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mzito
08-04-2010, 12:10 AM
I have a 1995 Pro Star 190 with a 350 275HP EFI with a power slot tran. The last few times out I have noticed that RPM's jump to 970-1100 when I shift into neutral. The RPM's usually run around 650-690 in neutral. This problem is not consistent, it only happens sometimes. If I shut the engine off and restart sometimes it will bring the RPM's back down sometime it doesn't work. I am confused with this one. Any help is appreciated.
Thx
Matt

dgaugler
08-15-2010, 04:59 PM
I'm having a very similar problem on my '96 Maristar with the 285hp TBI engine. My started the season with a little bit of a rough idle but with RPMs at around 650-700. Now it is idling at 1100 RPMs most of the time and running really rich. I replaced the IAC ( Idle Air control) but it is still idlingat 1100 a running really rich and if you open the throttle to fast it bogs out. (might be because the plugs are fouled now.) Anyone have any ideas?

dgaugler
08-15-2010, 08:17 PM
I know most of you on here are against just buying and replacing parts until you fix the problem, but it worked for me today. Solved the running rich and high idle problem with just $75 worth of parts. I replaced the IAC (Idle Air Control) and the TPS (Throttle Position Sensor) and it's running like a charm. I think it was the TPS that was the main culprit but she's running smoother than ever now so I think the new IAC may have helped clean that up. If you have a TBI (Throttle Body Injection) engine that is running rough, running rich, or has a high idle I think I would just replace these two parts and see what happens.

mzito
08-15-2010, 09:46 PM
I know most of you on here are against just buying and replacing parts until you fix the problem, but it worked for me today. Solved the running rich and high idle problem with just $75 worth of parts. I replaced the IAC (Idle Air Control) and the TPS (Throttle Position Sensor) and it's running like a charm. I think it was the TPS that was the main culprit but she's running smoother than ever now so I think the new IAC may have helped clean that up. If you have a TBI (Throttle Body Injection) engine that is running rough, running rich, or has a high idle I think I would just replace these two parts and see what happens.
Thanks for the info I will look at replacing those two parts. Today my MC ran like a top, but yesterday the idle was high. I will try your suggestion and let ou know how it goes.

Thanks,
MZ

Tom Jones
08-15-2010, 09:58 PM
Where did you get the parts so cheap?

JimN
08-15-2010, 10:00 PM
I have a 1995 Pro Star 190 with a 350 275HP EFI with a power slot tran. The last few times out I have noticed that RPM's jump to 970-1100 when I shift into neutral. The RPM's usually run around 650-690 in neutral. This problem is not consistent, it only happens sometimes. If I shut the engine off and restart sometimes it will bring the RPM's back down sometime it doesn't work. I am confused with this one. Any help is appreciated.
Thx
Matt

Find out if the parts are actually bad before replacing them. The TPS can be checked with a multi-meter.

Remove the throttle cable from the throttle lever- if it stays at normal idle, it's definitely not the IAC and TPS. You need no tools to disconnect the throttle cable.

Tom Jones
08-15-2010, 10:04 PM
Hey Jim,
my boat is doing this very same thing. restarting usually corrects it.
i had written it off to a perfect pass issue.

JimN
08-15-2010, 10:06 PM
On a 15 year old boat, I would make sure the throttle cable isn't binding- they do that and it doesn't always take that long to begin. Disconnecting the cable just removes one more possible cause from the list. Sometimes, the cable just needs to be adjusted.

Tom Jones
08-15-2010, 10:15 PM
Actually my profile is not correct.
I now have a 2004 197 with TBI
I have adjusted the cable and it seems to move freely when the PP is disconnected.
With it connected I can feel the throttle stick just before neutral.
Do you think it is the PP cable that could be sticking? It is only a year old.

JimN
08-15-2010, 10:40 PM
Actually my profile is not correct.
I now have a 2004 197 with TBI
I have adjusted the cable and it seems to move freely when the PP is disconnected.
With it connected I can feel the throttle stick just before neutral.
Do you think it is the PP cable that could be sticking? It is only a year old.

At only a year old, it probably just needs adjustment.

dgaugler
08-16-2010, 12:39 AM
I got the parts at the local Oreilly's Auto parts store. Only trick was I came with the part numbers because the parts for a GM pickup for the same year tend to sometimes be different. I looked online and the parts were considerably more expensive.

You have to be careful about just testing your TPS, just becasue it's returning some voltage doesn't mean it's the right voltage. Mine was still working just reporting that the the throttle is further open than it actually was at an idle. I think mine was just inconsistent because at times it would have rough idle, then a fast idle sometimes 900 RPMs then 1100 RPMs.

rwassman
08-16-2010, 05:32 PM
I had (have) the exact same problem on my '96 Prostar with 350 TBI. I took out the IAC and cleaned it with ether (didn't have carb cleaner handy). There was just a little bit of carbon in the throttle body - a few flakes. Since then it's only happened once and I cleaned it about five weeks ago.

mzito
08-17-2010, 07:32 PM
Well, I just changed the TPS and all seems well. The RPMs are normal now when in idle. 75.00 part well worth it.
MZ

Tom Jones
08-17-2010, 10:48 PM
Question for JimN
How do you test the TPS with a multi-meter
What are the values?

