94extreme Posted December 5, 2008 Share Posted December 5, 2008 no man, the speed sensor syhould have anything to do with your troubles.. it only reads and sends info related to the vehicle's speed. now, i have no idea why the light didn't come on.. does your speedo work? if yes, the the sensor is probably just fine. Link to comment Share on other sites More sharing options...
MY1PATH Posted December 5, 2008 Author Share Posted December 5, 2008 (edited) no man, the speed sensor syhould have anything to do with your troubles.. it only reads and sends info related to the vehicle's speed. now, i have no idea why the light didn't come on.. does your speedo work? if yes, the the sensor is probably just fine. yeh the spedo works, and I can't see any relation either. but I'm stumped. If ecu says eveything else is fine then why is it still acting up? I guess I'll just endure the costly process of replacing @!*% untill it works. on the brightside all the replaced parts will be less likely to fail. Edited December 5, 2008 by MY1PATH Link to comment Share on other sites More sharing options...
bitemedoughboy.com Posted December 5, 2008 Share Posted December 5, 2008 yeh the spedo works, and I can't see any relation either. but I'm stumped. If ecu says eveything else is fine then why is it still acting up?I guess I'll just endure the costly process of replacing @!*% untill it works. on the brightside all the replaced parts will be less likely to fail. i know this is slightly unrelated but from a Nissan. in my '87 with the 300zx ECU i couldn't get it to run in "closed loop" mode, according to the FSM you are supposed to adjust the mixture feedback ratio until the lights blink simultaneously, and if you cant get them to blink at the same time, it tells you to replace the AFM. well i tried 2 different AFM's that i know to be good, and i get the same thing. so after scratching my head for a few days and searching every known z31 site i decided to change the o2 sensor. after that it ran like a top, and all the lights were blinking like they should. although everything pointed to the AFM it was the O2 sensor the hole time...... i would start with the less expensive o2 sensor and go from there. Link to comment Share on other sites More sharing options...
MY1PATH Posted December 5, 2008 Author Share Posted December 5, 2008 well, running same tests with same non concluive resuts I got mad and threw my foot into the pedal @ WOT It sounded throatyier than it ever had B4 (untill it hit 2800) don't know if this has to do with anything but I'd put it out there. also would a fuel filter cause a problem that is consistantly @ 2800? I changed it a year ago but??? Link to comment Share on other sites More sharing options...
bitemedoughboy.com Posted December 5, 2008 Share Posted December 5, 2008 (edited) well, running same tests with same non concluive resuts I got mad and threw my foot into the pedal @ WOT It sounded throatyier than it ever had B4 (untill it hit 2800) don't know if this has to do with anything but I'd put it out there.also would a fuel filter cause a problem that is consistantly @ 2800? I changed it a year ago but??? Pull your mass airflow sensor. It takes a Philips screwdriver. Make sure the element and sensor wires are still intact, if so clean them with a q-tip and alcohol. If a wire is broken or almost-but-not-quite making contact with the base, you found your problem. Check the MAFS wiring connector for looseness or corroded contacts. Common problem, though I've never heard of a 2000 RPM cut-off so specifically. The ECU is designed to run in a "Safe Mode" under MAF or TPS failure, which limits RPM's to 2800, but not 2000. something is triggering "limp" mode.... Edited December 5, 2008 by bitemedoughboy.com Link to comment Share on other sites More sharing options...
MY1PATH Posted December 6, 2008 Author Share Posted December 6, 2008 something is triggering "limp" mode.... I've had the MAF 2x I've cleaned it, tho I did that a few months ago too. and the wires are firmly attached. maybe the chip inside it failed or maybe something else grrr... Link to comment Share on other sites More sharing options...
MY1PATH Posted December 6, 2008 Author Share Posted December 6, 2008 I noticed when I pulled the ecu to check wires that there was another plug on the harness that was capped off. What is that for? Nissan dealers? Auto tranny? is it possible a part of the ecu that was fighting the timing got cooked and thats keeping it in "limp mode" Link to comment Share on other sites More sharing options...
trogdor Posted December 6, 2008 Share Posted December 6, 2008 Yes! the fuel filter could cause that same problem it did on mine mine had all the same symptoms yours does. $12 part and it runs great! Link to comment Share on other sites More sharing options...
