2008 4runner Serious Cold Start Issues

[Veritas]

I have run into an issue with my runner here lately, it has been VERY cold in Colorado and I have never had cold start problems until this year and could use some help figuring this out.

After leaving my car sitting for several hours I get into it and try to start it and the engine tries turning over about 20 times before it stops trying, then I have to switch the key to Off and try again and it usually works on this "second" try. The best way I can explain the issue is it goes Ra-Ra-Ra-Ra-Ra-Ra-Ra-Ra-Ra-Ra-Ra like it is trying to turn over but cant. Once it does finally start there is a VERY rich gas smell, similar to a lawn mower with too much gas in the starter. This is NOT an issue in the Summer time.

I thought that MAYBE the battery was going bad so I bought a new one hooked it up and several hours later I tried to start my car and got the EXACT same issue, so I know for a fact it is not a battery issue.

To me this leaves the fuel pressure regulator, the injectors or the fuel pump, I think...and on top of that there are no warning lights.

Anybody seen this before? Any help will be very appreciated, thanks!!

Here is a good example, watch it from the mark, video was painful to watch

https://www.youtube.com/watch?feature=player_detailpage&v=-_2SgIldqM8#t=81

Stats:
102,000 miles
2008 V6 SR5
K&N Aircharger intake


EDIT TO ADD:

I am going to make a list of things that people have said in this thread that they have done to narrow our results, please notify me to add something to the list if it is missing:

1. Seafoam in fuel tank to clean injectors
2. Seafoam in the vacuum brake line
3. Seafoam through the oil fill-up
4. Clean MAF
5. Clean Throttle Body
6. Verified Intake Air Temperature (IAT) is reading right
7. Verified Coolant temp is accurate
8. Tried high octane fuel (this has been the best solution)
9. Priming the engine

 

[LobstaMobsta]

I've had the same issue for 3 years in winter mornings below 25.....done everything I can think of maintainance wise

 

[Veritas]

I've had the same issue for 3 years in winter mornings below 25.....done everything I can think of maintainance wise

Just out of curiosity did you try a new fuel pressure regulator or new fuel pump?

 

[Range]

Maybe try an engine block heater?

 

[LS2Cobra]

Sounds more like a tuning issue whenever the IAT reads really low.

 

[Veritas]

Sounds more like a tuning issue whenever the IAT reads really low.

Can you expand on why you think it would be a air charge temperature sensor?

 

[541joseph]

I'll bet intake air temp or the coolant temp. The best way to see is to let it get cold and out a scan tool on it a read live data when the engine is not running and see it they both match the outside temp or really close

 

[Veritas]

I'll bet intake air temp or the coolant temp. The best way to see is to let it get cold and out a scan tool on it a read live data when the engine is not running and see it they both match the outside temp or really close

I will check that, that sounds like a good idea, I will report back after trying.

 

[Robs08Runner]

Plugs, low fuel pressure?

 

[Burt]

Hmmm, got the same model as you, also in CO and had no problems with starting below zero. Seems like an electrical problem since excessive fuel is present. Maybe a good bottle of injector cleaner is needed.

 

[Veritas]

Hmmm, got the same model as you, also in CO and had no problems with starting below zero. Seems like an electrical problem since excessive fuel is present. Maybe a good bottle of injector cleaner is needed.

Yeah Last year and the last 4 winters I have had it there have been no issues, this just started happening about 2-3 weeks ago. I cant explain why since I have not made any modifications that would have effected this issue or caused it, that is what makes it so frustrating the only thing is I finally went over 100,000 miles.

I may try injector cleaner though since I think it is something with the fuel system whether it is clogged injectors or low pressure that is not allowing the fuel to atomize properly. The injector cleaner is cheap enough to test easily. I also have a can of Seafoam and was going to use that but was waiting until I changed the oil next, as I want to put in the Seafoam run the miles and then drain that oil out and put in fresh after being Seafoam'd

As for the other issues, the fuel pressure cant be easily tested on a 4runner since Toyota did not include a check valve and it is a "sealed" system. I don't even know if I can easily splice into the line since it is rubber coated plastic...they obviously designed it to be under pressure and did not want to make it easy for people to tinker with. Only instructions/recommendations I found was a guy drilled and tapped the fuel rail on his 3rd gen to do it, I am not doing that.


