OK so i made the mistake of trying to jump start an old tractor with a positive ground with my 89 240. It was running perfect before this..
I had my wagon running with the cables hooked to the tractor maybe 3- 4 times with no issues. I shut the car off the final time it did not die or anything like that but then when i came back to start it a couple hours later it would not start. I had unhooked the cables so it didn't just sit there with them on the tractor.
So now there is no spark...
I don't know where to even start can anybody out there please give me some guidance on where to start. Did I fry my control box?? Does that put out spark somehow even?? I know it controls the FI system...
Please help!! I love my volvo..
AL from Indiana.

 

If you have done it successfully 3-4 times before, what makes you think that now it caused a problem?
What does it do?
No crank, or not turning over?
Make sure you have good battery situation before all else... Sounds like you don't.

 

get a volt meter, check your battery, how many volts across it ?

the only positive ground tractors *I've* seen have been 6V, surely you didn't jump that with a 12V electric system and leave it connected for any longer than it took to crank the starter over?!?


(my recent acquisition, with my son at the helm, a 1948 Ford 8N that was converted from 6V positive ground to 12V negative ground...)

 

Ya my battery is fine..hence being able to see that I have no spark. Motor cranks but won't fire........
any ideas??
does the main box relate to the spark at all??

 

there's two controllers in a redbrick, the ECU for the fuel injection, and the ICU for the ignition.

the ECU system is all on a inline 25A fuse thats in a fuse holder near/behind the battery, near the power steering reservoir... check this fuse, make sure its good.

on an LH2.4 car, the timing information comes off a 'crank position sensor' thats reading notches on the flywheel between the engine and transmission, it goes to the ICU, which uses it for spark timing and also passes it onto the ECU which uses it for fuel injection timing.

the LH2.4 ICU is on the left side up under the dash on a 240, while the ECU is on the right side near the passenger lower door hinge behind the footwell side panel.

the ICU sends the ignition spark timing signal to a 'power module' thats mounted near the coil, this is more likely to fry than the ICU itself.

the ECU also controls the dual fuel pumps via a fuel pump relay.

I think I'd pull out a spark plug, hold it against a ground with insulated pliers, and have a friend crank over the car, if you see SPARK SPARK SPARK then your ICU etc is fine.

when you first turn on the ignition, the ECU should spin the fuel pumps for about 1 second, then they go out again until the car turns over (as sensed by that crank position sensor). when the car stops cranking, the pumps run another second and stop. they can be kind of hard to hear if they are happy pumps (noisy pumps are sad pumps). put a test light or volt meter between fuse 4 and ground, and turn the ignition on, you shoudl see 12V for a second or so then go out. crank the car, the volts should come back til a second or so after you stop cranking. if you see this, your ECU is alive and well, and your fuel pump relay is sending power to the fuel pumps.

also, a LH2.4 car has a diagnostic box under the hood, this reads out codes from the ICU and ECU as blinking light sequences (no tools required). if you get 1-1-1 on each of pin 2 and pin 6, then the ICU and ECU processors are alive and well. if you get any code at all, the processors are alive but unhappy about whatever that code is. See Onboard Diagnostic Codes

 

Hey Pierce thanks for all that detailed info that is good stuff to know..
My friend and I did check for spark but there was nothing...
However I have a happy ending.!
I unhooked the battery and hooked it back up and guess what?! She fired back up..whooo hooo.. happy dance haa
Thanks alot guys !

 

By the way Pierce that is a nice tractor..
My father in laws is an old John Deere don't really know much about it other than it is probably twice the size of your ford.. other than its a postive ground 12v that is a bitch to get fired.. lesson learned though i will never be jump starting anything like that again!!

 

as long as you hook plus to plus and minus to minus and the vehicle bodies aren't touching, it should be fine to jump that.

but, me, I'd probably use a seperate external battery. or take the tractor battery back to he barn and charge it overnight.