Problems After Dealership Oil Change - Any Ideas?

[Picasso]

Originally Posted by cupidstoy

couple of things i didn't see mentioned.

did you check the motor mounts? a loose or cracked motor mount could be a possible source of vibration.

you said your exhaust still sounds louder. any chance the muffler shop ripped you off and put a used or bogus (or non at all) catalyst in your cat location on the side they replaced? that might cause the type of left/right bank imbalance that could introduce vibration and would also account for a different exhaust note and the CEL.

just some thoughts. sorry your having trouble.

cupidstoy

I've checked the motor mounts a couple of times over the past year. They are in good shape.

I purchased the cat myself and have removed it once to check the honeycomb elements. It's all there. I also peeked at the cat element through the y-pipe a few days ago while changing the graphite donut gasket where the y-pipe connects to the muffler.

Appreciate the help.


Paul

[cupidstoy]

hmmm.. ok, you said you changed your 02 sensors around and the cel didn't follow the change. that may point us to a problem in the wiring harness between the sensor and the ecu or the ecu itself? did you trace back the wires between the sensors and the ecu and look for any type of damage or pinching?

anybody know how to diagnose something like that? is the toyota ecu able to diagnose itself or do you have to find a different one to swap in temporarily to verify a problem like that?

just another idea ;-)

[Picasso]

Originally Posted by cupidstoy

hmmm.. ok, you said you changed your 02 sensors around and the cel didn't follow the change. that may point us to a problem in the wiring harness between the sensor and the ecu or the ecu itself? did you trace back the wires between the sensors and the ecu and look for any type of damage or pinching?

I don't think that I'm following your line of thought.

Ever since installing the S&S headers, I've had low catalyst efficiency codes a number of times. Once for bank 1, the rest for bank 2. With the exception of having the cat element on bank 2 fracture requiring its replacement, each low efficiency trouble code was corrected with either the install of new gaskets for the cat or welding shut a pinhole.

This most recent time, I didn't replace the gaskets. I only tightened down the flange bolts which may have been too late for the gaskets to effectively seal. They are the inexpensive paper ones that get hard after a short period of time.

So, I still think that there are other more likely possibilities for both the CEL and the problems with my engine than the wiring harness or the ECU. The ECU has been on my mind for a while though, I just hope it's not that.

I'll add one strange thing regarding the low cat efficiency CEL. When I replaced the 4th coil, the CEL went out immediately following two 26 mile trips that I made that day. It went back on the following day though. This makes me think that I have an injector or valve issue.

What am I missing?

Many thanks,


Paul

[cupidstoy]

my line of thought was that i, like you in your previous post, have a hard time believing a small, pin-hole or gasket leak would be enough to set off the cel. i also have a hard time believing that your are having so much trouble with your catalyst. they are usually fairly trouble free. so, i was just thinking that maybe it was all the moving around in that area that was jostling the wiring harness or something.

you may provide more evidence for that theory with your statement about the 4th coil install. here i'm assuming the fourth one was the one closest to the rear of the engine back near the area where the o2 sensor leads come up.

i really don't think a pin hole or exhaust donut leak would cause a vibration or 20% decrease in engine performance. especially when accelerating or driving at a steady speed when the exhaust system is pressurized. you aren't sucking any fresh air in to mess up your ratio readings, you are just losing a very small amount of spent exhaust to atmospheric before the tail pipe. i may be underestimating this effect, but i don't see how it could account for vibration or significant loss of power.

your theory about the the problem possibly being in the heads is a possiblity, but usually a valve problem wouldn't be intermittant, could possibly be caught by a compression check, and aren't very common on our engines. i think a very serious problem in this area would get noticeably worse (not better) fairly quickly and would not cause a low cat efficiency cel.

i realize you've thought about this and worked on it a great deal and it's probably pretty frustrating. you've replaced or moved almost every other part. i think it may be time to start looking at the harness and wires. at least go over them really closely with a visual inspection and look for anything unusual/pinched/worn etc.

probably someone else on the board with more experience than me can chime in at this point now that you've provided new info???

cupidstoy

ps: just as an afterthought, have you looked really closely for a vacuum leak somewhere on the bank in question? i don't know if our engines have egr valves, but they can sometimes be a source of difficulty as can the brake vacuum booster or clogged pcv valve, but i think they through a cel code. just thinking out loud here.

