20 Most Recent 1990 Volvo 780 Questions & Answers

If the car is in a secure area, raise the hood to vent air from the engine compartment when you park. The symptoms sound like Vapor lock or a bad coil. Check fuelpump pressure when it acts up again.If this vehicle has an ignition Relay, or a Fuelpump Relay, they may be affected by heat. Replace those Relays.I am thinking the starters failed because of extreme cranking usage. Next time you replace one, get a Lifetime gaurantee.There can be a strenuous condition for a starter when the engine is overadvanced. GM had a problem with its Crankshaft sensors which kept the Cams overadvanced and it fried the starters when the Owners tried to start their motors. But this was not due to heat and occured on cold motors too.I hope my solution is helpful. Please rate my solution.

It sounds like the OD solenoid to me you can either replace it or use this bypass kit offered by IPD. Like the desciption for it says "How many times have you used the OD button on the shift lever to shift down for hills or while towing?" http://www.ipdusa.com/products/4793/110397-automatic-over-drive-solenoid-bypass-kit The "Bertone" is a great car. Keep it running and happy! Not many around.

sounds like blocked fuel filer

Sounds like a intercooler coupling or hose blew off. The shop or mechanic might not have tightened a clamp all the way. Check that out first before going into further troubleshooting.

pretty straight foreward but its the window winder on these earlier cars ,their is a horseshoe clip behind the handle and use a flat screwdriver to push the inside part back and a stout piece of fence wire with a small hook on the end which you make with two pairs of pliers and then you turn teh screwdriver to push the interior piece in and then look for the cilp and then hook the out ,make sure you not lose the clip as they tend to go ping and can travel up to 20 ft away ,i always hold a piece of rag over the front while iam doing this as i have lost no end of them ,the rest of the door panel is straight foreward and needs no explanation

OK. Several ideas. The 760 is really a 740 with a fancy body. Start with the brake light switch on the brake pedal. Use a short jumper with two alligator clips to bypass the switch. If the brake light works, bingo! A good substitute for the jumper is a cheap 12 volt test light from AutoZone or Sears. Clip one end to a good ground, and probe for voltage with the sharp tip. If the bulb lights on one side of a switch, you have 12 volts coming in. If you activate the switch and there's not 12 volts on the other side, the switch is suspect. Check the fuse. The fuse functions are labelled on the iunside of the ash tray door. Check the @#$%^@# bulb sensor in the relay rack behind the ash tray. It's the big, round red relay in the rear left position closest to the firewall. Failure there can knock your brake lights out. A used one fetches about $10 on ebay. I always carry a spare. You didn't tell me if all the brake lights are out, or just one. If they're all out, it's a systemic problem. One out, it';s usually a bulp or bad socket.

Check for Poor Connector in Trunk the GROUND WIRES GET Corroded and also the connector for the rear lights should be in trunk on the Drivers side

Bad ABS control module. This guy rebuilds them: http://home.earthlink.net/~vicrocha/Volvo_Parts/Volvo_ABS_removal.htm

I just had this issue fixed after a year of pain and suffering seem to find out it is a bad park break sensor it was 36.99 at volvo and took 5 mins to fix it is located under your driver side dash behind the clutch next to the yellow air line best of luck to you my truck is a 2011 vnl 670

The code means that the temperature in the catalyst is not high enough to support hydrocarbon conversion. Some ways to troubleshoot are: 1. Replace the EGR cooler 2. Check for exhaust leaks 3. Install clean DOC and DPC 4. Check that there are no issues with the 7th injector, fuel metering block for injector, WGR cooler, the engine's wiring and DPF sensor 5. Check if the 7th injector is receiving good voltage when the car is on 6. Replace the wire harness if the issue is persistent If the issue isn't fixed now, drive down to the nearest mechanic.

Is it possible to take out that DEF injector and put it in DEF tank so you have a closed loop? Then it can use that def as much as it wants. Right?

Try disconnecting the battery negative cable at the battery for 5 minutes.

check the drive shaft for faulty u-joints . check for failed engine mounts

I would purchase a shop manual with wiring diagram as the wiring was hot wired for a reason. Usually it meand something failed and was bypassed. You will need a diagram to sort it out.

You will find what means all that fault codes here: Cummins Signature ISX and QSX15 Factory Manual Repair Servic Download... Good Luck!