'97 4Runner 5VZ-FE drowning in fuel

[BN-2B]

Greetings!

Seven months ago I acquired a 4Runner (190,000) and have been consistently improving its condition thanks to the information gleaned from this invaluable resource.
Much gratitude to you all.

She was running great until the moment she sputtered and stalled while driving normally.
No amount of cranking would even pretend to fire her up.
At first it seemed she was starved of fuel. Upon checking the plugs, they were soaked in fuel.
Drying the cylinders an plugs enabled her to fire up under full throttle.
Runs strong. Release the throttle, instant stall. Wet dirty plugs.

There was a 'rattle' coming from the IAC only when the ignition was on. Never heard that before.
Removed the IAC, cleaned it, verified it's working properly. Rattle went away, then returned, never changing the outcome.
Replaced the IAC (new one rattles too), replaced the Fuel Pressure Regulator.
Cleaned the TB and MAF. Fuel filter, air filter, PCV and plugs are less than 6 months old. Got fresh plugs anyway.
Checked the timing belt, all marks line up.

Tried one of them Foseal Wifi ObdII scan plugs. It detects battery voltage.
After multiple attempts however, "the connection is not established".

Could this be a computer issue?

Again, Big Thanks to the contributors on this Forum.

 

[LittleCaesar]

I'd start with a fuel pressure test. If you replaced the FPR with a new OEM one, look elsewhere.

I'd try another code reader to see if it connects. If not, then you may have an electrical issue.

Any CEL's?

 

[BN-2B]

FPR is OEM Denso.

Could the pump push more pressure than the FPR can handle?

Seeking another reader.
...Small island charm. Local mechanics work with 'eyeometer' and 'earometer'.

The constant CEL was attributed to a transmission solenoid which was dealt with a few months back. The CEL continued to glow however.
ABS light is always there due to the fact that the system was removed.

 

[nissanh]

Did you check the fuel injectors? Can one or more be stuck open?

 

[BN-2B]

Ok.
The truth is, I myself applied my 'earometer' to a 'stickascope' in order to localize the sound of the IAC.

 

[BN-2B]

Did you check the fuel injectors? Can one or more be stuck open?

Not yet.
How would one check for that?
Could they all go at once?
She passed out cold without a struggle. One time. Done.

 

[nissanh]

You can unplug the wire plugs and then give 9V to each injector. You should hear a sound like "click"
Also how about the spark plug coil packs? and wires? Are they OEM? any loose connection at the wire connector to the coil packs?

 

[BN-2B]

First order of business 7 months ago was replacing the forward-most coil pack due to a code concerning a cylinder 4? misfire.
The other 2 coil packs are OEM.
Installed all new wires at that time as well as new plugs.
Poor thing had single ground plugs in her.
She ran like a champ after that.
I visually inspected the injector harnesses today while replacing the FPR.
Looked clean and snug. Did not run any tests however.
Besides a 9v source, will continuity tell me anything?
Been in and out with the plugs over a dozen times throughout this oddessey.
Connections seem secure.

 

[TXRick]

Check the timing belt.

 

[BN-2B]

Check the timing belt.

Check. Timing belt is intact. "All marks line up".
It would not start otherwise. Which it does only under full throttle (with dry plugs).
Release the throttle, no sputter, no cough, just straight to zero.
Drowned again.

 

[nissanh]

check

First order of business 7 months ago was replacing the forward-most coil pack due to a code concerning a cylinder 4? misfire.
The other 2 coil packs are OEM.
Installed all new wires at that time as well as new plugs.
Poor thing had single ground plugs in her.
She ran like a champ after that.
I visually inspected the injector harnesses today while replacing the FPR.
Looked clean and snug. Did not run any tests however.
Besides a 9v source, will continuity tell me anything?
Been in and out with the plugs over a dozen times throughout this oddessey.
Connections seem secure.

If injectors are stuck open, the continuity will not show it. Best is to send a 9V and hear clicks. I will not remove plugs any more. You can damage the threads by removing it many times. Do you have access to another coil pack to replace the front most one that you replaced? If that is faulty you basically don't get sparks into 2 pistons, which can shut down the engine at low rev's. I have a feeling this is something to do with spark plugs or injectors.

Don't worry about having single ground spark plugs. It will wear out pretty fast that is the only downside with that type.

Did you check the condition of throttle position sensor? How many miles do you have in the truck?

 

[BN-2B]

If injectors are stuck open, the continuity will not show it. Best is to send a 9V and hear clicks. I will not remove plugs any more. You can damage the threads by removing it many times. Do you have access to another coil pack to replace the front most one that you replaced? If that is faulty you basically don't get sparks into 2 pistons, which can shut down the engine at low rev's. I have a feeling this is something to do with spark plugs or injectors.

Don't worry about having single ground spark plugs. It will wear out pretty fast that is the only downside with that type.

Did you check the condition of throttle position sensor? How many miles do you have in the truck?

The truck has 190,000 miles.

The only other coil pack I have is the OEM one that I removed. It ran badly, but maybe enough to demonstrate if the new coil has failed.

Had not considered the TPS. Will search that out. Seems to be a tricky sensor which not all 3rd gens have in common. Any diagnostic links?

Lastly I will remove the plenum again to apply 9v to the injectors.

Been very careful with the plugs. I prefer to not leave them in the cylinders soaked in fuel after failed attempts.

Thanks for your help.

 

[jeremyc74]

A bad MAF could cause these symptoms.

