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-   -   Starting issues (https://www.toyota-4runner.org/3rd-gen-t4rs/292078-starting-issues.html)

mendozer 12-10-2020 04:56 PM

Well the shop has had it for two days now and they tested the fuel pressure and said it was fine. They can't figure it out yet. That doesn't bode well. These are smart guys. I've got a gut feeling that it's the remote start job I installed. It worked well for a year or two then wouldn't start over so I never used it after. Then randomly started using it in the cold and sometimes it works again. But also my lock and unlock chirps are gone now. Weird

mendozer 12-12-2020 01:11 AM

latest update:

Shop guy reached out to his friend who went through toyota tech school for help. He started getting weird readings for the MAF sensor. He said there's visible corrosion on the filament as well. So potentially this is all coming from a bad MAF sensor. I clean that thing at least 1x/year when I do the TBI valve.

The toyota guy says this can be fairly common apparently.

brillo_76 12-12-2020 10:32 AM

The MAF sensor very important so good deal hope this fixes your rig.:)

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mendozer 12-14-2020 10:48 PM

ok they got a new MAF sensor in there (was reading 10 g/s instead of 3.6-3.8 spec) but it still has an extended crank. They said it's common for these trucks but the reasons can differ. He straight up told me they have no idea why it's doing this. He was apologetic but at the same time really wanted to figure it out. I told them I plan on picking it up on friday for a sunday ski trip, hopefully it's done by then.

So it's not:
fuel pump or internal filter
fuel filter inline
fuel injectors
fuel pressure regulator (he tested it)
MAF sensor


Thoughts:
what about the wire that goes from the fuel pump to the sender unit? The internal wire, I couldn't find a part number for that.
He said he doesn't think it's the remote start, that checked out
He mentioned something about a crankshaft sensor maybe being out of whack, but once it's running it'll test good, so you have to bench test it.

Skulking 12-14-2020 11:29 PM

Quote:

Originally Posted by mendozer (Post 3579519)
ok they got a new MAF sensor in there (was reading 10 g/s instead of 3.6-3.8 spec) but it still has an extended crank. They said it's common for these trucks but the reasons can differ. He straight up told me they have no idea why it's doing this. He was apologetic but at the same time really wanted to figure it out. I told them I plan on picking it up on friday for a sunday ski trip, hopefully it's done by then.

So it's not:
fuel pump or internal filter
fuel filter inline
fuel injectors
fuel pressure regulator (he tested it)
MAF sensor


Thoughts:
what about the wire that goes from the fuel pump to the sender unit? The internal wire, I couldn't find a part number for that.
He said he doesn't think it's the remote start, that checked out
He mentioned something about a crankshaft sensor maybe being out of whack, but once it's running it'll test good, so you have to bench test it.

Can you clarify what he means by "extended crank"? Is it just a longer crank, or are there any symptoms that would suggest a problem? How long is extended? These engines do take longer to start, so I want to make sure you aren't chasing a problem that is actually the engine behaving normally.

mendozer 12-14-2020 11:31 PM

extended meaning it takes 3 or 4 key turns to turn over. That is unless you want to just hold it there forever flooding the engine. I'll give it 2-3 mississippi seconds per crank and it still does this. this is not a normal situation, I've had the rig for 5 years now.

mendozer 12-17-2020 11:10 PM

Another update. Crankshaft sensor is good. He has no idea. All fuel things check out. He said my fuel pressure reg is registering 44 and spec is 33-36(or in the thirties) but based on some vapor pressure lingo he mentioned that I have no clue of...he doesn't think it's that. So he spent today unplugging the remote start to eliminate variables. I'm worried were not gonna get to the bottom of this. And I don't even know how many hours they've put into it at this point. He said they're not charging me all the labor thank God bc they want to figure it out

mendozer 12-24-2020 10:49 PM

I got it back so I could ski a bit before Christmas. I dropped it back off right after. So the remote start wasn't it, nor was the Crankshaft, vacuum leaks, fuel lines anywhere, etc. They put 10 hours of labor diagnosing stuff, thankfully only charging me for 4. his thought now is maybe valve lash on the camshafts. When reassembling they were a lot tighter than when I took them off. I attributed that to new tighter tolerances, but he said that bench measurements can look good, but when torqued down, the head can stretch a tiny bit and now you're at zero valve lash, which could lead to the stubborn struggling start. Based on feeling how snug they were to me, I don't disagree.

