potential causes,
Id also suggest testing the alternator, bad diodes or a defective alternator might be to blame, keep in mind the cars electronics are now 32 years old and the O.E.M. dash gauges are fairly well known for weak solder connections, and corrosion on push-on electrical connections, so the dash gauge cluster may need to be repaired or replaced.
as always ISOLATE AND TEST
I've seen guys rush out and spend hundreds of dollars on parts,too fix a problem, take a great amount of effort to tear apart the dash or other area and once the new parts installed it still won't work, so forced to do further research at that point they only then find a blown fuse or corroded electrical connection.(that was the true initial cause)
G104-G107 are very suspect, it the dash and gauges are having problems
reading through the links below and the sub-links will help you locate the source of the problem
and yes skipping the links and sub links that contain a huge amount of info is a mistake
this infos bound to be helpful at times
Sensor Locations
Sensor
Location
Engine Coolant Temperature Sensor. Front of engine, below Throttle Body.
Engine Oil Temperature Sensor. Left rear of engine, just above the oil filter.
Oil Pressure Sender/Switch. Top, left hand rear of engine.
Fuel Quantity Sender. Top of fuel tank, beneath filler pipe escutcheon panel.
MAT (Manifold Absolute Temperature Sensor). Underside of manifold air plenum at rear.
Outside Temperature Sensor. Right side of engine, top right corner of radiator.
In Car Temp Temperature Sensor. Coupe: above left seat near interior courtesy light, Convertible: center of cargo compartment lid.
MAF (Mass Air Flow) Sensor. Front of engine ahead of throttle body.
Oxygen (O2) Sensor. Left side of engine, in exhaust pipe.
TPS (Throttle Position Sensor). Right side of throttle body at the front.
Sensor Outputs:
Sensor
Measured Value
Engine Coolant Temperature Sensor. 185 Ohms @ 210F, 3400 Ohms @ 68F, 7,500 Ohms @ 39 F.
Engine Oil Temperature Sensor. 185 Ohms @ 210 F, 3400 Ohms @ 68 F, 7,500 Ohms @39 F.
Oil Pressure Sender/Switch. 1 Ohms @ 0 PSI, 43 Ohms @ 30 PSI, 86 Ohms @ 60 PSI.
Fuel Quantity Sender. 0 Ohms @ Empty, 45 Ohms @ 1/2 Full, 90 Ohms @ Full.
MAT (Manifold Absolute Temperature Sensor). 185 Ohms @ 210 F, 3400 Ohms @ 70 F, 15,000 Ohms @ 40 F.
Outside Temperature Sensor. 4400 Ohms @ 60 F, 2200 Ohms @ 85 F.
In Car Temp Temperature Sensor. 4400 Ohms @ 60 F, 2200 Ohms @ 85 F.
MAF (Mass Air Flow) Sensor. .4 Volts @ idle, 5 Volts @ Full Throttle.
Oxygen (O2) Sensor. .1 Volt Lean Mixture, .9 Volt Rich Mixture.
TPS (Throttle Position Sensor). .54 Volts Idle, ~ 5 Volts Full Throttle.
