I have a 99 3.4L 4runner, and have been having an issue where it takes a few extra seconds to turn over and fire up when turning my key. Its getting worse. I changed the oil, all fluids are okay, I did injectors 10-15k miles ago, and had one fail shortly after. So I change it out and all was good, also changed fuel filter then too.. The local shops say they think it's a sensor. But I hooked my obd up and the 2x O2 sensors are reading pretty normal. I thought maybe it's a fuel pump issue, I rented a fuel pressure kit from oriellys , but Schroder doesn't work on yotas, and not many solutions online. The check valve is fine, I tried turning the key for 10 seconds, then trying to start, and it didn't make a difference. Just kind of looking for ideas. It kinda bogs down and once it does start, it takes a couple seconds then runs fine. Any suggestions?

 

Just where did you buy your injectors Lots of Knock Offs out there.

Sure sounds like injectors leaking fouling the plugs long crank times to burn them off.

Are Hot starts just as bad as Cold Starts

What do your plugs look like ??

Remember the fuel pump only runs while cranking and the engine running.

With a gauge on I bet the fuel pressure bleeds away

 

Ebay, I went with the middle priced ones. They were 140 a pop from Toyota, and there was a set of 6 for 60, I went with full set for like 180 or so.. and only had to replace one,since it started misfiring and threw a code. . . When I punch the throttle it does pop as if an injector is having an issue, I only know that cause it'd do the same when my injectors first started throwing codes 1.5 years ago, before it got worse and I had to change them... but also I figured if it was the injectors then they would atleast throw a code no? Thats why I kind of ruled it out, atleast for now until a code triggers. . .I haven't looked at plugs recently, when I did injectors the plugs were all within gap range. I did change one or two plugs though since they had some carbon build up. Besides that. The other 4 plugs have around 35k on them.
yes hot starts are just as bad as cold, an some times it fires up fine, and more times than not it struggles. I will pull the plugs and check gaps and how they look, I suppose thats a cheap place to start eh?

 

They will not cause a code if they are leaking after the Truck is shut off!!!

There is a thread about this on Here that went on for weeks maybe months ( Tacoma 3.4) then moved to Tacoma World it took some of the best Toyota Dealer Techs to figure it out in the end using a Camera. Never did trip a code.

Truck will always start just long crank times!

 

I had a stock injector go bad (220K miles) and tried a set of roughly $200 eBay 'Genuine!!!! OEM!!!! Really!!!' injectors. Said to be genuine, came in plastic baggies, and even looking at them up close the seemed pretty legit. The 'wrong' o-rings (if you google around, that seems to be one of the tip offs that they're fake).

Anyhow, put them in and drove it for a few days. And it had a somewhat more uneven idle, and long crank to get started that gradually seemed to get worse. I contacted the seller, they said they need to 'break in' over a hundred miles or so. LOL, srsly, I yanked them right back out and returned them and was lucky enough to get my money back (less my return shipping).

They were clearly leaking a low flow rates (the idle) and when shut off (long cranking to start).

After that I visited a pick-n-pull style junkyard and pulled a set off a wrecked 4Runner. Despite it being crashed and not running for about a month and a half (at least) when I cracked the fuel rail, fuel sprayed out under pressure. Put them in mine and... it ran perfectly. Smooth idle, normal starts.

Yeah, beware of all the lousy counterfeit junk being sold on eBay.

 

Not sure whether it really helps or not, but I dump a bottle of Techron in my tank a few times per year. For the last 20 plus years.

Original fuel injectors, 490,xxx miles....



Andreas

 

It can`t hurt but you have taken care of it from new.

I kinda think OP`s issue is more poor quality injectors.

Myself I am not sure who to trust anymore to rebuild and flow test injectors I would get used original injectors and have them rebuilt

 

The only places I've heard of over the years are RC Engineering & WitchHunter Performance.



Andreas

 

I just tested my fuel pump pressure the other day, I used a pressure gauge and some 3/8 fuel line, instead of testing at the rail I tested at the hardline that runs along the frame Right where it comes out near the brake booster, I just put a spring clamp over the threaded adapter of my pressure gauge and the flared end of the hard line, The only downside is this test your fuel pump but not your fuel pressure regulator

 

I have heard WitchHunter has had some quality problems though always two sides to the story.

Covid Delays and Growing Pains over loaded with work and no help who knows.

 

I used WotchHunter for my 22RE injectors. My 5VZ injectors had internal issues that would show during heat soak. For my 5VZ I went with low mileage Camry injectors.