Hello everyone! I am again having a CEL for 2-4-1, and after I reset the code, by disconnecting the battery cable, it usually lasts around 1000 miles until it agains turns on. 1991 Volvo 740 non-turbo, 181,000 miles and it runs so sweet, many parts have been replaced! This is the only issue I have with this car! Which is the most likely to have worn out first: The EGR Vacuum controller, or the EGR Temp Sensor? If it is the EGR valve itself: I have no darn remedy for that possibility! Thanks so much! Jeff

Last week I did all of the tests with the diagnostic black box in positions 2 and 6. Everything worked! I tried to reset it but I could not. Then after restarting the car, the light was off! I did not this time, dc the battey to rest it for the next, hopefully, 1000 miles! I guess this is this cars future!
Jeff

Hi Jef,

Did you service the EGR piping, check the vacuum, check the little vacuum solenoid where you have the white cap and the foam underneath that Phil Machine Man suggest removing the foam with some sort of fiver material that works in underhood conditions?

Did you take apart the EGR piping and inspect for clogging. Mine was clogged on my 1991 in 2000 when I bought it a bit. Cleaned it all out, moved to Mobil 1 10W40 oil, not clogged again.

So, all is well, I hope. In that you do not have a socket 6 (ignition) fault code 2-4-1?

Hope so. Hope all's clear! Happy Friday!

I'd not ever researched whether EGR equipped autos produce drastically lower NOx versus the same config non-EGR auto model counter parts. When last checked, the 1992 LH-3.1 240 GL produced as clean an exhaust as the 1991 and 1990. Makes me proud with some simple stage 0 tune-ups on both sides of the engine control makes a Volvo 240 get some good and 'clean' exhaust with good fuel economy.

I also drive with light pressure, usually, on the gas pedal. May make for slow starts at the green light, and like Uncle Old Duke states, you'll get peer motorists sometimes giving you some manner of disapproval.

Hopes to have a technical writer / illustrator job and new pad with garage. The 240 service work can recommence 7 years on.

Please lettuce know.

Iced Tea Boyeeeeeee
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I was able to remove the plastic cap on the top of the Vacuum Controller!!! The small round sponge essentially "dissolved" into fine pieces upon its delicate removal! May I use sponge from a pillow or a dishwashing sponge cut to fit? How about cotton? How about using the paper from a respiratory mask cut to fit? The EGR valve is heard moving (soft click), and the car stumbled when suction applied while running. Am I getting close to resolution??? Thanks so much ! Jeff

That sure sounds like a problem!

You can carefully bend the 3 metal crimps out of the way and open up the controller. Then you can clean all the little bits out of it. Then I would replace that sponge with something like a piece of dust mask. It is only there to keep crud from the air from getting into the valve.

While you are at it, I would replace the vacuum tubing because it likely has little crumbs of open-cell foam in it. Take photos every step of the way on disassembly! You don't want to have to replace it or reassemble it 5 times to get it right.

I had a LOT of issues with an EGR code that resulted in buying a sensor that cost quite a lot of money. That's what it took to fix it. You can search my old posts about it if you wind up going down that rabbit hole.

Is the 2-4-1 EGR flow too low? Basically, the sensor is not detecting a change in temperature that it expects to see, if that's what the code is.


The car stumbling when vacuum is applied to the hose means the EGR tubing is clear (enough) and the valve is moving and not sticking in the range where you're moving it.

Good luck!

Please choose the column to indicate year.

Yes, maybe. There may be other issues. Please see my post I just, well, uh posted.

I'll disconnect the EGR valve vacuum line and use a vacuum pump with gauge or merely suck on the line to see that the EGR valve opens and closes, or that the vacuum you apply holds.

I guess some nylon fiber. As I state in the post, and as Phil Machine Man says (search for "Machine Man" and EGR with and without the and ... using the search here or through Bing or Google.)

I'm unsure the material. Something that survives under-hood conditions. So maybe some sort of nylon fiber? I'll ask Phil Machine Man to provide guidance. Or search Bing or Googled fo rsome temp resistant fiber. Yet maybe polyester fill would work. I'm unsure. I forget what I've used.

Hope that helps.

https://www.brickboard.com/RWD/volvo/1650145/220/240/260/280/egr_temperature_sensor.html

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Thank you again Kitty! Jef

If the fault persists and you reset the code using the OBD-1 code check and the CHECK ENGINE light returns, well, you have a fault with the EGR.

Are you in CA or CO-state?

Didja check socket 6 (ignition) for fault codes? The ignition ECU is what controls EGR. The fuel LH-Jet ECU merely takes signal and will set fault code. So, a fault in 2 may mean a fault in 6, also.

Be nice to know which ECUs you have by Bosch and Volvo number.

If the EGR temperature sensor is working, the faulty may mean
- EGR vacuum control if not working
Failed vacuum, failed EGR valve, malfunctioning EGR vacuum controller. That little think with the white cap.

- Temp sensor has failed (the wire frays and breaks inside the insulation at the sensor where the metal ends and the wires pass out).


- EGR piping is clogged with exhaust vapor condensates. These clogs usually form at the intake end as it is more or less cooler than what comes out of the exhaust.

Another option is to cap the exhaust manifold and install a known good Jetronic 2.4 ECU and a corresponding ignition ECU. Most of the control of EGR is in the EGR-enabled ECU.

Yet we do not have a comprehensive table of these ignition controllers in the FAQ.


