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240 poor running problems[ALL/1998] posted by Jack Austin on
Wednesday, 26 November 1997, at 9:44 p.m.
Okay...I give up! Kathleen is all over my back to figure out what is wrong
with her car, and I am failing miserably at being The SMARTEST GUY IN THE
WORLD. If anyone out there has had some experience with these symptoms on a
similar engine/injection set up I would be most greatful to hear from you.
THE DETAILS: 1986 244 / B230F engine with L Jetronic injection and about
125,00 miles. Excellent car, well maintained, I am the second owner. After
about two months of ownership it started to hesitate very slightly. As I
recall, it began doing this only upon cold start and through the earliest
stages of warm up. As time went on, perhaps two weeks or so, the symptoms
became progressively worse until the hesitation (dropping of cylinder(s)?)
had become alarming. In some instances the fault disappeared after warm up,
in others it would persist for days, bsing at times more or less obvious.
During my diagnostic efforts I have replaced all of the fuses in the fuse
block making sure that there was no corrosion on any terminal. I noticed
that the fuel pump was somewhat noisy, not just the usual high pitched hum,
but a lower rumble like failing bearings or rough impellers rollers. The
pump and filter were replaced. At the same time fuel pressure tests were
done, both before and after the replacement, and everything was found to be
within spec. This could be misleading though, as during this particular time
although the pump was noisy, the engine was running well. Actually, for a
period of about two weeks after the fuel pump replacement the engine ran
almost perfectly, with only an occasional slight hesitation. I have also
inspected and cleaned the distributer cap and rotor. I also pulled the
spark plugs and found them to be as new. The high tension ignition wires
appear as new and there is no evidence of arcing during inspections at
night. Likewise, the ignition coil tower is clean and shows no
deterioration although it appears to be original. I have made certain that
grond connection under the rear seat for the fuel pump is good. The air
filter is perfectly clean, and I can detect no vacuum leakage along the
flexible air intack ducting. I have run one bottle of "fuel injector
cleaner" through the fuel system. I buy gasoline from only one source, and
I fuel my three other vehicles at the same pump and have experienced no
problem with contaminated gasoline. I have removed and inspected both the
throttle position sensor and the air idle controller. I could not get
inside the position sensor case, but it appeared to have some oil in it so
flushed it with electrical contact cleaner. The rotating shutter in the air idle controller was found clean and free, but I hosed it down with
contact cleaner and then gave it a blast of WD40 so that I could feel like
I had done something positive. I did both of these operations during a
mild episode of rough running and neither seemed to make much if any
difference. During earlier episodes of the problem I had disconnected
each injector electrical connection plug, both at idle and at about 1200 rpm or so. Insome cases the roughness increased with each disconnection, but at
other times there seemed to be no change. When the described problem is not
present the car starts and runs perfectly, with an even idle, correct warm
up charactoristics, excellent power and smooth running. The problem can
come and go abruptly or it can come on progressively. Today, Kathleen
explained that it had been running very well for several days, and then
without warning, after a few moments of being shut down and then restarted,
it began it's hesitation routine with a vengeance. I drove it when I came
home from work this evening and the problem is as severe as I have
experienced it. A few weeks ago during a similar spell I was fishing
around looking for the fault and noticed that the sheath covering the
heavily bundled wiring harness passing over the rear of the intake
manifold area and behind the cam cover had become cracked and nasty looking.
It looked as if the insulation of some on the wire could become worn
through if left in that position so I lifted the whole bunch and postioned
it so that there was less strain on the iwres until I could find time to
clean it up and improve on the deterorated sheathing. Lo and behold the
rough running problem seemed to be reduced considerably. Over the next few
days the engine ran well, with little or no roughness. I tried the same
thing this evening, but there was no improvement this time. PLEAS HELP!
