At a loss here, so hope someone may have some wisdom to impart before I bring the matches to my '92 240 Wagon!

Have been chasing a "poor acceleration" ghost for probably 6 months now, have replaced fuel filter, 02 sensor, catalytic coverter, etc without too much luck. Car just never seems to accelerate well from a standstill compared to friends' 240 wagons, and my own previous 240's. Not a huge deal, as I am totally fine with characteristically sluggish 240 performance, but occasionally it will just bog down to the point where I KNOW something is very wrong. Very sluggish in the lower RPMs, but after a few seconds the lagging dissipates with RPM and acceleration is as expected. On one occasion this past winter, car simply would not respond the any throttle input--engine just bogged and shook if accelerator was depressed more than 1/10. Once the engine heated up, the problem dissipated (this has not happened since). Combined with less than ideal gas mileage (compared to other 240's), I thought I had received a gift from the Volvo gods when the car stalled/lost power for a split second the other day and the CEL lights up on the dash--surely this will lead to a code which will provide some insight and allow me to correct this problem once and for all!

On the same day the CEL light comes on (Code 144), the car stalls and dies while driving. After waiting a few minutes, car starts again after cranking longer than usual, stalls again a mile down the road. Wait a bit longer, car starts again and successfully makes it another 3 miles home where it now sits.

I have read Code 144 to mean "Fuel System ECU Load Signal", which as it turns out, is not a simple "replace this part" type of code I was hoping for, but rather a more ambiguous general heads-up that something is amiss, somewhere, probably in the ignition system. Great.

Searches for code 144 yield conflicting results--some say Ingition System Relay, or Injection System Relay, some Radio Suppression Relay (which I'm relatively certain that this car does not contain), bad Crank Position Sensor, bad ECU, bad ICU, etc. etc.

It seems there are so many possibilities, I'm not sure where to start. Car starts and runs fine now, but I'm afraid to have my wife resume use as it will likely leave her stranded.

So far, I've checked both the fuel pump relay (even though pump always primes when key is turned) and the "Radio Supression Relay" mounted to the ignition coil, which I'm sure is actually the relay for the AC auxiliary fan. Opened them up too see if I could find any obvious problems, both look alright (no broken connections, burns etc). I have cleaned the MAF, Throttle Body (as suggested by some forum, but assumed not to help). Don't have spare relays to swap in, but I'd assume if these were bad they'd likely not produce intermittent problems anyways, right?

Additionally, I have pulled the ECU and checked the voltage on harness pin 8 as suggested here-- http://www.volvoforums.org.uk/showthread.php?t=121971 (post #5), and did not the get .1v as suggested I should. Instead got something like .04 or .05 when grounded against the ecu bracket. The poster says if .1v is not read, then there could be a wiring problem or one of the control units (Fuel, Ignition) may be bad. I've looked for a .pdf Volvo Greenbook that verifies this to no avail and would rather not buy new ECU's before knowing if it is likely the problem. Testing other pins (like the diagnostic unit, which produces 11.6v) gives about the right voltage, FWIW. So with this supposed incorrect voltage output, should I be replacing the ECU, searching for some wiring issue, or what? I know for a fact that I will crush this car before tracing that little yellow and brown wire (pin #8) that is wrapped up with at least 20 feet of factory electrical tape for who knows how many miles from sensor to sensor, underneath the dash, etc.

Is .05v in place of .1v even a problem (considering the diagnostic unit produces .4/.5v less than specified as well)?

Sincere thanks for any insight which may be provided, as failure to diagnose this intermittent issue may otherwise spell the end of this car/driver relationship.

 

the official volvo troubleshooting documentation suggests 1-4-4 is a wiring problem between the ICU and ECU. on a late 240, the ICU is behind hte glovebox and the ECU is on the side near the passenger door hinges, so remove the kick panel under the passenger side dash, remove the glovebox, remove the panel on the right side of the passenger footwell to gain access to both of these.

disconnect both the ECU and ICU plugs, shine a bright flashlight inside the connectors, and you should see the pin numbers. take a digital volt meter in OHMS mode, and check for continuity between ECU pin 25 and ICU pin 8, this is the 'engine load' wire in question. also check to be sure this wire isn't shorted to ground (assuming there were zero ohms between ECU.25 and ICU.8, then check between ECU.25 and ground, which is ECU pin 17 or 5, this should be infinite).

