GrayWave Auto Diagnostics

05/08/2024

Not accepting work at this time due to medical reasons and a long recovery road.

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09/19/2022

1977 TransAm Rear Defroster Circuit Diagnosis and Repair. Rear defogger would turn on immediately when turning on ignition and if you tried to shut off the rear defogger pushing the switch down, it would short out and blow a 10A fuse. All caused by a shorted diode located on the back of the rear defogger switch between two important terminals.

Replacing the diode saved the customer from ordering another switch and allowed the circuit to operate as intended.

09/18/2022

2006 NISSAN ALTIMA 2.5L 4 Cyl. One of the most interesting cases by far.

Customer complained about the engine misfiring. Well to say it was misfiring was being a bit nice! The engine computer in this car could not compute the timing between the crankshaft and camshafts correctly and would not send control to the ignition coils and fuel injectors at random times. The engine was basically shutting off rapidly at random times for the first 30 seconds or so until enough oil pressure was produced to remove some slack from the timing chain.

After some in depth engine analysis, I found the crankshaft and camshaft timing correlation to be way out of spec. I was able to 100% confirm the problem and the fix required without tearing into the engine. Just hooked up my oscilloscope to a few different components on the engine.

After replacing the timing chain and sprocket, the engine ran great!

08/26/2022

2007 Volvo S40. Engine cooling fan not operating. Excessive vacuum in crankcase / valve cover causing vacuum leak and lean condition.

Found someone hacked in a relay and additional wires and cut the factory harness. Repaired factory harness and found no power to the fan control module (FCM).Found 50A fuse blown. Replaced fuse and then found the engine cooling fan had a bad FCM which kept the fan on all the time, even with the key out of the Ignition, engine cold, and no computer control.

After swapping in a different fan and FCM, found the Engine Control Module (ECM) still not controlling the fan. After some heavy Diagnostics, found out the wrong engine wire harness was installed on the engine and it did not have the fan control wire from the ECM which goes to the FCM to turn the fan on and off.

The fix was to de-pin another harness from another volvo with the correct terminal and wire and install it in the ECM connector on this car. Also replaced the starter relay control terminal and wire since that wire was broken.

The other problem with this vehicle was a Long Term Fuel Trim code in the engine computer. This was found to be caused by the engine running lean (not enough fuel). This was diagnosed to excessive vacuum in crankcase / valve cover cause by a faulty crankcase ventilation system. After replacing the crankcase ventilation system the engine ran normally.

08/26/2022

NEED DIAGNOSTIC SERVICES ON A VEHICLE OR EQUIPMENT? CALL 603-522-7027 or FILL OUT OUR ONLINE FORM @ http://service.gwdiagnostics.com

Example of how I test certain circuits. This test was on an engine cooling fan control circuit. I activated the control circuit with my diagnostic scanner, use an incandescent test light to supply power to control circuit and my handheld oscilloscope to monitor the signal which is created when the computer pulls down the power supplied by the test light.

This was after a long repair on a 2007 Volvo S40. I will post that case study soon.

08/19/2022

International 3616. Short circuit caused some wires to burn up and melt. Ran new wires and replaced two push button switches. Tractor now cranks and glow plugs work.

08/03/2022

Komatsu Forklift. No throttle response and would stall after idling for awhile.

I was not able to find wiring schematics for this forklift online. Due to that, I performed some heavy diagnostics to learn exactly how the computer in the Forklift worked. Since there was no throttle response, I decided to check the Accelerator pedal position sensor, after finding that had no obvious issues, I looked at the electronic throttle body and monitored each wire. I found there was no power to the throttle body actuation motor. I then looked for relays and fuses. Well, I found the fuse for the electronic throttle body had been removed previously. Replaced fuse, adjusted pedal sensor and the engine had throttle response once again.

Some may ask why I didn't start at the fuse panel to begin with. Well, when you don't have schematics and are not anticipating a fuse to be removed, and have never seen a fuse for an electronic throttle body to be blown after diagnosing for years, there is no reason to start at the fuse panel. Most of these problems are sensor, wiring, engine computer or throttle body related.

The stalling issue was due to a faulty oxygen sensor incorrectly reporting how much oxygen is in the exhaust. This caused the computer to remove a lot of fuel and stall the engine. Owner said to leave it disconnected.

08/02/2022

2016 Land Rover Discovery. Front and rear passenger side doors will not lock after doors were replaced. Diagnosed both front and rear door control modules which control all door accessories. So far, I am condemning both door modules and the front passenger lock actuator since one motor is no good.

Dealer says they need to replace the body harness, door harnesses and door modules and remove the headliner for over $1500! All harnesses ARE GOOD! They said they couldn't communicate with the door computer modules with their scan tool. I was able to communicate with all the door modules with both my professional scan tools.

Update: Customer did not want to put more money into it and wanted to send it to auction unfortunately. One module was replaced and both front and rear needed a factory reprogram since both doors were replaced due to an accident

07/28/2022

2009 Nissan Pathfinder. Passenger window doesn't work. Found two power feed wires to window motor shorting out on door chassis. Tested all circuits associated with the passenger power windows and found all to be good. Waiting for new door window switch.

07/28/2022

2020 Kubota BX2380. Crank No-Start. Sometimes starts but lacks power and runs rough. Found low side fuel flow to be near zero. Disconnected fuel tank from first fuel filter and no fuel came out of fuel tank pointing to a clogged feed line. Repaired problem and got engine running again.

07/28/2022

2008 Subaru Legacy 2.5 Non Turbo. Crank No-Start. No check engine light during key on bulb test. No communication via scan tool to ECM (Engine Control Module). Other computer modules lost communication with ECM. Tested ALL power and ground feeds to ECM and found all to be good. Tested 5v reference circuits and found them to only be at 325mV (0.325 Volts) instead of around 5Volts. Found ECM to be bad. Installed a replacement ECM, programmed to vehicle and engine starts and runs now.

07/28/2022

Toyota Forklift. Propane. Crank No-Start. Found a power feed from battery to be corroded and broken. Fixed power feed and now propane solenoid was operational. Engine still did not start, found fuel mixture to be way to rich. To much fuel was being injected into engine. Dialed in fuel mixture and adjusted engine timing. Engine starts up nice and runs smooth now.