Prior posts with my replies on EGR. I have a 1991 240 with EGR.

RWD - Some EGR Options for You - Brickboard

https://www.brickboard.com/RWD/volvo/1650093/220/240/260/280/egr_temperature_sensor.html

RWD - EGR temperature sensor - Brickboard

https://www.brickboard.com/RWD/volvo/1650110/740/760/780/egr_valve_delete_substitute_piping_parts.html


hacking the EGR system 200 1992

https://www.brickboard.com/RWD/volvo/1627292/220/240/260/280/hacking_egr_system.html

EGR Temp Sensor code 4-1-3 900 1994

You don't have this fault code, and yet ....

https://www.brickboard.com/RWD/volvo/1572807/940/960/980/V90/S90/egr_temp_sensor_code_413.html

Questions?

Hope that helps!!!

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Thank you so much for your response! You have given me much to look at and for!
I am in Colorado. I have been using ethanol-free fuel for over 1000 miles, and have a smoother idle, and increased mpg by 2mpg!
Where might I find parts? New or used? Jeff

Hi Rattlebone54,

Is your Volvo suspension so stiff it rattles your bones?

Nyuk! Har-har-ha-heh. Okay maybe not so funny.

Not Turbo in that 1991 Volvo 740. Normally aspired, yes? I'm not fluent in all OvLov configurations that may include EGR.

Also, all of the posts I list may provide a start to your strategy.

No such thing as Santa Rosa, Colorado. You used to reside in NorCally?

https://www.brickboard.com/FAQ/700-900/EngineFIComputer.htm

Though this table is wholly incomplete. It does not list the probable ignition ECU(s) that comes installed, mated, as it were, to the fuel injection ECU.

Please provide the Bosch / Volvo part number on the LH-Jetronic ECU. I'll guess you have the EGR-enabled:

0 280 000-933

or

0 280 000-946

The 700/900 ECU/AMM Reference Chart, incomplete as it is, lists the -933 as used with Turbo 700-900. The -933 I have I pulled from a non-Turbo 700 or 900, maybe 1991 or 1992.

I have a yellow label 0 280 000-556 from the factory for the 1991 240 with EGR and seized left front Bilstein HD (Billy HD sucks, btw, as they seize on other makes as water intrudes and freeze and the beark at the valve body). That 1991 240 has the 0 280 000-946 in there with the original ERG-enabled EZK116 ECU.

About the only part you may be able to find as new old stock is the vacuum controlled EGR valve. I believe the temperature sensor is also still available. Please read through the linked posts. The newer EGR valves, if you read them linkedin posts, install into the EGR valve body downstream of the actual valve.

There exists a cap nut, I guess, the part number can be found in them linked posts, to plug the second EGR pipe between the EGR valve output to the intake manifold.

The longest of the two EGR pipes that secures at the back side of exhaust manifold is NLA. Made of stainless, yet the stainless, I guess nickel (not chromium stainless) loses the stainless and begins to rust from the exhaust manifold end forward and can fracture there. You may be able to find spares at a salvage yard or online at eBay or who knows.

You can try by getting out your multimeter and check whether or not the vacuum servo, the cylinder thing with vacuum and electrical connection with white cap, receives power. Also, as Phil Machine Man repeatedly stated in many posts that there is a foam air filter under that white cap. If you read the posts or use the search feature to find Phil Machine Man's posts, he indicates that you carefully prise up the white cap, and remove the now old and collapsed foam with maybe some durable fiber material to pack in there that can take under hood conditions.

The filter is there as when the EGR control from the ignition control module de-powers that servo, the vacuum on the EGR valve is released closing the valve. So, I guess to filter out particles in the event, if momentarily, on vacuum enable or disable, the engine does not suck in particles.

Finally, with some spare gasket material, you may want to perform the EGR service. Volvo listed the service as 15k miles on K-Jet models and extended that to 40k miles? I guess? I forget now.

The service was to inspect and qualify proper EGR function. So, vacuum, when the EGR vacuum solenoid is powered as the engine coolant reaches minimum temp through the ignition ECU connection to the ECT,

The service can include an inspection of the second EGR pipe for exhaust vapor condensation. If this clogs, as it can if using dino oil, infrequent changes, short intown trips, and such, the exhaust flow diminishes through the EGR and so the EGR temp sensor encounters a flow that does not match the preset values in both ECUs. So, check the OBD socket six. Repeat until no new codes display.

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The causes are not so many with a vacuum gauge and voltmeter you cannot find the cause and remedy it.

Or, if I read the wiring diagrams right, though verify if you have to move wires to different connector pin positions, install a known good LH-Jet 2.4 "0 280 000-951" or Turbo non-EGR ECU and a known good non-EGR EZK ignition ECU.

And then plug the exhaust manifold with the flanged bung and washer (?) and plug, cover, fabricate a heavy aluminum or steel cap with holes for the two screws where the second EGR pipe terminate at the using gasket material appropriate for the application.

Does that restatement help? Again, look at the linked threads, Use the search feature to find out more.

Hard yet not impossible to find non-ethanol gasoline where I am in the toilet city with the arches and baseball cardinals. Yet corrupt Iowa and other ethanol producing states sure love them ethanol subsidies. Uses considerable carbon based power generation to process vegetative matter to make ethanol.

Human-induced climate catastrophe. What elocutionary without resolution. Like Brexit.
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