He wrote up a long list of things they ruled out. They were pulling their hair out and he said straight up if it's not the valve lash, then he has no idea.

brillo_76 12-25-2020 10:05 PM

"my fuel pressure reg is registering 44 and spec is 33-36(or in the thirties"


44 could be 2 high. If the limit is 36 then the regulator is not in spec and should be replaced. [ I didnt look up the specs just going off your statements]


The Factory Service Manuals give the specs for what is acceptable and what is not. So if it's not in the acceptable range I would replace it and verify the new one is in the spec range.




So your saying it's taking 3 to 4 seconds to start? All the time or just when its cold?

As 1.5 to 2 seconds is cold start normal for the v6. These ecu will not start the fuel pump until after they get a crank signal for our crank sensors.



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mendozer 12-25-2020 10:12 PM

Actually I just looked into the FSM out of curiosity. 38-44 is spec so it's just at the top

the slower starts are only when it's warmed up.

First thing when cold, is fine
If you drive, stop for only a few minutes then start up again, it's fine.

If it sits anywhere from 10 mins to 4 hours or so, then it doesn't start up, taking 3-4 turns and each turn lasts 3-5 seconds before I let off so I don't flood anything. I don't really count but it sputters a lot with each key turn

brillo_76 12-26-2020 09:56 AM

Being your throughly went through the fuel system and looks like you covered the ignition system.

Happens only when hot. Is making me wonder.

The fluid levels not changing like you not loosing antifreeze?

Compression good?

I wondering if your having a crank sensor or maf or anything of the ignition electrical side tasting good but still intermittently failing with it gets hot.


Did they check all these components when the engine is at operating temperatures.


Being it's not just dying going down the road and your are fine till restart or start. It almost has to be something involved in the starting process itself. Sorta would eliminate the crank and maf sensor.

Unless you have one heck of a vacuum leak when the engine is warm. That would make it hard to start as well.

How's all the vaccuum hoses looking? PCV value not stuck open?


I just trying to come up with ideas for you at this point. As I see you been working on the the rig for quite sometime.



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3bears 12-26-2020 01:41 PM

while not your problem maybe, I just had to replace a coil pack.I did have a check engine light. however in reading, a coil pack can test good cold and have issues when warm.
It may not be a coil pack, but like others have said, maybe something that tests good cold, after it is warm, then starts to fail. Ive known fuel pumps to do that too on a bmw and a volvo but I dont think fuel pump is your issue since it runs good after starting.
good luck

mendozer 12-26-2020 02:19 PM

I didn't do compression but it was all solid before the top end rebuild. I had a leak between cylinders 4 and 6 before the repair. This starting issue wasn't that bad before the rebuild either.

fluids fine.

He was testing the A/F numbers running and everything checked out. One hose had a crack but I knew that, it was the fuel pressure one that goes to the air box (I had it electrical taped). He replaced that.

I think I left the report of all the inspections in the car so he has it. Otherwise I'd list all the many things they ruled out.

brillo_76 12-26-2020 09:32 PM

Oh. You had top end rebuild. Did anything else get worse? Low power?? I am wondering in the rebuild they knocked the cams off or the timing belt off a tooth.

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mendozer 12-27-2020 02:27 PM

I did the top end myself following the FSM and helpful videos. I did make one boo-boo upon reassembly. I accidentally overtorqued the heads down. So I re-did it with new bolts and head gaskets. It wasn't driven in this state, I realized it the day after and slapped myself for it.

Speaking of the cams though, his thought is too much of a valve grind from the machine shop and incorrect puck sizing creating nice spacing on the bench but maybe zero lash once torqued down....?


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