Check engine lite and valves

[RalphE]

Every 30,000 mi my check engine light comes on and the dealerships always tell me that it is the after oxygen sencer and that they don't have one and that it is ok to go ahead and drive it. First time I did this in Texas I bernt two valves. Second time I lost compression on two cylinders, had the valves adjusted and everything ran good till the next 30,000 mi and then same thing happened. any ideas? Oh it is a 1992 toy with a dalphin coach with a V-6 3 leder engin.

[bajadulce]

Are you throwing any codes with the diagnostic jumper test? Those are some serious effects and would think about taking a shotgun to that dealership next time.

The CEL trips at every 30,000 almost exactly? Does toyota have some trip switch associated with the odometer as other cars do?

I am very interested in your findings and hope you report back when this all gets figured out.

[RalphE]

Are you throwing any codes with the diagnostic jumper test? Those are some serious effects and would think about taking a shotgun to that dealership next time.

The CEL trips at every 30,000 almost exactly? Does toyota have some trip switch associated with the odometer as other cars do?

I am very interested in your findings and hope you report back when this all gets figured out.

Update: The codes that come up are always 25 and 26. I just talked with a master Machanic at our local Toyota shop and was told -- the 3 leter engine is the worst engine toyota made. Only one large exaust valve per cylinder. Has a problem in warping. 3.4 leter has two exaust valver and no problem. I ask to change engines, he said couldn't do as Transmition wouldn't bolt up, different motor mounts, wireing harness, exaust, computer. would be better and cheaper to buy different M/H. Any Suggestions? rtwimmer@centurytel.net

[WME]

25 and 26 are too rich and too lean. Something is way outa wack to get both codes at the same time. Sounds like you have a lemon and require a real good Toyota tech and not a certified parts changer.

Can you say Chevy Vortec V-6 4.3L. If you want to keep this Toy otherwise get it running and sell it for what you can.

[RalphE]

25 and 26 are too rich and too lean. Something is way outa wack to get both codes at the same time. Sounds like you have a lemon and require a real good Toyota tech and not a certified parts changer.

Can you say Chevy Vortec V-6 4.3L. If you want to keep this Toy otherwise get it running and sell it for what you can.

After having the valves adjusted this last time it is running great but only got 7k mi and light came on again. I reset it (still blinking 25and26) and came home. running perfict. I have had it into 7 different dealerships, always the same answer.

[Tundrawolf]

Sounds to me like you have more than two scorched valves. A need for constant valve adjustments is not a good sign. Your options, if what I think is right, is either to continue to adjust your valves every few thousand miles, keeping in mind you may try and start it and have low compression in more than one cylinder, or upgrade your engine/transmission. Is there another engine that will mate to your transmission?

[RalphE]

Sounds to me like you have more than two scorched valves. A need for constant valve adjustments is not a good sign. Your options, if what I think is right, is either to continue to adjust your valves every few thousand miles, keeping in mind you may try and start it and have low compression in more than one cylinder, or upgrade your engine/transmission. Is there another engine that will mate to your transmission?

All the mechanics I have talked to at the toyota dealerships say there is not any engine that will match up to our transmition. I would have to have a compleete retro fit. engine, trans, exaust, motor mounts, wireing harness, computer and the cost would be astronomical. and that could lead to countless other problems. a retro fit is never as good or dependable as a factory built.

[Maineah]

Adjusting the valves on a 3 liter engine is not exactly an easy job and adjusting bent valves will not cure them. Valves don't just bend some thing has to collide with them some thing sounds fishy. Just about any NAPA store should be able to provide you with an O2 sensor they carry Bosch sensors, good brand. About the only real issue with the 3 liter engine was head gaskets and Toyota fixed them for free. I had an 89 4X4 3 liter still running strong at 192K that had never been apart when the frame got to rusty to be road worthy.

[Tom W]

I agree with the fishy,adjusting the valves they are shims they might need to be checked and may a couple that need adj they shouldn't change much over time. The shims are pricey from Toyota and a tool is needed to do it, this eng isn't that bad its just that rumors get started, sometimes a bad repair then they all get blamed.

[RalphE]

I agree with the fishy,adjusting the valves they are shims they might need to be checked and may a couple that need adj they shouldn't change much over time. The shims are pricey from Toyota and a tool is needed to do it, this eng isn't that bad its just that rumors get started, sometimes a bad repair then they all get blamed.