MY1PATH Posted December 6, 2008 Author Share Posted December 6, 2008 Yes! the fuel filter could cause that same problem it did on mine mine had all the same symptoms yours does. $12 part and it runs great! I'll try it, but it stops exactly @ 2800 under any throttle condition. hard rev slow rev I'd think it would happen sooner @ a harder rev if it were the fuel filter my currend one is 1 year old. but again, I'll try it OMW to CSK AUTO now. Link to comment Share on other sites More sharing options...
bitemedoughboy.com Posted December 6, 2008 Share Posted December 6, 2008 I'll try it, but it stops exactly @ 2800 under any throttle condition. hard rev slow rev I'd think it would happen sooner @ a harder rev if it were the fuel filter my currend one is 1 year old. but again, I'll try it OMW to CSK AUTO now. here are the FSM pages that you should need, theyre not perfect.... http://www.bitemedoughboy.com/pdf/EFEC42.pdf http://www.bitemedoughboy.com/pdf/EFEC74.pdf http://www.bitemedoughboy.com/pdf/EFEC75.pdf http://www.bitemedoughboy.com/pdf/EFEC88.pdf http://www.bitemedoughboy.com/pdf/EFEC89.pdf Link to comment Share on other sites More sharing options...
edicer2 Posted December 6, 2008 Share Posted December 6, 2008 I'll try it, but it stops exactly @ 2800 under any throttle condition. hard rev slow rev I'd think it would happen sooner @ a harder rev if it were the fuel filter my currend one is 1 year old. but again, I'll try it OMW to CSK AUTO now. you should pm me when you figure this out my freind has a 94 nissan quest van and it also have the same motor in it with the same problem. we are going to putmy spare MAF on tomorow to test it i think. Link to comment Share on other sites More sharing options...
MY1PATH Posted December 6, 2008 Author Share Posted December 6, 2008 New Fuel filter did not solve the problem Thanks for the FSM pages. hopefully my MAF comes in tomorrow and I can put it in @ work Link to comment Share on other sites More sharing options...
94extreme Posted December 6, 2008 Share Posted December 6, 2008 is it possible a part of the ecu that was fighting the timing got cooked and thats keeping it in "limp mode" i'm starting to think that's possible. but you ought to start testing all the main sensors. you can check most if not all with a voltmeter. i'd start with tps and cps. how's the oil look? Link to comment Share on other sites More sharing options...
MY1PATH Posted December 7, 2008 Author Share Posted December 7, 2008 (edited) i'm starting to think that's possible. but you ought to start testing all the main sensors. you can check most if not all with a voltmeter. i'd start with tps and cps. how's the oil look? I don't have time to check stuff with a meeter right now but I as soon as I can oil, I hadn't checked. But I changed it last month...BRB.... the Oil Level was below the dipstick, I added about 1 QT for it to show 1/3 on the dipstick. (huh? it's never burned or leaked maybe I was a mororn last month?) the Oil Color Had a good light bronze/gold color to it. what are you thinking as far as the oil? Is my oil light broke too? or does it only come on when its worse than that? I'm let it warm up and see what happens....nope still being stupid. I'm limp it to work and get into it with a voltmeter there. BITEMEDOUGHBOY does your FSM say anyting about the VSS being a cause for the fail-safe-system? Edited December 7, 2008 by MY1PATH Link to comment Share on other sites More sharing options...
