Scion tC long crank time

[agarb]

2006 Scion tC. Purchased in December for a soon-to-be teenage driver.

Seems like it has a long crank time; generally about 4-5 seconds. One time it was a no start for a few minutes until I tried again several minutes later. Suspecting a fuel delivery problem, I hooked up a gauge to monitor pressure at the fuel rail. The thing is, simply turning on the key doesn’t prime the rail with pressure, it takes 2-3 seconds to gradually build up to about 45 psi and then starts a second or two later. I can’t hear the pump whine until the cranking starts. Seems odd to me. Any suggestions?

Plan B is to go the library to do some research with their All-Data subscription but I won't be able to do that until next week on one of the days they are open late.

 

[Marcozi]

The first thing I'd do is scan the engine computer for codes. The Service Engine Soon light is on only when an emission related code is present. Do you have any maintenance history on the car? Does the car have a fuel filter? I'd search the internet for Scion forums. I bet other owners have had similar problems.

 

[atikovi]

The thing is, simply turning on the key doesn’t prime the rail with pressure, it takes 2-3 seconds to gradually build up to about 45 psi and then starts a second or two later.

Sounds like an issue with the fuel pump or it's control unit. Maybe the check valve failed and isn't holding pressure.

 

[agarb]

No engine light or codes. No service history. Need to look it up and see if there is a fuel filter. I have searched various forums but couldn't find much on fuel pressure or long crank times.

The thing that bothers me most is that it doesn't prime with key on but rather when the cranking starts. I'm not sure if this is expected behavior or not.

 

[researcher]

No engine light or codes. No service history. Need to look it up and see if there is a fuel filter. I have searched various forums but couldn't find much on fuel pressure or long crank times.

The thing that bothers me most is that it doesn't prime with key on but rather when the cranking starts. I'm not sure if this is expected behavior or not.

I have an 06 Scion tC, there is no fuel filter.. just a "sock" that is at the intake of the fuel pump in the tank. It only filters out big things that probably shouldn't be in a tank in the first place. When starting my tC it only takes 2-3 cranks of the starter before it's running. also the "priming" does not happen every time the tC's engine starts. I've listened and it would only prime when off for a very long time, or if the battery was disconnected. And even then all you heard was a high pitched, soft noise for about 2 seconds under the rear seat. And it's not normal to hear any noises from the fuel pump! If it takes awhile to come to fuel pressure, it's definitely the fuel pump. Mine can hold pressure for weeks without being started.

It simple, check the fuel pump, it's most likely dying. How many miles on this tC? I remember on the scion forums the fuel pump would die sporadically. It wasn't the same as being able to count on the alternator (Stock) dying at around 100-120k miles, the fuel pump, some made it to 300k others died early at 100k. Never did find out why.

 

[agarb]

I have an 06 Scion tC, there is no fuel filter.. just a "sock" that is at the intake of the fuel pump in the tank. It only filters out big things that probably shouldn't be in a tank in the first place. When starting my tC it only takes 2-3 cranks of the starter before it's running. also the "priming" does not happen every time the tC's engine starts. I've listened and it would only prime when off for a very long time, or if the battery was disconnected. And even then all you heard was a high pitched, soft noise for about 2 seconds under the rear seat. And it's not normal to hear any noises from the fuel pump! If it takes awhile to come to fuel pressure, it's definitely the fuel pump. Mine can hold pressure for weeks without being started.

It simple, check the fuel pump, it's most likely dying. How many miles on this tC? I remember on the scion forums the fuel pump would die sporadically. It wasn't the same as being able to count on the alternator (Stock) dying at around 100-120k miles, the fuel pump, some made it to 300k others died early at 100k. Never did find out why.

Thanks for the info. Good to know that it doesn't "prime" every time. I haven't paid attention to how quickly the pressure leaks off yet. I will do some testing on this. Yes, the pump is very quiet; a high pitch whine that is barely audible as you describe.

237k miles

 

[researcher]

Thanks for the info. Good to know that it doesn't "prime" every time. I haven't paid attention to how quickly the pressure leaks off yet. I will do some testing on this. Yes, the pump is very quiet; a high pitch whine that is barely audible as you describe.

237k miles

Glad I could give you the info you needed, be interesting to see what you find with more testing. There is one more issue that our engine has is the MAF (mass air flow) sensor, it's right on top of the lid to the air filter. It gets dirty because of the PCV system, how it re-routes the vapors to the throttle body. The MAF ends up getting dirty, and it will affect the idle quality. Since the screws holding it are in plastic, wait til the engine is cold and remove the sensor. Spray down the tube (you'll see two dental floss looking wires) gently with CRC's MAF sensor cleaner, and clean the amber bulb on the outside of the tube (IAT, idle air temp sensor). Let dry and reinstall. Just something extra I thought you could check. With those miles it would help to clean it.

I don't know if a dirty MAF sensor would cause the engine not to start quickly that's more of a fuel pump issue, just thinking of any engine-related issues that you could clean right now..

Also, have you checked the spark plugs? Who knows how long those have been in there.. the only ones I've used and others have liked are the stock NGK plugs part 4589, laser iridium. No need to gap them, they're pre-gapped to 1.1mm.

 

[JavierH19]

Could be the fuel diaphragm or also known as the pressure regulator. That failed on my sierra and had the same long crank symptoms. But if i would shut it off and immediately start it it wouldn't do that since it wouldn't lose pressure fast enough. Try that. If it still has the long crank time after just a second of being off before being restarted it's likely something else.

 

[agarb]

@researcher
Pressure didn't leak down immediately; from 38 psi (key off) to 22 psi over 3 hours. I put new NGK 3764 plugs (Iridium but not laser Iridium) in it less than 1k miles ago. I had a can of MAF cleaner so I went ahead and cleaned the sensor.

After taking my fuel gauge out (no residual pressure in the rail) it started in 1.5 seconds.

I think at this point I will drive it and see how it does over the next week or so.

 

[researcher]

@researcher
Pressure didn't leak down immediately; from 38 psi (key off) to 22 psi over 3 hours. I put new NGK 3764 plugs (Iridium but not laser Iridium) in it less than 1k miles ago. I had a can of MAF cleaner so I went ahead and cleaned the sensor.

After taking my fuel gauge out (no residual pressure in the rail) it started in 1.5 seconds.

I think at this point I will drive it and see how it does over the next week or so.

no problem about the spark plugs, as long as they weren't all crusty and old. I think the difference between what you installed and the part 4589 is how long they'll last. The 4589 is just a longer wearing plug. Sounds like you're headed in the right direction in fixing this! 1.5 seconds isn't bad, that's about 2-3 cranks of the starter, which is normal in my experience.

have to see how it goes, thanks for keeping us updated!

 

[agarb]

So far, I haven't had any more issues after cleaning the MAF.

 

[incognito_2u]

…The thing is, simply turning on the key doesn’t prime the rail with pressure, it takes 2-3 seconds to gradually build up to about 45 psi and then starts a second or two later. I can’t hear the pump whine until the cranking starts.……

I have a 2006 Corolla that does this exact thing….not quite as long to start, but noticeable. I was told that these engines don’t activate the fuel pump until the key is fully turned to the start position, thereby not pressurizing immediately. Other vehicles I own, I’m in the habit of turning the key to the run position for a couple of seconds, hearing the relay of the fuel pump activate, then start it normal.
Thats probably the OCD in me but it gives me the warm and fuzzies, if you know what I mean!