If you have had any similar experiences and have found a solution I would
be happy to hear from you. I can be reached VIA the BrickBoard as a response
to this posting, or VIA e-mail at twigwork@skybest.com, or directly through
a fax at 704.295.4814. Thanks again, Jack Austin
Re: 240 poor running problems[ALL/1998] posted by Mike Posner on
Thursday, 27 November 1997, at 1:21 p.m.
Two symptoms you mentioned are consistent with a bad tank pump. First the noisy main pump usually means the tank pump isnt providing enough fuel and air gets pulled in creating the noise. When the tank pump is working it helps prevent vapor lock which your problem restarting after sitting awhile sounds like.
You can put your ear, a rubber hose helps, to the gas filler opening with the cap removed, and you can hear it buzzing. Alternately, you can remove the
fuse which controls the tank pump(#5 on the 240, and see if the idle rpms drop. Good Luck.
Re: 240 poor running problems[ALL/1998] posted by Dave Stevens on
Thursday, 27 November 1997, at 1:22 p.m.
Sounds like the SMARTEST GUY IN THE WORLD has done a pretty good job of trying to isolate this problem. There have been similar problems posted on the Board so a few minutes of searching would probably be worth your while.
When you're experiencing intermittent problems, the first thing to suspect is electrical.
One common electrical problem that you appear tyo have overlooked and that can lead to stumbling is a faulty fuel pump relay. You should find it in the passenger footwell area on the firewall. It may have a cracked solder joint, pitted internal contacts or just plain fatigued from overheating. Behaviour can be very very erratic depending on temperature and humidity. About the only way to fault trace it is to catch it in the act, which isn't always easy. Eventually it will fail outright. You can attempt an R&R on it, but I would suggest replacement.
The only other thing that you haven't looked at is the AMM (the 'box' in-line on the air intake). You could be experiencing the beginning of a failing or fouling AMM. Pull the electrical connecter, check and clean the contacts. Also check your air filter box to make sure the big warmup air flap is free and working properly (check that it's open at cold and closes after full engine warmup). If too much hot air is getting to the AMM it can lead to failure.
Good luck -let us know what you find.
Re: 240 poor running problems[ALL/1998] posted by Mark Erickson on
Thursday, 27 November 1997, at 7:04 p.m.
My 83 240Dl started missing anytime the motor was cold and the temp started
dropping below 50 degrees, As winter set in it got worse and worse even
to the point where sometimes it wouldn't start. I finally took it in to a
shop (Gorshe bros. in Mpls.. Thanks Jarrod) They cleaned and tightened some connections in the distributor and replaced the cap and rotor and the
car runs fine now. It can be 0 degrees and it will fire right up and drive
away without even a stutter. Pretty good for 170,000 miles. I had replaced the fuel filter, O2 sensor, plugs, wires, and even had a shop time it.
I wish I could tell you what exactly they repaired, The Distributor cap had come loose and the rotor was pretty much destroyed but it had the hesitation problem before that came loose. They said that after they cleaned the connections and replaced the cap and rotor it ran so good they couldn't justify doing anymore diagnostics.. $64.00 bill I couldn't complain.
Before you go sinking big bucks into fuel pumps and Amm's maybe check the electrical connections and see what you can find.
Good Luck,
Re: 240 poor running problems[ALL/1998] posted by Topi on
Thursday, 27 November 1997, at 9:01 p.m.
Looks like it's time to spend some money!? Star with the cheapest and most logical parts: Buy a new cap & rotor, and also plug wires even if they're "as new", unless they are OEM Volvo. The cap will short out with most aftermarket wires and you'll not see it! (Too much resistance). New caps are beefier and there's more material between the posts.
Re: 240 poor running problems[ALL/1998] posted by Mark Klein on
Thursday, 27 November 1997, at 9:19 p.m.
The engine wiring harness can give these symptoms. Is the insulation flaking off the temp sensor wire for the gauge? The wire for the temp sensor for the fuel injection may also be flaking.
Also, the fuel pressure regulator can intermittently act up going to full fuel pressure when it is failing. This can give a variety of symptoms including a loud fuel pump and very similar running problems.