06 Tacoma: Hard start problems in the morning

Hi, I am new to this forum, been reading some of threads with very useful info. I own a 2006 V6 Tacoma Pre-runner just 9 months out of the dealer. I have had problems starting the truck in the morning for some time now. I took it to the dealer a few months ago, and of course they said there was nothing wrong.

Here is what's been happening. In the morning, when it has not been started since the day before, the engine takes a long time to start. I turn the key and the engine is very lazy starting. Some times when it doesn't even starts I have to turn the key a second time and then its starts very quickly, no problems. When it starts, the RPM's go up to about 2500 very rapidly, then they go down to 1000-1500 (don't know if this is normal). Lately, in addition to the hard start problem, the truck trembles for a few minutes after starting then it goes away when I start driving. This only happens in the morning. The rest of the day the truck starts just fine, no problems.

Anyone has the same problem or has any ideas about what could be wrong?

 

Lazy starting? cranks slowly..bad battery or cranks normal but hard to fire...then a possible bad oxygen sensor. It's job is to determine the proper fuel/air ratio's based on temp/altitude etc.. If the sensor is bad, the ECU ends up guessing on the proper ratio's and could be why you have a hard time starting in the morning(req's a richer mixture) vs no problems after vehicle has been started(leaner mixture). ECU may have defaulted to the warm or lean position. Has the problem just started since your last fill-up? If so, could be a case of bad gas. Also, it's normal for the high rpm's upon starting, this is to heat the catalytic converter faster for reduced emissions.

 

Thanks for the quick reply! In answer to your question, the battery is ok, the problem seems to be what you said better: "cranks normal but hard to fire". Sorry for not explaining better before. As far as the gas goes I have been using Shell Premium (93 octanes) since I bought it, even going to the same gas station all the time. So the problem has been going for a few months now. Again I took the truck to the dealer and they said everything was OK. If the problem, like you said, could be the oxygen sensor and this is causing the ECU to guess the fuel air/ratio, is it supposed to show any warning lights or codes? If no, then how can it be diagnosed. I say this because some this guys at the dealers only find "problems" if their computer gives any codes and do not listen to what one has to say about the problem. I mean if this sensor is damaged they are obliged under the warranty to fix it or install a new one no matter what. Any thoughts? Thanks again!

 

If the downstream O2 sensor is bad (heater circuit not working, loose or corroded wiring connector, contaminated sensor element, etc.), the ECU should detect the fault and send an oxygen sensor code. The same goes for a bad upstream O2 sensor/MAP sensor or any sensory input delivered to the ECU. Of course, this is ideally speaking and nothing is ever ideal. Sometimes a faulty sensor is not bad enough to send a code but is off just enough to affect the accuracy of the fuel/air ratio's. A good scan gage monitored during the 'actual' condition will possibly identify the problem. Unfortunately, intermittent problems can be extremely hard to pin-point. The chances are the problem will deteriorate to a point where the 'check engine light' will illuminate and a hard code will be stored.

 

Do you think it is a good idea to take the truck to the dealer again or let the problem progress unitl it is detectable, if in fact the problem is the sensor?
Also have you read about someone with the same problems and any other causes? I can't seem to find anyone with this same problem on this forum, all I read is about the ticking, the vibrations or the wind noise as most common ones. I went to the Carspace.com forum from Edmunds before joining this forum (which is much better than edumnds) and found a thread about the 03-04 Tacos with the same problem and apparently it was the "fuel suction assembly". They even issued a TSB. Go to www.carspace.com and then go to the "Toyota Tacoma: Problems and Solutions" forum message #1976.
Again, thanks for the quick reply!

 

Until you see the 'check engine' light illuminate or flash.. chances are the dealer is not going to able to pin point the problem. However, if the condition continues to deteriorate where the dealer can witness the issue at hand, then I would make an appointment asap with the dealer of your choice. Unfortunately, until the problem 'deteriorates' or until a 'hard code' is logged into the ECU.. there's not much you can do.

 

Yes, I have the same problem just on cooler mornings. And I run the same fuel as you ever since I bought my truck. (93 from shell)

 

You can buying your fuel from a different manufacture other than shell; however, I highly doubt shell is contributing to the problem. Having said all that:From what I read shell 93 octane is a great product. However, when I had my service station, the premium fuel tended to collect more containments(incl water) more so than the other octanes. This is because we sold a significant more amount of the lower octane fuels than we did the premium blends. Therefore, the premium blends tend to sit in the underground tanks longer than the non-premium blends(probably more so now with the high cost of fuel). I'm not saying this is necessary the case here; however, I would buy from a local station that sells larger quantities, at least, if nothing else, help reduce the possibility of contaminated fuel. Also, many believe the filters installed on the pumps get 100% of all the contaimants..I'm here to tell you thats not the case. I would try switching, if your condition resurfaces at least you eliminated a possibility.

