NissanNismoZ Posted November 1, 2011 Share Posted November 1, 2011 Ok, so im starting a clean slate as a few things have changed. My (i think it's hesitation?) For example, if i were to EVER pull out as soon as it stop idling high to warm up (usually around 30 secs to a min, depends) it acts like it doesnt have much power, and as you accelerate to get to speed, it acts like im pushing and letting off the pedal repeatedly, but gently..and it does this until its warmed up (usually around 2-3 miles, but the colder it is, the worse it is.. So i'm wondering, what could this be? I'm trying to figure it out before winter and it just..stops all together.. Ok so if i start it up and let it idle cold, if i listen closely, i can hear what sounds like a slight miss/stumble (i can video it if needed, but its slight..) My CEL no longer goes off, and my codes are: 12 Air Flow Meter/Mass Air Flow Sensor. 51 Injector Circuit. 45 Injector Leak. 34 Knock Sensor. 23 Idle Switch. Link to comment Share on other sites More sharing options...
sewebster Posted November 1, 2011 Share Posted November 1, 2011 Didn't you already determine that your MAF wiring was busted? Link to comment Share on other sites More sharing options...
silverton Posted November 2, 2011 Share Posted November 2, 2011 Clean or replace your MAF and air filter. Link to comment Share on other sites More sharing options...
Kingman Posted November 2, 2011 Share Posted November 2, 2011 Does it backfire a lot when you're slowing down? The "it acts like im pushing and letting off the pedal repeatedly" kind of feel like suddenly you're towing something or being held back then it's gone? Try something real quick, unplug the Coolant Temp Sensor from the upper housing and see if the slight miss goes away. I'm curious... Link to comment Share on other sites More sharing options...
NissanNismoZ Posted November 2, 2011 Author Share Posted November 2, 2011 (edited) Didn't you already determine that your MAF wiring was busted? Well i thoght so..but it runs better off stock wiring, than if i wire it directly... Clean or replace your MAF and air filter. I have two MAF's both clean along with a new air filter Does it backfire a lot when you're slowing down? The "it acts like im pushing and letting off the pedal repeatedly" kind of feel like suddenly you're towing something or being held back then it's gone? Try something real quick, unplug the Coolant Temp Sensor from the upper housing and see if the slight miss goes away. I'm curious... Hmmm..suddenly like im towing something..like something is pushing in front of the truck, then letting go.. The RPMS will go up faster, then not go up as fast, then go up faster..i want to say like a surging? I can video it, if you want.. I'll try that! Thanks! Edited November 2, 2011 by NissanNismoZ Link to comment Share on other sites More sharing options...
adamzan Posted November 2, 2011 Share Posted November 2, 2011 Try unplugging the o2 sensor and see if it runs better. Link to comment Share on other sites More sharing options...
NissanNismoZ Posted November 2, 2011 Author Share Posted November 2, 2011 Try unplugging the o2 sensor and see if it runs better. Actually, my gas mileage has SUCKED recently..im now getting 50-60 miles per qtr tank... :\ Where's the harness for the 02 at? I have been questioning my o2 sensor..and im sure the other night where i let it idle for 2 1/2 hours while i rewired all my speakers didnt help either..though i did drive it hard to drive out any carbon that may have built up... Link to comment Share on other sites More sharing options...
krmiller07 Posted November 2, 2011 Share Posted November 2, 2011 The O sensor harness comes up from underneath the truck and follows the firewall up the passenger side. There should be a connector in the middle of the wiring right behind the passenger side cylinder bank. Link to comment Share on other sites More sharing options...
