The 240 DL that does not like the cold.

Good day,

I have an 89 240 DL LH2.4 with aprox 245k miles with a good ole m47 transmission. She is most happy when its a nice sunny and 75 degree day (but who isn't??? ) On the other hand She is not so happy when the temperature dips into the 30's on my morning commute into work.

She fires right up every time and after a few minuets of gathering her bearings, has a nice and smooth idle. Its honestly pretty impressive. Typically when it is cold out in the 30's or so I let her warm up for about 5-10 min before I hit the road. This is about the time my my issue starts. I will do the best to describe it... It feels and sounds as if the motor is "stuffed up" she revs differently shifting through gears and kind of sounds bogged down, almost like the exhaust is trying to be passed through a pinhole. It just feels/sounds completely different than when the weather is warmer out.

I have replaced a few items all within the year that include new spark plugs (bosch coppers) spark plug wires, distributor cap and rotor as well as a new 02 sensor, ECT Sensor, MAF, air filter and have replaced pink label ECU with one from a 93. I have also cleaned the flame trap and currently running 10w30 oil.

No codes are being thrown and I do not have a CEL on the dash.

I am trying to see if anyone has experienced this with their red blocks or if its simply the temperament of an older engine. She is a bit slap happy when cold but hell I have very rarely met a 240 without piston slap.

The last thing I can think of is replacing the thermostat.

Thanks!

I've seen poor power when cold in a few situations. I say start off by cleaning the throttle body and MAF, then seafoam the cylinder head and the block. The slap can be lessened with a seafoam treatment. They all slap when cold, but as long as the piston rings seal that's what matters.

It may be a good idea to check out your ignition control module. Inconsistent spark from this module could cause the symptoms you're seeing. Is the temperature gauge rising past the 9:00 position when it's fully warmed up? Suspect parts could be the heater valve and the thermostat.

From your description it seems like a good idea to check the catalytic converter. You can do a pressure drop test if you have a port in the front pipe. Or you can shake the exhaust and see if there is loose stuff in there. Blocking up the exhaust flow.

I did clean the MAF before installing it but have not touched the throttle body just yet. I have been wanting to do a seafoam treatment for a while now. I was thinking a excess build up of carbon could be contributing to the issue.

As for the temp gage, The it has had the bypass done to the board. I have noticed often times that the gage will creep up past the 9 o clock mark but quickly fall back down to the mid way mark for the rest of the drive. I do have a new thermostat that I will be putting in very soon.

Thanks!

darkmountain said:

89 240 DL LH2.4....temperature dips into the 30's...

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1. At temperature, while stopped, rev up engine, then release accelerator pedal: result?

2. Inlet air thermostat working?

3. ECU's coolant sensor can be ohm spec'ed

4. Vacuum leaks, brake booster leak, or MAF is not "sucking" all of the air

Delete the hot air thermostat thing if you haven't already. Take the thermostat out of the airbox and use a rubber pipe cap on the inlet. (I think it's 2 or 2.5 inch)

So, what changes from "cold start" (runs fine) to "warmed up" (runs poorly)? I assume that the EFI goes to a leaner setting? Is there a cold start injector on these cars that may mask a regular injector issue when it turns off?

Newb advise... Please ignore.

Cwazywazy said:

Delete the hot air thermostat thing if you haven't already. Take the thermostat out of the airbox and use a rubber pipe cap on the inlet. (I think it's 2 or 2.5 inch)

Click to expand...

I actually just did this mod this morning. Unfortunately it has not been cold enough for the symptom to present itself. But wow it did make some difference with performance and sounds nice too. I feel like the motor can breath nicely now! Lets hope this did the trick when I drive tonight when its supposed to be cold.

84B23F said:

1. At temperature, while stopped, rev up engine, then release accelerator pedal: result?

2. Inlet air thermostat working?

3. ECU's coolant sensor can be ohm spec'ed

4. Vacuum leaks, brake booster leak, or MAF is not "sucking" all of the air

Click to expand...

1. When the engine is rev'ed once fully warmed, the throttle is nice and responsive but even when fully warmed it feels and sounds "stuffed up" after about 20 min of driving it will back to the normal feel I would get on a warm day. Sometimes if cold enough the "stuffiness" will come and go even with engine fully warmed up.

2. I have actually just as of this morning did the airbox mod that I've read a good amount of 240 owners have done. The weather has not been cold enough today to test its results but I did experience a little bit more pep and seems like the engine can breath nicely now.

3. Ill be honest I am not sure how to do this, I'm am not the most inclined with electrical work. Honestly working on my car is still pretty new to me, I try to get help or be careful on repairs out of my reach, though I did get the new coolant temp sensor from IPD.