JimN
08-17-2010, 11:00 PM
Question for JimN
How do you test the TPS with a multi-meter
What are the values?

It has a three wire harness with a blue, a black and a gray wire. The black is connected to ground, the gray has a 5VDC reference voltage and the blue is the return to the ECM and should have 2-4.5VDC, depending on throttle position.

A multi-meter will rarely show a glitchy TPS- the transients are too fast and occur over a really short time period, which a meter isn't made for. To really see a glitch from a TPS, a digital storage oscilloscope is needed.

JHogins
08-28-2010, 01:20 PM
I was having the same problem - idle would not come down below 1,100 rpm on my '94 Maristar 350 TBI. Cleaned the IAC valve but that didn't seem to help. Replaced the TPS and now we are back to a nice and smooth 650 rpms. The TPS cost ~$33 at O'reilys. Me Happy!
Thanks...
Jon

mcxfan
09-05-2010, 12:35 AM
Hey Guys, what are the steps to replace the TPS on an Mcx? I have an 06 X2 and I am having the same issue. Thx

JimN
09-05-2010, 01:19 AM
CHECK FOR CODES! The sensors cause codes to be stored in the ECM and that's how it's determined if you have a bad one. The IAC isn't a sensor but it could be sticking, which will cause the high idle. Make sure the TPS is actually bad before replacing it.

Engine Nut
09-05-2010, 10:14 AM
Your 06 model has electronic throttle control so there is no IAC valve. It does have a TPS but it is not the same as the TPS on a TBI injected engine or on a multi-port mechanical mono-valve. The signal that controls your engine speed comes from the PPS (pedal position sensor) also referred to as a throttle control potentiiometer. If the TPS or the PPS have a problem it will set a code and light the check engine indicator in the boat. If the TPS is bad you have to replace the whole mono-valve assembly. If the PPS is bad you have to replace the throttle/shift control assembly.

Hey Guys, what are the steps to replace the TPS on an Mcx? I have an 06 X2 and I am having the same issue. Thx

mcxfan
09-07-2010, 12:27 AM
I assume I will have to take it to the dealer to pull the codes. I was hoping this could be a DIY fix. Engine Nut, do you think this is the case???

brad
07-22-2011, 04:42 PM
Does anyone know the part # for throttle position sensor for a 04 prostar TT

TallSkinnyGuy
09-30-2014, 08:34 PM
Find out if the parts are actually bad before replacing them. The TPS can be checked with a multi-meter.

Remove the throttle cable from the throttle lever- if it stays at normal idle, it's definitely not the IAC and TPS. You need no tools to disconnect the throttle cable.

Resurrecting an old thread here because I have a 1997 PS 190 with the 350 TBI and my idle troubles have increased. I bought the boat a year ago and at that time it would only idle high after WOT (idle high = 1100 or so). It then started doing it after slalom speeds earlier this summer and now the idle stays high after every time I throttle up to any speed. I can bring the idle speed back down to normal (650 or so) by putting it in neutral and revving a bit, then bring back to neutral. It seems to work best when I briefly rev it in neutral reverse.

JimN says I can disconnect the throttle cable with no tools to see if that is causing the problem, but I can't figure out how to do that without screwing off a little bolt. Am I supposed to be able to just pop the throttle cable off somehow? I wanted to try this while it was idling high to see if it would settle down.

mikeg205
09-30-2014, 08:38 PM
Did you check your IAC?

TallSkinnyGuy
09-30-2014, 09:18 PM
I have done two things so far. I got some throttle body cleaner and cleaned around the butterfly flaps a bit (they were already pretty clean, but I tried it anyway just in case they were sticking). I also greased the throttle cable.

If I remember correctly, JimN suggested in this thread or another I've read on the subject that you should disconnect the throttle cable while it is idling high and see if it settles down after disconnecting. If it does then that means the problem is likely with the throttle cable. If it doesn't then move on and check the IAC and TPS. I'm trying to follow these steps but can't figure out how I'm supposed to disconnect the throttle cable with "no tools." I'm clearly not experienced with engines, but I am learning.

JimN
09-30-2014, 10:04 PM
Resurrecting an old thread here because I have a 1997 PS 190 with the 350 TBI and my idle troubles have increased. I bought the boat a year ago and at that time it would only idle high after WOT (idle high = 1100 or so). It then started doing it after slalom speeds earlier this summer and now the idle stays high after every time I throttle up to any speed. I can bring the idle speed back down to normal (650 or so) by putting it in neutral and revving a bit, then bring back to neutral. It seems to work best when I briefly rev it in neutral reverse.

