LX470 Intermittent Prolonged Starts Only at first start up

[MONT470]

Hey all! I did some MUD searching but couldn't find anything. Please point me to the right post/s if I missed something.
This occurs after the 470 sits for a period of maybe 20 min or more...the kicker is that doesn't do it all the time after sitting. Maybe 50% of the time.
-When I start it after sitting for awhile it does not fire right away. It turns over maybe three times longer than usual and then fires. It does tend to stutter just a bit before firing as well (but not every time)
-I can let it run for a couple seconds, shut it off and then start it again and it starts right away. I cannot duplicate this prolonged start condition when the engine has been recently run.
This issue presents itself when ambient air temps are hot and cold.
Things I have done recently:
*Replaced the Battery
*Replaced the fuel Filter with Toyota filter
*Checked 20 Amp EFI fuse (looked good) I replaced it with a new one just in case.

I have an appointment with my mechanic coming up in a couple weeks. He said the fuel system has a check valve that may need replacing. Does anyone know of this check valve? I have had no luck finding out if this vehicle has this check valve. I thought maybe it could be something I could do myself and let my mechanic handle the other larger items we have planned. Thanks for any help! CHEERS!

 

[krispykritter]

Off hand, I'd guess you've got a dying fuel pump that takes extra time to build up enough pressure to get the injectors working right. I believe most fuel pumps have a check valve that holds the pressure in the system after shutdown, but most slowly lose pressure over time. If it's a dying fuel pump, the check valve may help it fire up after the first start event of the day. Have you tried running it, then leaving it off for an hour or two and seeing if it takes a long time to start back up again?

Usually a strong fuel pump won't really need the check valve to be in good condition to start the engine right away - they'll usually build to operating pressure in a second or less.

 

[flintknapper]

Mechanic can check your fuel pressure and check valve. He may want to replace the fuel pressure regulator....depending on what he finds.

 

[shtbrwn86]

How many miles? If you are on the original fuel pump it wouldn't be the worst thing in the world to replace it if you are high mileage. I just did mine after some of the same symptoms you are experiencing. Normally I'd do more troubleshooting, but I was at 250k and it's a relatively cheap and easy job.

 

[MONT470]

Off hand, I'd guess you've got a dying fuel pump that takes extra time to build up enough pressure to get the injectors working right. I believe most fuel pumps have a check valve that holds the pressure in the system after shutdown, but most slowly lose pressure over time. If it's a dying fuel pump, the check valve may help it fire up after the first start event of the day. Have you tried running it, then leaving it off for an hour or two and seeing if it takes a long time to start back up again?

Usually a strong fuel pump won't really need the check valve to be in good condition to start the engine right away - they'll usually build to operating pressure in a second or less.

Okay good to know. The issue can occur within 20 min or so of shutdown. I checked the fuel pump price at the dealer and it was over $400 for just the pump..atleast it's an easy install lol. Not sure if that includes the check valve? Any opinions on aftermarket fuel pumps??

 

[MONT470]

Mechanic can check your fuel pressure and check valve. He may want to replace the fuel pressure regulator....depending on what he finds.

Cool. I'll defintley mention it with my upcoming appointment.

 

[shtbrwn86]

Okay good to know. The issue can occur within 20 min or so of shutdown. I checked the fuel pump price at the dealer and it was over $400 for just the pump..atleast it's an easy install lol. Not sure if that includes the check valve? Any opinions on aftermarket fuel pumps??

I installed this one. Very easy to install following this video.

Amazon product ASIN B00274QIVM
Doesn't include all the float or anything, but it's still really easy. Hardest part honestly was getting the new hose on the pump. Oh, and taking the seats out.

When I did mine I waited until the tank was empty, opened the gas cap for a few hours, pulled the EFI fuse and then cranked the engine for like 1-2 seconds. I don't know if this was needed or not, so someone please correct me, but I did this to hopefully not have gas shoot out of the lines when I pulled them off, and sure enough, no gas sprayed anywhere.

 

[shtbrwn86]

delete

 

[MONT470]

How many miles? If you are on the original fuel pump it wouldn't be the worst thing in the world to replace it if you are high mileage. I just did mine after some of the same symptoms you are experiencing. Normally I'd do more troubleshooting, but I was at 250k and it's a relatively cheap and easy job.