OK guys--please go back to my original messages and read all responces. One other thing is that toyota told me that the 3 L engine with just one big exaust valve pulling that much wait is asking to much. This engine was designed to be used on a pickup not a M/H. When even the dealer tell me that the 3 L is the worst engine toyota ever built. Even the old 4 cylinder was better. This problem only seems to arrise after or about 30,000 mi and the check engine light comes on.

[Maineah]

OK guys--please go back to my original messages and read all responces. One other thing is that toyota told me that the 3 L engine with just one big exaust valve pulling that much wait is asking to much. This engine was designed to be used on a pickup not a M/H. When even the dealer tell me that the 3 L is the worst engine toyota ever built. Even the old 4 cylinder was better. This problem only seems to arrise after or about 30,000 mi and the check engine light comes on.

Well the 4 cylinder (and that was asking a whole lot of a pickup engine) only has one exhaust valve so does my tractor and lots of big trucks. Granted twin exhaust valves breath better (more power in a small box) but not a necessity. I kind of remember a emission related mileage reminder that cycled X number of miles but I think it was in an older design. Both the codes are O2 related codes the O2 sensor is not overly expensive I would try replacing it. Do you have the manual for the truck maybe that might give you some insight into the light issue.

[RalphE]

Well the 4 cylinder (and that was asking a whole lot of a pickup engine) only has one exhaust valve so does my tractor and lots of big trucks. Granted twin exhaust valves breath better (more power in a small box) but not a necessity. I kind of remember a emission related mileage reminder that cycled X number of miles but I think it was in an older design. Both the codes are O2 related codes the O2 sensor is not overly expensive I would try replacing it. Do you have the manual for the truck maybe that might give you some insight into the light issue.

I have replaced the 02 sensor twice, $100 and the Oxygen regulator (just before the intake maniforl and I think ontop of the air filter $600 once) I do not have a manual for the truck but in AZ the mechanic copyed two pages out of his book that tell me all the blinking light codes. He also supplyed me with a jumper wire and showed me where to plug it in.

[Maineah]

O2 sensors do go bad they are expendable but not every 30K. Unfortunately it's not new enough to be OBD2 and you are stuck guessing. When you have a code there is no real definitive answer with blinking lights. In other words if a mouse took up residence in your air filter it would throw an O2 code for a rich mix but it would not be the fault of the O2 sensor. Sounds like you really need to find some one that really understands how all that stuff works.

[RalphE]

O2 sensors do go bad they are expendable but not every 30K. Unfortunately it's not new enough to be OBD2 and you are stuck guessing. When you have a code there is no real definitive answer with blinking lights. In other words if a mouse took up residence in your air filter it would throw an O2 code for a rich mix but it would not be the fault of the O2 sensor. Sounds like you really need to find some one that really understands how all that stuff works.

Got any suggestions or recomendation? I always felt that a dealership would be my best bet. suposed to be trained on Toyotas, should know. Now they are telling me that all my parts are "after market product" (which means they don't have in their parts house.) Found out that they called NAPA and had the pts delivered and charged me double. needless to say I am not to happy.

[Tom W]

Oxygen regulator thats a new one to me learn something everyday, Not sure about your mechanic though. Sensors every 30,000 miles ??? not trying to start a flame ifs its that bad get rid of it.

[Tundrawolf]

How much are you willing to spend? If it was me I'd stop driving it, and rebuild the engine if you are unwilling to swap out the motor/trans. And by rebuild I mean sit down and make sure it's done right, with the latest valves, valveguides, valve seats, etc. Or pay someone to do it because ti sounds like a valve issue. You should probably be going on a Toyota forum, if it is a common problem then people may have hashed out the solution. It's not a Yugo, the motor isn't hopelessly unreliable, so you are going to have to dig in and repair it. In the end you'll have a reliable motor, and isn't that what you want? Or, you can go to a bone yard and chance it.

[Maineah]

One of the problems at the dealer is old technology a lot of the guys are young they may understand a 2003 but when your MH was made they were 10 years old! I would look for a good independent shop that would take the time to sort your problems out. A lot of people own Toyota's ask around and see if they can suggest some one.

[RalphE]

One of the problems at the dealer is old technology a lot of the guys are young they may understand a 2003 but when your MH was made they were 10 years old! I would look for a good independent shop that would take the time to sort your problems out. A lot of people own Toyota's ask around and see if they can suggest some one.

