1991 volvo 240

I'm no slouch when it comes to cars and diagnosing problems, but being that I'm new to OBDI Volvos, I want some reassurance.

A while back I got the overdrive working by replacing the kickdown cable. This morning, the orange shift arrow appeared on the dash and the car began to idle very rough and lurch at stop lights like it was going to die. I was able to pull into a gas station and pop the hood, my first instinct was to unplug the MAF sensor because it had been problematic in the past. The car instantly idled better and would no longer stall at stops, however, the overdrive is not working again, and I know that all of the hardware for it is in working order. Every time I reconnect the MAF the car idles rough and eventually dies. I'm assuming the MAF is shot because I cleaned it with no luck, and this is causing the overdrive not to work. Any feedback??

 

the OD circuit is completely seperate from the ECU and MAF. OD is simply pushbutton to OD relay to light and solenoid. when the light is lit, the solenoid is OFF, and when the light is off, the solenoid is ON. when the solenoid is ON, then the transmission is allowed to shift into OD when it feels the need based on hydraulic pressure.

MAF faults will usually throw an OBD-1 code on a LH2.4 car (1989 non-turbo and 1990+ everything). The ultimate test for the MAF is to swap it with another car thats working fine. if the other car has the same symptoms and your car is now fine, then give the guy his good MAF back and get yourself a new one off brand MAF refurbs are sketchy, some work, some don't, some fail young.

 

unfortunately there is nobody local with a MAF for me to test so I'm stuck with just buying one for $160. As for the OD not working, im perplexed because it worked just fine up until now with no arrow light on. While I know either the relay or solenoid is likely bad, The OD worked just fine. Sounds like the relay or solenoid decided to work again but is now stuck in the "off" position.

If I buy a MAF and it doesn't solve the issue I'm just scrapping this piece of sh*t. Nothing but problems since I bought it.

 

What other problems have you had with it? How much money have you put in it?
Another suggestion for the idle is the Idle Air Control valve. Those can get gummed up and cause problems in stop-and-go traffic.

 

I bought the car knowing there were some issues, it was planned on being a daily beater/driver. But so far it has just been little stuff that bugs the hell out of me. The windshield started leaking, bushings are going bad, rear end started howling then went away, now the MAF gone bad, etc... I've only had it 3 months haha.

Good news though, the overdrive issue was actually fuse #11, which happens to be for the rear defrost and 4th gear overdrive. HOWEVER, MAF still seems to be shot, runs with in unplugged, rough but it runs and drives, simply dies when I plug it in.

 

Check to see if any of the hoses and intake pipe after the MAF is loose or disconnected. Every now and then my car (a 240) will start then immediately die with the MAF plugged in. It's usually because of loose clamps etc etc.

 

Im going to tinker with it some more tomorrow before I pony up for the new MAF. I will also look for loose vacuum lines and take a look at the Idle Air Control Valve. I just hope it gets me to and from work with no issues.

 

Indeed. Wish you luck. Post your results!

 

Well I fixed the rough idle, runs like a champ now. Still can't figure out the OD so I just ordered IPD bypass kit for $50 so I will have permanent OD also noticed the transmission pan gasket is leaking again, so I ordered another one of those. Hopefully ill get it all fixed this weekend! In the mean time I try to keep it 45mph or less so I don't burn up the transmission.

 

actually, you can go 75 in 3rd all day long, just waste a bit of gas.

 

A lot of gas lol. Any thoughts on the ipd plate? Does it work??

 

yes, but so does dremelling a notch on the end of your solenoid and leaving out the inner o-ring. if you do this, remove the OD relay to prevent possible short circuits down the road.

If it was mine, I'd take a stab at debugging the electrics. I live near mountains, and like being able to downshift to 3rd on grades.

The button on the shifter is a momentary contact normally open... this is wired to the OD relay which acts as a toggle. the OD disabled light is ON when the solenoid is OFF (how weird is that?!?), because the light is wired to power, and the solenoid is wired to ground, so when the OD relay outputs +12, the light goes out, and the solenoid turns on. when the OD relay output is grounded, then the light comes on and the solenoid turns off.

when the solenoid is powered, it allows fluid to flow from a little hole in the middle to another hole in the outer part, when that fluid is allowed to flow, the transmission will auto shift into OD as it sees fit.

possible failure modes:
1) pushbutton on sifter is munged or wires in shifter stalk are bad/flakey, so it doesn't toggle or only toggles sometimes.

2) OD relay is bad or flakey, so it either never works or only works sometimes

3) OD solenoid is clogged or dead, or wires to it are bad

4) transmission itself has an internal problem, probably a clogged hydraulic passageway.


1 is hard to fix. 2 and 3 are easy enough to fix, 4 is gonna be $$$ at a tranny shop. The OD solenoid replacement plate or notch trick will NOT work if 4 is your problem (luckily, this is quite rare).

said notch...

 

In this particular case I think that the solenoid is bad and the button is bad as well. Not sure about the relay...

The light on the dash is still functional because when I take the fuse out for electronic 4th gear/rear window defrost, the light comes on.

I live in a relatively flat area where I would rarely need to downshift manually with the button, so I'm gonna try this IPD plate out. It showed up in the mail yesterday and I'll be at the shop tonight to install, at the same time I'm going to put another new pan gasket in. Next step is to get the heated seats to work!

 

[QUOTE=Northboundndown;371225]In this particular case I think that the solenoid is bad and the button is bad as well. Not sure about the relay...

Why?

Your problem is most likely the relay and it is the easiest thing to change.
Just this past week I had two 740's with O/D issues and both were solved with new relays...

 

Not sure, I just had a hunch.

Took the solenoid out today put the IPD plate in and overdrive works flawlessly now. I do plan on debugging the entire electrical system for it at some point. For now, I cut the wire for the solenoid and removed it completely. I left plenty of wire to splice a new one in when I finally do decided to get it. As for the relay, I'll take it out and test it.

I also replaced the pan gasket for the transmission again. In the midst of all this I noticed that a transmission line was leaking where it is held in place by the bracket attached to the chassis. Years of metal on metal contact looks like it might be wearing through the line. So I'll need to order one of those ASAP!

Looks like a wheel bearing in the front is on it's way out so I'll cross my fingers and hope it makes it through winter at which point I plan on just getting a new car.


Otherwise, for the time being, all is well.

 

those tranny cooler lines are no longer available, you'll need to fabricate replacements... you can use steel brake line, or even plastic tubing as long as its reasonably heat resistant. you can splice with compression fittings, if you can find the right size.

 

This website has them: https://www.google.com/url?sa=t&rct=...gBzP23TwXk91nw


$65 each. But I think I'm just gonna use some oil resistant line from the shop and hose clamp them, as I have read that sometimes the lines like to twist off at the transmission where they are rusted and corroded. I will likely avoid compression fittings simply because the lines are so old I wouldn't be able to get a good seal. And since I will likely need a new wheel bearing shortly, I might as well save the $130.

 

I was able to fabricate new cooler lines using some generic steel brake lines from NAPA. Each line cost me around $12 plus some compression fittings from Ace Hardware to adapt the ends. Takes a bit of patience to bend them properly but it has worked fine for 6 years now.

 

I ended up cutting the lines and inserting rubber transmission cooler line with hose clamps on both ends. Seems to be working just fine. I also took a large rubber hose and cut it down the center to use as a flat pad so the lines won't rub on the existing bracket. Then I zip-tied the lines up to the bracket and now it's good to go!

 

hopefully you used the black quality brand zipties (G-B usually), they last for years, about everything else I've used has fails in a year.