does this pic show a jumped jetronic ECU?

durk80 · Post by **durk80** » 19 Dec 2015, 15:33

My 1990 240 has been running rich since the day I bought it. I've replaced everything that I thought it might have been (coolant temp sensor, flame trap, cleaned the throttle body, cleaned up the grounds, replaced the cold start injector, RPM sensor, cleaned the MAF, replaced the fuel pressure regulator, thermostat, intake manifold gasket, new vacuum lines, air filter, deleted the warm air valve on the air box, cleaned the idle air control valve, egr valve, pcv system and oil trap, professionally flushed injectors, new injector seals, 02 sensor, and new exhaust manifold gaskets) thinking it would cure whatever was wrong with the blasted car. Wrong!

I did a test today with the MAF. I unplugged it and cranked over the car. It ran really rough at about 500 rpms. Does this mean that I need to replace the MAF?

The other day, after resetting the dreaded pink jetronic unit, certainly a few notches below the awfulness of a dell dimension 2003, I reset the trim for the 02 sensor. I unplugged the sensor, drove it around until it warmed up, then I plugged it back in. While it ran better after doing this, I can still smell the richness in the exhaust. Yuck!

The only thing that I haven't thought about doing is taking the computer out and sending it out to be rebuilt for a tune of $450.00 USD. I guess the question is that in the picture below, do the two blue-looped wires attached to the computer show that it has been jumped?

If so, what would I have to do with the wiring after I get the computer rebuilt, if anything?

The reason why I ask this is because the guy who owned it before me did some really cool things to the car: siliconed the sunroof shut, turned down the rotors thinner than a piece of pounded veal parm, and let oil leak all over the inside of the engine bay just to name a few of the many examples.

The ECU does look like it was salvaged, because it has some matching pink paint marker on it with some letters and numbers, probably for inventory, I presume.

I am ordering a throttle position sensor and harness, because while it idles usually at 850 RPM's, sometimes after I shut it off, let it sit for 5 minutes, and then turn it back on, it revs up to 2000 rpms then eventually comes down to 850 after about10 seconds. Not sure if this would fix the richness or not.

Also, regardless of the temperature outside, the car starts and idles at 850 RPM's. It doesn't ever go any higher, unless it is misbehaving.

I apologize for the 240 tome, but hopefully someone can guide me in the right direction, so I can make it my daily driver (and not my daily polluter).

Thank you for all of your expertise in advance!

Andy

lummert · Post by **lummert** » 19 Dec 2015, 15:44

Notice that the wires at the connector running into and out of the loop are of the same color. Try checking the wiring diagram.

http://www.volvowiringdiagrams.com

Edit: wiring diagram shows the black/brown wires all going to chassis ground. The looped wires should be there. Try to find a compatible used ECU. Don't throw a lot of money at new parts before doing a little detective work. That is my advice.

Post by **jimmy57** » 19 Dec 2015, 21:55

The wrong coolant temp sensor can cause your symptoms and may not set codes.
The jumpers are normal.

The correct engine coolant sensor will check resistance to sensor body on both pins (and the sum of the two readings between the pins) and the wrong one will be open to sensor body but read resistance between pins.

93Regina · Post by **93Regina** » 20 Dec 2015, 07:17

durk80 wrote:..coolant temp sensor...

Part number of current one?

durk80 · Post by **durk80** » 22 Dec 2015, 10:42

The coolant temp sensor # is 0280130032. It is from Bosch purchased from rock auto.

durk80 · Post by **durk80** » 22 Dec 2015, 11:13

I wanted to thank every one who has provided me with the wealth of knowledge concerning this on going problem.

I would like to get a spare ecu for the 1990 240 DL, but am unsure of a replacement. I checked compatibility for various units, but the info is vague whether or not it will work with EGR/ no air pump option with 5 speed transmission, if that matters. It has the pink label 561 in there now, but like I mentioned before, it looks like it was from a junkyard, so who knows if it is even the correct one or if it is one that just fit and allowed the car to be drivable. Some more sagely advice would be appreciated and graciously welcomed!

93Regina · Post by **93Regina** » 22 Dec 2015, 12:50

durk80 wrote:spare ecu for the 1990 240 DL

ECU and AMM information

lummert · Post by **lummert** » 22 Dec 2015, 17:41

93Regina wrote:
durk80 wrote:spare ecu for the 1990 240 DL
ECU and AMM information

Link shows pink label 561 to be problematic. White label 561 is less problematic. 933, 935 and 951 are said to be known good substitutes.

durk80 · Post by **durk80** » 30 Dec 2015, 19:42

The ECU came in the mail tonight, the 951 model. From the moment I plugged it in, it ran much smoother. Gone is the shaking shifter at idle and rich smelling exhaust. I hope that this will keep the check engine light from coming on again.

I did notice that the engine is stamped b32 fe, so does that mean that I should plug up the egr valve, since it isn't controlled by this computer?

Would love to keep this car forever!

Andy

93Regina · Post by **93Regina** » 30 Dec 2015, 21:04

durk80 wrote:951...egr valve...

If located in an emission testing state, the 951 may not be a good idea since 951 does not control EGR valve. EGR valve should be closed since 951 should not be sending a signal to it (I'm not familiar with EGR setup, but I assume a ground would be sent to activate); hence, I'd leave it alone.

If living in a warmer state, where cold temperatures don't exist, the 951 may work fine. I assume your vehicle came with a cold start injector, the 951 does not control this injector. Bosch 0 280 155 746 injectors are 19#, so if installed, there will be a pinch more fuel on startups, due to better atomization.