NO CEL: Repeatable misfire/loss of power. With video for her pleasure!

[A.Wilson013]

MY CEL IS NOT BURNT OUT

In the video I am parked against a curb with the ebrake on. I accidently rev it in neutral, place it in drive, and then begin to apply pressure to the accelerator. The first two "creaks" you hear are my AWESOME 6 month old White Line LCA bushings that are already shot, it seems. At 1600rpm(16 seconds into the video) the misfire starts up. This was with the .032 gap. I can re-create this situation over and over without fail.


Well, here's what I am dealing with. I've been having a REAL rough idle for a few seconds (mechanic buddy called it a "hard" misfire ) on cold starts off and on for nearly a year now. He tried pulling the wires off of each cylinder "listening" for the missing cylinder, but by the time he makes it to each one the computer has compensated and it's hardly noticeable. It goes away within seconds.

No CEL.

However, recently it has gotten VERY bad, and as of late, has started misfiring almost every time I stomp the accelerator.

No CEL.

I replaced the fuel injectors on Sunday with new OEM injectors and took it for a test drive. Getting onto the freeway I was able to stomp it and it pulled hard up to speed. Slowed to 60, stomped it, and it pulled hard. I thought, "SUCCESS!!" and headed home.

As I pulled up to my garage (slight incline, but enough to make my nearly 6000lb 4Runner work) I could barely make it up the hill. Misfiring like mad until I stomped the accelerator to get over 2000 rpm.

No CEL.

Yesterday I pulled all of my plugs (Denso IK22) and checked the gaps. They were all at .032. I did some reading and found some folks reporting better results at .042 from the IK22s and decided it was free, so I'd give it a shot. No change. No CEL.

Within the past 6 months I have replaced the fuel pump (Denso from Evo 8), injectors (OEM), Plugs (Denso IK22), Wires (OEM). I've also checked my compression twice in the past 6 months and am at right around 185psi on all cylinders. I used one of those "block test kits" and found no combustion/exhaust gases in my coolant.

I read some stuff [MENTION=10169]TheDurk[/MENTION] posted years back about a seemingly similar issue, but I did not notice any strange marks on the plugs that would make me think the plugs were grounding off the side or anything.

What do you guys think?

Thanks

 

[AntleredRuin]

So it looks like it happens even when you accelerate slowly, correct?
Any stalls at all or just misfire starting at 1600?
When my FPR went, it was fine at highway speeds (2000-2200 rpm) but only if coaxed there very slowly. Any hard acceleration and it'd fall on its face starting around 1500 and 'hard misfire', then stall. Made merging onto the freeway terrifying.
This seemed more pronounced when cold also, so of course my living within 3 minutes of the freeway I take to work was great.

 

[A.Wilson013]

So it looks like it happens even when you accelerate slowly, correct?
Any stalls at all or just misfire starting at 1600?
When my FPR went, it was fine at highway speeds (2000-2200 rpm) but only if coaxed there very slowly. Any hard acceleration and it'd fall on its face starting around 1500 and 'hard misfire', then stall. Made merging onto the freeway terrifying.
This seemed more pronounced when cold also, so of course my living within 3 minutes of the freeway I take to work was great.

It really ONLY happens when I accelerate slowly. Since replacing the fuel injectors I can stomp the accelerator like a mad man and it'll seemingly run fine (won't misfire).

 

[AntleredRuin]

It really ONLY happens when I accelerate slowly. Since replacing the fuel injectors I can stomp the accelerator like a mad man and it'll seemingly run fine (won't misfire).

Hm...do you have the ISR mod on your intake?
If so, how do you have the vacuum hose from the FPR ran (the hose from under the top plenum that went to the intake baffle)? Did you drill a hole in the ISR and thread it in for a 'stock' approach, or just 'T' it into existing vacuum?

 

[A.Wilson013]

Hm...do you have the ISR mod on your intake?
If so, how do you have the vacuum hose from the FPR ran (the hose from under the top plenum that went to the intake baffle)? Did you drill a hole in the ISR and thread it in for a 'stock' approach, or just 'T' it into existing vacuum?

ISR mod was done years back. Long before the issue. FPR has a boost line going to it from the SC.

 

[AntleredRuin]

I don't think the ISR is the issue, per se, but it could be 'problematic'.
When my FPR went, it actually started dumping fuel into my intake baffle through that vacuum line. If I removed the baffle, I could hold it on its end and dump several ounces of fuel out at a time. I did this once a day until I replaced the FPR.
Since you don't have a baffle to 'safely collect' the fuel, if your FPR IS leaking, then it could be dumping fuel straight into the boost line for the SC.
I'll admit that I'm not super versed on the workings of a SC (although I know the basics) but I'd have to think that wouldn't be a good thing.

This might explains why your symptoms are similar to mine, but still different. It sounds like a pressure issue and if new injectors and a new pump did not fix it, this is really all that's left. That is, if the fuel filter is not clogged.

I can't tell of a way to really test my theory though, because there's nowhere for the fuel to collect on your truck. This is what let me know it was my FPR, and not fuel pump, MAF, etc.

 

[A.Wilson013]

I don't think the ISR is the issue, per se, but it could be 'problematic'.
When my FPR went, it actually started dumping fuel into my intake baffle through that vacuum line. If I removed the baffle, I could hold it on its end and dump several ounces of fuel out at a time. I did this once a day until I replaced the FPR.
Since you don't have a baffle to 'safely collect' the fuel, if your FPR IS leaking, then it could be dumping fuel straight into the boost line for the SC.
I'll admit that I'm not super versed on the workings of a SC (although I know the basics) but I'd have to think that wouldn't be a good thing.

