Help diagnosing check engine light/ Limp mode

[kirk_tx]

I am starting a new thread since the other one started to get to far off from the original question.
Old thread:
http://www.epicmarine.com/forum4/index.php?topic=1527.0

Basically I have a check engine light on. 
The light was dim at first but, on all the time. After a minute or so of running, the light gets real bright and goes into limp mode.
(only getting throttle in the last few degrees of the throttle lever)

I have cleaned the intake and spark arrestor.  Cleaned the MAF sensor. Replaced the MAF sensor.
Still no results.

I went to autozone and special ordered a throttle position sensor.  Hope it works.

Strange thing is that it worked great for about a minute when I first got out there today and then it kicked the light.
The light is staying on now too.

I am hoping the TPS will fix it but I am not sure.  Are you guys aware of anything else that can cause limp mode?

[wakejunky]

why ask 4 help if your not going to listen to suggestions

[kirk_tx]

Whoa, where did that come from?

What do you mean?
I did run your test.  I watched the butterfly with the key on , while working the throttle.
But from what I understand this just means it is in limp mode not necessarily a bad TPS.
But per your suggestion, I bought a new one, as I mentioned above....
It won't be here till wednesday night.   

So I was trying , to brainstorm in the mean time and see what else could cause limp mode and the light.
If there is nothing else, then great, my new part should fix it.

[kirk_tx]

Guess I should mention that it failed that test.

The butterfly valve did not move in conjunction with the throttle.

[wakejunky]

You have a bad throttle lever sensor..........I recommended the throttle lever sensor. NOT the TPS. I change throttle lever sensors all the time. never have changed a TPS. They are not the same part. They oppose each other on the throttle body. Do a forum search of "throttle problem" there is alot of good info. You are not the first to have this issue and i guarantee it wont be the last. This might be something we need to put in the maintenace section. I highly doubt the aftermarket has the correct sensor available. just a hunch.

[kirk_tx]

Yeah I was saying the wrong thing.  I meant the throttle lever sensor.  But I was saying the TPS.
I did a search before and found some good information.

I also now realize that I ordered the wrong thing at autozone because of what I was saying.

Junky, do you know the lexus part number for the throttle LEVER sensor.  Or is their part number the same as the TMS one on this site?
2206050020

Would like to just go get one and bolt it on.   I hate ordering stuff and waiting.

[kirk_tx]

Per a previous suggestion of wake junky.  I went and tried to trake down one of these lever sensors.
Came up with this.
http://www.autozone.com/R,APP263276/vehicleId,2565701/initialAction,partProductDetail/store,1534/partType,00136/shopping/partProductDetail.htm

Looks like it might work.  Plus it is only 250 instead of 300-400 at the dealer.

The only wild card is that the lever on the side would have to be swapped out with the cable guide on the the tundra version.

I am going to experiment and will update you guys on wednesday when I get one.

[TXHNTR]

You may want to try a salvage yard, Im sure it would be way cheaper...

[kirk_tx]

Update: I got the part in from autozone today.
It is identical to the sensor on our boats. EXCEPT for the plate on the side that the throttle cable bolts to.
You can just take the Tundra one off and bolt the boat one on.  Simple and quick.  Just watch out for that spring.

However, I bolted it on, plug it in and NO change.  The boat starts but then almost immediately goes into limp mode.

One other clue that I just noticed, when it starts up, it revs up and down probably 6-7 times.  Then it settles out at about 1000 rpm and stays there.

any other ideas?

PS - I don't know If I would use one from a junk yard since the tundras have just as much of an issue with the throttle lever sensors going bad.  Look on the Toyota truck forums.

[Ktown]

Kirk,

When I bought my boat; it was actually in some sort of Limp mode.  I didn't know it, because the dealer and I had never been in an Epic before.  I didn't realize it until I was trying to figure-out why I didn't get the same RPM and speed as everyone else  on the forum.  I did not have the light and the only obvious indication was the low idle RPM and low high-end RPM.  After changing the prop, spark plugs, and adjusting the throttle I finally found the culprit.  It was a loose plug on the back left side of the engine (front right for your boat).  I think it was a connection to a throttle sensor or something similar, but it definitely went from limp to normal afterwards.  This is probably not your situation, but it would be worth checking all your electrical connections for a loose connection. 

Ktown

[kirk_tx]

I went over every connection that was visible today to see if I could see anything obvious like that.

Didn't see anything.  I even made sure they were all firmly together.

I think the diagnostic computer is my only choice.  Well that or scuttling the boat.

[slowyota]

Not sure if this helps or not, but I have a Tundra with the 4.7 (same engine I design I think) in it and it did the exact same thing when you pressed on the gas - there was nothing there. The truck would run and move, but it was super slow.
So after some internet searching found the problem to be the Throttle Position Lever, the throttle position sensor was fine. So I'd say start by replacing that part like was mentioned before and that should fix it. It did for my truck.

[kirk_tx]

Thats the part I just finished replacing above that did not fix it.

Just to be clear.....  I replaced the The Throttle Lever Sensor and not the Throttle Position sensor.

Now, with that said since it didn't fix it, could it actually be the Throttle Position Sensor?

[flyn2001]

why ask 4 help if your not going to listen to suggestions

Well, Kirk listened but it didn't fix the problem.  Guess he should have went w/ the TPS?

[Ktown]

Make sure you get a "cover letter" on that TPS...