RedPath88 Posted December 7, 2008 Share Posted December 7, 2008 My truck just did this today (3k rpm), but I found a loose connection (right hand connector). I apparently did not get it all the way in when I cleared the computer afte installing the cams last weekend. With a little luck that is all it was. I pulled off the road and checked codes, which it returned 51 (Injector Circuit) I unplugged and ECU for about 20min, plugged it back in and off I went, not another problem... hopefully it stays that way. Link to comment Share on other sites More sharing options...
bitemedoughboy.com Posted December 7, 2008 Share Posted December 7, 2008 I don't have time to check stuff with a meeter right now but I as soon as I canoil, I hadn't checked. But I changed it last month...BRB.... the Oil Level was below the dipstick, I added about 1 QT for it to show 1/3 on the dipstick. (huh? it's never burned or leaked maybe I was a mororn last month?) the Oil Color Had a good light bronze/gold color to it. what are you thinking as far as the oil? Is my oil light broke too? or does it only come on when its worse than that? I'm let it warm up and see what happens....nope still being stupid. I'm limp it to work and get into it with a voltmeter there. BITEMEDOUGHBOY does your FSM say anyting about the VSS being a cause for the fail-safe-system? nope.... VSS is only for the cruise control and transmission computer its not even listed in the trouble shooting pages... i think you need to take a tester to each one of your wires and test for continuity and/or shorts also check your resistances at the ecu plug and at each sensor they should be the same if not you have a bad connection or wire. even if a plug looks clean it may or may not be making good contact. Link to comment Share on other sites More sharing options...
MY1PATH Posted December 7, 2008 Author Share Posted December 7, 2008 (edited) ok pulled my truck into the shop (nothing happens when I work weekends so I can do w/e) MAF checked out ok under the hood (didin't do ecu harness continuty) CAS checked out good, Injectors.... My brand new PYTHON injectors? NO! I want another opion; from the FSM EF & EC-89 (thanks doughboy) -Disconnect injector harness connectrorResistance: Approximately 1.5{OHM} the passenger side read .9-1.2 ( .6-.2 low) the driver side raead 1.7-1.9 (.2-.4 high)(EVEN SAID 2.0 FOR A SEC)those were bad readings from the wrong place NOW WHEN THE FSM SAYS APROXIMATELY I'M THINKING 1.4-1.6 FOR VARIANCE IN THE MUTIMETER. I just put these in are they really the culprit or am I being too picky? 1 year waranty... I guess It can't hurt to swap em out. If I do I think I'll go with NEIGHOF this time I don't really need performance injectors. Edited December 10, 2008 by MY1PATH Link to comment Share on other sites More sharing options...
RedPath88 Posted December 7, 2008 Share Posted December 7, 2008 You know, you don't need to keep "moving" this post to the end, anyone reading this thread has and/or will see it Link to comment Share on other sites More sharing options...
MY1PATH Posted December 7, 2008 Author Share Posted December 7, 2008 (edited) You know, you don't need to keep "moving" this post to the end, anyone reading this thread has and/or will see it sorry, had you moved it back the first time? I though I was losing it lol. I just didn't want to start page 3 out with seemingly un-helpful info since I already checked all plugs. I'm prolly getting a little odd cause this is the worst problem I've had with the pathy, its my daily driver and I was planning on driving it to cali. *sigh*Moving on, http://www.bitemedoughboy.com/pdf/EFEC89.pdf I get no voltage on 101, 102 & 114 it says to disconnect battery "W/L" connector (what is that? there's 3 connetors coming from batt+ and none look like the pic) AND safety realy, not sure which that is either. I re-checked injectors @ the harness and I must had bad connetion on one and my fingers or someting touching on the other cause both OHM'd out 1.4-.16 Edited December 7, 2008 by MY1PATH Link to comment Share on other sites More sharing options...