With that said I did a lot of work on it today and checked the Air intake temp with an ODB2 and it was only off by about +12 degrees Fahrenheit while driving, so that is good as I would expect it to be slightly hotter next to the engine under the hood, but I need to see what the intake temp is after the car has sat overnight and completely cooled down. It is starting to look like the air temp sensor is just fine.

I also checked the MAF and throttle body and cleaned both, the Throttle body had a lot of carbon build up so that got completely cleaned as did the MAF. Still too early to tell if anything got fixed by those issues.

That takes me right back to the fuel system and whether it is the fuel regulator or the fuel pump, without being able to test one of those I am not sure what to do, the only thing I can do is buy the parts and replace them and "hope" that it fixes the issue. I am going to let the car sit overnight and see how it works in the morning, then I will see how to work on the fuel system.

Also coolant temp was good and the fill level was good to(I did a full drain and fill on it this summer and have had 0 leaks) and the spark plugs were good too.

I did a little searching and found that the runner MAY have a door in the back under the carpet where I could access the fuel pump without dropping the whole tank. Can anyone verify that?

Thanks for all the help guys feel free to keep the recommendations and thoughts coming! :cheers:

 

[CXS]

Yeah Last year and the last 4 winters I have had it there have been no issues, this just started happening about 2-3 weeks ago.

Sorry I can't help but I'm interested in seeing what you find. I'm also in the Denver area and haven't had any issues. I like to be prepared if/when such a problem occurs so please keep us posted.

 

[LS2Cobra]

I suggested something amiss with a temp sensor and the tune as it fires right up on the second go. Clearly, spark and/or fuel isn't being delivered by the computer on Attempt One. Whether or not it's something you could help, who knows? Toyotas are famous for their over-complicated ECU algorithms, just ask the dead Prius owners. Their engineers essentially admitted they couldn't unravel the coding if they tried during the legal proceedings.

If it's not throwing a code for a faulty sensor, you've no idea where to start. Low fuel pressure, a 100% dead sensor, and/or something drastically wrong should throw a code. But then, removing the battery should also cycle the computer back to the base tune...

i.e. I dunno.

Try first cycling the key to run but not start, back to off, then run and crank. Perhaps that will "wake up" whatever is sleeping without burning your starter so hard.

 

[Veritas]

I suggested something amiss with a temp sensor and the tune as it fires right up on the second go. Clearly, spark and/or fuel isn't being delivered by the computer on Attempt One. Whether or not it's something you could help, who knows? Toyotas are famous for their over-complicated ECU algorithms, just ask the dead Prius owners. Their engineers essentially admitted they couldn't unravel the coding if they tried during the legal proceedings.

If it's not throwing a code for a faulty sensor, you've no idea where to start. Low fuel pressure, a 100% dead sensor, and/or something drastically wrong should throw a code. But then, removing the battery should also cycle the computer back to the base tune...

i.e. I dunno.

Try first cycling the key to run but not start, back to off, then run and crank. Perhaps that will "wake up" whatever is sleeping without burning your starter so hard.

I am with you it is EXTREMELY frustrating trying to figure this out with no direction(erorr codes). I am gonna check what the ODB reads tomorrow morning after it freezes overnight. The ODB2 app I am using gave temps and PSI values and all kinds of awesome stats that really answered a lot of questions for what is NOT wrong...

I tried the key cycle you suggested above thinking that would allow the fuel pump time to pump up since it is so cold and unfortunately it didn't help one bit.

Also, the 4runner does not report fuel pressure through the ODB2 :bored:

 

[Acidmeld]

Keep in mind that at colder temp fuel is denser and has a very hard time atomizing. I had the same issue 3 weeks ago when it was below zero. I switched to premium for a tank since prices have gone down and the temp was going for record lows. The higher octane helped a lot. Had to start when temp was -15 and it fired right up.

 

[m85476585]

Also coolant temp was good and the fill level was good to(I did a full drain and fill on it this summer and have had 0 leaks) and the spark plugs were good too.

Unless you switched to iridium plugs, the V6 calls for new spark plugs every 30,000 miles. The OEM ones can certainly last 100k miles or more, but it wouldn't hurt to change them now if they are original. The iridium plugs used in the V8 should work, but if you want to be absolutely sure of proper performance, go with what the manual specifies for your engine (it's near the back).

Not sure how much you drive it, but if you exclusively make short trips (not long enough for the engine to warm up completely), then it might help to drive it for a while to get everything fully up to operating temperature. These engines seem to warm up reasonably quickly, so this might only be a problem if you never drive more than two or three miles (maybe if you live in Boulder).