Kingman Posted November 2, 2011 Share Posted November 2, 2011 Hmmm..suddenly like im towing something..like something is pushing in front of the truck, then letting go.. The RPMS will go up faster, then not go up as fast, then go up faster..i want to say like a surging? I can video it, if you want.. I'll try that! Thanks! Your issue sounds exactly like my issue, which was the CHTS (your style of sensor goes in the coolant neck) even though it's new. Piss poor fuel mileage, hesitating, surging when cold (rich-lean-rich-lean...), slight "miss" at idle (although when cold or warm), no power when it's acting up, (comes from running way too rich), backfiring when slowing down for speed bumps (again running rich), and when it's bogging down it's slow to rev but when it's done with the morning freak out it'll rev freely. I also noticed that if I start the truck and it's not acting up, I can hold the RPMs steadily at 3K for maybe a minute. Then bam something happens and the RPMs will drop down to 2,500-ish and not want to hold there stably until it pops out of it's bogging mode, then all is well again. You can hear it in the engine and exhaust, it sounds like it's being completely restricted. When I unplugged my sensor every issue went away. Yeah, take a video? Link to comment Share on other sites More sharing options...
krmiller07 Posted November 2, 2011 Share Posted November 2, 2011 Come to think of it. My 85 300 ZX did the same thing. And I replaced everything from the CAS then the distributor to CTS and O2 sensors. Never figured out what caused it because I traded it for a New Pathy in 87. My 89 is starting to do something similar in that during warm up, once the temp comes up to about just off the 'C' on the temp gauge. The idle will kind of bounce or float between 800 rpm and 1000- 1100 like it's trying to figure out which speed it needs to settle into? Link to comment Share on other sites More sharing options...
MrT Posted November 2, 2011 Share Posted November 2, 2011 (edited) Not gonna be a popular call but I'd say take it to the dealer to at least get a diagnosis. Of course that is if you really need this vehicle to work properly. You seem to have been beating your head against a wall for some time now with very little progress. And this doesn't seem like one of those "one little thing" problems. To throw my .02 in... You probably have some atrocious wiring issues that you aren't going to be able to figure out for yourself, or a bad ECU. What you really need to do is go step by step through EF & EC-127 through 132 in the FSM. That's your baseline. Move on from there to individual components. It's going to be a giant pain and unless you are pretty good with wiring it will be next to impossible for you to get anywhere. Edited November 2, 2011 by MrT 1 Link to comment Share on other sites More sharing options...
NissanNismoZ Posted November 3, 2011 Author Share Posted November 3, 2011 Your issue sounds exactly like my issue, which was the CHTS (your style of sensor goes in the coolant neck) even though it's new. Piss poor fuel mileage, hesitating, surging when cold (rich-lean-rich-lean...), slight "miss" at idle (although when cold or warm), no power when it's acting up, (comes from running way too rich), backfiring when slowing down for speed bumps (again running rich), and when it's bogging down it's slow to rev but when it's done with the morning freak out it'll rev freely. I also noticed that if I start the truck and it's not acting up, I can hold the RPMs steadily at 3K for maybe a minute. Then bam something happens and the RPMs will drop down to 2,500-ish and not want to hold there stably until it pops out of it's bogging mode, then all is well again. You can hear it in the engine and exhaust, it sounds like it's being completely restricted. When I unplugged my sensor every issue went away. Yeah, take a video? Hmm..actually, that sounds just like my problem, only im fairly sure mine revs freely..no problem at all... But i havent tried revving it cold.. Come to think of it. My 85 300 ZX did the same thing. And I replaced everything from the CAS then the distributor to CTS and O2 sensors. Never figured out what caused it because I traded it for a New Pathy in 87. My 89 is starting to do something similar in that during warm up, once the temp comes up to about just off the 'C' on the temp gauge. The idle will kind of bounce or float between 800 rpm and 1000- 1100 like it's trying to figure out which speed it needs to settle into? Hmm..i dont have an idling problem, it definitely fast idles like its supposed to, but maybe yours is a MAF issue? Not gonna be a popular call but I'd say take it to the dealer to at least get a diagnosis. Of course that is if you really need this vehicle to work properly. You seem to have been beating your head against a wall for some time now with very little progress. And this doesn't seem like one of those "one little thing" problems. To throw my .02 in... You probably have some atrocious wiring issues that you aren't going to be able to figure out for yourself, or a bad ECU. What you really need to do is go step by step through EF & EC-127 through 132 in the FSM. That's your baseline. Move on from there to individual components. It's going to be a giant pain and unless you are pretty good with wiring it will be next to impossible for you to get anywhere. Hmmm..honestly, i would, if i had the money..but i have no idea what it would cost.. Yeah, for a whole 8 months, i've been battling these problems.. The ECU is good, i have tried numerous ECU's to come out with the same codes and the same problems... I'm feeling adventurous, im OK with wiring, but as far as understanding how wiring works, im good to go. But see, when i tried straight wiring my MAF sensor to the computer, it would idle extremely high (2k rpm) and wouldnt stop doing it! Anyway, here's the video.. It wasnt as cold out, so it didnt act up like it usually does..but maybe you can get an idea.. http://www.youtube.com/watch?v=2dtyg44GI1k Link to comment Share on other sites More sharing options...
