KA24 240 broke down, help is appreciated

[Klot]

Hey all,

I was driving the 240 home last night just like normal, went into third gear and it lurched real bad, like it went into limp mode. Won't go over 2k rpms, engine sound didn't change like something mechanical broke thankfully. Feels like timing is being pulled HARD, it's holding the rpms at 2k like launch control, if that gives you a better idea.

Anyone here well versed in KA24s have any opinions/pointers? Any in-person help would be incredibly grateful, reward would be a six pack or something :P She is my daily so I need her back on her feet ASAP. I'm ASE certified in electrical (big whoop) so don't be afraid to get technical electrically, like I said any help is appreciated! Shes running a new NA Bear Paw tune right now.

Much love, I was hoping to make it out to a track event at Topeka or a parking lot before summer was over, really hoping to meet some of you Kansas/Missouri guys in person.

[PapaSmurf2k3]

Is the CEL on? Have you pulled the code?

[Klot]

Is the CEL on? Have you pulled the code?

CEL isn't on, but the previous owner put on a naturally aspirated bear paw tune and said he told the guy to disable all the egr codes that would trip the CEL. I'm going to pull codes this afternoon after I get it towed back to the house, I'll update you then

[Klot]

Car is back safe and sound, pulled the codes and it's pulled these:

12 - MAF Sensor (code indicates circuit open or shorted according to FSM)
14 - Vehicle Speed Sensor (code indicates circuit is open according to FSM)

ECU went into safe/limp mode as I suspected, damn glad to know its only an electrical issue! I tend not to trust anyone else's engine work but my own lol... according to the FSM if no MAF is plugged in ECU will go into safe mode, limiting RPMs to 2,400. If the MAF is bad, it won't run at all, it'll either flood out and die or not start period. A new MAF sensor & connector are upwards of $400, but who actually throws brand new parts on their car? :p

Going to back probe the wiring on the sensor to make sure its getting good power/ground and all that good stuff, and I'll post my results.

[Klot]

Okay so here's what I found out. Went to check the signal voltage of the MAF on the harness side and it only has three pins, but the MAF itself has four pins. According to the FSM the harness side should have four pins, just like the MAF has four pins. The car is a '92 with a KA24DE, so it doesn't make any sense that the harness side would have three pins.

Since there are only three connectors on the harness side, does this mean it's not a KA24DE harness? If it were the other way around I would just go grab a KA24DE MAF from the junkyard, but it's the actual pigtail that is only three pin... can someone point me to a link of how to make a three-pin MAF work?

[mechanicalmoron]

I don't know anything about the number of pins (check where they actually go/what they do, and the reason for the change may be understandable) BUT the mafs doesn't have to be totally "bad" to mess up how the car runs - and maybe if it was, depending on exactly what happened, it would think it was unplugged and go into limp mode.

I'd try cleaning it, because, why not? mafs cleaner costs a bit more than a tenth the price of a used mafs.

[Klot]

Found the problem. Called ICEMAN and asked him about the pins, he said it's normal to have a three pin connector on the KA24DE.

I couldn't get any signal voltage, 12v voltage, or ground at the connector, so I backtracked and decided to trace the wires and found a spot where the harness was hanging down and rubbing on a pulley and had worn through the wires. Did a quick crimp connector fix and she works like she did before!

Can't believe I didn't see the worn through wires when I looked at the harness the first time, lol... thanks for you help guys!

[PapaSmurf2k3]

Glad you got some resolution. Sorry I couldn't be here to bounce ideas off of, I was driving across the country :P

[Klot]

Glad you got some resolution. Sorry I couldn't be here to bounce ideas off of, I was driving across the country :P

No worries daddy smurf