thanx
 

Just found one used on ebay 0280 000 556 Bosch no.

Should be just what I need alot more makes sense now. Thanks for all the info........ I will let u know how it turns out.


I have been readin on here since last fall, searchin for info......finally got frustrated and posted. Read alot of threadsand some very long ones had no reponse as to if it worked or not. I hate that read a long post all the way to end and they never come back and say how it turned out..... I mean u assume it works when they quit posting but it would be nice to know?

Anyhow thaks for all the help and I will post back how it turns out.

Sean

Back Where I started
 

Got the 0280 000 556 Fuel ECU in today. Put it on and now back to same problem as when I started.

No power to fuse No. 4 when key is turned on. Fuel pumps dont run. No pulse to injectors.

With the other Fuel ECU (0 280 000 572) when you turn the key on fuse No. 4 powers up for a few secs and fuel pump runs. Then it loses power to fuse 4 until the car starts and fuse 4 powers up.

With the 0280 000 556 Fuel ECU the diag lite is on constantly no flashes at all.

Any Ideas.............what are the odds i bought a used ECU on EBAY with the exact same prob as original.

The pumps not running sounds like a defective fuel pump relay. I believe, and hopefully someone will chime in if I'm wrong, if you jumper between fuse # 4 and 6 the pumps will run with the key on. If they run then you probably have a defective pump relay. Not that uncommon.

As for the diagnostic light be on all the time, haven't a clue.

Ron J

Fuel Relay
 

Ron,

I dont think so. If the prossesor grnds the bl/grn wire it wotks fine. With the 3.1 ECU all works fine just wont read thrtt corectly.

And I have alredy tried new relay way back in dec.

Sean

If that's the case then you are beyond my area of expertise.

Ron J

a 91 has the volvo OBD which both reads codes and has a series of diagnostic tests that test all the sensors, and exercise all the relays and actuators. between these tests you should be able to figure out what subsystem is bad.

this 91 240 is virtually the same engine as a non-turbo LH2.4 740/940 of the same year. Engine and OBD Diagnostic Codes

This might be going back two steps, but what shape are your injectors in?

Fuel Pump Circuit the same?
 

From the wiring dia in mitchell The processor grounds the yel/blk wire (pos 5 on the fuel pump relay) at pos 21 on ECU to close the power side of the relay from red wire pos 3 (from fuse 6) hot at all times.

Once this side of relay closes it sends power to pos 1 of fuel pump relay(org wire). The org wire then sends power to; puel pump relay pos 5, Fuel ECU pos 9, MAM pos 5, Fuel Injectors, IAC and Starting Inj.

All of this works with either ECU (0280 000 572 for 3.1; or 0280 000 556 for 2.4)

The system (so far as I can tell please let me know if I am wrong) then grounds pos 20 on Fuel ECU(this wire is pos 2 bl/grn on FP relay) for a cpl seconds to prime the fuel rail. When pos 2 bl/grn on FPR is grounded the other side of the FPR closes and powers pos 5 red/yel (from pos 3 red hot at all times) the red/yel powers fuel pumps thru fuse 4.

After fuel rail is primed the fuel ECU opens the ground of pos 20-(pos 2 bl/grn on FPR). The second part of FPR opens and cuts power to pos 5 red/yel and fuse 4 is no longer getting power on fuel pumps stop running.

The Fuel ECU then waits for a signal that engine is turning(from Crank pos sensor???) and grounds pos 20 again relay closes and fuel pumps run.

With ECU 0280 000 572 (for 3.1 syst) all of this works fine. The ECU grnds sec part of FPR, fuel rail primes, ecu opens grnd on pos 20, fuel pumps stop, turn key to start pos, engine turns over, ECU grounds pos 20, fuel pums run, injectors fire and car starts and runs fine as log as MAM is disconnected.

With ECU 0280 000 556 (for 2.4) the processor never grounds pos 20 and the second part of FPR never closes. Even with engine cranking. Never primes fuel rail. Injectors never fire. NO START

The wiring for this part of fuel ECU circuit is the same on dia for 2.4 0r 3.1 system. Same FPR connections, same ECU connections, same fuses etc.


I suppose what i need to find out is do both ecu's recive same input sig telling them when to groung FPR. If they do, the new (used 0280000556) ECU must be bad and has the same prob as org ECU (what ever number it was). If not what singal is the ECU not getting that the other one is.


Does any of this make sense to anyone besides me.........not even sure it makes sense to me.

