2005 4runner starting issue

[On the RX]

My son has a 2005 4runner SR5 with around 245K on the clock. It has the 1GR-FE V6.
Well Sorted did a pretty big refresh back in 2021 (see attached list) to update worn components and a thorough inspection.

My son decided to move back to Ohio the day after he let me know it was having this issue, so this is all passed to me without me seeing it in person.

So, the truck is starting intermittently and will run fine once started with no issues. It started to not fire a couple weeks ago and was pretty rare. Now it happens about 50% of the time. He claims that slamming the hood fixes it (I know, I told him to stop before he broke something that isn't broke!).
It had the issue on his drive to Ohio and had a parts store check the starter, battery, and alternator and they passed with flying colors.

He had someone check it in Columbus today. They said it didn't have any codes popping (there was no dummy light on) and they think the anti theft system is causing the issue, with nothing to back that theory up. I hope they didn't charge him! There is not an aftermarket alarm system on it that I could see. This "mechanic" told him it would cost more to fix it than what he paid for it. It was suggested that he trade it in for something newer than will run. My name is on the title and that ain't happening!

My thought is the fuel pump but no one has checked the fuel system. I also think that if it was a coil pack, plug, or wire, it would run bit misfire.

Give me your best guess to help diagnose from 1300 miles away!

@DaveInDenver do you have any thoughts?

 

[SteveH]

Does it fail to crank/turn over, or does it fail to start and run after cranking?

 

[On the RX]

Fails to start. The starter is engaging the flywheel but it won't fire.

 

[DaveInDenver]

I'm no expert. :-/ There's a hundred better mechanics to ask than me.

By engaging you mean starter is spinning? If it's turning does it sound like it's turning the engine? Thinking would be to eliminate broken or stripped teeth on the starter or flywheel.

If it's the stock immobilizer wouldn't you get the dash indication, the flashing key? I think 100 series have a common issue in that system, maybe it's similar in 4th gen 4Runner. Do Toyota immobilizer prevent starting altogether or do they start and run for a second before dying?

He hasn't had new starting keys made or anything?

Slamming the hood is pretty non-specific but might point to a loose wire or something like that. Could be as simple as loose battery connectors. Any number of things in the harness, really. Neutral safety switch in the transmission, I dunno. That would I think prevent cranking not starting.

If it was an important engine sensor I'd think he'd have diagnostic codes. The immobilizer might store codes, not sure about a factory anti-theft.

The EWD pages for a 2007 if he/mechanic wants to start checking for loose or broken stuff in the harness.

 

[IoN6]

Fails to start. The starter is engaging the flywheel but it won't fire.

So it just cranks over but never fires?

Reaching for straws here, but on my 5VZ-FE it was hard to start. I thought it was the injectors leaking, but a week or so ago it threw a code on 470. Pointed to a vacuum leak, which I had already checked for or the MAF. Replaced the MAF with a Denso model and it runs great AND starts much easier. Think the injectors are leaking a bit still.

 

[On the RX]

@DaveInDenver, it was mentioned to me that you have/ had the same engine, plus you are always a wealth of information! You're like Google on steroids!

It will still start about 50% of the time, so mechanically it seems sound. I had him pull the inspection panel for the fuel pump so he can see if it is pressurizing the system when it doesn't start.

The "mechanic" that looked at it didn't charge him and I question their morals. It screams "this 18 y/o is in a tight spot and I may be able to buy it cheap to fix and flip".

The MAF is my second suggestion to eliminate.

I also suggested that he quits driving it unless he needs it. Horse to water scenario.

 

[nakman]

Fuel filter. when it's been sitting the stuff in the filter dissipates a little bit and thus allows more gas through. but when it's been running the sediment in the filter all goes to one side, and clogs up more. I'd have him replace the fuel filter and see what happens.

 

[DaveInDenver]

Could be fuel filter. There's several trouble codes that I'd have thought might be stored for lean or misfire, though. Not that the mechanic who said it was clear is trustworthy.

 

[On the RX]

Good suggestion.

The fuel filter is part of the sending unit in the tank on this model. He would need to drop the tank and pull the pump unit. At that point, even though the filter is replaceable, I would suggest to him to just replace the entire unit with the amount of miles on the truck.

 

[DaveInDenver]

Correct me if I'm wrong but doesn't the 4th gen 4Runner have an access panel for the fuel tank? I don't think you need to drop it. If this was a pickup or something where it's relatively painful to get at I would agree on the "just 'cause I'm doing it" but I don't think it's necessary here.

 

[On the RX]

There is a access panel that is right above the sending unit. It is too small to remove the unit but it does allow you access to disconnect the unit. If he was here, I would cut it larger to make enough room to pull the unit and replace then make a replacement panel to cover the larger hole. Considering the company he is with, I don't trust them to open it up larger and make a cover that bolts back onto it. If by chance they didn't cut the support right there, they would probably just leave the hole and cover it with the carpet.

 

[fjc man]

Same setup as my FJ Cruiser, the access panel is to unplug the connectors. To get the sender/ pump assembly out of the tank you have to drop it. There is no filter, it’s a strainer/sock. There is a resistor block under the hood for the pump that might be worth looking at.

 

[ry303]

If it had an aftermarket alarm on it then you could check to see if the wiring harness is still there and see what kind of work the tech did. They usually put them under the plastic door sill on the the drivers side, near the fuse box. I had a weird issue with flickering brake lights that I traced to the PO's alarm harness. It was a bad ground that was easy to spot and fix.
Another thought is a loose spark plug? Not a loose wire (that would throw a code) but a physically loose plug in the hole. (Lol) I don't think that throws a code but it creates starting issues.
HTH

 

[On the RX]

He got stranded yesterday and I talked him and his dad through removing the fuel pump cover under the seat. The pump gave no auditory or tactile indication that it was charging the system. This leads me to believe that the pump has given up it's ghost. I'm not there and only going off what two ignorant (in the non-judgemental literal sense of the word) are telling me. They had it towed back to their house. My suggestion to them was to have someone drop the tank and replace the pump, and to consider replacing the entire unit since it is probably original with 240k miles worth of work under its belt.

 

[J1000]

My 100 has been shutting off after hitting bumps and I noticed it would die if I slammed the hood. I did some googling and apparently it's not uncommon on the 100 and most people point to old EFI or ECD relays. Also the fusebox in the driver's kick panel 10A ign fuse can be cooked, not blown but not making good continuity either. I am waiting on a new ECD relay for my truck, had to order from Japan.

 

[J1000]

Just looked at the 10A ECU fuse and sure enough it's cooked. I just replaced it and I can slam the hood all I want and it doesn't die anymore. Amazing. I also replaced the idle-up 7.5A fuse because it also looked cooked.