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P0200, misfire, backfire, VERY rich, lack of power after cam swap in 04 LQ4(6.0)

gmcxt Thanks for the ideas.

If I had the equipment, I'd go further into the diagnosis. It is starting to appear that the wideband isn't worth a damn. I moved it up to the passenger bank and it is still reading unreadable lean(ie 18afr+) I will be trying it over on the driver bank later today.

I'm not sure what the wattage of injectors is supposed to be. But without the wattage, you can't deduce the amperage draw ;)

According to the FSM, the driverside coils and injectors are on one 15A fuse while the passside coils and injectors are on another 15A. In my case, I have the circuits exactly the same except with a 20A fuse each.

According to the FSM, each bank of o2s are on a 20A fuse. In my case, since I am only running the front o2s, I have both tied into a single 20A fuse.
 
gmcxt said:
45 degrees of timing looks like a lot.
bank 1 looks lean
bank 2 looks like a dead O2 sensor stuck a low voltage.
Make sure your upsteam O2s are plugged into the the upstream connectors not switched with the down streams.

I would let it run at idle till it warms up into closed loop and have these graphed O2, MAF, RPM, B1S1, B2S1, STFT1 STFT2 LTFT1 LTFT2. make a big vacuum leak watch O2s go lean (down) watch STFT1+2 go up (positive). then start spraying carb cleaner into that vacuum leak and watch O2s go rich (up) STFT1+2 go down (negative).
all I got for know without throwin guesses at yya
Click to expand...

Sounds like you have lost your direction on this. Differential diagnostics is the fastest way to the one answer (if you have only one issue). Did you do whats in yellow? An a/f sensor or standard heated O2 will usually fail biased/stuck low voltage, high voltage, or right in the middle. If you force it lean and rich it will should shift high and low.

ohms law dictates wattage. your resistance is known, your voltage is known. Wattage is irrelevant your 8.1 injector should pull about 1 amp. A 6.0L injector will pull about one amp. If you have one that bench test wrong it is bad.
W=IxV
watts is amperage multiplied by voltage.
 
I missed some notifications for this thread.
gmcxt You are correct that I have lost a bit of direction and focus on this. Lack of anything positive causes a high dose of fug-it-all.
My brain farted over amps of injectors😐

I drop kicked the 8.1L injectors and bought a set of 6.0L injectors. I went back to the previous tune that is supposed to be for the 6.0L injectors(confirmed injector information) There was zero change in driveability issues.

I reached out to AEM on how to confirm my wideband gauge/sensor is working correctly. I did the gas wet rag test and it confirmed they were functioning as expected. So I'm back to the engine running so lean it should be blowing up.

Now I'm back to a somewhat step zero question: Do I need to do anything for the stock EFI grounds? I did not sand the hell out of the block for the EFI grounds. I used the stock bolt and harness lugs. Do I need to tap the holes to clean them out? Do I need to sand the block where the harness lugs touch? I have confirmed the continuity of the grounds in the harness(at pin out) to the battery.
 
SLOWPOKE693 said:
Have you checked the cam yet? :rolleyes:
Click to expand...
As noted when I replied to your post originally on this, it sounds like the process involves taking the engine down to a short block because of the hydraulic lifters.

I also don't have the equipment to accurately measure the cam from the two videos I caught.

If it gets that far, the project is going to get pushed to the back 40, down a hill into a creek, and set on fire.😲
 
Per your first post.... You changed the cam and it started running like shit. You have tried a ton of non cam related checks and repairs and it still runs the same. :rolleyes:

If you don't want to check it, put the stock cam back in. If it runs ok after that you will have your answer.
 
Other things to check that come to mind.....


Did you put new lifters in when you changed the cam? Maybe one or more isn't getting pumped up. Also, are your rockers adjustable or just bolt down and go? Is it possible the valves are hanging slightly open due to them being to tight?
 
SLOWPOKE693 said:
<snip>If you don't want to check it, put the stock cam back in. If it runs ok after that you will have your answer.
Click to expand...
Unfortunately, the stock cam is very long gone.

