NissanNismoZ Posted May 21, 2012 Share Posted May 21, 2012 (edited) Alright, so i thought i'd compile this into a new thread.. Since after my long 300mi. trip in Pathy, through long mountain slopes and being driven hard.. It no longer drives right; such as it has /ZERO/ power. Note: Before the trip Pathy had been doing the weird (acting like i was pushing and releasing on the throttle, when really i was holding my foot steady, slowly pushing it harder to accelerate) BUT. Only does it when it's cold. This video demonstrates to the best of my ability of the problem: http://s208.photobuc...20-22-39-40.mp4 And the lack of power.. It now has to downshift to 3500RPM just to maintain speeds of 55mph up small slopes, where as before would be 55mph torque converter locked, A/C on and cruising right up at 2200RPM. Here's a video demonstrating the lack of power of just accelerating. You can hear how deep it sounds because of how hard im actually pushing it to accelerate...: http://s208.photobuc...20-22-46-04.mp4 I haven't had a CEL come on either. Anyone have ANY ideas?? I've tried even changing the TPS, and it STILL does the problem mentioned in the first video... I have also went from getting a steady 20MPG to a now 15-16 MPG. Thanks...It's really embarassing to the point of taking back roads just to get home because i have to push it so hard to keep speed up hills... It does have a major exhaust leak now, since the trip, my guess is i blew an exhaust gasket, but is it really possible it could just be the exhaust leak causing all this?? I mean, yeah im having it fixed in the morning, but it feels like there's more to it than just that... Edited May 23, 2012 by NissanNismoZ Link to comment Share on other sites More sharing options...
Kingman Posted May 21, 2012 Share Posted May 21, 2012 (edited) O2 sensor, unplug it and see how it drives. Edited May 21, 2012 by Kingman Link to comment Share on other sites More sharing options...
JamesRich Posted May 21, 2012 Share Posted May 21, 2012 Check your convertor for a restriction. If the exhaust leak keeps getting worse and the power keeps going down it could be plugging up more and more. To check for a restriction I use an old vacuum/fuel pressure gauge in the O2 sensor hole. I'm not sure how much pressure is allowable but I would guess nothing over a pound when revving. You can also just unbolt the pipe from the convertor and take it for a spin. Check this ASAP. If it’s plugged that bad your holding a lot of heat on the motor that can burn exhaust valves. James Link to comment Share on other sites More sharing options...
NissanNismoZ Posted May 21, 2012 Author Share Posted May 21, 2012 yeah, its definitely getting worse .. I finally threw in the towel and did something I said I'd never do; take it to a repair shop. Having them fix the exhaust leak and check/remove the cat. Thanks! I didn't know it could be that serious! Link to comment Share on other sites More sharing options...
NissanNismoZ Posted May 21, 2012 Author Share Posted May 21, 2012 alright. so I decided to have them just install a new exhaust from the y-pipe, back. No cat or resonator now. It sounds mean, and power is increased a lot. But, it still doesn't feel like it has any power upon accelerating up small hills. it can hold its speed up small slopes now, but bigger it just can't hold it..I don't understand what could be wrong now.. still no CEL, BTW. thanks! Link to comment Share on other sites More sharing options...
Kingman Posted May 21, 2012 Share Posted May 21, 2012 Did you unplug the O2 sensor and see how it drives? Link to comment Share on other sites More sharing options...
Slartibartfast Posted May 21, 2012 Share Posted May 21, 2012 Vac lines? Link to comment Share on other sites More sharing options...
NissanNismoZ Posted May 21, 2012 Author Share Posted May 21, 2012 ill try the o2 sensor disconnected tomorrow.. and vacuum lines..I just checked them and they're all snug with no holes.. Link to comment Share on other sites More sharing options...
NissanNismoZ Posted May 22, 2012 Author Share Posted May 22, 2012 the new exhaust seems to have triggered a CEL... will check on the code tomorrow. I'm starting to wonder if the power loss may be related to the TPS adjustment.. because Pathy seems to downshift to 3k rpm a lot quicker and I have to now let off the pedal almost completely for it to shift back up. does the TPS control fuel mixture at all?? still going to try unplugging tthe o2 and hope for the best. thanks everyone for the help! Link to comment Share on other sites More sharing options...
