greetings

my 1990 volvo 240 has recently begun driving strange. Car starts fine, but has very little horsepower until I have driven it for at least 15 minutes. I have to push high rpms and it still barely moves, until i get it on the highway and force it to go fast. It doesn't move at all when idling in drive from a complete stop. Ive only driven it a few times since this started happening, as something is not right.

The check engine light is on and I got the code 2 3 2 from the obd. This points to my 02 sensor which i recently replaced myself because the old one got damaged. I purchased a universal Bosch sensor, it came with a weather pack connector to splice to the existing harness. I fear I may have accidentally left out one of the grommets that keep the connection water-tight. Is it possible that water got in and shorted the sensor out, and now it is causing these issues?

or is it possibly my transmission not switching gears when it needs to?

I'l admit I am a novice when it comes to mechanics, but i've had the car for 4 years and have done all repairs myself. I have been tempted to take it to a shop, but I figured I might ask here first and save some hassle.

any help is greatly appreciated!

 

Did you use a universal ONE WIRE O2 sensor? If so, as it is not preheated, it would affect driveability when cold. This and the code...

 

No, i purchased a 3 wire one just like this Bosch 15737 Oxygen Sensor | eBay. you can see the connector in the photo, I may have left out a little yellow piece when installing it.

I am tempted to buy another connector and install it, but is there a way to know if the 02 sensor itself has shorted out? Ive read you can take it out and test with a propane torch and multimeter, but I don't have a torch.

 

you can test it in the car if the car is running... disconnect the signal connector (thats the one wire thats a different color than the other two) and slip a thin bit of copper wire, like one strand of a lamp cord, a couple inches long around the pin and reconnect it. start and fully warm up the car, with it idling hook up a DIGITAL volt meter set for a single digit volts range (its harder to see the signal if the meter is autoranging). other volt meter probe to ground. with the engine idling and warm, the voltage should swing back and forth between about 0.2V and 0.7V every few seconds. if you elevate the engine above idle to like 2000 rpm, the swing should be about 1 second up, 1 second down. if so, then your O2 is working /and/ your engines lambda control cycle is working.

 

Hey Pierce, thanks for the reply.

now when you say disconnect the signal wire, should i disconnect where i spliced the wires, or should i disconnect from where it plugs in normally?

If you are suggesting i disconnect from where the original harness plugs in, could you point me to where that is?

 

on a 240, I believe the O2 sensor connectors are on the firewall not far from the wiper motor. there's a round single pin signal connector and a square 2-pin heater power connector. its that round single pin I'd disconnect, wrap the thin wire around and reconnect to do this test.

 

okay thanks I found It I'm pretty sure. it was a black circle shaped connector with a rectangular pin inside. I used a wire and tried to fit it back on as best I could. I only got .1 jumping to .3 on occasion.

just to be safe and save some hassle/cash, I'm going to put a new connector on and waterproof the crap out of it. see if that helps.

now if I put on a new connector or install a new o2 sensor, is there a way to reset the fuel computer so I can see if it changed anything? I've read unplugging the ecu could do this? I'm not sure

 

a 1990 LH2.4 system learns pretty fast, like a 20-30 minute drive should be virtually a fresh start, but if you disconnect the battery ground cable for 10-15 mins, its as good as forgetting everything it knows so it will start from initial conditions.

 

okay thanks so much pierce.
I plan on putting a new connector on tomorrow. if that doesn't work then il swap an o2 sensor. if that doesn't work then I may be back for more questions. either way I will post again with results.
thanks again for sharing your extensive knowledge of 240's!

 

Okay, so I installed a new oxygen sensor connector and that seemed to fix the check engine light issue, I drove the car for 20 minutes and the check engine light stayed off.

The issue now seems to be with my transmission possibly?
when I was driving home the car would randomly sometimes lurch forward or backward at high speeds. Sometimes even at a stop light with the brakes on my car would lurch forward.

any ideas?

 

Does it still go away with time? If yes... I'd think transmission issue all right. Did you have the fluid in your tranny changed recently?