 

[BN-2B]

A bad MAF could cause these symptoms.

Ok.
The MAF can drop out without prior warning?
One of my attempts involved unplugging the MAF.
Same results. She roared to life with throttle fully open.
Then died instantly when I backed off.

 

[jeremyc74]

Ok.
The MAF can drop out without prior warning?
One of my attempts involved unplugging the MAF.
Same results. She roared to life with throttle fully open.
Then died instantly when I backed off.

Yeah, they can die instantly. The MAF could be telling the ECU there's a lot more airflow than there actually is, which can cause too much fuel.

The fact that it acted the same with the MAF unplugged as it did with it plugged in could mean you're on the right track.

It should throw a code though. Is the CEL on?

 

[AntleredRuin]

If you want to replace the MAF, consider this replacement to not waste money during diagnostics:

https://www.amazon.com/gp/product/B006WHKKGY/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Not OEM, but a perfect fit. I bought one when diagnosing a fuel issue (found out it was the FPR). Only $13. My truck drives great with this one in, but I put the stock one back in for now. I have this as a backup just in case.
Reviews say it lasts only around 2 years, but it costs less than 1/5th the price of OEM, so for diagnosing, it's perfect.

The TPS can only go on 2 different ways. Make sure that the plug is facing the passenger side and it should be good to go. No adjustment needed. Should look like this:

 

[BN-2B]

Yeah, they can die instantly. The MAF could be telling the ECU there's a lot more airflow than there actually is, which can cause too much fuel.

The fact that it acted the same with the MAF unplugged as it did with it plugged in could mean you're on the right track.

It should throw a code though. Is the CEL on?

Yes. Unfortunately, she's one of those with the constant CEL.

In the beginning, PepBoys scanned 2 codes. One for cylinder 4 misfire, the other a transmission code.

I switched a coil pack and the misfire disappeared, a transmission shop switched a shift solenoid 4 months ago and the CEL remained.
Transmission dude was baffled because the only code present (he said) was for a shift solenoid 5. Of course, there are only 3.
That's another story, but the CEL is on.

I dropped the ball not scanning since. Small island logistics.
Recently I tried a Foseal wifi scanner but, "the connection is not established".

Thinking I should acquire a proper scanner before continuing down this dark road barefoot.

 

[jeremyc74]

Thinking I should acquire a proper scanner before continuing down this dark road barefoot.

That would be my next step.

 

[BN-2B]

If you want to replace the MAF, consider this replacement to not waste money during diagnostics:

https://www.amazon.com/gp/product/B006WHKKGY/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Not OEM, but a perfect fit. I bought one when diagnosing a fuel issue (found out it was the FPR). Only $13. My truck drives great with this one in, but I put the stock one back in for now. I have this as a backup just in case.
Reviews say it lasts only around 2 years, but it costs less than 1/5th the price of OEM, so for diagnosing, it's perfect.

The TPS can only go on 2 different ways. Make sure that the plug is facing the passenger side and it should be good to go. No adjustment needed.

Appreciate the link. Unfortunately, that item does not ship to my remote location.
Besides, it could get me burnt to a crisp by our honorable Seniors for "throwing parts at the problem".

Coincidentally, in that link, "frequently bought together" with the MAF was a cheapo Autel scanner (which also does not ship here).

So on a side note, I'm tapping the collective experience (searching) for a scan tool compatible with the illusive '97 4Runner.
There is almost too much general information about said gadgets, not enough specifics.

The TPS has not been altered. Could it drop out cold without warning?
If time allows I will check into it, as well as switching out a new aftermarket coil pack for an old OEM one which at least allowed her to Run.

 

[AntleredRuin]

Appreciate the link. Unfortunately, that item does not ship to my remote location.
Besides, it could get me burnt to a crisp by our honorable Seniors for "throwing parts at the problem".

Coincidentally, in that link, "frequently bought together" with the MAF was a cheapo Autel scanner (which also does not ship here).

So on a side note, I'm tapping the collective experience (searching) for a scan tool compatible with the illusive '97 4Runner.
There is almost too much general information about said gadgets, not enough specifics.

The TPS has not been altered. Could it drop out cold without warning?
If time allows I will check into it, as well as switching out a new aftermarket coil pack for an old OEM one which at least allowed her to Run.

I'm not sure if the TPS can just die without warning, or if it always takes a while. I have a 'bad' TPS. I had a CEL that alerted me, and then it went away the next day. So 'bad' but not completely shot, it seems.

And absolutely no offense to the more knowledgeable senior members, but if you want to 'throw parts' at it, go for it. It's your money. The MAF was mentioned (or at least 'liked') several times by different people and your CEL refers to it. If you can find a cheap aftermarket one (with good reviews) that WILL ship to you, I say have at it.
Worst case scenario, you have $13 invested in a spare part for when it actually DOES go bad, and you have to keep looking.
Best case scenario, a $13 part solves all your problems, and you can decide whether or not you want to buy a proper OEM part. You've not paid a mechanic $100 an hour to potentially tell you you have a bad MAF and then stick in an aftermarket anyways (unless the stealership) and charge you out the ass in parts markup.
Throwing around parts usually is not good practice, but when all (most) signs point to it, sooner or later you have to bite the bullet and replace the part and hope for the best.

You said that the old OEM coil pack keeps her running at least? Why/when did you get the new aftermarket one? I may have misunderstood; I though you simply swapped locations. So you got a whole new one?