NissanNismoZ Posted May 22, 2012 Author Share Posted May 22, 2012 I lied, it's still doing the hesitation thing...just noticed it this morning, but i think my whole problem is connected to that hesitation problem. I cannot get to the O2 sensor connector to disconnect it..is there any other way to text the O2? I also have a few questions.. The O2 sensor..aren't readings from it ignored until the engine is warmed up? I think the whole problem lies within the hesitation as its most noticable on cold starts..and it FEELS like Pathy is normal again, until it gets extremely LOUD and bogs. What im trying to say is..itll have power for a few seconds at a LOW speed (1mph-10mph then it feels like it bogs and is stuck in bog mode.) Meaning, the 'hesitation' feeling stays there throughout the rest of the trip, until im accelerating lightly at a LOW speed.. Is this clear? I'm sorry, I really dont know how to describe it..but it feels just like im pushing the pedal, then im letting off and accelerating lightly, when really its accelerating LOUD and struggling because im pushing it a lot harder than usual... Thank you. Is there anything else i can test? I really dont know where else to start.. and i dont want to have to pay hundreds of $$$ to have a shop troubleshoot and fix it... I appreciate the help! Link to comment Share on other sites More sharing options...
adamzan Posted May 22, 2012 Share Posted May 22, 2012 Why can't you get to the 02 sensor plug? Its on the little tree of connectors by the fuel filter. It has 3 wires 2 white and 1 black I believe. Link to comment Share on other sites More sharing options...
NissanNismoZ Posted May 23, 2012 Author Share Posted May 23, 2012 Thank you!! I was reaching.up and over the tranny and couldn't find the connector..Doh! anyway. Disconnected it..and..the hesitation iis now gone, but it drives roughly the same now...i want to say if not better but still leaning toward the same...so does that mean the o2 sensor is gone? Thank you! Link to comment Share on other sites More sharing options...
NissanNismoZ Posted May 23, 2012 Author Share Posted May 23, 2012 just ordered the Beck/Arnley O2 for 41.06 from RockAuto..Thanks guys. I appreciate it! Link to comment Share on other sites More sharing options...
NissanNismoZ Posted May 24, 2012 Author Share Posted May 24, 2012 I just don't know what to do. Swapped O2 with a friends working one and still the same problem. I bought a ECT sensor, and now the hesitation is fully gone. It also accelerates more smoothly bow. I decided to see what would happen if in neutral under no load. I found out: If I stomp the pedal it gets loud and accelerates extremely slowly Yet if I slowly rev it up it accelerates a lot faster and quieter??! I don't want to have to sell the Pathy but I'm close to giving up... Link to comment Share on other sites More sharing options...
Slartibartfast Posted May 25, 2012 Share Posted May 25, 2012 Is the exhaust sorted out already? Link to comment Share on other sites More sharing options...
Tungsten Posted May 25, 2012 Share Posted May 25, 2012 (edited) Don't stomp the pedal! When you stomp the pedal, you flood the engine with too much air. That's completely normal on these trucks (at least with my experience). You accelerate better with 1/2 throttle than with WOT. Although somehow you will accelerate better with WOT when the engine is cold. Most likely an ECU fuel management issue as it is tuned to save you gas. I lied. Keep reading... Edited May 26, 2012 by Tungsten Link to comment Share on other sites More sharing options...
NissanNismoZ Posted May 25, 2012 Author Share Posted May 25, 2012 (edited) Cat is removed. But my friend thinks my muffler may be stopped up.. I don't know how to check really..but it feels like it puts out some..I just know up some hills it would only have to unlock the torque converter and it would climb fine..now it has to be at 4500rpm to just keep a steady speed up that same hill going the same speed..its really emvarassing with semis passing me.. how can I check to see if its clogged? It just has less power the harder I push it up a hill.. it definitely drives better with the new ECT though. Tungsten: actually I didn't know that.. I.have hears a clogged exhaust can lower engine vacuum which may explain why it idles at 400rpm. I was idling out of a drive thru when someone pulled out in front of me and I slammed on the brakes and it just kept rolling.. I seem to have no.brakes at that low of rpm.. Edited May 25, 2012 by NissanNismoZ Link to comment Share on other sites More sharing options...
JamesRich Posted May 26, 2012 Share Posted May 26, 2012 To see if your muffler is clogged just disconnect it after the cat and take it for a drive. If you have a vacuum gauge you can check exhaust restriction with it. When you hold the motor at a rev say 2000rpms it should have more vacuum than at idle. When you let the throttle go it should jump up a few inches and then come down. If you get less vacuum the higher you rev it then it's definitely clogged. The reason you never heard what tungsten told you is because it's bull @!*%! You ever see a dragster run a quarter mile by giving it half throttle to take off? If the motor is tuned right and nothing is wrong it will go no matter how much throttle you give it. It's not normal for these trucks either. I can stomp mine to the floor and it goes with no hesitation from being flooded with air! Maybe tungsten has too much air somewhere. If his truck does this then there is something wrong with it. James Link to comment Share on other sites More sharing options...