If you have a good video to recommend showing how to verify the cam vs spec sheet, I would appreciate it. My youtube search foo is crap. Or how to verify the mark is in the correct spot. I think I've mentioned that I've already ripped the front of the engine apart to verify that the crank and cam dots lined up.

SLOWPOKE693 said:
<snip>Did you put new lifters in when you changed the cam? Maybe one or more isn't getting pumped up. Also, are your rockers adjustable or just bolt down and go? Is it possible the valves are hanging slightly open due to them being to tight?
Click to expand...
Thank you for another item to look into.

The lifters are the stock ones with ~60k miles on them now. When I installed the cam and new hardened push rods(7.4") along with new valve springs(Brian Tooley for stock rockers)

The rockers are stock LQ4 non-adjustable style.

I have watched the rockers move while cranking the engine and the valve appear to fully close. At least I didn't see any valves not moving.
 
Bringing this back up from the grave... unfortunately:rolleyes:

To recap issue: cam swapped 6.0L LQ4 is severely under powered and running extremely lean.

Latest diagnosis attempt: I have verified that the cam appears to be correct. Sadly, the cam company has refused to send me a cam card so I checked against another cam. I found TDC and then used a dial indicator to check cam degrees. My half ass attempt came up with 106 degrees which is less than my other cam of 111 degrees. Given my attempt, I'm reasonably comfortable that the cam isn't completely screwed up.

Summary of results from previous work:
  • Injectors are brand new(under 2 months old.
  • Wiring harness is bone stock with minimal rework done to it - grounds are stock in stock location. Power wires are fused per stock configuration. Checked continuity and resistance of all injector wires.
  • Spark plugs are "new" with under 1k miles on them.
  • Spark plug wires are "newish" with maybe 5k miles on them. Stock shielded type.
  • Most sensors are new.
  • PCM has been tuned for new cam. Quick scan using HP tuner shows the tune to look reasonable. I've also tried two other PCMs with same tune.
  • Wideband o2 was tried in driver and passenger side bungs... reads lean in both cases.
  • Tried running in speed density mode(unplug MAF and o2s) - no change in bad running
Any thoughts or ideas on where to continue looking?
 
Lil'John said:
Good question. I don't think that the 2004 LQ4 has an egr valve. It did have a gas vapor valve on the front of the intake. That was pulled and plugged with one of the common aftermarket plugs.
Click to expand...

Well I didn't know these engines didn't have egr valves thanks.
the reason I was asking is I have a older truck that the egr would open as soon as I pushed the gas pedal and it would pop, run lean and not have any power.
 
Buy a stock cam and put it back in. You have been chasing this issue for a while and it didn't appear until you did a cam swap. Common sense says its the cam. You can change and check everything you want, but i feel that a cam swap is the only thing that's going to fix it. Unless you pulled the engine apart and degreed the cam to check for TDC the other number you came up with is just lobe separation. How will that tell you if the dowel pin on the cam is in the correct place?

:homer:
 
SLOWPOKE693 said:
Buy a stock cam and put it back in. You have been chasing this issue for a while and it didn't appear until you did a cam swap. Common sense says its the cam. You can change and check everything you want, but i feel that a cam swap is the only thing that's going to fix it. Unless you pulled the engine apart and degreed the cam to check for TDC the other number you came up with is just lobe separation. How will that tell you if the dowel pin on the cam is in the correct place?

:homer:
Click to expand...

I actually did check for TDC and the 106 is based upon TDC. I followed this video:
https://www.youtube.com/watch?v=Y5DSviX9Tiw
Short for tdc:
  • Use a piston stop tool and remove exhaust rocker.
  • Turn engine to find stop one direction
  • Turn engine to find stop other direction
  • Split difference for real TDC
Short for lop top:
  • Turn engine over until pushrod starts going up
  • Set dial indicator on rocker at pushrod then note dial value and degree
  • Continue turning engine until pushrod starts downward travel and dial value is same as above. Note degree.
  • Split difference in degrees for intake lob event
  • Check against cam card
I don't have the cam card for this cam but as noted, I checked against a slightly more aggressive cam and my number was reasonable.

As for "how this tells me if the dowel pin on the cam is correct", the number is against TDC and thus tells me it is correct against the cam card. Since I don't have the cam card for this cam, it doesn't 100% tell me the pin is correct. But it does confirm that the pin isn't 10s of degrees off.

