weak start/long start

so recently i've been having, what i would consider, troubles with my '06 4.0L taco...i've been noticing that when starting it after it's been off for a couple hours, turning the engine over takes a little bit longer than i'm used to...also, when i was up in the mountains it took 3 tries to get the engine going after riding for the day...when it finally started that day at the mountain, my buddy smelled a distinct gas smell coming from the exhaust, i was assuming from the numerous start attempts without a successful start would have loaded the engine with gas that was unused...

so i've been working on eliminating possible causes to my starting issue and i just went to autozone to run some tests and it is not the battery, starter or alternator...just pulled my volant air filter to clean, and didn't notice any excessive debris on, in or around the filter box...

so my next thought would be something with the fuel system, but i do not know any good tests to perform on the system (fuel pump, injectors, or testing the spark).

and the bottom line is, i'm trying avoid an expensive trip to any mechanic or stealership...i have a decent handle on working with cars and what i can't handle or comprehend, i have a buddy across town who is a mechanic who can lend a hand, most likely will call him up after this as well...

so any thoughts/suggestions is greatly appreciated...

 

bump

 

Time for a tuneup? New plugs perhaps?

Cheers.

 

I had some bad cells in my battery that caused this issue. It was the beginning of the end of the battery. Get your battery checked.

 

battery was the first thing i checked, auto zone check the battery, alternator and starter and didn't see any problems.

Spark plugs are <10k miles old...

might take it in to the dealer and have them run through some tests...really don't want to put my truck in their money hungry hands though...

 

you may have gotten some bad gas.

I would put in a gas additive, we used to call it dry gas, to prevent gas line freezing if any water was in the gas, clean the fuel nozzles, etc.

then fill with a known good, high octane gas and see if that makes a difference.

 

could be fuel related.

when I bought my truck, it had 36k on it. It would take a long time to start after sitting over night.

I suspected a bad fuel reg or a bad check valve in the pump. or a plugged fuel filter.

I put the S/C on and the X1 and went out tuning with Gadget. At WOT the the injector duty cycle was 95% ( almost wide open, they should be more around 80% with my setup.

I put a fuel pressure gauge in to see what was going on. At WOT the pressure would nose dive from 39 psi to 30. BINGO, there was my lean out problem. Plugged up filter and crappy stock pump

Also, I checked how it held pressure at key off, it is supposed to hold 75% pressure for hours after you shut it down to ensure a quick restart. Well, when I keyed off, it would fall right to 0. That narrows it to a faulty regulator or check valve in the fuel pump.

Since I was putting the URD upgraded pump in the truck anyway to handle the lean out problem, I did that first to see if it fixed both issues.

put the pump in, Lean out issue gone ( 75% duty cycle at WOT), and it help 30 PSI at shut off, and the long start went away.

so to simplify, the check valve in my stock pump had crapped out, and would loose pressure at key off.

Just a possibility for you to think about

Justin

 

i had the same thing just happen to me in my 06 and eventually wouldn't start turned out to be the battery was toasted and needed to be replaced might wanna try that

 

just ordered the URD pump, i was actually looking at it before while i was browsing the Thorley long-tube group buy....how was the install on the pump?



as far as the battery goes...it was tested at autozone and they did not see any problem with it, but i was planning on upgrading to an optima one of these days so..who knows might grab one soon, wouldn't hurt...

 

got the new URD fuel pump kit installed today and so far i've noticed the truck idling much smoother at stop lights and has had some quick starts so far...project was pretty straight forward and the directions are easy to follow...the "quick" disconnect hoses are not real easy to come out but with some persistence they made it out and had very few hold ups...i still have the directions and was going to try and scan them in next time i get a chance if anyone would like to view the directions before ordering the part...

 

IF Its not the battery or the starter, it usually ends up being a fuel system leak or clogged vent.
Leak back my friend, its not just for carbureted vehicles. THough, its uncommon on EFI vehicles.

And just cause a new pump fixes the symptoms doesn't mean you don't have clogged vent lines. Extra vacuum pulls the fuel back past an older weaker pump, a strong pump can overcome it, but will fail eventually.

 

you need to run either a voltage drop or an amp draw test
when starting you need power from the battery to go both to the ign system and to the starter, these systems compete for power, suppose your starter is worn and drawing more power (more amps) so there's less power going to your ign system (s plugs getting a weaker spark)
The battery can be at fault too, the alternator may not be pushing out,
a good mechanic can figure that out with the right test equipment
also look up (paracitic load test)

http://www.youtube.com/watch?v=egbnCIK3_CU

 

Here's my put on this. My 2010 has had similar issues. Not as bad, but it has happened. After starting and running my rig in the morning and parking it at work I noticed the hard start issue. Actually thought I was gonna flood it a few times. I posted and got a pretty advice that seemed to help. It seems that when you start your rig if your like me you put the key in an immediately turn it over. Someone suggested that because the Taco's has electric fuel pumps you might want to wait a couple of seconds before turning the truck on. The suggestion was to let the door chime a couple of times before turning it over. This gives the fuel pump a chance to prime.
All I can say is when I have done this I have had less issues. Give it a shot before going all out. Never know. Ken