5vz cranks an uneven number of times before starting

[sctrsk]

I have an odd "problem":

my v6 will crank a random number of times before it starts, and it also sort of stumbles to life. Sometimes its 3-4 times, sometimes its 5-6 times, and it will usually cough and fire at least once in the process but if you don't continue to crank it for another revolution it wont catch.

It very much feels like its "stumbling to life". However, it runs wonderfully and gets 19 mpg and has no problems.

This is quite different from most cars, which crank a certain number of times and then just fire.

Does anyone have any idea what could be the root cause? Or do they all do that?

 

[Saybo]

I'm assuming it's cold in Maryland right now. Mine does the same. Think it just has something to do with the cold and have heard others talking about it on here as well. As long as it runs smooth like mine once it starts I wouldn't worry about it.

 

[jgue467]

Many variables here (plugs/wires/fuel filter, fuel pump, ect). To narrow down, does it do this Hot or Cold? Only after sitting a while after having been run? :cowboy:

 

[silver4est]

mine does as well, sometimes I fear it will not start but it always does, just takes 2 tries at times. starts much better when warm or after running recently, have been considering battery???

 

[DaMonkey]

leaking injector?

I think our crank sensors are variable reluctance. If they start to go bad they will go bad at lower revolutions. But the stumbling part makes me think of maybe an injector leaking

 

[jgue467]

mine does as well, sometimes I fear it will not start but it always does, just takes 2 tries at times. starts much better when warm or after running recently, have been considering battery???

That's the sign of a fuel pump that works fine yet it's anti-flow back valve doesn't. So when it's shut off for an longer than an hour or two, the fuel flows back out from the pump into the tank, so it takes extra time to prime it. When its run in the last short while, it'll fire right up because the fuel hasn't had time to drain out of the pump yet.

You can try turning ignition on and waiting a few seconds until you hear pressurizing cycle complete, that helps mine.

Buy yeah a well charged battery to spin the motor as quickly as possible also helps. Luck and enjoy. :cowboy:

 

[Xntrik7]

I am having the same issue and plan on replacing the fuel pump, fuel strainer, check valve and both gaskets in the next couple of weeks. There is a decent Denso set for pretty cheap but I am going to go with the factory Toyota(made by Denso).

I’ll let you know how it goes.

-Dan

 

[OrRunner]

That's the sign of a fuel pump that works fine yet it's anti-flow back valve doesn't. So when it's shut off for an longer than an hour or two, the fuel flows back out from the pump into the tank, so it takes extra time to prime it. When its run in the last short while, it'll fire right up because the fuel hasn't had time to drain out of the pump yet.

You can try turning ignition on and waiting a few seconds until you hear pressurizing cycle complete, that helps mine.

Buy yeah a well charged battery to spin the motor as quickly as possible also helps. Luck and enjoy. :cowboy:

Replaced my fuel pump to fix this concern and had absolutely no change. I have a constant 5-6 crank start. New plugs, clean maf and throttle body, new battery and runs great... just always a slightly long crank. After replacing the pita fuel pump and having no change I'm officially not worrying about it.

 

[gamefreakgc]

Just make sure your battery is charged and good. Doesn't matter how many cranks. Mine sometimes takes 10+ cranks before it fires but that's because I've messed with the crank sensor wiring. It'll start.

 

[phattyduck]

just always a slightly long crank.

My 4Runner (bought new by my dad) has always taken longer to start than most other cars I have used/known... (other than carbs on a cold morning) Now, 280k miles / 20 years later, it sometimes has a hard start (more than ~2 seconds starter engaged) but it still always starts.

-Charlie

 

[sctrsk]

To clarify:

The first start of the day it seems to crank a nice even number of times (6 cranks or so, a normal amount in my estimation). Then it fires and revs up to whatever its supposed to based on outside air temp. If its been run and the engine is warm but its been sitting for a few hours, it does the crank-crank-crank-half fire-crank and then stumbles to life. When its been run and its really hot, it will sometimes only need one revolution of the motor and just go crank and then stumble to life, but its very clear that all cylinders don't fire for the first revolution. The second its running, its perfect. And at no point does it feel like it takes too long to start, its just that its an uneven start. Almost like its trying to start before it's had enough revolutions?

Battery is toyota brand (PO did dealer maintenance) and it is healthy enough that it will start the car even if its been sitting for a month in the winter. plugs look new enough I decided not to change them. Wires/coils/sensors are unknown. I was going to do the fuel filter but the lines look a bit rusted on the fittings and after putting some torque on them and not breaking them free, I decided I would rather leave well enough alone for now. Plus the lack of other running problems makes me think the filter is probably fine.

Its not a problem per-se, its just I'm not used to it. Most of my cars crank the same number of times no matter what.

 

[Renegade_Medic]

I had this exact problem and I replaced my MAF and it fixed the problem. I cleaned it, no change. Changed the Air Fuel ratio sensor, no change, check cam and crank sensors, both good. Gave up and bought a new denso MAF from Amazon. Worked perfectly after that. May be worth a shot. I also tried the fuel pump and filter, no change.

 

[sctrsk]

I had this exact problem and I replaced my MAF and it fixed the problem. I cleaned it, no change. Changed the Air Fuel ratio sensor, no change, check cam and crank sensors, both good. Gave up and bought a new denso MAF from Amazon. Worked perfectly after that. May be worth a shot. I also tried the fuel pump and filter, no change.

I assume the california models are different than federal and the best way to make sure I have the right one is to pull the part number off the one in my engine bay, correct?

 

[Renegade_Medic]

I assume the california models are different than federal and the best way to make sure I have the right one is to pull the part number off the one in my engine bay, correct?

The MAF shouldnt matter which emissions. That's only the front o2 sensor. I'd look at the cats vs hood sticker. 2 cats=cali for 99-00.

 

[rwrobs777]

I have an odd "problem":

my v6 will crank a random number of times before it starts, and it also sort of stumbles to life. Sometimes its 3-4 times, sometimes its 5-6 times, and it will usually cough and fire at least once in the process but if you don't continue to crank it for another revolution it wont catch.

It very much feels like its "stumbling to life". However, it runs wonderfully and gets 19 mpg and has no problems.

This is quite different from most cars, which crank a certain number of times and then just fire.

Does anyone have any idea what could be the root cause? Or do they all do that?

Sounds like a bad ECT (Engine Coolant Temp) sensor...if the sensor is bad when the engine is cold and started the ECM/PCM doesn't increase the injector pulse (like the choke). the engine computer thinks the car is hot so no increased fuel...once the engine is fully warmed up and the engine starts fine that's where I'd look...also a bad Crank Sensor will exhibit those "long" start times !!

 

[sctrsk]

Sounds like a bad ECT (Engine Coolant Temp) sensor...if the sensor is bad when the engine is cold and started the ECM/PCM doesn't increase the injector pulse (like the choke). the engine computer thinks the car is hot so no increased fuel...once the engine is fully warmed up and the engine starts fine that's where I'd look...also a bad Crank Sensor will exhibit those "long" start times !!

Thats the thing, its not a "long" crank time, by my estimation. And it cranks repeatably when its cold.

In addition, the stumbling and the randomness manifests when hot. Also, the OBD shows the temperature without issues.

I'm going to hazard a guess here and say that I think these are less likely the culprit.