Slow to Start and running Rich

B

BOCK

New member
Hello, I am not well versed when it come to vehicles and I have been running through the forums here to try and find a solution to my answer but thus far have not found one so perhaps someone could help point me in a direction.

I have a 2000 4runner Limited, 3.7 V6 with 125,000 miles


I had installed a K&N cold air intake and air valve extension. With that process I took apart the air valve (proper name is escaping me at the moment) and cleaned it. Upon screwing it back into the air intake plenum I cracked the exterior surface for one of the screw holes. So I went to a junkyard and got the top piece for the air intake plenum and replaced it. I also replaced the small allen wrench screw, after a friend broke it when he was working on the vehicle with me, that controls those levers connected to the valve. I made sure to have proper cold start rpms and proper rpms for when the engine is warm in accordance with the Haynes manual and I tightened the cables that control those arms connected to the air valve which has helped with the overall acceleration response time when driving.

Since all of this has happened (note that these replacements have happened over the course of a year and I am just finally able to deal with this issue) I have noticed that my 4runner has been running rather rich and is slow to start (instead of the usual quick crank up... it will cycle 4-6 times). Because of this I have used fuel system cleaners...replaced the O2 sensor, timing belts, spark plugs and wiring, battery, air hoses, fuel filter.... and I still have the same issue.



Any suggestions? Could it just be that I need to have a tune up?
 
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How do you know you're running rich?

I think the "valve" you're talking about is the throttle body, no?
 
Yeah the "valve" is the throttle body... sorry the word was escaping me at the time.

No vacuum leaks... checked all the hoses.... unless something is not tightened down enough.

I know its running rich because I can smell it and there is some condensation coming out of the exhaust every now and them.... I don't think its a coolant leak because the level is still sitting the same and I am pretty sure the fuel lines are good.

My only other guess I can make is that it could potentially be the starter going bad and maybe that is causing it to run rich?
 
Condensation is not sign of rich, its just that, moisture in the exhaust. If you dont have any cels than your afr's should be good. Hard starts usually caused by mad sensors, which cause CELs, bad plugs, wires, ignition system, low voltage due too bad battery and or alternator. You will need to do some testing to see whats going on.
 
slow to start? not sure if this applies to you but i just changed out my fuel pump, but that was for a whole other reason, but now my rig starts up pretty darn quick.

why do you think your running rich? try and pull your plugs and inspect them. if your worried about the slow start you can start with rebuilding your starter first since its cheap and relatively easy.
 
Have similar issue as you, I think. Have a scangauge 2 hooked up to my recently acquired '99 limited with 105k miles. The afr (via xgauge) reads in the 7's on cold start and slowly, over the course of driving for 20-30 minutes or so, work its way to mid twelves to 13's. If I'm lucky it'll pop into the 14's, but I've only see that happen a couple times. Not sure how accurate those readings are though, as I'm unsure of my O2 sensors...
 
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BOCK said:
Yeah the "valve" is the throttle body... sorry the word was escaping me at the time.

No vacuum leaks... checked all the hoses.... unless something is not tightened down enough.

I know its running rich because I can smell it and there is some condensation coming out of the exhaust every now and them.... I don't think its a coolant leak because the level is still sitting the same and I am pretty sure the fuel lines are good.

My only other guess I can make is that it could potentially be the starter going bad and maybe that is causing it to run rich?
Click to expand...
I checked all my hoses and all seemed fine. Took to mechanic bc mpg so low. Mechnanic drove it with scanner hooked up, "found that computer was trying to remove 9% fuel." smoke test showed 2 vacuum leaks. tightened hose clamp and zip tied other. Also cleaned MAF, which was filthy even though I had just cleaned it twice the week before with spray MAF cleaner. retest showed "fuel trim is back in line .8%." .8% within spec, 9% out of spec running rich. Computer was adding extra gas to compensate for extra air getting in via 2 vacuum leaks. All I'm saying is I had 2 vacuum leaks and never knew it. Can you do a smoke test? May be irrelevant to your issue.
What do you mean "you can smell it"? smell what where when?
Its possible the slow starting and "rich" smell are coincidental and unrelated.
Find a really good mechanic ( I use 'Yelp' for recommendations). pay him his $100 to diagnose it. He will confirm if it is running rich. Get his advice and fix it yourself. Replace-a-part roulette is the least effective approach.
This manifested after you disassembled and cleaned and reassembled the throttle body? Maybe it is not reassembled properly or bit of gunk is still in there somewhere. Tell the mechanic, in fact show him this thread, and let him do his thing.
 