having a wire roll caddy , thats easy to access or fabricating one for working around the cars helpful
http://garage.grumpysperformance.co...er-repair-or-replacement-link.1006/#post-8030
https://batee.com/collections/84-89-corvette-parts
http://garage.grumpysperformance.co...uys-don-t-look-at-the-clues.11176/#post-50124
http://garage.grumpysperformance.com/index.php?threads/chasing-a-crazy-electrical-glitch.986/
http://garage.grumpysperformance.co...wrong-after-alternator-swap.13580/#post-70168
http://garage.grumpysperformance.com/index.php?threads/c4-c5-corvette-trouble-codes.2697/#post-6985
http://garage.grumpysperformance.co...wrong-after-alternator-swap.13580/#post-70168
http://garage.grumpysperformance.co...ir-of-circuit-board-solder-connections.16362/
http://garage.grumpysperformance.co...tting-out-low-voltage.12221/page-2#post-59599
http://garage.grumpysperformance.com/index.php?threads/electrical-problem.10714/
http://garage.grumpysperformance.co...ing-down-an-electrical-drain.8493/#post-37179
http://garage.grumpysperformance.com/index.php?threads/testing-an-alternator.3222/#post-46703
http://garage.grumpysperformance.co...lay-switch-locations-and-info.728/#post-54562
http://garage.grumpysperformance.com/index.php?threads/diagnoseing-tpi-lt1-problems.1241/#post-2648
http://garage.grumpysperformance.co...uel-injector-resistance-reading.606/#post-805
http://garage.grumpysperformance.co...rvette-after-battery-failed.10291/#post-41710
http://garage.grumpysperformance.co...questions-can-be-found-here.12892/#post-66934
http://garage.grumpysperformance.com/index.php?threads/engine-test-run-stand.930/#post-40783
http://garage.grumpysperformance.co...rical-glitches-in-newer-cars.5492/#post-18411
http://garage.grumpysperformance.com/index.php?threads/digital-dash-swap-questions.3399/#post-8970
http://garage.grumpysperformance.co...er-repair-or-replacement-link.1006/#post-8030
http://garage.grumpysperformance.com/index.php?threads/c4-c5-corvette-trouble-codes.2697/#post-6985
http://garage.grumpysperformance.co...ntermitant-electrical-glitches.987/#post-1739
Hi everyone
I noticed a flicker with the dash lights and well timed high pitch pulse when the radio is on - as well as a moody tach readout - the interference seems to keep close time with what sounds like the pulses of the motor - I was wondering if anyone else has come across that? I saw somewhere that the '85 has a tachometer filter - does that have anything to do with it? - sorry this is on a 1985 standard
any thoughts or opinions would be greatly appreciated
Sean
http://garage.grumpysperformance.co...hooting-tip-for-electronics.11317/#post-51557
https://batee.com/pages/repairing-the-1984-1989-c4-corvette-digital-instrument-panel-cluster-dash
http://garage.grumpysperformance.co...instrument-cluster-has-stopped-working.16375/
Id start by pulling trouble codes and checking fuses
but a loose electrical connections , bad electrical ground connection's on the battery and engine and frame would be very high on my list of potential causes,
Id also suggest testing the alternator, bad diodes or a defective alternator might be to blame, keep in mind the cars electronics are now 32 years old and the O.E.M. dash gauges are fairly well known for weak solder connections, and corrosion on push-on electrical connections, so the dash gauge cluster may need to be repaired or replaced.
as always ISOLATE AND TEST
I've seen guys rush out and spend hundreds of dollars on parts,too fix a problem, take a great amount of effort to tear apart the dash or other area and once the new parts installed it still won't work, so forced to do further research at that point they only then find a blown fuse or corroded electrical connection.(that was the true initial cause)
G104-G107 are very suspect, it the dash and gauges are having problems
reading through the links below and the sub-links will help you locate the source of the problem
and yes skipping the links and sub links that contain a huge amount of info is a mistake
this infos bound to be helpful at times
Sensor Locations
Sensor
Location
Engine Coolant Temperature Sensor. Front of engine, below Throttle Body.
Engine Oil Temperature Sensor. Left rear of engine, just above the oil filter.
Oil Pressure Sender/Switch. Top, left hand rear of engine.
Fuel Quantity Sender. Top of fuel tank, beneath filler pipe escutcheon panel.
MAT (Manifold Absolute Temperature Sensor). Underside of manifold air plenum at rear.
Outside Temperature Sensor. Right side of engine, top right corner of radiator.
In Car Temp Temperature Sensor. Coupe: above left seat near interior courtesy light, Convertible: center of cargo compartment lid.
