240EFI throttle problems

[lyttlea]

Hi, hope someone can help.

I have been working on the challenger 2000 for a while finally have her starting up but only enough power to get her to edge forward in the water.
Full advance of the throttle only revs the engine a little. I have adjusted the throttle cable at the throttle leaver but this makes no difference apart from the leaver only travels half the distance and gets stuck. Thinking it's the stop screws of the throttle cam setup, any ideas?

The second thing is that it's really smokey any pointers for that would help too.

Thanks.

 

[philipmurphey]

Can you go full throttle by pulling cable on engine or moving arm on engine?

 

[Dr Honda]

Is the throttle actually opening at the engine?

 

[lyttlea]

No, nothing. Push the arm as far as it goes and it just starts to rev. Any ideas where to start?

 

[lyttlea]

Hi Tony,

Only just starts to rev when I push the throttle arm with the cable disconnected too?

Thanks

Alan

 

[Dr Honda]

Hi Tony,

Only just starts to rev when I push the throttle arm with the cable disconnected too?

Thanks

Alan

I don't care about it revving... I'm asking if it's physically opening. Stick your head in the engine compartment, and have someone push the throttle lever, and watch the linkage at the engine.

 

[lyttlea]

Sorry that's what I meant all the linkage is moving.

 

[lyttlea]

Here it is. https://youtu.be/OzpRzOI2o9Q

 

[lyttlea]

And this https://youtu.be/oYQot_7wCS4

 

[Dr Honda]

I'd have to go look at mine... but I don't think the actual throttle is moving too much. If you look at the cam with the arm, that has the roller following it... that roller is the actual throttle. The rest is the links for the timing. Anyway... push on that roller and see how much more it can move.

 

[Dr Honda]

Yep... just looked over the book... and it's not moving all the way. And as you can see by the shape of the cam... it moves more toward the end.

1) The roller should be touching the cam at idle. With it up... it doesn't even start to move the actual throttle until your lever has moved half way.

2) The cable should be on a point at the throttle handle (up at the helm) so the long bellcrank should touch that lower stop screw. (it's not in the vid)


So... couple #1 and #2... and you are only moving the actual throttle a small amount.

 

[lyttlea]

Great this is starting to make sense. I took the VST of and found that the spring loaded pivot at the top of the plastic link arm was rock solid! (The one at the top of the picture) this is stoping the cam from springing back and stopping the oil pump link rod. I can't seem to get it off or losen it up. Does it even come off?

Thanks

Alan

 

[lyttlea]

They are both actually stuck tight. The roller isn't moving with that cam. It's just stuck in the same position! Ever fixed this before?

Thanks

Alan

 

[lyttlea]

To get round the problem I have done away with the plastic link rod that attaches the steering power to the idle speed adjustment screw. Is this going to cause a problem?

 

[Dr Honda]

Can't say I've had to fight a stuck throttle... but I took the extra cable off along time ago. (The one that adds power when you turn) I personally hate "Automatic" things. If I need power at full steering... I can add it with the throttle lever. SO... no... there's no issue with removing it. (the cable)


BUT... the actually plastic link is what opens the second set of butterflies. (as I recall) I'll have to check the parts diagram.

 

[lyttlea]

I have added a photo to illustrate my issues, The blue arrows show the points that are seized up, they barely move, it is stopping the full range of movement in the cam. The way I got around this (i couldn't get them moving after hours of trying) was to take the section circled in red off, the cam follow through adjuster. The rest of the attachment spun freely at the back of the thread allowing the roller to follow the cam. Then I took the plastic link rod off (green arrow).

I did this before I saw your post, I'm guessing the only way forward for me now is to get the black link rod back on and those points marked by the blue arrow moving? Do you know if i can get the spring off the top blue arrow, it looks like it doesnt come off?

The cam system is not stopping the full throttle movement now but when I started her up we were just stuck on 1000rpm despite moving the throttle arm back and forth. I guess that's because the second set of butterflies are not moving now. Looking back at the video I posted it did have a little movement before.

 

[Dr Honda]

If you take off the black plastic link... does both sets of butterflies move free?


With the part in red removed... the cam moves... but do the butterflies? (it holds the roller in place, and actuates the black link)

It's sounding to me, that the part in red is bent, and is simply hitting something.

 

[Dr Honda]

After thinking about it.....


I would probably take the top off the throttle body, to make sure something isn't stuck in there, holding the butterflies closed. If you haven't noticed... there isn't an air box on these engines, and it can suck things in.

 

[lyttlea]

Thanks Tony, I will see if i can get it off tonight and report back. This is hopefully the cause of my power issues but could it account for the smoke?

 

[lyttlea]

Hi Tony,

So I took the throttle body apart... took a lot longer than I thought, the butterflys were jammed shut... that was my problem. It took hours to free them but it sorted and I have full throttle now. I have attached a photo of what they looked like before!
The only thing now is a large amount of smoke.

I'm guessing the things to check next are the TPS and the portside temp sensor? I can't find how to test the TPS on the forum with only a voltmeter, is it possible?

Also, I haven't done a compression test yet which io guess could be a cause of the smoke but would that not cause it to smoke all the time and not just below 3000RPM?

Thanks

Alan

 

[Dr Honda]

Smoke is normal with these engines. But it should be minimal after you get it warmed up, and raise the throttle.

TPS: yes, you can check it with a regular meter. With it disconnected from the ECU... just put a meter on the center, and one of the edge wires. (put it in resistance mode) Then slowly open it. Just watch for a smooth change. If it jumps, or has a dead spot... it's bad. For the actual test, with voltage... you will have to dig into the manual. (I don't have mine in front of me at the moment. I Travel for work now)

Compression is always a good thing to know... but I'm not worried about it since it's starting well.

Port side temp sender is cheap, and you may just want to buy a new one. Even if it's OK, they have a semi-short life, and it's good to have one in the tool box.



Knowing that things were stuck... I would verify that the link from the throttle to the oil pump is set right. If it's not set right... you could have a lot of smoke. (Or run the engine lean on oil)

 

[lyttlea]

So I got home whipped it off and there is zero continuity between any of the wires. Took the conector out of the equation and still nothing. I take it this means it's dead?

 

[lyttlea]

And the engine has been running in safety mode and dumping in the oil?

 

[philipmurphey]

I think that you have to leave that on the engine to test it. Remove port side temp sensor and open throttle and watch for changes to be consistent.

 

[lyttlea]

I was definitely dead and as it cost $500 i thought i would at least open it up and take a look. see the photo attached.

The problem was that the conductor around the edge of the sensor on the inside had worn away. Its like tin foil, no wonder i see lots of posts about this sensor failing. I glued a new pice of tinfoil in place and think may have fixed it. Im going to glue it back together and test it tonight but hopefully i have saved myself a lot of cash!

Its a simple enough component inside. its a bit like the contact on the scalextric car that touches the silver tinfoil and it just spins around varying the resistance.