4Runner Issues (1 Viewer)

pappy

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I've been fighting a rough running condition on the 4Runner for a few months now. As Onur will testify I've spent a lot of time and coin at AmToy chasing this gremlin. As I've replaced parts the issues seem to get less, but are still there.

The truck now starts fine. At around 150° the truck starts to stumble. It was very bad before the part replacements, but still exists. If I let the truck sit for 20 minutes or so the truck will hardly run until I put some throttle and a little time into it. My air/fuel meter shows a lean condition under load.

To date:

Replaced cold start injector
Replace cold start time switch
Replace fuel press regulator
Replace fuel filter
Replace TPS (code)
Replace Ox sensor (code)

Tried a different ECU
Tried a different AFM
Tried different plug wires

After talking with Evan last night I decided to rule out head gasket. So this morning I ran a compression test.

No1: 180
No2: 195
No3: 170
No4: 180

Not bad for an engine with 120K+ miles on it. I think I can rule out head gasket.

What was not good was the condition of the No4 plug. It was melted. I'm suspecting a lean condition, which I have been suspecting all along. Now, why? I'm thinking about replacing intake gaskets.



 
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pappy

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Umm, crack in the intake that opens when warm?

I've ordered a new set of clean injectors and will order gaskets from Dan tomorrow. Once the manifolds are off I can inspect them for issues.
 
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I wasn't so much thinking a crack (but that's certainly possible) but a situation where there is complete sealing with the intake gasket when its cold but then the manifold heats, warps, and opens up gaps. I've seen this happen with aluminum heads and gaskets (especially when bolted to and iron block) where the head warps under heat and opens up gaps. You can do cold compression checks all day long and find nothing. Usually the head warping happens after an overheating event, but doesn't your manifold also have like a bizilion miles on it?

Just a guess given that you've rounded up all the usual suspects.

That number 4 plug looks pretty bad and knowing you, I'm sure you haven't let them sit in there for 60K miles or more.

Why not switch injectors from a different cylinder and see what you get?

One more thought. The little rubber gaskets (grommets) for the injectors could also be bad, alhough usually you get gas spraying out, not air sucking in.

It just seems like one clogged injector shouldn't be giving you so much grief.

My 0.02

Umm, crack in the intake that opens when warm?

I've ordered a new set of clean injectors and will order gaskets from Dan tomorrow. Once the manifolds are off I can inspect them for issues.
 

alia176

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If it's a vacuum leak, I assume you've done the "spray WD-40" everywhere to see if the idle speed comes up.
 

pappy

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I heard from Ryan. He thinks it might be a gunked up intake manifold. The PCV valve inserts at the rear of the plenum, close to the No4 runner. He is thinking that oil build up might be contributing to the problem. I'll know once I get the manifold off.
 
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I intentionally didn't ask that because knowing Jon he'd done it already. Right Jon?

That said, from experience that trick doesn't always work for stuff that's down low, like under an intake. If the fan is running it blows the flammable away from the leak.

FWIW, WD40 works in a pinch but carb cleaner or better yet propane is more flammable and doesn't leave a residue that can cause belts to slip, etc.

If it's a vacuum leak, I assume you've done the "spray WD-40" everywhere to see if the idle speed comes up.
 

Onur

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I saw him at American today...buying parts .

We'll hear soon enough.
 

pappy

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So Jon, did you ever figure anything out?
Nope.

I pulled off the intake today and found what looked like fuel ponding in the intake runners. Instead of the runners being oiled up they were very clean from the throttle body all the way to the head. Some spots actually looked washed. The injectors were taken to Budlong for inspection and cleaning. I'll know Monday if there are any issues with them.

Not issue related, but I figured while I was messing with the intake I would take care of a few other issues. There are three coolant hoses that run under the intake that are impossible to replace. I took the opportunity to replace them while I had the intake off.

Of course ... I broke the head off one bolt, and stripped one hole on the plenum (to the EGR). Thank goodness for easy-outs and helicoils.
 

pappy

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you sound like me! a 30 minute job turns into 4 hours!:lol:
It took me almost exactly one hour to have the plenum off and the injectors out. It then took me 4 hours to get the lower manifold off, clean it up, replace the hoses (which sounds easier than it was), do the fixes, and put the lower manifold back on. I also unwrapped the harness to look at the injector splices. Somebody has been in there before. They were fixed. Not the way I would have done it, but acceptable.

Now I wait on injectors.
 

pappy

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New gaskets in: check
Rebuilt injectors in: check
Everything hooked up: check

Turn key: crap. Thanks goodness for headers. No1 is cold. No fuel. Long story short, I had the same problem this guy did: 22re injector problem i had. I think I aggravated the problem removing the manifold.

Engine now runs, but I ran out of time to take her for a putt.
 

pappy

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Yes, it was a wiring issue for No1, the injector was not firing because of a broken ground. That still doesn't explain the other issues I've been having.
 
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Lets cut to the chase. Are you gonna be ready to leave at 4am on Thursday or do I need to clean out the spot where there used to be a passenger seat in Pristine?

-Mike-
Good question! Pappy's coming down to the wire. I'm sure you guys will have a great trip regardless. :cheers:
 

pappy

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Lets cut to the chase. Are you gonna be ready to leave at 4am on Thursday or do I need to clean out the spot where there used to be a passenger seat in Pristine?

-Mike-
Good question! Pappy's coming down to the wire. I'm sure you guys will have a great trip regardless. :cheers:
4AM? Yer nuts. I'll know what I'm driving when I pick the truck and clean the windows.
 

Onur

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I keep hearing rumors that you are seriously contemplating taking the 40....

Really?

Seriously?

I think that would be a very bad idea for this type of trip..
 

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