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Generally a +/- of about 25% STFT (Short Term Fuel Trim) is acceptable, LTFT (Long Term Fuel Trim) should be roughly +/- 10%, its a good way to find out if you are in fact running rich or not.

If you are running rich, you'll see your LTFT in the positive space (the PCM is increasing pulse width/adding fuel to compensate for un-metered air being picked up by the O2 Sensors post combustion because it thinks it is running lean) and STFT should be pretty high as well.

Also if the vehicle was in fact running that rich, I would suspect a DTC to be set and the MIL to be turned on. Condensation is a normal byproduct of the internal combustion process. Its hard to say what to check. Has this rich running issue been around for the entire year or is this something very recent? You've done a lot of serious work to the vehicle (Timing belt, hose replacements, O2 Sensors, ect) that any one of those could have been done improperly and/or a part/hose/line partially disconnected, ect ect.

We need to narrow down when this problem started, what you did after noticing the problem, how long its been around, ect... Its a much different thing if you did all this and just the other day it started doing it vs. 6 months ago you did the timing belt and it's been doing it since. I also am having a hard time understanding exactly what you are talking about in terms of what you did to the Throttle Body itself?
 
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I have recently taken it to a mechanic to do an inspection and see if we could deduce the problem.


Now when I say running rich and the "smell" I'm referring to that fact that I can smell gas/chemical of some sort (honestly I think the issue has been the fuel octane I have been using.... I was using a higher octane and I believe that was causing the fuel smell.... I don't know if that is possible, but once I started using the lowest octanes I have not noticed any issues)

All the repairs were doubled checked to ensure they were done properly.


To answer the question in regards to the throttle body, all that was done was a tightening of the cables and replacement of the allen wrench screw that sticks out essentially controlling the idle valve opening ratio after a cleaning.



We are looking into it possibly being the fuel pump.....that was something he suggested......testing it by turning the power on for the car but not cranking it to see if its a pressure buildup issue. Results as of right now are inconclusive.



I'll go ahead and do a smoke test, and clean the MAF but visual inspection of the air hoses shows no cracks and they are really tight (I don't even need the clamps for most of them, but I still use them)


Blackworks if I were to go to a mechanic and ask them to test the Short Term Fuel vs Long term Fuel trim what verbiage should I use so they know what they need to do?





One other small issue I started having today is that when I turn my car on the radio backlight (original stock) will start flashing...... I don't know if that means anything or if it is just a loose cable (going to investigate this weekend)
 
BOCK said:
I have recently taken it to a mechanic to do an inspection and see if we could deduce the problem.

Now when I say running rich and the "smell" I'm referring to that fact that I can smell gas/chemical of some sort (honestly I think the issue has been the fuel octane I have been using.... I was using a higher octane and I believe that was causing the fuel smell.... I don't know if that is possible, but once I started using the lowest octanes I have not noticed any issues)
Click to expand...

I had a funky chemical/gas smell coming from the engine compartment of my subaru. It seemed to appear during especially hot days or on normal days if the engine was working hard, like when driving in the mountains. It was the charcoal canister that filters the recirculated gas vapors/fumes/whatever as part of the emissions system. I was told it was not a failure of the canister, it is vapors escaping from a pressure relief valve. I think the very hot whether and the very hot engine compartment make all gasses under the hood, even those contained within a "closed" system, to expand and increase the pressure in the fuel/emissions recovery system. Plus, the charcoal has been filtering vapors for so long it must be saturated with chemicals, maybe even kind of clogged. I know that this canister was/is the source of the subaru's sharp and very distinct chemical smell. Again, may be relevant to your 4R smell, may be unrelated to other issues. Should be easy to locate place from which smell emanates. My canister made a very quiet high pitched whistle (relief valve) which I followed and realized was the source. A mechanic then told me about the relief valve. I made my own assumptions about the charcoal being saturated with a variety of chemicals which, when heated up and released under pressure, created this unique odor. Yours may not be running rich, i.e. this smell may not be the result of running rich. Perhaps the prolonged cranking required when starting is an issue entirely unrelated to your assumption that it is running rich.