88pathoffroad Posted December 7, 2008 Share Posted December 7, 2008 According to the FSM for an 88, your problem is either the MAF sensor or the injectors. The ECU will go into fail-safe mode (engine operation limited to 2800 RPM) if either the MAF or injectors fail to operate. From the FSM:Fail-Safe System Description 1. Air flow meter malfunctioning: if the air flow meter output voltage is lower or higher than the specified value, ECU senses an air flow meter malfunctioning. In case air flow meter malfunctions, the throttle sensor substitutes for the air flow meter. Though air flow meter is malfunctioning, it is possible to drive the vehicle and start the engine. But engine speed will not rise more than 2800 rpm in order to inform the driver of fail-safe system operation while driving. 2. Injector malfunctioning: When engine speed is less than 2000 rpm in the alternating injection mode (except during acceleration) and injection pulse angle is less than 79 degrees (Crank angle), if at least one injector does not inject fuel four times successively because of the electric problem, ECU senses injector malfunctioning. If one injector malfunctions, it is possible to drive the vehicle and start the engine. But engine speed will not rise more than 2800 rpm in order to inform the driver of fail-safe system operation while driving. I suppose that COULD point at a crank angle sensor being off, but I think it'd run pretty ratty with that many errors. Sorry I didn't see this post earlier. The Recent Posts function of this board frequently drops topics off the list on me for some reason. Link to comment Share on other sites More sharing options...
RedPath88 Posted December 7, 2008 Share Posted December 7, 2008 Well not truely unrelated as it supports the bad connection theory, but anyway.... W/L should be a White wire with a Blue strip Nissan Wire Color CodingB = Black W = White R = Red G = Green L = Blue Y = Yellow LG= Light Green BR = Brown OR = Orange P = Pink PU = Purple GY = Gray SB = Sky Blue And for reference, on W/D21's the page your looking it as for code 51 (not 43), They contain the same info, just the wrong code for a Pathfinder/Hardbody ECU. *continues looking at the FSM for more information* Link to comment Share on other sites More sharing options...
RedPath88 Posted December 7, 2008 Share Posted December 7, 2008 If you need copies from an original WD21 FSM, PM me. I live and Yelm and could meet you tomorrow (kinkos or someplace with a copier?) and you could get them directly from my 1989 FSM. Link to comment Share on other sites More sharing options...
MY1PATH Posted December 7, 2008 Author Share Posted December 7, 2008 (edited) guys I thank you all for the help, I feel my self running out of steem trying to fix my beloved pathy (that I prolly broke). with not results to prove exactly what is causing failsafe mode (exept lack of continutiy to 101, 102 & 114 on the ecu harness) and tons of money spent on "maybe its that part" (they still havn't come and I was paniced and foolish when I ordered)I think I'm gonna return all the parts, get my money back and the I think I might go to a japanese auto specialist or "total performance" here in tacoma as they have done me fair and well since I got here. EDIT: I put everything back together, pulled it out of the shop ran self diagnostics 1 more time: 51 Injector Circuit. (finally it tells me something) so I know my injectors work, and the those 4 pins above lacked proper continutity... I'm so close but so far away. electrical is not my strong point I've checked all the harneses and looked for the obvous along the way. should I start un-wraping wire bundles? Safety relay???"W/L" connector??? Tell a mechanic my findings and have them deal with it? Edited December 7, 2008 by MY1PATH Link to comment Share on other sites More sharing options...
Terrano1992 Posted December 7, 2008 Share Posted December 7, 2008 there was another plug on the harness that was capped off. What is that for? Nissan dealers? Auto tranny?is it possible a part of the ecu that was fighting the timing got cooked and thats keeping it in "limp mode" This plug is not a part of ECU. This is "jumper plug", i.e. part of harness. It serves as interconnection between harness wires to join multiple wires in the same circuit (for example, to ground). It has only jumpers between contacts inside the plug case. Link to comment Share on other sites More sharing options...
MY1PATH Posted December 8, 2008 Author Share Posted December 8, 2008 Well not truely unrelated as it supports the bad connection theory, but anyway.... W/L should be a White wire with a Blue strip And for reference, on W/D21's the page your looking it as for code 51 (not 43), They contain the same info, just the wrong code for a Pathfinder/Hardbody ECU. *continues looking at the FSM for more information* I think the wires are differant for differant years because the colors listed on doughboys paged don't match my underhood wire colors... redpath I think I might need those '89 FSM pages about the injector circut and injecotr safetey realy. do you think you could post them? Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now