[Picasso]

Originally Posted by cupidstoy

my line of thought was that i, like you in your previous post, have a hard time believing a small, pin-hole or gasket leak would be enough to set off the cel. i also have a hard time believing that your are having so much trouble with your catalyst. they are usually fairly trouble free. so, i was just thinking that maybe it was all the moving around in that area that was jostling the wiring harness or something.

These S&S cats have been far less robust than the stock ones were. Others with the S&S headers have also reported low cat efficiency trouble codes. I still don't know why one of my S&S cats fractured.

Originally Posted by cupidstoy

you may provide more evidence for that theory with your statement about the 4th coil install. here i'm assuming the fourth one was the one closest to the rear of the engine back near the area where the o2 sensor leads come up.

I replaced the coil for cylinder no. 8 first, and then went down the firing order 8-4-3-6-5-7-2-1. The 4th coil was at cylinder no. 6.

Originally Posted by cupidstoy

i really don't think a pin hole or exhaust donut leak would cause a vibration or 20% decrease in engine performance. especially when accelerating or driving at a steady speed when the exhaust system is pressurized. you aren't sucking any fresh air in to mess up your ratio readings, you are just losing a very small amount of spent exhaust to atmospheric before the tail pipe. i may be underestimating this effect, but i don't see how it could account for vibration or significant loss of power.

I don't think the cat CEL and my engine performance problem are related to each other in terms of cause and effect. I do think that they are both the effect of the same cause however.

Originally Posted by cupidstoy

your theory about the the problem possibly being in the heads is a possiblity, but usually a valve problem wouldn't be intermittant, could possibly be caught by a compression check, and aren't very common on our engines. i think a very serious problem in this area would get noticeably worse (not better) fairly quickly and would not cause a low cat efficiency cel.

Completely agree.

Originally Posted by cupidstoy

i realize you've thought about this and worked on it a great deal and it's probably pretty frustrating. you've replaced or moved almost every other part. i think it may be time to start looking at the harness and wires. at least go over them really closely with a visual inspection and look for anything unusual/pinched/worn etc.

I've only recently considered that. I hope to do that this weekend.

Originally Posted by cupidstoy

ps: just as an afterthought, have you looked really closely for a vacuum leak somewhere on the bank in question? i don't know if our engines have egr valves, but they can sometimes be a source of difficulty as can the brake vacuum booster or clogged pcv valve, but i think they through a cel code. just thinking out loud here.

Aside from one cylinder seemingly off from the others, my engine feels very much like there is a vacuum leak somewhere. I would really like to check the Evap VSV that is attached to the manifold, but I'm not entirely sure how.

I'm going to do a few more tests with my vacuum gauge beyond hooking it up directly to intake manifold. I haven't tested any of the lines on the driver's side of the engine yet.

One last observation. Ever since replacing the graphite donut gasket at the y-pipe to muffler joint a few days ago, my truck has consistently had a slight problem starting. It feels like the engine is a little flooded. Not much, just a little. It has previously started with more of a bang. Not sure what this indicates.

What I think (hope) is going on is that I have one bad fuel injector on bank 2 that is pumping in to much fuel. The ECU adjusts the mixture of all 4 injectors by reducing their duration at each pulse. This results in 3 cylinders running very lean and 1 running rich. In my mind, this explains the one odd sounding cylinder, the rough performance, and the continuing low cat efficiency CEL.

When I swap the injectors between each bank this weekend, hopefully the trouble code will follow the injectors. If not, I'm going to have to hit the Prozac.

I do appreciate the input. If you can think of anything else, let her rip. This has been a very good discussion.


Paul

[mustang67408]

What I think (hope) is going on is that I have one bad fuel injector on bank 2 that is pumping in to much fuel. The ECU adjusts the mixture of all 4 injectors by reducing their duration at each pulse. This results in 3 cylinders running very lean and 1 running rich. In my mind, this explains the one odd sounding cylinder, the rough performance, and the continuing low cat efficiency CEL.

I have seen this before and it's a B$T$H to diagnose.
I think your on the right track.
ARE S&S Headers LONG TUBE? Is the 02 located in the same spot as the factory spot, or does it isolate it to 1 tube in the approximate location?
I have not found a set of aftermarket cats that do not set codes. EVERYONE I know that went AFTERMARKET eventually went back to Factory ones.
You probably already answered this, but I dont remember, t-belt ok?
Brake booster vac leak?
If the EVAP VSV WAS BAD, it should theoretically set a code.
Here is a few pdfs to check it, I hope they help.
I wish I was closer to look at this thru the toyota scan tool.
Back to the drawing board.................

