Okay, so I cranked it over without letting it sit on acc mode and it was just fine, this was my original throttle body I put back on. After this, I took off the air duct so I could have someone look at the butterfly while on acc mode (the turnkey position right before crank). My throttle body was working just fine, and the butterfly valve was turning with each press of the pedal. So now I shifted away from the bad throttle body scenario. I pulled the montero out of the garage and let it run for a while (about 6 minutes). The first 3ish minutes there was smoke pouring out of the exhaust, and the smoke smelled like wet cardboard or a used firework if you will. I turned the car off after it was running for a little without smoke and the exhaust was very very very hot, the muffler was just radiating heat like crazy. I thought this was strange because it was only running for a couple of minutes and it was crackling and popping from the heat. I also noticed the gas smell was not coming from the engine bay, and even though it started smelling less like fuel after running for a while I still believe the fuel smell was never coming from the engine bay. I decided I was going to check the fuel trims now that I had the vehicle pulled out of the garage, that way I won't inhale the fumes. When I started the Montero again two sputters or pops sounded like they came from the exhaust area maybe just underneath the front seats or a little further back, and it started to pour smoke again like before. My short term fuel trims read SHRTFT1(%) 25.0 and SHRTFT2(%) -5.5, the SHRTFTB1S2(%) was 25.0 as well. When I decided to pull the Montero back into the garage I put it into drive and it started to idle poorly, almost wanting to stall in gear and started making popping noises from the exhaust area once again, but this time in succession. I turned the car off and the exhaust once again was very hot, just from the car being on for around 4 minutes more. I have no clue what all of this means, I'm not sure if it could be an EGR system issue or what? I just don't know if the exhaust should be heating up to that temperature that quickly, is that normal for it not running for a while, followed by pops and loss of power? The Montero is throwing a P0300 code, I should have deleted it before doing this today, just to see if what I'm experiencing is causing that or throws it again (under my pending codes P0300 is popping up there as well). Sorry for this whole essay of troubleshooting lol. I appreciate the feedback!
Gen 3 Throttle Idle Issue
- Thread starter Ashton_59
- Start date
Michael Brown
You followed me, so now we're both lost
When was the last time the timing belt was changed, and what are the chances that it is not aligned correctly? Also could check the spark and ignition along with battery voltage. It is strange that it started immediately then had issues on the second start.
The timing belt was changed around 10k miles ago, and I was not the owner of the vehicle when that was done. But I have a receipt that shows it was done along with the pulley and water pump, that would be good to look into. The spark plugs are brand new as well as the plug wires, and brand new ngk coils. I haven’t had the battery checked but I’m not sure if that would be the problem, but hey... who knows haha. And it was strange, to sum up the exhaust noise it sounds like a bad backfire popping noise. While in park the rpms are about 1500, but when put in drive the rpms go down to 900. Another thing is that the montero is leaking a little oil, I want to put that dye stuff in because I think it’s coming from the valve cover gaskets, but I’m not sure. Even though those gaskets were changed around 15k miles ago, but it looks like they were sealed with straight rtv. Thanks for the advice and help!
Fuel trims pegged at their max is the clue to solving the problem. Your computer thinks your truck is running lean so it’s dumping tons of extra fuel in there, but if you are smelling fuel, that tells me it’s not running lean. Exhaust manifold gasket leak, down pipe leak, which is letting outside air into the exhaust stream and fooling the o2 sensors.
I have no clue as of how old the o2 sensors are
Not necessarily. I’d do two more things: 1. do a diagnostic check on the oxygen sensors and 2. check for an exhaust leak between the engine and the first (upstream) oxygen sensors. Could you post a screenshot from you gauge, showing fuel trims at idle? You should have a short and long term % for bank 1 and bank 2 . I doubt it is your EGR system since that’s only activated under high loads and not at idle. What color is your exhaust smoke? Also are you sure you don’t have a vacuum hose off somewhere? Or something connected wrong after your coil job?
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Thinking about this more, if this problem didn’t exist before the maintenance you did, I doubt an exhaust leak or bad o2 sensors is the cause. I’ll bet you still have an air leak from your intake work. Your exhaust is getting hot because you are running super lean, to the point where not even your fuel trims can adjust enough for it. If the o2 sensors are reporting similar numbers from both banks that makes a plug, wire or coil problem unlikely since that would most likely only trigger a problem on one bank and your misfire code wouldn’t be random it would be bank or cylinder specific.
What doesn’t make sense to me yet is why, if you are really running so lean, are you smelling unburned fuel......still thinking about this one.
What doesn’t make sense to me yet is why, if you are really running so lean, are you smelling unburned fuel......still thinking about this one.
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Yea... I'm kinda stumped on this one. With the intake gaskets, they have an indented and non-indented side (FEL PRO). I did not know which way to install them on the manifold, does this make a difference? There were no instructions with them neither with the FSM, so I figured it wouldn't really matter or else there would be information in one or the other.
I don’t remember having a choice since they were not symmetrical. They could only go on one way. Do you have a photo of your tear down, before you started putting it back together?
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offthepath
Adventurer
Not sure where you ended up on this, but I re-created your throttle body noise. I was wiring driving lights and had the battery terminal loose while messing around with the harness. When testing the lights with the key on and loose terminals, my throttle body made the same noise yours did.
FYI, I'm not sure if this would address all your problems but maybe clean and check all the battery cables for tightness and corossion.
FYI, I'm not sure if this would address all your problems but maybe clean and check all the battery cables for tightness and corossion.
Bringing this back from the dead LOL. The Montero has been sitting in the garage, I have had a lack of time and motivation to work on it. I have a new game plan, somebody told me on a forum "only rule things out that you do". I am going to take that approach since it is still throwing the P0300 code and nothing else I have no clue what it could be. First, off I am going to replace the MAF sensor, then remove the intake manifold again, while down there I will remove the fuel injectors and get them cleaned at a shop (because its dumping raw fuel and it's igniting in my exhaust like I said the rule of elimination.), I will also replace the valve cover gaskets because I do notice a little leakage and you can't go wrong a fresh gasket, I will replace the manifold pressure sensor, as well with the fuel pump and strainer. Finally, after all this, I will have somebody with more knowledge of manifold application put the manifold back on, as I don't think I have been correctly putting on the gaskets. Yes, this might be a little overboard, but I want my Montero finally driveable, this will also be some good preventable maintenance. The throttle body stopped making the noise