Help Please

[David87Pathy]

Hey folks I joined this forum to try to find out what's wrong with my pathy. I just bought an 87 Pathfinder 6cyl 4x4 manual. Has a rebuilt motor. I'm not sure much else was touched. I've had it for 2 weeks with no issues. Then while trying to make a turn quickly I lost power. Found out it happens at 3000 rpm Everytime. After reading the forum I know that's it's in limp mode. It starts right up and idles perfectly. Drives fine but I when I hit the gas hard it acts like it's not getting enough fuel or air and bogs out for a second and I can't rev past 3000. I pulled the error codes and they are 13, 42, 43. Coolant temp sensor, fuel temp sensor, throttle position sensor respectively. I don't know how accurate it is or even if the ECU functions properly. I did run mode 4 to test the TPS and it is not functioning. I don't know if that was the case or not when the truck was running fine. Would this cause the car to go into limp mode? Could it be something else that is not giving a code?

[Slartibartfast]

 

Limp mode kicking in during a hard turn makes me suspect a wiring issue. I would check that the battery is secured properly, and that the cables, terminals, fuse links, and engine grounds are clean and tight. If you find something loose/suspicious, clean it up, clear the codes, drive it, and see if the issue (and the codes) come back. I don't know that the computer would throw random codes if it lost power briefly while driving, but I don't know that it wouldn't, and it's easy enough to rule that out. If/when the codes return, use the troubleshooting section for each code in the EF&EC section of the service manual to chase them down.

 

Which manual are you using? You have the wrong code table for '87. I don't know why, but the code table changed somewhere between '87 and '89. The code table from the '87 manual is as follows.

 

11 Crank angle sensor circuit

12 Air flow meter circuit

13 Cylinder head temp sensor

21 Ignition signal missing in primary coil

33 Oxygen sensor circuit

42 Throttle sensor circuit

43 Injector circuit

44 No malfunction in above circuits

 

So you've got the temp sensor, the TPS, and the injector circuit code.

 

The service manual has troubleshooting info for all three. I do not know of a PDF of the '87 manual, but I have an '89 manual up on Dropbox (which I found somewhere, naturally I can't remember where, or I'd send you there instead). '89 had the same throttle body injection, but the later code table, and likely various other small differences here and there. I have a paper copy of the '87, so if something isn't matching up, let me know, and I'll take some pictures of the relevant sections.

[David87Pathy]

@Slartibartfast could you possibly get me a pic of the injector circuit page and wiring diagram? I just now have time to start checking the truck fully and I'm new to this so I would like to confirm I'm testing the correct stuff.

 

Also the vehicle stopped starting. I disconected the wires for one of the injectors and it fired right up. I checked the injector fusible link and it was fine. It's the only one I checked as it seems to be the only one in that circuit.

 

 

[Slartibartfast]

Here you go, EF&EC 88 and 89 from the '87 manual.

 

 

Hopefully that helps!

[grygorie]

Yes, the failed TPS can clearly trigger the degraded mode, especially if the mode 4 test does not pass. I would start by replacing it, it is a common cause on these models. Then, see if the other codes come back after reset.

 

 Tutuapp

Edited July 20 by grygorie