Repeated fuel filter clog, failing fuel pump, or ?

[hour]

What are your thoughts as the gas tank going under vacuum or pressure? Is a new gas cap a possibility?

What do your spark plugs look like?

Tested the tank pressure theory last week before doing the pump, desperately trying to avoid dropping the tank. Took the gas cap off, drove the same (like dook). Made sure no pressure had built up in the tank by pressing the flapper. Also checked any line I could for blockages with a blow test and pinching along soft lines.

Plugs I should check again, but I had done plugs and wires (correct NGK-correct gap) in the earlier stages of throwing money at this same problem - but before the problem got this bad.. maybe 7k miles ago? I remember being pissed because I took the old ones out expecting to find some cheap generic plugs - and they were the exact same ones as I was putting in, looked ok, and were gapped properly. If this is an injector problem I might learn something looking at the plugs... will put that on the list

 

[theesotericone]

Reading through all this a second time. Just so I'm clear, you have never thrown a code in this rig or never thrown a code that's related to this problem?

 

[hour]

Reading through all this a second time. Just so I'm clear, you have never thrown a code in this rig or never thrown a code that's related to this problem?

I've thrown codes when I've forgotten to plug the MAF back in, or when I had a grounding issue with a tail light turn signal converter - so I know the CEL is functional - but other than those things, the light has never come on.

 

[theesotericone]

I've thrown codes when I've forgotten to plug the MAF back in, or when I had a grounding issue with a tail light turn signal converter - so I know the CEL is functional - but other than those things, the light has never come on.

Cool. I was gonna suggest you unplug the MAF and fire it over to make sure the ECU is reporting codes.

It's indeed weird not to have a code and to have fuel related fixes alleviate the issue. Have you checked compression on the cylinders at all? Just wondering how tired the motor really is?

 

[hour]

Cool. I was gonna suggest you unplug the MAF and fire it over to make sure the ECU is reporting codes.

It's indeed weird not to have a code and to have fuel related fixes alleviate the issue. Have you checked compression on the cylinders at all? Just wondering how tired the motor really is?

Haven't checked compression - I was starting to think the motor was just tired too at the beginning of this summer until I did the fuel filter and was blown away at how great it performed. If it can do that towing for hundreds of miles, it's gotta be something stupid.

I don't assume valve problems can be a come and go thing?

With the fuel smell today and the quick hiccup the car still does on warm restarts - I think I should pull my plugs and look for any obvious evidence that a cylinder or multiple are running rich/lean. I also kind of want to get a USB borescope camera since they're so cheap - saw a video on youtube of a 3.4 where guy removed intake plenum and could see bottom of injectors leaking. Similar symptons

 

[JBurt]

My father in laws taco had a bad injector with similar symptoms, but the word party is yours running well after filter replacement.

 

[St Runner]

Sucks that the fuel pump did not correct the problem. I feel kind of responsible after pushing you to change it, but when fixing difficult problems like this you have to keep trying. What we know. It does run a little better, no codes and you smell gas. Gas smell is most likely a leaking injector. I would do a visual check and think about getting them cleaned with new o-rings. As others have said get a compression check done. I don't think it is a problem but it will write off any mechanical issues if the compression is even. My theory on this is that the extra fuel pressure from the new pump is showing in issues with the injectors. Also just thinking out loud, I wonder if the valve that returns the excess fuel to the tank is not working correctly. I am not totally sure how the system works so I am just throwing the idea out

 

[AntleredRuin]

So you've not looked at the FPR yet? Really does sound like a pressure issue.

If you have the stock Air Intake Baffle, remove it to see if there's any gas in it. When My FPR went, it just started dumping gas through that vacuum line into the Baffle. I had the same basic issues as you, but I also stalled out when flooring it. I could get to speed, but it took quite a while.
That's not to say that the FPR ISN'T bad if it's not dumping gas.

And I may have missed it, but did you actually replace the MAF, or just clean it?

 

[hour]

Just checked, air box free of gas, residue, or indication of any fuel. Vacuum tube to FPR is also clean inside - checked with q tip, didn't smell any gas. Only thing odd was my charcoal canister was buzzing when I popped my hood - 16 hours after I parked it.