[cupidstoy]

glad to see you chiming in, mustang!

picasso, with the 'stangs help, you are well on your way to solving this.

i didn't know that it was a common problem with the s s cats. sounds like the 02 sensors ARE very sensitive to both location and cat design.

i like your theory about one injector over producing. moving them around to the other side should definitely identify the problem. a dump of excess fuel into the cat would also explain the fracture (extreme high temp)

i'll ad that an easy, old school way to locate a vacuum leak to the outside air (ie, not in between components) is to spray a mist of water from a mister bottle around where you think the leak might be. if you hear a change in the engine rpm or pitch, you have a possible leak location. the engine shouldn't be drawing outside air from anyplace but the air filter box.

sounds like you have a busy weekend ahead!

keep us posted....

[Picasso]

Originally Posted by mustang67408

I have seen this before and it's a B$T$H to diagnose.
I think your on the right track.
ARE S&S Headers LONG TUBE? Is the 02 located in the same spot as the factory spot, or does it isolate it to 1 tube in the approximate location?

The sensor is located at the end of the headers close to the cat. Here's a picture of the sensor on my truck that I took after the install. It's from the front looking to the rear.

Originally Posted by mustang67408

You probably already answered this, but I dont remember, t-belt ok?

The timing belt has not been replaced yet, but my engine problems started almost 2 years and 20K miles ago.

Originally Posted by mustang67408

Brake booster vac leak?

Haven't tested this yet. Wouldn't there be some brake performance problems associated with that?

Originally Posted by mustang67408

I wish I was closer to look at this thru the toyota scan tool.

I have seriously considered driving to Vegas with my truck so that you could take a look at it.

By the way, I purchased a PC based scan tool from Auterra a few months ago in hopes that it would help point to the cause of my engine problems. I initially looked closely at the trim figures for the O2 sensors but didn't see anything unusual. I'm not sure what the short and long term trim figures are supposed to look like but each sensor value was close to its counterpart on the other bank.

Something that did surprise me was the timing advance figures. According to the scan tool, the engine's timing is almost constantly advanced at around 25 degrees ± 5 degrees while driving at a constant speed. I can't find anything that tells me if this is normal.

I can record live engine data while driving and play it back later. I can then take a screen shot of either the numerical data or a graph of the data. Now that all of my coils have been replaced, I plan to take a few more data runs. Which parameters would you recommend that I record?

Cupidstoy,
I'll do the waterspray test to see if my engine reacts to it.

Many thanks,


Paul

[mustang67408]

Originally Posted by Picasso

The sensor is located at the end of the headers close to the cat. Here's a picture of the sensor on my truck that I took after the install. It's from the front looking to the rear. The old 22r's had issues with long tubes and 02 sensor location, just a thought, but if it started 2 years ago, thats probably not it.

The timing belt has not been replaced yet, but my engine problems started almost 2 years and 20K miles ago. Just curious, might not be a bad idea to check. 25 DEG timing at idle is a bit much, its usually 15 or so. But if it was off it should set a CAM position sensor code too.

Haven't tested this yet. Wouldn't there be some brake performance problems associated with that? NOT ALWAYS, I have seen brakes perform flawlessly with a bad booster, but it usually whistles while stepping on the brakes gently.

I have seriously considered driving to Vegas with my truck so that you could take a look at it. I cant promise anything, but I will use my fine tooth comb.

By the way, I purchased a PC based scan tool from Auterra a few months ago in hopes that it would help point to the cause of my engine problems. I initially looked closely at the trim figures for the O2 sensors but didn't see anything unusual. I'm not sure what the short and long term trim figures are supposed to look like but each sensor value was close to its counterpart on the other bank. LONG TERM SHOULD BE NO MORE THAN 10% positive to negative 10%. It should stay in that range.
Short term should be in approximately the same ranges.
The combined LT/ST Fuel Trim should add up to no more than 25% and no less than -25%, over 25% in either direction wll cause a fault code.

Something that did surprise me was the timing advance figures. According to the scan tool, the engine's timing is almost constantly advanced at around 25 degrees ± 5 degrees while driving at a constant speed. I can't find anything that tells me if this is normal.

I can record live engine data while driving and play it back later. I can then take a screen shot of either the numerical data or a graph of the data. Now that all of my coils have been replaced, I plan to take a few more data runs. Which parameters would you recommend that I record? As many as you can and then send me the info to my e-mail. Do I need a special program to watch the recorded files?