 

[Veritas]

Keep in mind that at colder temp fuel is denser and has a very hard time atomizing. I had the same issue 3 weeks ago when it was below zero. I switched to premium for a tank since prices have gone down and the temp was going for record lows. The higher octane helped a lot. Had to start when temp was -15 and it fired right up.

Understood, but it never did it in the past and last year I was driving downtown when it was -20 and had no issues starting up.

Also, I am very surprised that a higher octane fuel worked better for you, I though the same thing until I researched it this morning. That is contradictory to what it should do, higher Octane fuels actually have a harder time burning in colder temps, the lower the octane the easier the burn. High Octane fuels have a longer burn rate which negatively impacts combustion, especially at colder temps. Very interesting that it fixed the problem, I cant imagine why it would

 

[Veritas]

Unless you switched to iridium plugs, the V6 calls for new spark plugs every 30,000 miles. The OEM ones can certainly last 100k miles or more, but it wouldn't hurt to change them now if they are original. The iridium plugs used in the V8 should work, but if you want to be absolutely sure of proper performance, go with what the manual specifies for your engine (it's near the back).

Not sure how much you drive it, but if you exclusively make short trips (not long enough for the engine to warm up completely), then it might help to drive it for a while to get everything fully up to operating temperature. These engines seem to warm up reasonably quickly, so this might only be a problem if you never drive more than two or three miles (maybe if you live in Boulder).

I swapped the factory plugs at 60,000 miles (they were the factory NGK & Denso Mix) and replaced them with Denso's which should last more than 40,000 miles. Maybe not, when I checked them they looked good, not running rich or lean.

It definitely goes away once the engine heats up, for example if I have trouble starting in the garage and drive 20mins to the store and then go back an hour later the car starts almost always with no issue, but stuff like sitting at home or at the office is where it will bite me in the ass sitting all day waiting for that 45min commute. It's a serious head scratcher

 

[Tx9812valve]

My runner did the same thing for the first time the other morning. It was -4 outside and my engine temp was 3 degrees on my scangauge. It cranked for a few seconds, fired, dieseled like the video for a few seconds until I hit the gas and it stalled out like it flooded. I immediately cranked it again and it fired right up and sounded great but also had a super rich gasoline smell out the exhaust for a few moments and then it cleaned up. I didn't have any codes come up on the scangauge or lights on the dash either. I have the pre vvt-i 4.7l v8 with the trd supercharger so i have only been running 91 octane for quite a while.

I also have a 12 valve Dodge Cummins that did the same thing at those temps when I tried a cold start without the block heater. Totally different motor but exact same symptoms down to the heavy fuel smell immediately after fire up. It almost seems like it floods a couple of the cylinders momentarily which causes it to stumble until the fuel gets blown out the exhaust valves. My Dodge has several fueling upgrades and no electronics to meter it so I know why my Dodge does it but I think your on the right track with figuring out what sensor is causing the overfueling since that seems to be what it's pointing to. I'll be trying to figure it out too if mine decides to do it again.

 

[Veritas]

My runner did the same thing for the first time the other morning. It was -4 outside and my engine temp was 3 degrees on my scangauge. It cranked for a few seconds, fired, dieseled like the video for a few seconds until I hit the gas and it stalled out like it flooded. I immediately cranked it again and it fired right up and sounded great but also had a super rich gasoline smell out the exhaust for a few moments and then it cleaned up. I didn't have any codes come up on the scangauge or lights on the dash either. I have the pre vvt-i 4.7l v8 with the trd supercharger so i have only been running 91 octane for quite a while.

I also have a 12 valve Dodge Cummins that did the same thing at those temps when I tried a cold start without the block heater. Totally different motor but exact same symptoms down to the heavy fuel smell immediately after fire up. It almost seems like it floods a couple of the cylinders momentarily which causes it to stumble until the fuel gets blown out the exhaust valves. My Dodge has several fueling upgrades and no electronics to meter it so I know why my Dodge does it but I think your on the right track with figuring out what sensor is causing the overfueling since that seems to be what it's pointing to. I'll be trying to figure it out too if mine decides to do it again.

Thanks for the post definitely sounds like we have the same issue, I hope yours doesn't get any progressively worse like mine, I am a stubborn bastard so i gotta try to figure this out! haha