A few years ago I bought an 88 240 from a charity (donated) it wouldn't run, but hmmmmm, the gas guage read empty. I put a few gals of gas in it and started it up and drove it home. It ran rough, but it ran. After a tune up and a few cans of sea foam, it ran like a charm. I sold it a few months later.

Now, tempting fate, I just bought an 84 240. It ran, the engine sounded pretty good, no knocks or anything. It idled very roughly and was a bit hard to start. There was a pretty bad hesitation on initial acceleration. Body is good for the year. Very rough idle, and a few noises from the rear end, but I thought I'd try another Volvo for a cheap price and hope to do the same. WRONG idea. This one, evidently has been sitting a while. The power steering leaks like a spaghetti strainer. I put fresh gas (7 gals) plus a can of sea foam in it, hoping to get a cheap clean on the fuel system.

I tried to drive it a few miles to run the sea foam through the system, after the idle seemed to smooth out. It hesitated severely on initial acceleration, but it eventually took off. As i ran it down the road, at about 4K rpm in 2nd gear (auto trans) it just died. As I hit the gas, i could hear the engine taking in air, but it wouldn't fire. once on the side of the road, it would turn over freely, but just wouldn't start. Stupidly, I didn't bring my cell phone or wallet, so I was left with a nice lil 3 mile hike home...

I know there are a ton of issues that could cause this, especially on a car that's been neglected, but after it's towed home, does anyone have any ideas where to start?

guess that's what i get for buying a $450 car to try to save some gas money. :-(

Regards,
dlsipe1

 

It sounds like you have a few problems.
A massive vacuum leak could explain the acceleration problem.
Replace all the vac lines and the intake manifold gasket.
Be sure to clean the throttle body and idle control valve while you're at it.

A failed or extremely dirty MAF sensor could also be the problem.
Trying cleaning it and changing the air filter at the same time.

Once you get running (even passably) go to a transmission shop for a diagnosis to see if it's worth fixing.

 

Thanks Philip. I think the trans is ok. It shifts nice and firmly between gears 1-3 and fluid looks just fine. I do think the O/D solenoid is bad. I just don't get the immediate and sudden shut down of the engine. Of course I have to have it towed back to the house so I can play around with it and check some simple details. I will clean the MAF, and check vacuum lines, etc, but it sounded like it just either lost all spark or all fuel suddenly.

 

If you lose vacuum the fuel pressure regulator stops working.

By all means, check everything there is to be checked.
(plugs, wires, fuel pump, lines, etc..)

 

Thanks! Will do. I wish there was a guide to the vaccuum lines so I knew exactly what I'm looking at. Haven't messed with this kinda stuff in over 20 years. Looks like I just found a new hobby - like it or not.

 

There should be a vacuum hose routing diagram somewhere near the front bumper.

 

Thanks, I'll check. The car was repainted at some point of its life. Hopefull they're not painted over. Looks like I need to start looking at the fuel system beginning with fuse, relay and pump. No classic humming noise from the rear of the car when I try to start it.

 

Don't 84's have a K-jet system? If so, you won't find a mass airflow sensor in the usual sense. I would check and see if cam shaft still turns (timing belt isssue). Also, with all no starts, see if you are getting fuel and spark. That will point you in the right direction. I agree with the other previous suggestions too, especially the vacuum lines.

 

Well, I found a bad fuse near the ignition coil. Replaced it and it fired right up. It still runs poorly - surging at idle, hesitating and missing. Pulled spark plugs and replaced them (they were damp) and replaced plug wires, cap and rotor. I cleaned the throttle body and what I assume is the MAF on this old thing. Found a pinched vacuum line and replaced it. Still runs poorly - maybe a little better but still hesitates severely under load and surges as it idles. Could the fuel pressure regulator be a suspect here or perhaps the flame trap thingy - if I can figure out what and where it is? I don't know how to test sensors for voltage, but I guess I'm gonna figure out how.

 

Not true.