Kingman Posted November 3, 2011 Share Posted November 3, 2011 (edited) Here's the thing... But see, when i tried straight wiring my MAF sensor to the computer, it would idle extremely high (2k rpm) and wouldnt stop doing it! The CHTS, MAF, and CAS are all grounded together through the ECU at multiple pins and the chassis. Mess one common ground up (mainly to the ECU) and everything on that circuit could start acting screwy. Nissans love grounds. Did you unplug the temp sensor? Edited November 3, 2011 by Kingman Link to comment Share on other sites More sharing options...
NissanNismoZ Posted November 3, 2011 Author Share Posted November 3, 2011 (edited) Here's the thing... The CHTS, MAF, and CAS are all grounded together through the ECU at multiple pins and the chassis. Mess one common ground up (mainly to the ECU) and everything on that circuit could start acting screwy. Nissans love grounds. Did you unplug the temp sensor? hmmm..so do you happen to know where the common grounds for those are?? I even went as far as adding two extra grounds to the MAF sensor! I just dont get why when i straight wired it, wiring it the same way its supposed to be, according to the FSM, it would idle extremely high like that.. Not yet, but when i head out for work i will.. Thanks! Will post back with results when im able! Edited November 3, 2011 by NissanNismoZ Link to comment Share on other sites More sharing options...
krmiller07 Posted November 3, 2011 Share Posted November 3, 2011 Were you driving the truck when you shot that video? I noticed your speedo was reading nearly 40mph (Electronic Speedo) while the tach was reading 2-2500 rpm. If the speedo is acting up at the same time, I'd say you definitly have an electrical issue or like Kingman mentioned above 'a ground' thats screwing things up. Link to comment Share on other sites More sharing options...
Kingman Posted November 3, 2011 Share Posted November 3, 2011 hmmm..so do you happen to know where the common grounds for those are?? No, the FSM does though in the wiring diagrams. I even went as far as adding two extra grounds to the MAF sensor! I just dont get why when i straight wired it, wiring it the same way its supposed to be, according to the FSM, it would idle extremely high like that.. It's not supposed to, did you try any other MAFs at the time or only just the one? Have you looked inside your ECU at all? If you've got a bad piece of wiring somewhere it could be frying it every time you drive the truck, maybe why multiple computers are giving the same codes. This is what happened to mine and it took A LOT of troubleshooting and time before I opened up the ECU to find the problem right in front of my face. Honestly now that I think about it, what I'd do is go to the junkyard and pull a good wiring harness from the lowest mileage, cleanest, unmolested rig you can find. That'll more than likely let you know if wiring is your issue or not. 1 Link to comment Share on other sites More sharing options...
sewebster Posted November 3, 2011 Share Posted November 3, 2011 I think your problem lies in the wiring.... it doesn't matter if the truck seems worse when you think you fixed it... if you are measuring different signals at the MAF and ECU when they should be the same then you need to fix that. Once you've done so you can figure out why your truck idles too high with it fixed or whatever. I don't know if that's actually what's causing your problem, but it's really hard to diagnose stuff like this (especially over the internet) without being methodical about it... Link to comment Share on other sites More sharing options...