 

[hour]

Bit the bullet, taking it to a place called 'Toy Doctor' in Denver tomorrow morning. If they can tell me it's for sure the injectors, or even an injector o-ring, I'm going to just replace all six of them with GB Remanufacturing OEM rebuilds. Better route than Witch Hunter for me - if I don't finish something the day I start, it might have to sit for a week in pieces.

Plus, it's less than $160 shipped for all 6 after I return my cores.

Will update with their findings

 

[hour]

Classic. Shop called to say the mechanic drove it and thought it ran strong, said I should take it to a 4x4 shop because it's so much heavier than a stock 4runner. I explained that it drove better while towing 1,500 lbs a month ago right after I changed the fuel filter the first time than it does now or ever had before - even stock form. Mechanic is baffled but hasn't done any diagnostics yet.

So I'm going to tell em I want to know the fuel pressure running, WOT, and how long pressure is maintained after engine is cut off... check for vacuum leaks, make sure all my hoses are routed properly, FPR and canister not cracked, etc.

Really sucks, even if guy drove a stock 4runner right after mine he'd probably blame my issues on weight. 1980's fully armored 4 banger tacos on 35s can dust me.

 

[hour]

TL;DR as much as possible...

Tech thought it ran smooth and that there wasn't much if anything to be done with the performance. We went for a test drive, mashed the pedal, didn't feel nearly as good as it could - but it wasn't as pathetic/undrivable as usual. If only he could have been with me struggling to get up some hills yesterday.

I threw out a bunch of suggestions of things to check- FPR, injectors, TPS, etc.. none seemed to interest the guy based on what he felt, nor what I described - especially without throwing a CEL ever. He did not check fuel pressure which I was kind of bummed about.

Hooked up the computer and watched things, verified TPS reads from 10 to 70something with pedal on the floor, all ok. Said the numbers on my front and rear o2 sensors were within spec, but that the rear sensor was fluctuating too much or was inconsistent with the first sensor, or out of sync with the front sensor reading - something like that. Said the cat was on its way out.

That lead him to look under the car as I started blabbing about how I couldn't remove the front o2 sensor due to a stripped nut, and he noticed my cat was "significantly smaller than a factory cat". The car did fail emissions many times before I bought it (can view online) and then passed about a month before the owner sold it to me. It's possible he swapped in a cheap tiny cat just to pass emissions and then dumped it when it ran terribly.

Conclusion:

No conclusion, but cat is undersized and thought to be failing - and he said that my throttle and transmission kick down cables were adjusted improperly - claimed that I wanted a little slack in them

I tightened those cables up years ago trying to make it run better and removed all slack. I thought the only way to screw that up was overtightening to the point of making the car idle higher. I guess I could have overtightened the transmission kick down cable but I can't see how that would have had the effect I experience.

So whatever. No explanation or theory on why the fuel filter wakes the car up briefly. Will adjust my cables again to add back in a little bit of slack, will test back pressure of exhaust by removing front o2 sensor, and replace cat if it seems to be the bottle neck. If no dice then I'm back to fuel system diagnostics.

 

[Crowcifier6]

Best of luck , know the feeling chasing down tiny problems.... It's why I won't buy anything newer than 99, for now. Goddamn computers...

 

[theesotericone]

Chop the cat out of the system and run a single wall pipe to the muffler. See if that does anything. I've had a clogged muffler on my van render it with less power but that was easy to hear. It finally completely clogged one day driving back to meet my wife from an out of town trip. I was 2 hours from home and the van just lost power. I was going down hill. Pulled over at the bottom of the hill and it idled fine. Put it in gear and it barely moved. I could hear the exhaust and motor struggling. I checked cell reception and of course had none. Next I did what I always do in those situations. I put it in neutral and stood on the gas hard. It hit 2000RPMs and bogged for about 15 seconds. At 16 seconds I heard a very audible pop from the muffler and the RPM's shot up way high. I put it back in drive and it's run fine ever since. Pressure can work to your advantage. lol

 

[hour]

Thanks Crowcifer, it's been a ridiculous process to say the least.

theesotericone- a little beyond my level of expertise to do that but I am pretty set on ordering a cat.