 

The vaccuum line to the regulator has suction when the engine is running. I tried the "propane test" around the intake manifold gasket, but couldn't find any leaks. I ordered a new fuel pressure regulator yesterday. I hate to feel like I am randomly throwing parts at the problem though.

 

well, normally you'd test a fuel pressure regulator with a fuel pressure gauge, this connects in series with the input line to the fuel rail, then you start the engine and it measures the actual fuel pressure, which should be about 43 psi above the manifold vacuum (disconnect that vacuum line to the regulator, and you'd see 43psi, connect it and see about 8-9 psi less)

 

thanks, Pierce, I wish I had such gadgetry, I may need to pick up a fuel pressure gauge and many other things if I want to continue deeper into this mess. I tried to replace the fuel pressure regulator this eve and planned on relieving the pressure in the system by removing the #s 5 & 7 fuses and running till the engine ran out of fuel. funny thing is, it never ran out of fuel. Very strange indeed. I couldn't kill the fuel pump(s) by pulling the fuses?

 

I swing by my friendly neighborhood import car garage when I need to check something like that, they'll do it for me for like 1/2 hour of shop time, and half the time they wave me off when I try and pay. yes, they've done several big jobs for me like head gaskets.

I forget, does your car have the OBD blinky box? test mode 3 on the fuel side cycles the injectors with the fuel pump off. all fuel pressure is relieved almost instantly. the 7xx FAQ on the VCOA site explains how to use the OBD stuff.

 

From what I've read, the OBD boxes started on the 1989 model year. Mine was 5 years too early.

 

ah, yeah. when I posted that, I wasn't in the mood to scroll back and double check the year

anyways, while there's residual pressure in the fuel system, there's no real volume behind it, so when you unbolt the fuel line it will just spurt a little bit out.

but your car is, I believe, a K-jetronic, not a LH-Jetronic, thats a totally different system. CIS-E rather than EIS. K-Jet has significantly HIGHER fuel pressure than LH. I don't really know much about troubleshooting it, the only K-Jet cars I had were VW's and were dead-nuts reliable the entire time I owned each of them (an 84 rabbit convertible with the 1800cc GTI engine, and a 89 jetta gli with the 1800cc 16V).

 

If I have read correctly, mine should be an LH 2.0 system (83 and 84 240s). Guess I'll just grab some rags and slowly unbolt the fuel pressure regulator. A lil scary, but I don't know how else to take pressure off the system. I checked the best I can for vacuum leaks and replaced a few suspect hoses. The car runs the same with the MAF wiring harness plugged in or not. The car runs VERY rich.

Anyway when I put the MAF and all the plumbing leading back to the throttle body together, I noticed something a lil strange and maybe a clue to one of my problems? When i plugged the large vacuum line leading to the Air control valve, the idle smoothed out completely. When I gave it throttle, however, it still had a nasty hesitation. If I slowly applied or feathered the throttle it would rev easily.

Could this be the air control valve causing this and is there any way to further diagnose the problem given the additional findings?

 

if its LH anything, the injectors have electrical connectors on them. if its K/KE-jet, they don't. LH, all the injectors are connected to a common fuel rail, while K/KE, they each go to a fuel 'distributor'.

the idle air control valve acts as a throttle plate bypass, and lets the ECU regulate the idle speed. for all practical purposes when its open, it acts like the throttle is a little opened a little bit wider.

Now, the fuel pressure regulator, which is at/under the front end of the fuel rail, it has a vacuum hose, if thats leaky, there will be way too much fuel pressure at idle and smaller throttle settings, which will cause the injectors to squirt more fuel than intended on each cycle which certainly would make the engine run rich.

otherwise, I dunno, maybe your MAF is hosed. or the ECU. or a wiring problem.

 

Thanks, Pierce. From your description, I can now confirm that its definitely an LH.

 

Well, I finally got around to replacing the FPR valve...no change. Removed my new spark plugs and they were very dark in color and smelled of gas. The Air control valve appears to be functioning properly. Still, I have the surging idle... I even sprayed nearly an entire can of throttle body cleaner through the intake. I'm stumped...but not willing to give up.