NissanNismoZ Posted November 3, 2011 Author Share Posted November 3, 2011 (edited) Were you driving the truck when you shot that video? I noticed your speedo was reading nearly 40mph (Electronic Speedo) while the tach was reading 2-2500 rpm. If the speedo is acting up at the same time, I'd say you definitly have an electrical issue or like Kingman mentioned above 'a ground' thats screwing things up. Yeah, i was driving up the highway..why..what's wrong with that? My speedo works fine compared to the GPS.. I just dont floor my pathy.. i usualyl try to make it shift asap to save on gas.. at the most i let it shift at 3200RPM i definitely have electrical issues..but..i cant figure it out... Have you looked inside your ECU at all? If you've got a bad piece of wiring somewhere it could be frying it every time you drive the truck, maybe why multiple computers are giving the same codes. This is what happened to mine and it took A LOT of troubleshooting and time before I opened up the ECU to find the problem right in front of my face. Honestly now that I think about it, what I'd do is go to the junkyard and pull a good wiring harness from the lowest mileage, cleanest, unmolested rig you can find. That'll more than likely let you know if wiring is your issue or not. Hmm..the only pathy i know is one that has had a lot of stuff pulled from it..but engine and tranny wise, it ran and parked itself in the junkyard.., it was only junked because of its frame.. How long is the wiring harness? would that be a job one person could tackle in a day, or would it be more of a project..? I'm very adventurous and desperate to do what it takes... You had a bad solder in your ECU..or..what? where was your problem at? the actual wires at the connector? I think your problem lies in the wiring.... it doesn't matter if the truck seems worse when you think you fixed it... if you are measuring different signals at the MAF and ECU when they should be the same then you need to fix that. Once you've done so you can figure out why your truck idles too high with it fixed or whatever. I don't know if that's actually what's causing your problem, but it's really hard to diagnose stuff like this (especially over the internet) without being methodical about it... You do have a point.. But thats why i tried to 'fix' the wiring by wiring it straight to the ECU..and when i did that it idled extremely high and everytime i just -tap- the gas pedal it would idle down then back up... In theory, wiring straight to the ECU should eliminate all electrical problems...right?? I tried mixing my wiring (one wire mine, one wire factory wiring) and it ran at 2RPM (no joke!) I totally agree, but i really appreciate EVERYONES input on this issue..really, i do.. Edited November 3, 2011 by NissanNismoZ Link to comment Share on other sites More sharing options...
sewebster Posted November 3, 2011 Share Posted November 3, 2011 You do have a point.. But thats why i tried to 'fix' the wiring by wiring it straight to the ECU..and when i did that it idled extremely high and everytime i just -tap- the gas pedal it would idle down then back up... In theory, wiring straight to the ECU should eliminate all electrical problems...right?? I tried mixing my wiring (one wire mine, one wire factory wiring) and it ran at 2RPM (no joke!) It sounds to me like you have more than one problem... I would be curious if you still get the MAF code when you have the wiring straight to the ECU (after resetting codes). But maybe it doesn't even run well enough for you to check? If it's just idling at 2000 rpm that is probably ok... If fixing the wiring DOES get rid of the MAF code then I'd move on to solving the next one. If you don't want the ecu to be able to increase the idle speed unplug the AAC connector. Then your idle will just be based on the mechanical stuff... idle adjust screw, vacuum leaks etc.... 1 Link to comment Share on other sites More sharing options...
MrT Posted November 4, 2011 Share Posted November 4, 2011 I'm feeling adventurous, im OK with wiring, but as far as understanding how wiring works, im good to go. But see, when i tried straight wiring my MAF sensor to the computer, it would idle extremely high (2k rpm) and wouldnt stop doing it! Well... What you really need to do is go step by step through EF & EC-127 through 132 in the FSM. That's your baseline. Move on from there to individual components. It's going to be a giant pain and unless you are pretty good with wiring it will be next to impossible for you to get anywhere. You need to test every one of these voltages. Print out the pages and write down what you are actually getting. When you know what's out of range you know where to start. Check these wires with the wiring diagram and see what if anything is common to them. It'll take a lot of time and patience. 1 Link to comment Share on other sites More sharing options...