NissanNismoZ Posted May 26, 2012 Author Share Posted May 26, 2012 I don't have a vacuum gauge but it drives the same without a muffler, just louder.. That's what I thought..because over floored mine before and it straight up went. Now of I do that it doesn't even try to rev up. It just bogs. It now doesn't idle. I had to push it into my parking spot here at work because it won't idle. I have to hold the pedal down, then put it in gear and NOT let it idle. Its really embarrassing. I was told by a friend to check the coil..is that a possibility? If the coil is getting weak that would be an easy fix.. Thanks guys for sticking with me on this..I really appreciate it.. Link to comment Share on other sites More sharing options...
Slartibartfast Posted May 26, 2012 Share Posted May 26, 2012 Not sure how the coil would cause this... seems like it would be spark or no spark, but I could be wrong. Since you don't need to measure vacuum exactly, perhaps you could make a redneck gauge. I'm thinking a one- or two-liter plastic bottle, with a vac line fitting in the end (try the drip line irrigation section at the hardware store), cut the bottom off, stretch a balloon over it. Epoxy a straw or something into the middle of the balloon... then when vacuum is applied, the straw moves. It won't give you numbers, but it should show the fluctuations James is talking about. You changed the TPS, but have you checked the wiring harness? Link to comment Share on other sites More sharing options...
Tungsten Posted May 26, 2012 Share Posted May 26, 2012 (edited) You ever see a dragster run a quarter mile by giving it half throttle to take off? If the motor is tuned right and nothing is wrong it will go no matter how much throttle you give it. Drag racers are not set up for low end performance. A road car will have the most torque around a middle rpm range (for fuel conservation and cruising efficiency reasons) while a dragster makes the most torque near or at the redline. On a road car, it is pointless to mash the gas pedal since all you will get is more noise after the torque band peaks. You are still spot on about the throttle. The engine should be able to accelerate no matter where the throttle position is. Maybe tungsten has too much air somewhere. If his truck does this then there is something wrong with it. Yeah disregard my previous post, there was something wrong that caused hesitation at full throttle. Every WD21 I drove did that so I thought it was normal but apparently not. I guess they all had cracked vacuum hoses. Found a vacuum leak here and replaced it with a crappy hose just for testing purposes. Doing that solved all my funky problems I had before when the engine was cold. It will no longer hesitate at full throttle either. However, there is still not much difference between going all the way down and half way down as there is a limited amount of airflow to the engine. Every road car is designed like this and there isn't much you can do about that unless you plan to convert it into a race car. Check all your vacuum hoses for cracks and tightness on the fittings. If you have a leak somewhere, the MAF sensor will get a wrong reading and you will have fun issues. You can check for any major leaks by squeezing the blow-by hose near the IACV. If the engine speed goes up, you have a big leak somewhere. Edited May 26, 2012 by Tungsten Link to comment Share on other sites More sharing options...
NissanNismoZ Posted May 27, 2012 Author Share Posted May 27, 2012 That's true. You know..I might try that if I can get the supplies..I'm trying everything you.guys are throwing at me. I really appreciate it! It's just embarassimg with it dying all the time.. when itndoes that I have no brakes and roll through a stop light.. Link to comment Share on other sites More sharing options...
NissanNismoZ Posted May 27, 2012 Author Share Posted May 27, 2012 The IACV blow by hose..where is that and ill try that too! Link to comment Share on other sites More sharing options...
Tungsten Posted May 27, 2012 Share Posted May 27, 2012 It looks like a U shape. Look by the firewall on the driver's side, you can't miss it. Link to comment Share on other sites More sharing options...
JamesRich Posted May 27, 2012 Share Posted May 27, 2012 (edited) It's really hard to diagnose something like this without seeing the vehicle. If you are loosing brakes as soon as it dies out you brake booster could be what is leaking. Or the check valve is broken. IF the motor still has good vacuum even with the motor shut off for days the booster should still have vacuum in it. It still sounds like stopped up exhaust to me but you said you checked all that. If the air can't get out the motor can't pull any air in which would cause low vacuum. The only other thing that would cause low vacuum (other than a big leak) is if you ran the motor hot for a long period of time and collapsed the rings and it just doesn't have enough compression to pull much vacuum. Get a compression gauge and run a compression check on it. Most part houses loan them. First thing you need to do is pull the vacuum hose off of the brake booster and plug it to see if that makes a difference. James Edited May 27, 2012 by JamesRich Link to comment Share on other sites More sharing options...
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