Every time I spot a toy M/H when we are out camping or in a parking lot I ask them, no one seems to have ever had the check engine light come on or had problems with burnt valves. Thanks to everyone for all the suggestions. I am supprised that no one has suggested it might be the computer. Something is shuting down the air supply and causing the valves to burn, is my guess. I used to be partners in a auto Machine shop in the early 60's. but I know nothing about all this pulution control equipment or computers. You don't go from running great to loosing compression on two cylinders over night. that sort of thing usualy takes time and is a gradual process. All I have to do is open the hood and see all the garbage in there and I ge scaired. I am 71 now and can't see myself taking on a job like that. Would spend the money but also want some one dependable.

[Maineah]

The ECU's take a lot of information into consideration in order to make the fuel mix correct and other then the O2 sensor they have a big effect on the running of the engine, if they are bad it runs bad. The O2 sensor reads what it is given and acts to correct the mix if you looked at a graph what you would see is rich/lean, rich/lean repeated and if you looked at this information over time it would average out to a respectable mix your engine is a pretty good engine is it one of the best maybe not but is it bad if it only lasts 200K? Frankly I think you have been a victim of lack of knowledge or effort to really try and find out where your problem lies. When I mentioned asking people about their experiences with repair shops I meant Toyota's in general they made millions of 3 liter 6 cylinders in trucks and pickups some one out there knows what makes them tick. You are right about the loss of compression I can't answer what happened there but I would have liked to have seen the valves.

[Tundrawolf]

Every time I spot a toy M/H when we are out camping or in a parking lot I ask them, no one seems to have ever had the check engine light come on or had problems with burnt valves. Thanks to everyone for all the suggestions. I am supprised that no one has suggested it might be the computer. Something is shuting down the air supply and causing the valves to burn, is my guess. I used to be partners in a auto Machine shop in the early 60's. but I know nothing about all this pulution control equipment or computers. You don't go from running great to loosing compression on two cylinders over night. that sort of thing usualy takes time and is a gradual process. All I have to do is open the hood and see all the garbage in there and I ge scaired. I am 71 now and can't see myself taking on a job like that. Would spend the money but also want some one dependable.

Ralph,

I respect you trying to figure out.

I am less than half your age, but I have been working on engines of all kinds for a while.

That jumble of vacuum lines, wires, sensors, and plastic crap is merely covering up what is beneath: A piston engine. It is not my intention to sound condescending. If you can get past the sensors, the vacuum garbage, and all that, you are just left with an ordinary gas engine, that you could fit a carburetor and points ignition to. With the exception of the points, this goes for every gasoline piston engine made currently, Bentley or Mazda.

All that O2 (Oxygen) sensor does, it determine the amount of oxygen in the exhaust stream. With this calculation, the computer tell the injectors to dump more, or less fuel into the engine.

Yes, you have an OBDI system, but that doesn't mean an OBDII system is easier: Actually, it's harder, because you have twice the sensors, and in many ways, it's just as dumb (Throwing a lean code in bank 2, erratic idle, misfire, when it's actually the fuel pump) as the OBDI.

If I was you I'd consult a forum that deals with the 3.0l Toyota 6, because I guarantee you, those people have hashed out a solution to the majority of the problems you are having. You might get the immediate answer to your problem there.

Try:

www.camryforums.com

www.toyotaownersclub.com

www.tundrasolutions.com

www.yotatech.com

www.toyotanation.com

[RalphE]

Ralph,

I respect you trying to figure out.

I am less than half your age, but I have been working on engines of all kinds for a while.

That jumble of vacuum lines, wires, sensors, and plastic crap is merely covering up what is beneath: A piston engine. It is not my intention to sound condescending. If you can get past the sensors, the vacuum garbage, and all that, you are just left with an ordinary gas engine, that you could fit a carburetor and points ignition to. With the exception of the points, this goes for every gasoline piston engine made currently, Bentley or Mazda.

All that O2 (Oxygen) sensor does, it determine the amount of oxygen in the exhaust stream. With this calculation, the computer tell the injectors to dump more, or less fuel into the engine.

Yes, you have an OBDI system, but that doesn't mean an OBDII system is easier: Actually, it's harder, because you have twice the sensors, and in many ways, it's just as dumb (Throwing a lean code in bank 2, erratic idle, misfire, when it's actually the fuel pump) as the OBDI.