the wire connecting ECU.25 to ICU.8 is yellow/brown, and has no intermediate connectors in the diagram (unlike a 940 where the ICU is on the other side of the car, and the signal is looped under the hood)


that test you mention doesn't make sense, as ECU.25 is an OUTPUT, ICU.8 is an INPUT, so if you're checking the harness connector on the ECU side, you're measuring the voltage of a floating input, which doesn't mean much.

rather than buying new ICU or ECU, the best thing to do is find a compatible working car (any 240 1989+) and swap the ECU, see if your ECU works on the other car and if the other ECU works on your car, if thats yes and yes, your ECU is fine. do the same with the ICU.

also, when you're in there, look up the number of your ECU, the last three digits. see Engine ECU. If its 0 280 000-561, the ones with pink labels are considered highly suspect and likely should be replaced with a suitable newer one (see that table for lists of what works).

 

oh. 240. what do your fuses look like? corroded fuses could cause all kinda sketchy behavior.

I would get out on ebay, and find yourself a batch of "W124 mercedes ceramic fuses" (a W124 is a late 80s/early 90s 300E/300D)... these are the same fuses as our 240's use, and they are the CORRECT kind which are ceramic, not plastic, and have brass or copper fuse elements, not aluminum. replace ALL your fuses with these. clean the inside of the contact fingers with a soft pink pencil eraser, this removes any oxide without stripping the gold coatings.

On a 240, there's another 25A fuse which powers the whole fuel injection system including the ECU, this is under the hood on the left fender, either on the little relay strip, or floating between the battery and power steering pump, its a 'blade' type fuse. the fuse holders for these get corroded and crappy, I replace them if they are suspect with a waterproof marine fuse holder that I squirt full of silicone electric grease for good luck.

 

Pierce,

Many thanks for your help and suggestions, I performed the continuity test between 25 and 8 as recommended, no resistance and infinite resistance between 25 and 17--I suspect this is good news on the bad wiring front.

I could not locate the 25A fuse between the battery and PS pump, was this present on the 1992 245? I have read that starting in 1990 this was relocated or removed entirely. Only power stage and headlight relay on strip. While looking however, I did find what may be the absolutely WORST ground connection I have ever seen--the secondary ground coming off the (-) terminal on the battery which mounts to the inner drivers fender was rusted to the point of having to grind the bolt head off. I relocated the two grounds mounted here to the bracket of the relay strip (where the ABS grounds to). I assume this will not be an issue?

The interior fuse panel looks pretty good, all fuses are ceramic/copper as when we acquired the car it was a single owner vehicle that was dealer maintained 0-240,000 miles. Not a part on the car that is not genuine Volvo. Will clean seats just in case.

ECU ends in -556, so no issue there.

A few more questions, if I may:

1) Do you think that it's likely that the long standing issue of abnormally poor acceleration of the line is connected to this Code 144 issue?

2) Could code 144 be caused by a bad ignition coil? The current part looks pretty old, any way to test? Wires and plugs all look like they've been replaced recently (plugs are swanky new with coffee colored electrodes, plug wires look new). How about distributor cap, could this cause the problem? Don't want to blindly through parts at the car unless I have a feeling it may help.

3) Does a 1992 245 have a Radio Suppression Relay? The relay mounted on the Ignition coil has the same part number, but the wiring leads to the auxiliary AC Fan. Is this a multipurpose part, or is it just for the fan, and the 1992 245 does not have an RSR? For what it's worth, I did pull the relay apart and did not see anything obviously wrong with it.

4) Is there anything else that could cause a code 144 fault other than faulty wiring? If there is continuity between 25 and 8, it must be another component that is part of that system (or ECU), correct? Do you know of any other tests or checks that I could perform? What about the speed sensor, I have read that this creates the impulses for ignition timing? is there any way to test the CPS without removing it (which I bet will be a PITA)?

Thanks again for all your help, we love this car and I've put tons of $$ and work into it over the past 6 months. I plan to keep it for another 100,000 miles or so, so hope I can get this issue corrected!

 

RSR is purely a 740/940 thing. and yes, they use the same relay PN for other things.

crank position sensor problems are usually wiring, insulation flaking off etc.