So after blow torching, dremeling, chiseling, and beating on... I finally got the second bolt of my upstream o2 sensor off. Left the good bolt on finger tight and took it for a spin.

While it was loud and didn't run all that great, it was definitely more responsive to throttle - especially off the line. It also downshifted without smashing the pedal at interstate speeds. I was only out for about 10 minutes because I didn't want to blow anything up with the front o2 sensor loose in the pipe - but I think the change was enough to justify a $90 Magnaflow cat and some cash at the exhaust shop.

None of this really adds up to me - but it never has...

 

[JBurt]

At least you've got something to go on. Can you post picture of your cat?

I don't know how often you have to smog it but could delete your cat and run an o2 simulator?

 

[shootmymime]

^ I would do that as well. I'm thinking of just pulling my cat because. Plus being supercharged would be better


Sent from my iPhone using Tapatalk

 

[hour]

At least you've got something to go on. Can you post picture of your cat?

I don't know how often you have to smog it but could delete your cat and run an o2 simulator?

Have to do emissions every 2 years, and get checked on on-ramps multiple times a month since they have mobile testers setup all over the state. I think I'd be happier not having to worry over swapping a cat back in...

Pics though - I can't find good examples/pics of single cat 3rd gen 4runners so I'm not sure if it's truly undersized. The technician was 100% convinced that it was tiny and not original. I confirmed it isn't original by the code stamped on it (after some googling) - apparently the N indicates new aftermarket.

"YYYY - The date of manufacture. The first two digits indicate the month, and the last two the year. " - taken from Understanding Catalytic Converter Labeling

The only group of four I have are [25 13] but if the 13 is an indication of year, that's when it failed emissions a bunch of times and then passed, and I bought the vehicle in November of 2013. Possible that PO did indeed swap in a pee wee cat to pass emissions.

The central body of the cat is ~6 inches long and then tapers on either side...

Thought these numbers were gone forever but hit it with a sanding block really fast and ta-da. If I understand correctly, manufacturer (MM) is code for Maremont

And emissions test fails prior to me taking ownership in Nov of 2013

 

[JBurt]

I wonder if we can get an emissions guru to see of those failures could be attributed to a bad cat?

 

[hour]

I wonder if we can get an emissions guru to see of those failures could be attributed to a bad cat?

Interwebs would suggest lean fuel mixture, defective egr system, defective catalytic converter.

Oh no sh!t... just read through the receipts from the glove box - I probably should have done some detective work a while ago.

5/9/13 - Brake shop receipt has a comment 'customer has check engine light on'. Unless policy was different, I don't believe they would have hooked him up to the dynamometer and gotten those readings in the screen shot of 5/11 if he had a CEL - so maybe he got the light out for a while.

5/11/13 - Exhaust Pro's installed a new Catalytic Converter, PN# 650005 seems to be an Eastern Cat per google but that doesn't match the mfg stamp on the current one unless I'm interpreting that wrong. Done at noon - same day he failed the first e-test...

[Fails e-test 4 x in a row]

Receipt at 5pm on 5/22, the day he failed twice, for an air filter at O'Reillys. Wonder if he bought it and went back to try again - it's free to re-test in a certain time frame.

5/23/13 - 6 x NGK (4302) BKR5EKPB-11 @ Napa
5/26/13 @ Noon - BG 44K Fuel system cleaner @ Napa
5/26/13 @ 2pm - Bosch 13104 - Oxygen Sensor (up or downstream) @ Napa

No more receipts after that, passes next e-test. Mine was certainly running like dook when I passed this June and I recall the #'s not being near the max allowed.

The downstream o2 sensor looked much newer tonight when I was working on breaking the bolt off of the upstream. The upstreams bolt was already rounded and like fused to the stud, so I don't think he managed to get that one off. The rear's harness's body clip is also broken, which he may have done installing it.

So the guy (a middle aged guy) did all of this work, even installing a crappy BOSS head unit and subwoofers, finally gets it to pass emissions and sells to me 5 months and 6k miles later and I talk him down like $1,300. I wish I knew what the CEL was on 5/9/13. But it seems like he had problems, got the light to go out, failed a bunch of tests, and then started doing the same sh!t I've been doing to try and make it run 100% for 3 years