If I was you I'd consult a forum that deals with the 3.0l Toyota 6, because I guarantee you, those people have hashed out a solution to the majority of the problems you are having. You might get the immediate answer to your problem there.

Try:

www.camryforums.com

www.toyotaownersclub.com

www.tundrasolutions.com

www.yotatech.com

www.toyotanation.com

Thanks for the suggestions. Have tried three of the sites and all three wanted me to give them my credit card number and pay for a answer. I am just a little learry of doing that, not for the cost but don't like to give my number out to just anyone. Also why pay for info that I already have. I guess I just have to make my mind up as to what I want to do. Love the M/H but don't like being stranded someplace for a week or two everytime I have trouble.

[Tundrawolf]

Thanks for the suggestions. Have tried three of the sites and all three wanted me to give them my credit card number and pay for a answer. I am just a little learry of doing that, not for the cost but don't like to give my number out to just anyone. Also why pay for info that I already have. I guess I just have to make my mind up as to what I want to do. Love the M/H but don't like being stranded someplace for a week or two everytime I have trouble.

You're welcome, Ralph. Are you sure that you didn't select the pay option? There's usually two options, the free option with limited storage (PM, etc), and then the paying member which give sou more perks-but all can post in the forums. I found those forums by typing "Toyota 3.0l v6 forum". The search engine hashes those terms together and gives you forums that include vehicles with that engine.

[Maineah]

Thanks for the suggestions. Have tried three of the sites and all three wanted me to give them my credit card number and pay for a answer. I am just a little learry of doing that, not for the cost but don't like to give my number out to just anyone. Also why pay for info that I already have. I guess I just have to make my mind up as to what I want to do. Love the M/H but don't like being stranded someplace for a week or two everytime I have trouble.

It's all most impossible to fix some thing that you are not standing in front of every thing is just a guess with out hands on. I taught for Bosch in the 80's and the first question was what's the fuel pressure? and I all ways got "I'll have to call you back" so it's a multifaceted interrelated system. I'm sorry you can't find some one that you can trust to help you out and it really does suck to brake down when all you want to do is have some fun. Have you checked the phone book to see if you could find an independent that specialized in Toyota's?

[RalphE]

It's all most impossible to fix some thing that you are not standing in front of every thing is just a guess with out hands on. I taught for Bosch in the 80's and the first question was what's the fuel pressure? and I all ways got "I'll have to call you back" so it's a multifaceted interrelated system. I'm sorry you can't find some one that you can trust to help you out and it really does suck to brake down when all you want to do is have some fun. Have you checked the phone book to see if you could find an independent that specialized in Toyota's?

We live in a town of 400 population. the nearest town of any size is The Dalles 45 mi. One toy dealership lots of independents non specializing in anything. Would have to go to Portland to find a independent. I do remember while they were adjusting the valves in Texas, they checked the fuel pressure. Three years ago I had to have the fuel pump replaced (inside the gas tank) The pick up filter on the pump was badly pluged. had the main fuel filter changed also.

[RalphE]

It's all most impossible to fix some thing that you are not standing in front of every thing is just a guess with out hands on. I taught for Bosch in the 80's and the first question was what's the fuel pressure? and I all ways got "I'll have to call you back" so it's a multifaceted interrelated system. I'm sorry you can't find some one that you can trust to help you out and it really does suck to brake down when all you want to do is have some fun. Have you checked the phone book to see if you could find an independent that specialized in Toyota's?

[RalphE]

Tundrawolf: You snowed me on the web sites, It takes me at least three try just to answer this one. When it comes to all this new tec stuff I'm lost. I could have punched the wrong butten.

[RalphE]

Tundrawolf: You snowed me on the web sites, It takes me at least three try just to answer this one. When it comes to all this new tec stuff I'm lost. I could have punched the wrong butten.

[Gulfstream Greg]

Every 30,000 mi my check engine light comes on and the dealerships always tell me that it is the after oxygen sencer and that they don't have one and that it is ok to go ahead and drive it. First time I did this in Texas I bernt two valves. Second time I lost compression on two cylinders, had the valves adjusted and everything ran good till the next 30,000 mi and then same thing happened. any ideas? Oh it is a 1992 toy with a dalphin coach with a V-6 3 leder engin.

Read my post!

http://toyotamotorhome.org/forums/index.php?showtopic=2784