NissanNismoZ Posted November 4, 2011 Author Share Posted November 4, 2011 (edited) It sounds to me like you have more than one problem... I would be curious if you still get the MAF code when you have the wiring straight to the ECU (after resetting codes). But maybe it doesn't even run well enough for you to check? If it's just idling at 2000 rpm that is probably ok... If fixing the wiring DOES get rid of the MAF code then I'd move on to solving the next one. If you don't want the ecu to be able to increase the idle speed unplug the AAC connector. Then your idle will just be based on the mechanical stuff... idle adjust screw, vacuum leaks etc.... You have a point, ill try that Monday..i'm starting my big long troubleshooting deal then..and hoping to get somewhere.. Well... You need to test every one of these voltages. Print out the pages and write down what you are actually getting. When you know what's out of range you know where to start. Check these wires with the wiring diagram and see what if anything is common to them. It'll take a lot of time and patience. I'll do that starting monday, as it looks like its come to that. Thanks! At least then i can narrow it down to one thing..hopefully. ANYWAY. I brought it to school shop today and ran a bunch of tests on it.. Here's what i've come to: When checking my codes, i get 14 Vehicle Speed Sensor Circuit 32 EGR System Problem why i'm getting only getting those two, i have no idea..coz if i check the codes via ECU..i get the codes listed at the first post of this topic..but yet, if i check them with our scan tool..i get the VSS and EGR... which one should i trust?! So i check the Air/Fuel mixture..it said as long as the air and fuel matched up with the exhaust readings..its within specs. Both were alternating between Rich and Lean at 2k rpm. (good or bad? (according to the scan tool its within specs because they were reading the same.)) I do the Real Time Fault Monitor..all checked out OK at idle, but as soon as i put it at 2k RPM again, it showed AIRFLOW CKT (FAULT) FUEL PUMP (NORMAL) CRANK ANGLE SENSOR SIGNAL (NORMAL) IGNITION COIL PRIMARY SIGNAL (NORMAL) at idle, AIRFLOW CKT (NORMAL) FUEL PUMP (NORMAL) CRANK ANGLE SENSOR SIGNAL (NORMAL) IGNITION COIL PRIMARY SIGNAL (NORMAL) so..i figure this may help a LOT Im going to clean my EGR valve and see if that helps.. Once again..thank you EVERYONE I really appreciate everyone's input in helping me..along with the patience you're giving. If cleaning the EGR doesnt help, i will start troubleshooting by the FSM as MrT mentioned. Edited November 4, 2011 by NissanNismoZ Link to comment Share on other sites More sharing options...
adamzan Posted November 4, 2011 Share Posted November 4, 2011 There is a little hose on the EGR BPT valve (rubber one) thats about an inch long. Check for cracks in it, mine was broken in half and it gave me an egr code. 1 Link to comment Share on other sites More sharing options...
NissanNismoZ Posted November 4, 2011 Author Share Posted November 4, 2011 There is a little hose on the EGR BPT valve (rubber one) thats about an inch long. Check for cracks in it, mine was broken in half and it gave me an egr code. WOW Ok, so the long hose running to some thing under the intake to the EGR valve.. had a big hole in it from dry rotting.. replaced itand other vacuum lines..and tada! idle switch works too! So i'll see if it does any better..But..definitely a big improvement.. Link to comment Share on other sites More sharing options...
Kingman Posted November 4, 2011 Share Posted November 4, 2011 Link to comment Share on other sites More sharing options...
NissanNismoZ Posted November 5, 2011 Author Share Posted November 5, 2011 I have to admit, it definitely gives it a LOT more power..I tend to spin tires where I'm used to having to push the pedal down fairly hard..and it downshifts quicker, whereas before it would take even more pedal pushing to get it to.. Cel is stil on, haven't checked codes or erased them yet. But I can say the cel stayed off until I started rolling around 15mph. Possibly speed sensor but I'll check when I'm home. I hope this did it!! Link to comment Share on other sites More sharing options...
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