I have a Cat 242B skid steer with 3800 hrs. The machine will not run unless the key is held in the start position. The problem started about a month ago. Put a new key switch in and nothing. found out it wasn't getting fuel, so I replaced the shut off solenoid and then it ran. About 2 weeks later it started to not run unless the key is held on. This time I called modern equipment out of reading pa. They showed up and told me it needed a new shut off solenoid and there was a shorted wire at the ECM. I gave them the green light to fix it, it ran for about a day now it only runs when I hold the key to start. so far i've spent a month and $3,000 and i'm back to the original problem. any help would be appreciated!
There are two hot leads to the fuel solenoid, one in the "start" position and one in the "run". You've got a problem in the "run" line. I'm having the same trouble with my Cat 248 and I just haven't had the time to trace it out. I've been told there's a relay in that circuit and that's where I suspect my problem is but I haven't located it yet. In your case it will take some patience with a circuit tester to find where your break is. In the meantime you could run a jumper wire from the battery to the "run" side of the solenoid and connect it each time you use the machine, this is what I've done. It's a little inconvenient but it will get you working. Be sure you don't hook to the "start" wire, you will burn out the solenoid.
Is there any way to get those 2 wires to the solenoid mixed up, if so that would burn out a new solenoid fast. Steve
I just picked a 242B model at random so I may be off base here, but I only see 1 hot wire (plus a ground of course) to the fuel shutoff solenoid. What I did notice is that the feed to that solenoid comes from a relay in the fuse panel via a diode block before it gets to the fuel shutoff solenoid. If anyone wants an Electrical Schematic all you have to do is PM me your machine Serial Number and your email address.
no its all one plug, triangle shape with 3 wires( pink, black, and green.)
Machine Serial Number..?
Cat00242ccmb00352
That's what got me confused. Your OP listed the machine as a 242B, your Serial Number corresponds to a 242(A) model. I was looking at the wrong electrical schematic for your machine. As Steve mentioned above, there is a fuel shutdown relay involved here in addition to the solenoid. The fuel shutdown relay activation signal comes from, and is grounded back to, the ECM. The problem is that there are 6 relays all the same Part Number (Main Power A, B, & C; cold start, fuel shutdown, & start) and the Parts Manual doesn't indicate which one is which. The fuel shutdown relay has 4 wires - 109 Red, 327 Pink, A346 Blue, & M732 Orange. The cold start relay has 109 Red, 877 Yellow, L987 White, & 200 Black. As a first step try swapping the cold start and fuel shutdown relays and report back what happens. If you want the Electrical Schematic for your machine drop me a PM with your email address. It might be helpful to you.
I replaced the fuel cut relay this morning. Cat PN 115-1615. still nothing changed. there is no reisitance from the relay to the solenoid. my guess would be the problem lies between the ecm and relay. my email is [email protected] . Thanks for all of your input.
What's weird about this is twice the fuel solenoid was replaced and it ran for a while, if there was other problems why would it run.? I'd sure try Steve F advice with the jumper wire to see if that makes it run, at least you eliminate the fuel solenoid that way. Could be a bad connector right at the fuel solenoid which might explain it running for a while as it would have got wiggled around when replacing the solenoid. Steve
My suspicion is an (almost) break in a wire harness somewhere. Ringing out the affected wires for continuity along with the good old-fashioned "wiggle test" ought to hopefully show up something.
Any updates yet? Steve
no updates yet. just got back to the shop this morning. ill hopefully figure it out by days end.
I ended up paying a friend to fix it, since I cant seem to find the time to do it. he redone all the ground wires on the machine, and found a short in the wire harness between the ecm and fuel cut relay. thanks for the help guys!
I suppose you have 2 chances of getting back anything from the $3,000 you paid the first outfit to fix it, slim and none - and slim just left town...... Anything's worth a try though. Even if you get something back it would be worth your while and make you feel better about it. The offer's still open for the Electrical Schematic BTW. see above.
A short in the wiring harness makes sense as most likely got wiggled some when working on it making it work for a while, hope that fixes it for good. Far as some dealers they start with the most expensive fix first as in the trucking business when a truck wouldn't run the first thing they did was to put on a $1400 pump and after it still didn't run they would fix the cracked fuel line. Steve
Wires are the last thing checked by most, but are often the cause of intermittent issues or other issues that don't make sense. Continuity alone isn't always an accurate test, you need a load on the wire to get a good feel for things. Even then you still need the jiggle test and visual inspections. Glad it's solved.