BOCK said:
All the repairs were doubled checked to ensure they were done properly.
To answer the question in regards to the throttle body, all that was done was a tightening of the cables and replacement of the allen wrench screw that sticks out essentially controlling the idle valve opening ratio after a cleaning
Click to expand...

"controlling the idle valve opening ratio" sounds like something that could be directly related to your issues. Especially if it was something you busted and replaced and coincides with this starting problem.



BOCK said:
We are looking into it possibly being the fuel pump.....that was something he suggested......testing it by turning the power on for the car but not cranking it to see if its a pressure buildup issue. Results as of right now are inconclusive.
Click to expand...

thats smart and easy



BOCK said:
I'll go ahead and do a smoke test, and clean the MAF but visual inspection of the air hoses shows no cracks and they are really tight (I don't even need the clamps for most of them, but I still use them)
Click to expand...

again, i cleaned my maf twice thoroughly with MAF cleaner but apparently it was still 'filthy'. i assume a smoke test is simple, so even if it is a dead end it will be inexpensive (or free if you do it) and conclusive.

is the battery good? is the battery ground good? i've had issues with a ground getting corroded. unbolted it and sanded connector and spot it contacts the frame/body to expose fresh metal, put dielectric grease on it, reattached it and problem solved. This is also a very easy thing you can do, won't cost anything.
 
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slapdappy said:
I had a funky chemical/gas smell coming from the engine compartment of my subaru. It seemed to appear during especially hot days or on normal days if the engine was working hard, like when driving in the mountains. It was the charcoal canister that filters the recirculated gas vapors/fumes/whatever as part of the emissions system. I was told it was not a failure of the canister, it is vapors escaping from a pressure relief valve. I think the very hot whether and the very hot engine compartment make all gasses under the hood, even those contained within a "closed" system, to expand and increase the pressure in the fuel/emissions recovery system. Plus, the charcoal has been filtering vapors for so long it must be saturated with chemicals, maybe even kind of clogged. I know that this canister was/is the source of the subaru's sharp and very distinct chemical smell. Again, may be relevant to your 4R smell, may be unrelated to other issues. Should be easy to locate place from which smell emanates. My canister made a very quiet high pitched whistle (relief valve) which I followed and realized was the source. A mechanic then told me about the relief valve. I made my own assumptions about the charcoal being saturated with a variety of chemicals which, when heated up and released under pressure, created this unique odor. Yours may not be running rich, i.e. this smell may not be the result of running rich. Perhaps the prolonged cranking required when starting is an issue entirely unrelated to your assumption that it is running rich.




"controlling the idle valve opening ratio" sounds like something that could be directly related to your issues. Especially if it was something you busted and replaced and coincides with this starting problem.





thats smart and easy





again, i cleaned my maf twice thoroughly with MAF cleaner but apparently it was still 'filthy'. i assume a smoke test is simple, so even if it is a dead end it will be inexpensive (or free if you do it) and conclusive.

is the battery good? is the battery ground good? i've had issues with a ground getting corroded. unbolted it and sanded connector and spot it contacts the frame/body to expose fresh metal, put dielectric grease on it, reattached it and problem solved. This is also a very easy thing you can do, won't cost anything.
Click to expand...


The screw is factory designed so you can only put it in so far and thus giving you the proper ratio so its hard to mess up.

After about a month.... this is going to sound really dumb.... but I started using a lower octane gas (I don't have the owners manual so i have no clue what is recommended... I was using 92/93) and I have not had any smell issues. As far as the start up... some times its a little slow and other times its spot on... especially after the engine has been warmed up.... I don't know if maybe its just an age thing or what, but aside from that the only thing still "wrong"

Is the backlighting for the radio... I took it out and cleaned it... still just dances around... again I am assuming age and its not a big deal, just drives my OCD nuts.


Other than that I think I may have just been chasing a ghost.
 
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