Cupidstoy,
I'll do the waterspray test to see if my engine reacts to it.

Many thanks,


Paul

We fixed a 07 Tacoma today with a P0451 (Vapor pressure sensor fault).

The customer had installed a NEON license plate frame and had it wired into the trailer wiring. The neon converter box was BACKFEEDING Thru the tailight ground circuit to the ECU and causing ELECTRICAL FEEDBACK NOISE on the Vapor pressure sensor Feed wire.

Have any aftermarket parts installed??????
I know thats probably not your issue, but it can happen.
I'd like to see whatever info you can send, IF I AM ABLE TO VIEW IT.

[mustang67408]

Originally Posted by Picasso

The sensor is located at the end of the headers close to the cat. Here's a picture of the sensor on my truck that I took after the install. It's from the front looking to the rear. The old 22r's had issues with long tubes and 02 sensor location, just a thought, but if it started 2 years ago, thats probably not it.

The timing belt has not been replaced yet, but my engine problems started almost 2 years and 20K miles ago. Just curious, might not be a bad idea to check. 25 DEG timing at idle is a bit much, its usually 15 or so. But if it was off it should set a CAM position sensor code too.

Haven't tested this yet. Wouldn't there be some brake performance problems associated with that? NOT ALWAYS, I have seen brakes perform flawlessly with a bad booster, but it usually whistles while stepping on the brakes gently.

I have seriously considered driving to Vegas with my truck so that you could take a look at it. I cant promise anything, but I will use my fine tooth comb.

By the way, I purchased a PC based scan tool from Auterra a few months ago in hopes that it would help point to the cause of my engine problems. I initially looked closely at the trim figures for the O2 sensors but didn't see anything unusual. I'm not sure what the short and long term trim figures are supposed to look like but each sensor value was close to its counterpart on the other bank. LONG TERM SHOULD BE NO MORE THAN 10% positive to negative 10%. It should stay in that range.
Short term should be in approximately the same ranges.
The combined LT/ST Fuel Trim should add up to no more than 25% and no less than -25%, over 25% in either direction wll cause a fault code.

Something that did surprise me was the timing advance figures. According to the scan tool, the engine's timing is almost constantly advanced at around 25 degrees ± 5 degrees while driving at a constant speed. I can't find anything that tells me if this is normal.

I can record live engine data while driving and play it back later. I can then take a screen shot of either the numerical data or a graph of the data. Now that all of my coils have been replaced, I plan to take a few more data runs. Which parameters would you recommend that I record? As many as you can and then send me the info to my e-mail. Do I need a special program to watch the recorded files?

Cupidstoy,
I'll do the waterspray test to see if my engine reacts to it.

Many thanks,


Paul

We fixed a 07 Tacoma today with a P0451 (Vapor pressure sensor fault).

The customer had installed a NEON license plate frame and had it wired into the trailer wiring. The neon converter box was BACKFEEDING Thru the tailight ground circuit to the ECU and causing ELECTRICAL FEEDBACK NOISE on the Vapor pressure sensor Feed wire.

Have any aftermarket parts installed??????
I know thats probably not your issue, but it can happen.
I'd like to see whatever info you can send, IF I AM ABLE TO VIEW IT.

[Picasso]

Originally Posted by mustang67408

We fixed a 07 Tacoma today with a P0451 (Vapor pressure sensor fault).

The customer had installed a NEON license plate frame and had it wired into the trailer wiring. The neon converter box was BACKFEEDING Thru the tailight ground circuit to the ECU and causing ELECTRICAL FEEDBACK NOISE on the Vapor pressure sensor Feed wire.

Have any aftermarket parts installed??????
I know thats probably not your issue, but it can happen.
I'd like to see whatever info you can send, IF I AM ABLE TO VIEW IT.

The aftermarket stuff that I have includes:
- S&S headers
- Cap that's been on since day one
- USA Spec aux input adapter that's plugged into the back of the head unit
- XM satellite radio tuner that draws power from the head unit power leads

I think that you need the Auterra application to replay its data files but I'm not sure of that. At the very least I can take screen shots of the line graphs which would give you a pretty good idea of what's going on, especially if I zoomed in on any part of the graphs. The screen shots are saved as JPEG files that I can then send to you.


Paul

[mustang67408]

All your A/F stuff sounds very safe....
Send away mustang67408@cox.net