If I remotely thought that going to the stock cam would magically fix my issue, I'd consider spending money on one. But given that the cam I have is VERY mild, it isn't like I am fighting a loppy cam.
 
Lil'John said:
If I remotely thought that going to the stock cam would magically fix my issue, I'd consider spending money on one. But given that the cam I have is VERY mild, it isn't like I am fighting a loppy cam.
Click to expand...

You changed the cam on a good running engine and it has not ran right since....... :homer:

Seems to me you have tried EVERYTHING but the cam.
 
SLOWPOKE693 said:
You changed the cam on a good running engine and it has not ran right since....... :homer:

Seems to me you have tried EVERYTHING but the cam.
Click to expand...

As noted, the new cam does not appear to be wrong(ie mis-pinned) I have visibly watched the rockers moving. I have double checked that the new push rods are the same length as stock. I have not physically checked firing order while hand cranking. But I would think that a cam so fawked up as to be that badly timed would be backfiring during normal running.

If you have a stock low mileage cam you want to ship, I'll give it a try. If not, yanking the cam doesn't provide a reasonable chance at solving my issue. If your only answer is going to be "swap to stock cam", your opinion has been noted.

I'm not convinced that I have tried everything thus I'm asking for other ideas.
 
You changed the cam on a good running engine and it has not ran right since...... Something YOU did or PUT IN the engine during the cam swap is the fucking cause of your problem. Why are you not understanding this??? It ran FINE before.....

Im not sending you shit, I didn't fuck it up. But if I were you and I actually wanted to drive this thing instead of bitch about it on the internet over and over again, I would have already located a stock cam and had it swapped in. I'd try Ebay or an LS forum if I were in need of a stock cam. But hey, thats just me.

So what haven't you tried yet that you think is going to be the next miracle fix? Replace the entire engine but keep that same cam in the new one? :lmao:
 
...Worst that happens is you verify the cam is the issue. Then put it back in and pay for some dyno time.
 
Summary: Slowpoke has no confidence in his great almighty solution. It has already been brought up that more than 'just the cam' were swapped. Stiffer valve springs(BTR #SK001S), injectors, and tune. Engine had also been sitting for well over 2 years. I'm not an engine expert but obviously sitting for 2+ years caused the original injectors to stick... what else is stuck? Did the lifters turn to crap?

I've mentioned that my noid light test was not conclusive: it is almost not bright enough to see. I've asked if the noid light should be easily visible or not. So I'll ask again, should I be able to see the noid light without it being midnight?

If the cam is bad and not something related to the injectors/tune, where is a shit load of gas going? The wide band o2 is unregisterablely lean. It isn't going into the oil pan.

I have verified that ALL the rockers are operating when cranking the engine. Is it possible for the lifters to just collapse when running?
 
Lil'John said:
Summary: Slowpoke has no confidence in his great almighty solution. It has already been brought up that more than 'just the cam' were swapped. Stiffer valve springs(BTR #SK001S), injectors, and tune. Engine had also been sitting for well over 2 years. I'm not an engine expert but obviously sitting for 2+ years caused the original injectors to stick... what else is stuck? Did the lifters turn to crap?

I've mentioned that my noid light test was not conclusive: it is almost not bright enough to see. I've asked if the noid light should be easily visible or not. So I'll ask again, should I be able to see the noid light without it being midnight?

If the cam is bad and not something related to the injectors/tune, where is a shit load of gas going? The wide band o2 is unregisterablely lean. It isn't going into the oil pan.

I have verified that ALL the rockers are operating when cranking the engine. Is it possible for the lifters to just collapse when running?
Click to expand...

[video]https://linksharing.samsungcloud.com/owYGkeGcrA14[/video]
I don't know if the link works but this is a stock '02 5.3 at 3:35 pm today using only the shade of the hood.
 
Lil'John said:
I have verified that ALL the rockers are operating when cranking the engine. Is it possible for the lifters to just collapse when running?
Click to expand...

If the lifters were collapsing I would think the valvetrain would be super noisy and you would probably have low(ish) oil pressure due to them bypassing oil.