Sean

injectors
 

BPAT,

When i first got car going with 3.1 sys ECU.......at the time i did not know it was incorrect.........and it did not want to take any throttle(bogs down when press accel) i considered injectors could be clogged. With AMM unplugged I have been driving the car. It has been very reliable. never let me down. I have run 5 or 6 tanks of fuel thru it and 3 cans of berrymans fuel inj cleaner.

Runs great above idle with 0280000572 ECU as long as AMM is unplugged. Does not get great mileage but not sure how bad as odometer does not work.

If the 0280000556 ECU would pwp up fuel pumps and fire injectors I have to believe it would still run with same injectors.

Cleaning/changing the injectors could not hurt but at this poit I cant see that as the problemn.

Sean

Does the car run if you ground the blue/green (#20) wire? The fuel ECU won't ground this wire until it detects ignition pulses from the ignition control unit - this is a saftey feature. Some of the LH2.4 cars prime the pumps on start up, some don't. This seems to be a difference in the ECU's software.

I would try a different fuel ECU, look for a white label -561. The pink label -561's are known to be defective. Your best bet is to get one from a "you-pull-it" yard, since most offer a 30 day exchage only warranty.

Take a look at the ECU link I posted. It says -556 was only used in 89 240's, it also says "california model". Does that mean it expects a EGR valve?

Fuel ECU
 

Bubba,

No it will not run with bl/grn from FPR grounded. Still no injector pulse. Either the two ECU recieve cranking signal in diff ways or ECU is Bad????

Thats all I can figure.......just cant figure how to tell if ECU is getting cranking signal.

The 0280000572 must be......it grnds relay and pulses inj when you crank the car.....it runs.

The 0280000556 either is looking for some signal it is not getting

OR

It is getting correct signal and dont care......it's a bad bad bad ECU and must be punished.

Sean

I am back to looking at new/used ECU's
 

Any ideas.

per my VADIS parts CD, a US model 1990-1992 240 B230F/B230FD should have one of the following ECU''s...

>> 5003954 (5003833)(3501687)
>> 5003926 (3517407) w/o EGR
>> 5003780 (3517885) w/ EGR

the #s in () are superceded versions. no, I don't know what the first line means relative to EGR/no EGR, its not explained.

Ecu
 

Thanks Pierce,

I have also has people tell me and found on line that 0280000951 is a good onr for this car.

Any Thoughts?

Sean

I don't know the bosch P/N's, which I'm guessing that 028... number is. the numbers i gave are the volvo p/n's.

ah. Tasca says...
5003954 $942.57 $50.00 $715.42
Fuel system - Fuel induction - Fuel injection - Control unit
Yellow code
Mark #556 (guessing thats 0280000556...)


5003926 $942.57 $50.00 $715.42
Fuel system - Fuel induction - Fuel injection - Control unit
Control unit, 240, stamped, 0280000561 1991 - 1993
Purple code

5003780 $957.17 $50.00 $726.49
Fuel system - Fuel induction - Fuel injection - Control unit
Claret code
Control unit, 240, stamped, 0280000572 1991 - 1993
(discontinued)


don't see any 951's there. this page VOLVO 240 FUEL SYSTEM 1975-1993 at Swedish Auto Parts says the 951 is volvo 5003926? near as I can deduce from this pile of intel, the 951 and 561 are for non-EGR cars, while the 572 is for an EGR car ?

Radio Supression Relay
 

Pierce,

Thanks for the input. The 0280 000 572 (Volvo 5003780) is for the few cars (i suppose with EGR) that came with the LH3.1 Inj System. Slightly diff from the LH2.4. It uses a diff MAM and Thrott switch.

As far as I can tell the fuel inj circuit on the cars is the same with regards to when the ECU grds FPR and pulses injectors.

The only reason I havnt bought annother ECU and tried it is this radio supression relay i have been reading about on here.

I cannot find it in any wire diag. or any location that I have seen in many threads on here.

Does anyone know on a 91 Sedan 2.3L non turbo with Auto and LH2.4 Fuel Syst If it has a Rad Supp Relay and if so where it is located?

Sean

afaik, the 'radio suppression relay' was only used on 740/940s, not on 240s. on the 240's, the ECU is far enough away from the radio such that the power pulses don't 'bleed' into the radio, but on the 740/940, the ECU is right behind the center console (I think) and had this problem, so they added a relay out in the engine compartment to keep the high current pulses away from the stereo.