4. I have had my very trusty local Volvo mechanic check and he told me he was not able to find any vacuums leaks. The tube after my MAF has no cracks either. I have also replaced the MAF with a new known properly working sensor

Its a bit of a rabbit chase haha but I am hoping the airbox modification with help. It might just come down to the fact that its an older car and thats how it runs in the cold. I just want to ensure its running as efficient as possible.

darkmountain said:

1. When the engine is rev'ed

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Example - quickly advance throttle to a high RPM when STOPPED, out of gear, then quickly take your right foot off accelerator.

Ohm spec you DISCONNECT the connector at each the EZK and the LH box, stick a needle to front probe (a no-no; can damage pin) or unsheath connector, and measure between the correct pin and ground the resistance of the temp sensor. Find a wiring diagram and the specs!

LC4CARL said:

So, what changes from "cold start" (runs fine) to "warmed up" (runs poorly)?

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Air density...colder air is more dense

He didn't say what brand of spark wires he bought, nor what plug gap is being used, but more electrical spark energy is needed with colder days at higher road speed RPMs.

Normally, vehicles run better with colder air, due to increased air density (more oxygen molecules). "A cold air intake system is one way to increase engine performance"

During a cold start, LH-2.4 will add extra fuel for 5 seconds or so...and running "fine" at cold idle does not require much spark energy.

So, if he bought a cheap spark wire set, instead of a Genuine Volvo Ignition Spark Plug Wire Set (Bougicord), then as dl242gt noted,

"Many aftermarket wires have higher resistance than the stock Bougicord wires. Volvo specification is for 500 ohms per foot. Many aftermarket wires can have as much as 1500 ohms per foot and that is an acceptable spec if that is what is called for. But not on Volvo cars."

Backprobe!

Backprobe is the way to avoid terminal damage.

ZVOLV said:

Backprobe

Click to expand...

The basics may be a better starting point...

1. Does battery's grounds go to engine and frame?

2. Does engine's two grounds go to firewall?

3. What is ohm spec on coil

4. Which plug wires were bought?

5. Which spark plugs, and gap?

6. Brand name of distributor cap, and rotor?

7. Clean up wires to coil, and 'power stage'

I suspect his spark energy is weak

He asked how to "Ohm spec" an ECT and I provided an answer, Kansas.

darkmountain said:

1. When the engine is rev'ed once fully warmed, the throttle is nice and responsive but even when fully warmed it feels and sounds "stuffed up" after about 20 min of driving it will back to the normal feel I would get on a warm day. Sometimes if cold enough the "stuffiness" will come and go even with engine fully warmed up.

2. I have actually just as of this morning did the airbox mod that I've read a good amount of 240 owners have done. The weather has not been cold enough today to test its results but I did experience a little bit more pep and seems like the engine can breath nicely now.

3. Ill be honest I am not sure how to do this, I'm am not the most inclined with electrical work. Honestly working on my car is still pretty new to me, I try to get help or be careful on repairs out of my reach, though I did get the new coolant temp sensor from IPD.

4. I have had my very trusty local Volvo mechanic check and he told me he was not able to find any vacuums leaks. The tube after my MAF has no cracks either. I have also replaced the MAF with a new known properly working sensor

Its a bit of a rabbit chase haha but I am hoping the airbox modification with help. It might just come down to the fact that its an older car and thats how it runs in the cold. I just want to ensure its running as efficient as possible.

Click to expand...

What was the part number of the new coolant temp sensor. What color is the plastic part of the new sensor?

What color is the car?

84B23F said:

The basics may be a better starting point...

1. Does battery's grounds go to engine and frame?

2. Does engine's two grounds go to firewall?

3. What is ohm spec on coil

4. Which plug wires were bought?

5. Which spark plugs, and gap?

6. Brand name of distributor cap, and rotor?

7. Clean up wires to coil, and 'power stage'

I suspect his spark energy is weak

Click to expand...

1. Yes
2. Yes
3. That I do not know to be honest
4. Unfortunately they were bought at auto zone after one of the spark plug boots broke off when changing the spark plugs. Its my only car so I had to go with them at the time. New Volvo wires are on their way!
5. 0.028 Though it was my first time gaping spark pugs but my buddy checked to make sure they were gaped accurately.
6. Bosh
7. I have not done this yet.

I agree with you, I feel like I have covered all temperature suspects other than the thermostat which I am still doing very soon. The car never over heats and gets to full temp fairly quick. Especially how the symptom happens sometimes even when the car is at full temperature.