BOGGING BADLY! - SOLVED

[Doubeleive]

No sir.. but I did watch the pedal and throttle blade percentages in the Tech 2, and they both moved accordingly.
Other reason I don't think it's the throttle blade, when I do hit the gas and it bogs, you still hear the intake resonate..
Also can free rev motor fine.. Do get 3deg knock retard when I rev it fast off idle.

Tried unplugging the MAF as J91 suggested, no change.
As far as injector duty, the o2's seem indicate rich when bogging.
I don't see puffs of black smoke or smell gas, so I don't think it's overfueling enough to do anything..

Will log more channels tonight or tomorrow.. getting worried, keep the ideas coming!

any difference if you shift it to m1?, the rev's in park fine makes me think it might be transmission related

 

[mikez71]

It also bogs in Manual modes... (misfires w/no code?) Bogs under load.

Don't think it is tune related (happened out of the blue). I did try reflashing a stockish tune.

I'm also thinking (hoping) something simple. I'll check the coils/plugs/wires next.. (2 year old OEM Delco iridiums from autozone and a-zone wireset)

 

[j91z28d1]

It also bogs in Manual modes... (misfires w/no code?) Bogs under load.

Don't think it is tune related (happened out of the blue). I did try reflashing a stockish tune.

I'm also thinking (hoping) something simple. I'll check the coils/plugs/wires next.. (2 year old OEM Delco iridiums from autozone and a-zone wireset)

I was thinking more along the lines of weak power to the coil packs.

only because I fairly recently had weak coil feel exactly like a carburetor accelerator pump issue. it's pretty normal over time for the diaphragm to tear and get no pump shot. felt just like that, rebuild the carb, didn't see anything wrong but cleaned and replaced it anyways. after it still did it I went to swapping ignition parts to see, turns out the old coil was weak. didn't have enough power to fire the plugs with the extra pump shot, but would. idle and slowly Rev just fine. blow out spark felt just like the lean bog of no pump ahot


just a random thought. I think you'd see it as fluffy rich plugs too, bit a hassle tyring to test voltage at the coils on these.

 

[mikez71]

Thinking it mybe a coil as well... pulled plugs, looked normal. If anything 4,6, and 8 had a little less soot around the edges.

bottom right is cylinder 1, top left cyl 8.

Plug wires ohm'd out at .385-.410, -EXCEPT!- one wire at .765. I had 3 left over OEM wires which all came in at .9something.
There has been ripples in my voltage levels in the datalogs.. swapped the wire, still stumbles/bogs.

Planning to pull the coils next. If I can't find anything there, I'll look into the knock sensor.
No burst knock, so either an ignition miss sets of the knock sensors, or something else is. (or something wrong with the wiring/sensors)

 

[j91z28d1]

I've found ohm doesn't tell you a ton with wires.. they are this weird carbon core stuff, and if you go down the rabbit hole deep enough, they say the 30k or so volts travels on the pitside of that center conductor. it's all kinda wild but yeah, the higher the load in the cylinder the more power it takes to jump the gap. of at any point alone the way it's either to jump a gap to ground it will. open air is way easu eaiser gap to jump than in cyl plug gap.

who knows, maybe fresh plug and wires fix it. but if you can back probe the pos and neg at the main coil pack plug and voltage drop each to the battery while running, you could atleast rule one more thing out.


if you don't have them, I find these type super useful. you can get around the seals and not damage them while still getting to the pins while plugged in.

 

[Geotrash]

For it to be bogging so badly, it would have to be something that affects multiple coil packs at the same time, like a common ground. But I'm skeptical of poor spark as the root cause theory. Could there be something else restricting the exhaust like a mouse of some other critter having set up shop in the exhaust system somewhere?

 

[mikez71]

OK, not sure if I didn't check properly, or if I introduced a new problem after pulling the plugs, but the Tech2 is showing me MISFIRES on cyl 2!
It seemed to idle rougher this morning, but the Tech 2 did show about 6.0 g/s MAF signal at idle.
Not sure why the reading was higher before. (hptuners?) Cooler now in the morning, so I would have expected MAF reading to be higher..

Swapped plug/wire/coil with #1. still misfiring #2. Using the Tech2, you can disable injectors while running. Some are more noticeable than others, disabling #2 of course had minimal if any change. Leaning towards fuel or compression now..

 

[j91z28d1]

is that with new plugs and wires? or put the old ones back on?

is really eazy to damage these wires pulling them off, I've done it. I've also somehow cracked a plug when tightening them down too. I stopped using my cordless ratch to install plugs after that haha.

if you have compression gauge, that's a eaiser test then fuel injector.

 

[mikez71]

Pulling those wires can be tough! I grabbed some regular pliers which help.

I put old (2-3 years) wires and plugs back on, but swapped some around. Also tried some of my OEM wires I have left over.
Engine idles/revs smoothly minus the occasional miss at idle..
I listened with a stethoscope for lifter noise, seemed quiet enough. injectors all clicked...

Found my compression gauge, hose is cracked to hell.. tonight or tomorrow after I buy another gauge!

I have a feeling some old(er) guy would have figured this out at a glance.
Here I am with my datalogger and Tech2 and I'm still wondering WTF!

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BRAIN FADE!

I swapped #1 and #3! coil/plug/wire.. #2 is on the other side! Wish me luck, who know's what I'll muck up..
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Not a plug wire issue.. or coil..

 

[j91z28d1]

I know that feeling, I've definitely been known to start at the exact wrong end of a issue and have to work thru it till the very last thing left is the issue haha. but you'll get it.


did you rule out the exhaust clogged up completely?