As I understand it... sometimes transmissions get "morning sickness" and only start shifting smoothly after the system has all warmed up. What happens is the seals wear, and when they heat up and expand, everything seals tightly again, and you get decent shifts again. This can be aggravated by changing the transmission fluid if you never have and it has been a long time. But it can also just happen with wear.

If this is the case... I don't know much about solutions. I had the same fundamental problem with my power steering unit (which at a fundamental level is remarkably similar) and the solution was to replace and/or rebuild the steering rack. Doing the same for a tranny is more difficult. I know for engines, they have "high mileage" oil that essentially has chemicals in it to help the seals swell, and thereby stop leaks. I don't know if they make a similar product for transmissions... but that may be worth considering.

Just my thoughts. I'm sure someone will chime in with better ideas. The one thing I don't get is why the car would randomly lurch even with your brakes on.

 

brakes on at a full stop, or braking at speed? do these lurches feel similar to the ones you get if you downshift/upshift ? what gear are you typically in when its lurching?

 

I have not changed my fluid recently, might be a good idea to check it.

The lurching does feel similar to when it shifts gears. The transmission is automatic and I do not have a tachometer in my cluster unfortunately.

It will lurch when I'm coming to a stop, but one or two times i was fully stopped and the car was trying to jump forward even with my brakes depressed.

It seems to act funny in first gear, shifting in to second seems to make the car push forward for a sec.

I was also driving it on the freeway and it was doing great until all of sudden it felt like it dropped a gear and started struggling.

about a month ago, the belts on my engine snapped off while I was driving due to worn alternator bushings. I kept driving because I wasn't sure what happened, eventually my battery died and i limped to a stop. I was able to replace the bushings and get new belts on and it seemed to be ok. Could My car have gotten damaged while it was running without belts? these issues did not start appearing until after that incident

I have also read something about a kick down cable being dirty or stuck and causing issues, im not sure.

 

also now that I am thinking about it, the new belts we put on didn't seem to fit well and they weren't a matched pair. One of them was actually almost too wide to seat properly in the pulleys. Could slipping belts be my issue?

 

have you checked the trans fluid?

 

well, you have multiple belts. the only one thats critical to driving is the water pump. as you found, lack of the alternator belt will discharge your battery. lack of the AC belt (generally shared with teh power steering) just means no AC or power steering, at speed you'll hardly notice, but parking will be more challenging.

I second the 'check the transmission fluid'. get the car fully warmed up, as in a 15-20 minute drive on the highway, then park on a dead level spot, leave the engine idling, pull the tranny stick, wipe with a clean white rag, inspect what comes off (ideally its clear red, its probably golden to light brown, but if its dark brown and/or has a strong burnt smell, you DEFINITELY need to flush it and replace it), now reinsert the clean dipstick, wait a few seconds, pull it out again, and the level should be between min and max on the HOT side.

to flush it, first get about 8 quarts of quality ATF, I like the Castrol "Multi-Import" stuff thats for older Toyotas etc, as these AW7 series transmissions in fact ARE Toyota. get a clear vinyl hose the right size to fit snugly on the transmission cooler return line. also need a clean(!) transmission funnel, and a 'flare wrench' plus open end to fit the tranny hose-to-radiator fitting.

With the tranny warm, pull the drainplug off the bottom and drain out what comes out, thats only about 1/2 of it. let it drain for a couple hours. put the plug back in, disconnect that return line at the radiator and hook up the hose with the other end into the collection bucket... now add as much ATF as came out via the funnel through the trans. dipstick tube (probably about 4 quarts). start and idle the engine, and watch what comes out of that hose, and each quart that comes out, pour a new quart in, repeat until its coming out clear red. shut engine off, reconnect the cooler hose, start the engine again, and check the dipstick for the 'cold' marks, adjust if needed, take it for a 20 minute highway run, and check again for the 'hot' marks, add more if needed.

 

Thank you for all your help. I decided that the transmission fluid change was a bit over my head and took it to a local shop. after a long *** time, my car is back. turns out there was a leak in one of the trans lines. had new fluid put in and now it shifts fine. Also had a tune up and replaced engine mounts fixed my leaky exhaust etc. Again thanks for the diagnosis, you were correct.