MAF (Mass Air Flow) Sensor. Front of engine ahead of throttle body.
Oxygen (O2) Sensor. Left side of engine, in exhaust pipe.
TPS (Throttle Position Sensor). Right side of throttle body at the front.
Sensor Outputs:
Sensor
Measured Value
Engine Coolant Temperature Sensor. 185 Ohms @ 210F, 3400 Ohms @ 68F, 7,500 Ohms @ 39 F.
Engine Oil Temperature Sensor. 185 Ohms @ 210 F, 3400 Ohms @ 68 F, 7,500 Ohms @39 F.
Oil Pressure Sender/Switch. 1 Ohms @ 0 PSI, 43 Ohms @ 30 PSI, 86 Ohms @ 60 PSI.
Fuel Quantity Sender. 0 Ohms @ Empty, 45 Ohms @ 1/2 Full, 90 Ohms @ Full.
MAT (Manifold Absolute Temperature Sensor). 185 Ohms @ 210 F, 3400 Ohms @ 70 F, 15,000 Ohms @ 40 F.
Outside Temperature Sensor. 4400 Ohms @ 60 F, 2200 Ohms @ 85 F.
In Car Temp Temperature Sensor. 4400 Ohms @ 60 F, 2200 Ohms @ 85 F.
MAF (Mass Air Flow) Sensor. .4 Volts @ idle, 5 Volts @ Full Throttle.
Oxygen (O2) Sensor. .1 Volt Lean Mixture, .9 Volt Rich Mixture.
TPS (Throttle Position Sensor). .54 Volts Idle, ~ 5 Volts Full Throttle.
having a wire roll caddy , thats easy to access or fabricating one for working around the cars helpful
http://garage.grumpysperformance.co...er-repair-or-replacement-link.1006/#post-8030
https://batee.com/collections/84-89-corvette-parts
http://garage.grumpysperformance.co...uys-don-t-look-at-the-clues.11176/#post-50124
http://garage.grumpysperformance.com/index.php?threads/chasing-a-crazy-electrical-glitch.986/
http://garage.grumpysperformance.co...wrong-after-alternator-swap.13580/#post-70168
http://garage.grumpysperformance.com/index.php?threads/c4-c5-corvette-trouble-codes.2697/#post-6985
http://garage.grumpysperformance.co...wrong-after-alternator-swap.13580/#post-70168
http://garage.grumpysperformance.co...ir-of-circuit-board-solder-connections.16362/
http://garage.grumpysperformance.co...tting-out-low-voltage.12221/page-2#post-59599
http://garage.grumpysperformance.com/index.php?threads/electrical-problem.10714/
http://garage.grumpysperformance.co...ing-down-an-electrical-drain.8493/#post-37179
http://garage.grumpysperformance.com/index.php?threads/testing-an-alternator.3222/#post-46703
http://garage.grumpysperformance.co...lay-switch-locations-and-info.728/#post-54562
http://garage.grumpysperformance.com/index.php?threads/diagnoseing-tpi-lt1-problems.1241/#post-2648
http://garage.grumpysperformance.co...uel-injector-resistance-reading.606/#post-805
http://garage.grumpysperformance.co...rvette-after-battery-failed.10291/#post-41710
http://garage.grumpysperformance.co...questions-can-be-found-here.12892/#post-66934
http://garage.grumpysperformance.com/index.php?threads/engine-test-run-stand.930/#post-40783
http://garage.grumpysperformance.co...rical-glitches-in-newer-cars.5492/#post-18411
http://garage.grumpysperformance.com/index.php?threads/digital-dash-swap-questions.3399/#post-8970
http://garage.grumpysperformance.co...er-repair-or-replacement-link.1006/#post-8030
http://garage.grumpysperformance.com/index.php?threads/c4-c5-corvette-trouble-codes.2697/#post-6985
http://garage.grumpysperformance.co...ntermitant-electrical-glitches.987/#post-1739
Last edited: