940 Regina starts fine, runs for a bit, then dies. Repeat.

bharman · Post by **bharman** » 02 Jun 2020, 14:11

My 1990 B230 Regina has been sitting for a few months, ran sweetly before. Now it starts readily, idles, will go in gear for varying amounts of time, 30 seconds, to half a mile down the road, then it starts to sputter, cough, bogs badly on pressing gas, then dies. She starts right up immediately, idles and maybe gets me back home barely before quitting again. Put new fuel filter first, no change. In-tank pump works but I don't know how to check pressure, sock is fine. I removed the pulse regulator thing above the pump(some other thread said it might be leaking air), no change. Put a few gallons of fresh gas in, thought it might be spoiled gas, no change. Fuel lines all look fine. Changed out the radio suppression relay, no change. Swapped a used fuel pump relay, no change. The crank sensor wire looks fine. Any ideas?

Post by **volvolugnut** » 02 Jun 2020, 18:33

Will the car idle without moving for long enough to get to full warmup?

volvolugnut

bharman · Post by **bharman** » 03 Jun 2020, 12:44

Wow, no. It idled fine until needle started to climb, then it stumbled and died. What's that about?

Post by **volvolugnut** » 03 Jun 2020, 13:59

It could be related to the engine temperature sensor. If the sensor does not report the rising coolant temperature, the computer will continue to provide excess fuel for cold idling. I am not sure if this explains the restart and run after it died on the road.
Search this forum for temperature sensor. There are two.
volvolugnut

bharman · Post by **bharman** » 03 Jun 2020, 18:47

So, I pulled the old coolant temp sensor, cleaned the contacts, put a new one in. No change in the condition. Starts, idles for a while, chugs and dies. Would the fuel pressure regulator be next?

bharman · Post by **bharman** » 03 Jun 2020, 19:45

Update: Put a known fuel regulator on there, condition persists the same...

Post by **volvolugnut** » 04 Jun 2020, 09:56

Check the Ohms of the coolant sensor at a known temperature. Repeat at a higher temperature. Use top radiator hose as the temperature reference. You can do this in the car if your arms are skinny. If you do not have the recommended Ohm rating, post here for more information. Contacts may be good and the sensor bad. I had to replace mine on '83 245 to fix rough idle after warm up.

volvolugnut

Bodhi5 · Post by **Bodhi5** » 15 Jun 2020, 02:10

Hi, I've always bought old beater projects for 25yrs, from 244 turbos, to Honda, Toyota, now got ,s40. I've noticed many YouTube n forum complaints about idling, reving, stall, n engine dies.

These are electrical problems caused by:
1) loose battery terminals,
2) uncharged dying battery under 10volts,
3) rusted negative blue wire terminals to engine n frame, under battery.
4) dead alternator not charging battery properly,
5) bad plug wire n solid state coil sparkers.
6) engine idle control that YouTubers allege get dirty from controlling air intake to cylinders. Not sure about this, I haven't changed this yet, but maybe in a month will.

I do notice that all Volvo's do not sand off paint to steel frame when grounding negative terminal to frame under battery. This can cause rough idling cause spark cannot return to battery n alternator, and paint can disrupt this because there is oil insulators silicon, sealers that slow, prevent electrical flow.

Volvo engines are great, I've seen some go to 1 million miles like Honda's Toyota's. U just have to keep electrical, plugs, coolant oil flowing. Buy one of the new genius battery multi chargers, tester. If u run low on sulfuric acid in battery, try vinegar or clear coca cola.

Hope this helps everyone!
Cheers.

bharman · Post by **bharman** » 18 Jun 2020, 00:56

Solution update on my problem! It was an oxygen sensor connection problem by the catalytic converter. I cleaned my idle air control valve, almost bought a new one (phew), checked my coil pack, seemed to be ok, almost lost my mind, then read yet another forum reply and checked my oxygen sensor. A wire was broken. Problem solved.