240 EFI - Adjusting the famous TPS

[nenikol23]

I'm attempting to adjust my TPS. 2000 Challenger with the 240 EFI.
Reason for adjustment: Engine slowly bugs down from idle to about 1/3 throttle, feels like it's about to die then just surges. Once it's past 1/3 throttle it is fine and accelerates smooth.

TPS Adjustment: Following ALL the manual procedures, I am able to set it between 0.240-0.260 Volts. Tighten screws. While slowly moving the throttle, I see a smooth increase up until about 3/4 throttle where I hit 3.95V and then the voltage disappears.

Suggestions?

 

[Tim75]

I'm attempting to adjust my TPS. 2000 Challenger with the 240 EFI.
Reason for adjustment: Engine slowly bugs down from idle to about 1/3 throttle, feels like it's about to die then just surges. Once it's past 1/3 throttle it is fine and accelerates smooth.

TPS Adjustment: Following ALL the manual procedures, I am able to set it between 0.240-0.260 Volts. Tighten screws. While slowly moving the throttle, I see a smooth increase up until about 3/4 throttle where I hit 3.95V and then the voltage disappears.

Suggestions?

Your tps is dead.
There should be smooth transition from idle to wot.

 

[nenikol23]

Tim, I just put in the 3rd TPS in and this one acts the exact same way as the first two. If they were all dead as you suggest, what are the chances that all 3 act exactly the same. I am putting used TPS's but I still have a hard time believing that all fail the same way. I did have the first TPS when I had the boat fail, I was just unable to get it to adjust between .240-.260, voltage would be jumping erratically...

Here's the link to a video to show exactly what happens when I go from idle to almost wot.

When I got the boat initially, a know it all buddy played with every single adjustment lever (timing, idle stop, max throttle....) I feel like something is just not adjusted properly but then again, its just a speculation from my end.

**NOTE** The reason why I am trying to adjust the TPS is because I have the following symptoms: Engine starts up fine. Idles fine. the first 1/3 of the throttle lever the engine bugs down as if it's about to stall, I push the throttle to about 1/2 then it will take a few seconds until it finally "jerks" and RPM's suddenly pick up. The second half of the throttle travel works as it should, smooth acceleration. The issue seems to be more pronounced when engine is cold. When I use the boat for a little , stop and start again it seems to be less "jerky" but definitely still there and abnormal.

Any input is much appreciated.

 

[poppie]

Did you disconnect the black and tan leads from the port side head temperature sensor? This will affect the reading of the tps if it's still connected.

 

[nenikol23]

Did you disconnect the black and tan leads from the port side head temperature sensor? This will affect the reading of the tps if it's still connected.

Yes, I have them disconnected during the adjustment procedure.

 

[Tim75]

Yes, I have them disconnected during the adjustment procedure.

From your video, I can't tell what you are measuring: ohms or volts. I see "OL" and think you are measuring ohms. If you are checking ohms with tps wires disconnected, and your meter reads "OL", it means your tps has a bad spot on its "internal track" and should be considered dead. Sorry to tell you that.

From your comments, it sounds like you have a problem with the timing trigger base.
The engine runs on one system to about 2500 rpm, then changes electronically to another system at sbout 3500 rpm. Don't ask me- I don't understand it either. Trigger is easy to check. Been there-, bought that. Trigger is about $125 compared to $525 for a new tps.

 

[nenikol23]

Definitely measuring Volts on Blue and Tan TPS wires. Not sure what to tell you regarding the OL past 4volts...Following all instructions per manual.

Trigger assembly test just performed:
Brown/Yellow = 1244 Ohms (within spec 1100-1400 ohms)
White/Red = 1247 Ohms (within spec 1100-1400 ohms)
Purple/Blue = 1235 Ohms (within spec 1100-1400 ohms)

I've been dealing with this for so long that I could only wish a new TPS and/or new trigger assy. would fix it. I also wish there were boat mechanics in Hawaii that are willing/knowledgable to work on this boat and fix it for me...

Would a vacuum leak cause symptoms I have?

 

[nenikol23]

Today I put the boat in the water to look for leaks in the engine compartment as I've noticed water accumulation after a few hours.

Pleasant surprise, no bugging down like before. This is with a different TPS (used) and one that also did not show voltage past 3.98 volts. Boat ran absolutely great.

 

[Tim75]

Today I put the boat in the water to look for leaks in the engine compartment as I've noticed water accumulation after a few hours.

Pleasant surprise, no bugging down like before. This is with a different TPS (used) and one that also did not show voltage past 3.98 volts. Boat ran absolutely great.

Vacuum leaks cause a myriad of problems. Fluctuating idle speed, stumbling, lean at wot that can cause a piston meltdown. The old crusty black bleed hoses are known to crack and leak at each end. Rubber hose 21 years old. I use weed eater fuel hose from lawn equipment shop. AKA Tygon tubing.

My trigger checked OK, but still caused issues about 3000rpm.

Water leak-- Check the vacuum break in the syphon hose. Make sure the vent hole is clear or you can syphon water into the bilge.

Glad you are running good. What rpm are you getting at wot?

 

[nenikol23]

Vacuum leaks cause a myriad of problems. Fluctuating idle speed, stumbling, lean at wot that can cause a piston meltdown. The old crusty black bleed hoses are known to crack and leak at each end. Rubber hose 21 years old. I use weed eater fuel hose from lawn equipment shop. AKA Tygon tubing.

My trigger checked OK, but still caused issues about 3000rpm.

Water leak-- Check the vacuum break in the syphon hose. Make sure the vent hole is clear or you can syphon water into the bilge.

Glad you are running good. What rpm are you getting at wot?

Bleed hoses replaced last year with green Tygon tubing.

I didnt get a chance to go wot as I really just put it in the water for a few minutes to manly check for water leaks. Will report back once I get back on the water for the wot RPM.

Noticed fuel drips on the lower side of the vapor tank, never ends lol...

 

[Tim75]

Bleed hoses replaced last year with green Tygon tubing.

I didnt get a chance to go wot as I really just put it in the water for a few minutes to manly check for water leaks. Will report back once I get back on the water for the wot RPM.

Noticed fuel drips on the lower side of the vapor tank, never ends lol...

Gas in the bilge--- Never a good thing.

Since our "gas" has oil in it, if any goes overboard, you could face a $100,000 fine from the Coast Guard. They do not mess around with oil spills.

 

[Malkel123]

Hi...sorry for hijacking the treat...just a crazy stupid question...would this boats turn on without a TPS?


Thanks

 

[Malkel123]

I'm waiting on a new one.

 

[Hawk111]

I replaced my TPS sensor. Now at 3k RPM and above my boat won’t hit full acceleration because the engine is hopping and skipping. What’s wrong? 240 EFI also. Check my other thread out. I don’t know if this is really the problem. And sorry to hijack your thread

 

[Hawk111]

Hi...sorry for hijacking the treat...just a crazy stupid question...would this boats turn on without a TPS?


Thanks

Wouldn’t you think so, now I’m wondering.