I'm at 228k. Not sure if it's on the original fuel pump. Did you go with an oem fuel pump for yours? thx

 

[MONT470]

I installed this one. Very easy to install following this video.

Amazon product ASIN B00274QIVM
Doesn't include all the float or anything, but it's still really easy. Hardest part honestly was getting the new hose on the pump. Oh, and taking the seats out.

When I did mine I waited until the tank was empty, opened the gas cap for a few hours, pulled the EFI fuse and then cranked the engine for like 1-2 seconds. I don't know if this was needed or not, so someone please correct me, but I did this to hopefully not have gas shoot out of the lines when I pulled them off, and sure enough, no gas sprayed anywhere.

That's great! I'm going to replace it for sure. I'll update with results. I really appreciate it!

 

[krispykritter]

I'm only at 163k and have had teh LX for ~30k miles, so I haven't done a fuel pump on it yet - no help on aftermarket pumps here. Generally, Denso does make good stuff so I'd echo a previous commenter on going with one of those. I believe the checkvalve is normally built into the pump but that's probably not a hard and fast rule.

 

[MONT470]

I'm only at 163k and have had teh LX for ~30k miles, so I haven't done a fuel pump on it yet - no help on aftermarket pumps here. Generally, Denso does make good stuff so I'd echo a previous commenter on going with one of those. I believe the checkvalve is normally built into the pump but that's probably not a hard and fast rule.

Denso pump to come!

 

[shtbrwn86]

Denso pump to come!

Sweet rig BTW. Love that color combo!

 

[MONT470]

Sweet rig BTW. Love that color combo!

Thanks!

 

[MONT470]

UPDATE: I replaced the fuel pump last weekend. Unfortunately this didn't fix the problem...maybe the fuel pressure regulator? I'm running out of things that I can try. I've got an appointment comimg up with my mechanic (to replace the passenger exhaust manifold)...hoping they'll get it figured out. I'll be sure to update

 

[Slotheye]

If the car always ran fine under load and didn't have fuel delivery issues (misfire) while running, the fuel pump was fine. When a pressure regulator leaks, it can bleed off the fuel left in the fuel rail while the car sits and then the pump has to work longer to re-prime the fuel rail on startup.
Normal operation of a regulator sends excessive pressure at the fuel rail back to the tank in a return line while the car runs, you just don't want it leaking fuel back to the tank while the car sits.
You could always just turn the key on for a couple seconds to prime, turn it off, and then on and crank. That will give it that little extra prime it needs.

 

[medtro]

You could always just turn the key on for a couple seconds to prime

Turning the key on does not prime.

 

[flintknapper]

If the car always ran fine under load and didn't have fuel delivery issues (misfire) while running, the fuel pump was fine. When a pressure regulator leaks, it can bleed off the fuel left in the fuel rail while the car sits and then the pump has to work longer to re-prime the fuel rail on startup.
Normal operation of a regulator sends excessive pressure at the fuel rail back to the tank in a return line while the car runs, you just don't want it leaking fuel back to the tank while the car sits.
You could always just turn the key on for a couple seconds to prime, turn it off, and then on and crank. That will give it that little extra prime it needs.

All the above is accurate except for the last two sentences. This is a common misnomer. Neither the 80 series or 100 series (if not modified) will 'prime' the fuel system UNTIL the engine is cranking. I know....that is unlike just about every other vehicle out there...but that is the way Toyota engineered it.

 

[UltTrail runner]

@MONT470 Do you also experience slow acceleration? My truck take longer to start when it is cold (1s for multiple crank), and take shorter time to start when the engine is hot (0.5s for just few crank). But I have slow acceleration in low speed. Not sure it’s an issue of fuel pump or the 100 is born like this.

 

[MONT470]

@MONT470 Do you also experience slow acceleration? My truck take longer to start when it is cold (1s for multiple crank), and take shorter time to start when the engine is hot (0.5s for just few crank). But I have slow acceleration in low speed. Not sure it’s an issue of fuel pump or the 100 is born like this.

Acceleration, and overall performance seems normal. Occasional prolonged starts is my only issue. Also, ambient temperature does not seem to have an effect on the frequency of this issue. It does most commonly occur when the engine is cold but I have had it occur when it is warm as well...just not as often.