Valve springs are not the problem unless they are broken or the incorrect height for your application.

That only leaves the cam or tune as being the culprit. Try a different tune or replace the cam. Your choice

I've seen many EFI engines sit for years and fire right up. Why would yours be any different? I can see the injectors getting gummed up and stuck from the shit gas we have, but what else can really happen? Didn't you say AFTER the cam swap and horrible running condition you parked it for 2 years?
 
M92PV4U said:
[video]https://linksharing.samsungcloud.com/owYGkeGcrA14[/video]
I don't know if the link works but this is a stock '02 5.3 at 3:35 pm today using only the shade of the hood.
Click to expand...

Thank you VERY much for taking the time to take that video. My noid light is 100x dimmer than that.

What brand/model of noid light are you using? I'd like to use that as a double check to my "cheap" version.

If my noid light is correct, that tells me that something is beyond fawked up in my injector circuit.:homer:
 
Lil'John said:
Thank you VERY much for taking the time to take that video. My noid light is 100x dimmer than that.

What brand/model of noid light are you using? I'd like to use that as a double check to my "cheap" version.

If my noid light is correct, that tells me that something is beyond fawked up in my injector circuit.:homer:
Click to expand...

Proformance tools
 
OTC makes good noid lights if you can find some local. If not, put yours on a good running engine and see if it gets brighter or stays the same dimness. Could just be the brand of bulb in the noid light that is dim.

Did you swap or modify the harness in between having a good running engine and it running bad?

Signs of mice in the vehicle chewing wires?

Was the tune installed onto the same computer you were originally running with the stock engine?
 
M92PV4U said:
Proformance tools
Click to expand...
I have the following(Performance Tool W89501):
https://www.amazon.com/gp/product/B000YF6TN8?tag=91812054244-20

SLOWPOKE693 said:
OTC makes good noid lights if you can find some local. If not, put yours on a good running engine and see if it gets brighter or stays the same dimness. Could just be the brand of bulb in the noid light that is dim.

Did you swap or modify the harness in between having a good running engine and it running bad?

Signs of mice in the vehicle chewing wires?

Was the tune installed onto the same computer you were originally running with the stock engine?
Click to expand...
I'll see if I can get the noid on either the 00 S10 or 02 Tacoma to check if mine is junk or not. From what I recall, the S10 stuff was all buried under/in the intake.

The original harness that was on the engine was hacked up pretty well before I downed the rig for the cam swap. The horrible running issue "forced" me to buy another stock unmodified harness from another 2004 LQ4. I checked continuity and resistance of the injector circuits on both harnesses and found them to be exactly the same.

I haven't seen signs of mice but I will double check shortly.

I checked the battery and it showed 12.31v. I checked power to an injector and it showed 12.26v with just the key in hot.
 
Lil'John said:
I have the following(Performance Tool W89501):
https://www.amazon.com/gp/product/B000YF6TN8?tag=91812054244-20


I'll see if I can get the noid on either the 00 S10 or 02 Tacoma to check if mine is junk or not. From what I recall, the S10 stuff was all buried under/in the intake.

The original harness that was on the engine was hacked up pretty well before I downed the rig for the cam swap. The horrible running issue "forced" me to buy another stock unmodified harness from another 2004 LQ4. I checked continuity and resistance of the injector circuits on both harnesses and found them to be exactly the same.

I haven't seen signs of mice but I will double check shortly.

I checked the battery and it showed 12.31v. I checked power to an injector and it showed 12.26v with just the key in hot.
Click to expand...

That looks like the kit I have. Well my dad (where I work) has:grinpimp:
 
Do you have a scanner that reads injector milivolts? With the scanner hooked up and the engine running back probe each injector and see if the voltages from scanner and volt meter match? Might be able to unplug one at a time and go directly to the pins but having one injector down may have other affects so id try the backprobe deal.
 
I just checked exact noid light on the 02 tacoma. Still much dimmer than the video but much brighter than the LQ4.

I forgot to address the PCM. I have used the new tune on the original PCM that came with the engine. I have also used two other PCMs with the exact service number as mine. I've got a fourth hanging around that I could try tuning.
 
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