I can't tell of a way to really test my theory though, because there's nowhere for the fuel to collect on your truck. This is what let me know it was my FPR, and not fuel pump, MAF, etc.

This is likely why my buddy told me to see if the line smelled like fuel or dripped any fuel when removed. It did not/does not.

I just drove it on the freeway for the first time since setting the plugs to .042 and it's absolutely terrible. Waiting for it to cool down so I can pull the plugs and put them back at .032. It seems that any time my TPS shows a value greater than 30ish it starts to misfire.

Going to get together with [MENTION=82154]GSPRunner[/MENTION] this evening and see if by replacing my coils, wires, and TPS with his we can make any headway... Luckily I can replicate the issue so easily. Should make it simple to pinpoint what (if anything) fixes the issue.

My only real question is why the heck is there no CEL? I unplugged my TPS and it immediately triggered the CEL so I know the damn thing works. I thought misfires from plugs, wires, and coils triggered the lovely p03xx codes and the TPS the p0120. This is the main reason I replaced the injectors, honestly.

 

[thegipper]

This is kind of a shot in the dark but have you checked to see if your cat is clogged? A clogged cat will do all sorts of weird things like make your tranny shift weird, loss of power, misfires and so on. They almost never throw a CEL either when they get clogged.

It's worth checking to make sure it isn't clogged.

 

[rideexileex]

What's your AFR gauge showing during the hesitation? Rich? Lean? Normal 14.7?

 

[AntleredRuin]

Going to get together with [MENTION=82154]GSPRunner[/MENTION] this evening and see if by replacing my coils, wires, and TPS with his we can make any headway... Luckily I can replicate the issue so easily. Should make it simple to pinpoint what (if anything) fixes the issue.

My only real question is why the heck is there no CEL? I unplugged my TPS and it immediately triggered the CEL so I know the damn thing works. I thought misfires from plugs, wires, and coils triggered the lovely p03xx codes and the TPS the p0120. This is the main reason I replaced the injectors, honestly.

My CEL went off for about 5 miles and then went away by itself, and that was it.
Sounds like a good plan with [MENTION=82154]GSPRunner[/MENTION]. Consider borrowing his MAF too (if the model years are compatible).

 

[BrianSD_42]

Subscribed. Sorry to hear about your continuing troubles. My 4Runner has been collecting dust while I get my savings in order.

Have you had a leak down compression test done?

 

[Myrunr2010]

Sorry to hear about your ongoing issues, hopefully you get it figured out soon! I'm curious to hear what the issue turns out to be

 

[A.Wilson013]

It's worth checking to make sure it isn't clogged.

Cat is new. Neglected to list it as I didn't see the relevance.

What's your AFR gauge showing during the hesitation? Rich? Lean? Normal 14.7?

It appears to be normal.

My CEL went off for about 5 miles and then went away by itself, and that was it.
Sounds like a good plan with [MENTION=82154]GSPRunner[/MENTION]. Consider borrowing his MAF too (if the model years are compatible).

I swapped in my spare MAF and the issue persists.

Subscribed. Sorry to hear about your continuing troubles. My 4Runner has been collecting dust while I get my savings in order.

Have you had a leak down compression test done?

When we bought my wife's new car I sold off my pickup to free up garage space for her. 4Runner is back to DD duty, so unfortunately collecting dust (as much as I would like it to be) is not an option anymore. Honestly, 2016 has me not even enjoying driving the thing anymore. Every time one creak, squeak, or rattle gets fixed, two more pop up. Driving it is becoming more of a chore than the pleasure it used to be, it seems.


I've not done a leakdown test. I wonder if my little TJM compressor would work for one. I don't have a garage air compressor, unfortunately.

 

[Brentif]

I was having similar issues, ended up being the throttle positioning sensor. Give that a try, it was cheap for my 97.

Brent

 

[pauldub]

Have you checked to see if there are any codes stored that may not have yet triggered the CEl?

 

[GSPRunner]

I'd sell that ****er and let's just go to Trivia night tonight

 

[rideexileex]

That's odd - I finally just watched the video. Is it usually just at 1600 RPM or was that just a coincidence with the video?

Does it seem dependent on engine load? Potential timing error?

 

[A.Wilson013]

That's odd - I finally just watched the video. Is it usually just at 1600 RPM or was that just a coincidence with the video?

Does it seem dependent on engine load? Potential timing error?

Yesterday it happened at 1600rpm every time I tried to make that video. I did it about 6 times before it was clear enough.

I tried to do it again today after re-gapping back to .032 and routing the wires a little differently and it's no longer doing it at 1600, but is now missing only when I hammer on it.

Now I feel like it's just messing with me.


So today's updates:
With the plugs gapped at .042 it was not road worthy. Could not hold 60 on the freeway, misfired on any sort of incline where my throttle position was over 30 or so (as reported by scangauge).

With the plugs back to .032 my issues are:
-Slight intermittent miss at idle.
-Noticable (like in the video) misfire when hard on the throttle

 

[JRZEE2000TR4LTD]

Boots under the coil packs? Coil packs themselves? Ignitor?

 

[ThorInc]

Subbed....I am with BrianSD_42, you need to do a leak down test. Maybe try a new set of plugs at the least.