Various Volvo 740 and 760 Stalling Fixes
dmf volvo freak » 88 760T wagon… so far it always starts back up and I experience strange erratic rpm on the tach when it is acting up. It sounds like from my research that we are both suffering from ignition issues particularly related to the hall sensor (88) or RPM sensor in the distribution (89 is RPM) , the potential for shorts in the wiring harness or bad connections in the ignition, and also a failed or fluky ignition power boost unit. Not that I am advocating radom changing of parts to find the bad one, but I picked up a ignition power boost with nothing but a screwdriver and $10 at the junk yard off a nice 9 series – same part number etc. I installed and yet to see if that solves, but if $10 gives me a 1 in 3, it is well worth it. Careful on the sensor connector on the back of the distributor, I may have just screwed that up sufficiently for me to think about replacing the distributor itself.
http://www.swedishbricks.net/700900FAQ/ … n%20System
LaRy » I would say that this is a typical Hall sensor problem or ignition power module. Also the fact when and how it happens is typical. The fact that the tacho is dropping is definitely showing that you do not have any ignition. The tacho is checking the frequenzy of the pulses coming from power module to the ignition coil. If tacho is showing zero or crazy values, with stalled still rotating engine, ignition is also definitely zero! The tacho is actually one of the wires connected straight to the ignition coil pimary side, so it is giving very valuable information of the condition of ignition. It is very hard with ordinary tools to find out if it is the hall sensor or the power module. So I suggest that you should change both.
Volvo Phil » I had an 87 Volvo 760 turbo that did the same thing and I replaced all the parts…fuel filter, pump, etc., only to discover that it was the electrical connector that went to the injectors. It is located on the drivers side of the engine compartment about 1/2 way between the front of the car and the firewall. The connector had worn out over the years and the spade connectors would just come loose enough to kill the engine. You can verify this by using a light connected to your injectors electrical connection and see if it is getting power. Good luck.
NRK » Do the basic (and cheap) things first!
1) Check every vaccum line. If any have cracks, feel soft & gummy, or 90 degree kinks replace them. If the line is not tight, i.e. the line turns easy on the nipple, replace the line. If it still turns use a hose clamp, or if you are cheap do the three wire wrap and twist tight. The adaptors on top of the engine that go from large to small lines are Volvo only but the rest of the lines are shop-stock, available at any auto parts store.
2) Clean your battery teminals and grounds to the frame and engine. Use dielectric grease to prevent further corrosion when you are putting it all back together. http://brickboard.com/ARCHIVES/1998JAN/7808.shtml
3) Get the gaskets for the throttle body and TSP and clean them. Some folks say to scrape and wire brush the passageways. I would not. Use a good cleaner (talk to your auto parts store) and at most some crocus cloth.
4) Clean and gap your spark plugs. If any wires are cracked or show heat deterioration they need to be changed, and then look at the cap and rotor.
These four items will cure a host of ills and cost $10-20 with stuff left over for the next time or you are fixing your friends Volvo and impressing them with your skill.
If this doesn’t work then you have some much deeper diagnosis to do.
This and more found in the Volvo Forums.
89 Volvo 740 Random Stalls Ignition Failure
The Volvo 740
The highly successful Volvo 760 GLE was developed and expanded to give birth to the Volvo 740 GLE in 1984. This new Volvo model was a 4-cylinder alternative to the 760.
The Volvo 740 estate car owed its immense success primarily to factors such as its sheer reliability and renowned safety levels.
Over the years, the Volvo 740 was powered by a range of different engines, mostly 4-cylinder in-line units with or without turbochargers, and there were also 6-cylinder diesel variants.
The exterior underwent a minor facelift in autumn 1988 to carry the model into the 1989 model year.
From August 1990, the Volvo 740 was made in parallel with the 940 for two years, after which the latter took over completely from the 740.
Last Updated on May 16, 2022