 

yeah, I don't think its the shell gas. But shell is the only good gas unless I start using the off the wall stuff (Ackerman Oil) supplies all the other gas stations. I'll just bear with it until starts becoming a bigger problem and then I'll worry about it, cause it starts up, just a little embarrising when someone notices.

 

Sorry, I have not being able to log in the last few days. Again, thanks for the replies. Hey, brant, how long have you had your truck and what year is it? I am curious to see if this happens on the 06's only. I use Shell because is this closest station to me, and they only service 93 and 87. I don't want to go down to 87, I might try to find 91 or 89 in some other station and run on it for a while to see what happens. I checked the owner's manual and it says to use a "Select Octane Rating of 87 (Research Octane Rating 91) or higher", what is the difference between SOR and ROR?

 

The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel through a specific test engine with a variable compression ratio under controlled conditions.

Then there's Motor Octane Number (MON) which is a better measure of how the fuel behaves when under load.

In the United States, Canada and some other countries the 'octane pump number' is the average of the RON and the MON, or more commonly refered to(R+M)/2 or 'select octane'. Bottom line: research method(approx 4 to 5 points higher than select octane) is used outside the USA and utilizes different methods for determining octane ratings. Select octane is what is represented as the 'octane pump number'(USA/Canada) that you see when filling up.

 

Try using a product called "Heat" in your gas tank. Is helps eliminate water within the line. You can find it at any local automotive supply store or your closest friendly Wal-Mart

 

Guess what guys. I filled my tank with Esso 87 octanes (Exxon in the U.S.) and my truck starts perfectly. It has been a week since and I have not had any problems starting. So now, I am guessing if it was the gas station with the problem or the octanage. I will try Esso 93 and see what happens. Then I will go with the Shell 87. But for now problem solved, thank god it wasn't anything worse. Of course acceleration is not the same but I can live with that. The problem is I couldn't find 89 or 91 on any brand here. Does anybody knows if it is a good idea to mix 89 with 93 to fiil the tank?

 

I meant to mix 87 with 93 to fill the tank?

 

I glad to hear switching brands, has at least temporary, solved your problem. Like I said in a previous post, most all brands of fuel is pumped from the same fuel terminal locally; however, it's the additives that can sometimes make the difference. If your problem resurfaces again, I would consider following up with the dealer to get the ECU reflashed as per the 'hard to start' or 'extended crank operation' TSB.

Mixing octane's will not do any harm. The ECU will adjust the timing based on avg octane... so it won't be an issue.

 

I owned a 2008 tacoma 4x4, and the thing always had a starting problem in the spring and fall of the year, when it was +5 and damp. You would turn the key, and it and would crank and crank, and never catch, you had to stop and try a second time, which would usually turn the engine over. The truck had that problem from day one, and kept doing it until I traded it in for a 2011 Tacoma (Same truck basically just newer.) And guess what?!? The 2011 has the exact same problem! hahaha Come on Toyota can't we fix this kind of dumb problem?

I do love Tacoma's, just wish they could make them start like north american trucks.

 

I had a VW GTI for 4 years which required a minimum octane of 91. They only sell 93 in this part of the state. I would always try to fill up with Shell 93 at one of 3 different Shell stations. I discovered that sometimes the car would run great on a tankful pumped at one station, and run poorly on a tankful from another station. My home is out in the boonies and the closest Shell station is 10 miles away on a very rural road. Whenever I'd fill up with 93 at that station, the car seemed to run slightly poorer and had harder starts in the morning. However, if I filled up with 93 at another Shell station located near I-95 (major highway), the car would run excellently. My untested hypothesis is that in the boonies, much less people run 93 octane in their cars, and therefore the station rarely received new shipments, which caused longer holding times in the UST's and degraded the quality of the gas. The station next to the major highway was probably frequented more often by vehicles requiring the higher octane gas, and therefore the turnover was much higher. The gas was fresher.

So I guess that what the lesson is here is that just because you're pumping high octane doesn't mean that it's better than the 87+ octane at the same station.

 

i had this problem for a bit..

http://www.tacomaworld.com/forum/2nd-gen-tacomas/136616-weak-start-long-start.html

ended up swapping out my fuel pump and filter for the URD fuel pump kit and has made a noticeable difference..

 

Weird. One of the things I love about my truck is just how easy it starts up no matter the temperature. Do you have the 6 cylinder? Maybe the 4 is different in that respect.

 

hey guys i have the same problem in my 05 prerunner it just started a couple weeks ago and it was only in the morning time. now it happens on every start i did check the batt. and getting a little over 14 on the test so any other ideas im really leaning towards the fuel pump cause i do not hear it come on when i turn the key just to on thanks for any replies