Hello all, I have searched and search but have not been able to figure this one out. I have an 86 Volvo 240 wagon that only spudders when taking off from a stop or when floored at speed. It drives flawless when the engine is cold however once it's up to oppressing temp it starts the sputtering aruff which is quite annoying since the whole wagon will jerk until it's up to speed. Something you can feather the throttle to help tone the sputtering down but almost every time from a stop it does it. I've recently replace the in tank pump and sending unit along with a new cap/rotor, spark plugs and wires and also fuel pump relay. Any ideas?

My '88 wagon had the exact same problem. When started, the engine ran fine until it warmed up, started sputtering, and died until the engine cooled off. This was accompanied by black smoke from the exhaust and black, sooty, fouled spark plugs. My problem was the engine coolant sensor. As the engine warmed, the sensor sent the signal that it was still cold and continued pumping excess fuel.

This may not be the most logical trouble spot but i have two 86 and both had very intermittent(difficult to diagnose) coil failures when warm. Of the other ten or so 240,s from 78 to 93 no issues with coils. So just on that i would swap coil on any troublesome 86.
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Rene

Hey, you came back!
So I didn't scare you off with so many questions.

Let see you squared away the ignition system and replaced the AMM.
I am gathering the idea the problem has persisted despite these changes or all of this was done prior to this happening now?
You might want to slip a history lesson to us!

60 degrees is not cold but you had snow there and not that long a ago!

I suspect your running a little bit lean. But "As" the engine warms up, it "might" be getting even more lean.

A Fuel Pressure Regulator is suppose to enrichen the mixture slighly under acceleration but actual sputtering should not result from its function. A little lag in power is what is felt most of the time.

The FPR main failure is usually an excess of fuel mixture because their diaphram ruptures. Extra fuel get into the intake through the vacuum line from it.
It creates hard starting problems like in long cranking time until it clears itself of the fuel or the fuel rail, has lost its rest pressure volume.

You can check it by pulling a vacuum on the line and check for fuel in it. Do you have an idea how old it is?
It might be worth checking fuel rail pressure and or volume of deliver. There is a specification for that.

Since you changed the pumps.
I assume, whoops, that you cruised an eyeball and a bright light around inside the tank back then!

Have you ever changed the main fuel filter/accumulator. They last a long time but it's only a thought.
If your fuel volume was low, consider that item.

That about all I can think of until "we" on the Board get our history lesson! (:-)

Phil

Sputtering is a word I use for water in the gasoline.

Hi there!

You must be a newbie with only one post!
I looked to see where you are located, so as to ascertain what cold is?
Do you know if your a USA, Candian or an European model car. Heck, it could be from the California country!
How cold is that?

If it runs flawlessly when cold, then the enrichment for that condition, is either working correctly or your are running to rich at operating temperature.

It could be an Engine Coolant Sensor signal problem to the ECU?
The ECU bases its timing and mixture perimeters off it and the AMM!

What does the rear area scene look like behind you?
Is the tail pipe inner circumference rub out with a rag excessively sooty!
Excessive is, with lots of soft black stuff. Some soot is always there from in the town drives.

When you did the tuneup, were the plugs showing gas fouling?

If none of the above, then you could be too lean, which would cause misfiring or shuttering.

When you took out the plugs were they really clean and whitish looking?

If you still have them around did the insulator noses show cracks, speckles or spots? There could be a timing issue. Lack of advancement.

Are you hearing any rattles or pinging when it shudders?

You could check the according tube behind the AMM for fit and holes!
Is the idle normal at all times! No things like it suddenly quits at lights?

It only does it when stepping on the gas could be a maladjusted or bad throttle position switch. That might help describe the high speed flatness of power. A bit far fetched though!
A bad AMM, could pop a bubble, on that one easily.

If you could get back with some answers, for or against, it might help pick on someone's else's brain of experiences with having the same symptom.

Is this car a stick or an automatic shifter and some mileage ideas could help also!

Phil

Hi Phil! Yes I'm a newbie here. This is my 2nd 240 so I've been reading here a lot over the past two years but never had to post since almost all of the info needed if available. I'm here in Texas and it's about 60 degree outside. There are no odd noises when the sputtering happens. The plugs where a whitish color presuming they were a bit lean. I did replace te Mass airflow unit on this one which is right in front of the intake accordion hose and also replaced that as well. The plugs and wires are less than 100 miles old right right as well. It's an automatic. Thanks for any assistance,
Kenny