JimN says I can disconnect the throttle cable with no tools to see if that is causing the problem, but I can't figure out how to do that without screwing off a little bolt. Am I supposed to be able to just pop the throttle cable off somehow? I wanted to try this while it was idling high to see if it would settle down.

At the throttle lever, there's a ball on a threaded stud. That ball fits into a socket on the end of the throttle cable. If you look at the end of the cable, you'll see a thin spring, which has the sleeve closer to the end. Grasp the sleeve and slide it toward the spring, then pull the end of the cable away from the ball. The cable should come off easily. If the cable has stretched or is binding, it can easily keep the throttle from closing.

DO NOT adjust the idle stop screw!

TallSkinnyGuy
10-01-2014, 04:22 PM
Here are some pics of the attachment. I assume what I am supposed to do is grab onto the brass "sleeve" (the "cable end retainer" according to the manual) and pull it back towards the jam nut. I don't see a thin spring. The only spring I see is the big orange one which looks like it is supposed to apply pressure to push the throttle lever up against the idle stop.

Anyway, the brass cable end retailer won't budge. Is it possible that it is stuck or am I trying to move the wrong part?

JimN
10-01-2014, 04:59 PM
Here are some pics of the attachment. I assume what I am supposed to do is grab onto the brass "sleeve" (the "cable end retainer" according to the manual) and pull it back towards the jam nut. I don't see a thin spring. The only spring I see is the big orange one which looks like it is supposed to apply pressure to push the throttle lever up against the idle stop.

Anyway, the brass cable end retailer won't budge. Is it possible that it is stuck or am I trying to move the wrong part?

Congrats- that's one of the cleanest engines I have seen, especially in a 17 year old boat.

The spring is inside of the sleeve- I don't have an engine in front of me, so I had forgotten that detail.

The sleeve that's almost to the end of the cable- slide that back, toward the jam nut. If you look at the side of the sleeve where the ball end of the stud on the throttle lever is, you'll see that a slot allows the sleeve to slide over the stud. Inside, you'll find a ball on the stud and a round hole behind the sleeve. As clean as your engine is, it should slide easily.

TallSkinnyGuy
10-01-2014, 07:16 PM
Despite the engine being clean, that brass sleeve was stuck, but with the knowledge that it was indeed supposed to move I felt comfortable giving it a tap with the end of a screwdriver and that worked to get it unstuck. Now it moves freely so I can pop the cable off easily tomorrow when I get the boat on the water. Thanks for the help.

Worthing skier
10-02-2014, 04:01 PM
Hello there

Does your dash engine check light work , if so is lighting up when the engine is running to indicate a fault ?,
Maybe worth code reading it , or do a blink read with a led , should start pointing you in the right direction.

Kevin

TallSkinnyGuy
10-02-2014, 05:01 PM
I was able to test it today. Throttled up to slalom speed, came back down to idle and (as usual now) the idle speed stayed at about 1200. I then disconnected the throttle cable and the idle speed immediately settled down to 650. So, my throttle cable is apparently the culprit.

I need to look more closely but I haven't found a place where the cable might be binding. In a 17-year-old boat, should I try adjusting the throttle cable or should I just assume I need to replace it?

If I need to replace it, is there a step-by-step guide somewhere? I've searched on the forum and can only find various posters saying the process is easy, but not how to do the process.

Jayhawk
10-02-2014, 06:26 PM
I have this doc on my laptop, but not sure if it applies:

JimN
10-03-2014, 11:21 PM
I was able to test it today. Throttled up to slalom speed, came back down to idle and (as usual now) the idle speed stayed at about 1200. I then disconnected the throttle cable and the idle speed immediately settled down to 650. So, my throttle cable is apparently the culprit.

I need to look more closely but I haven't found a place where the cable might be binding. In a 17-year-old boat, should I try adjusting the throttle cable or should I just assume I need to replace it?

If I need to replace it, is there a step-by-step guide somewhere? I've searched on the forum and can only find various posters saying the process is easy, but not how to do the process.

If you release the throttle cable from the throttle body, grasp the end, then push and pull on it, it shouldn't move in or out very much. If it does, the end at the throttle may be loose. Conversely, if you move the throttle handle when the cable is off of the throttle lever, moving the handle forward and back should show immediate results- if you increase throttle, it should move without delay and when you move it as if you were decelerating, the handle should cause the cable to move back immediately.

TallSkinnyGuy
10-06-2014, 05:13 PM
It seemed fine based on the test suggested above by JimN, so I carefully read through the instructions in my Clymer manual for adjusting the throttle cable. It said that the ball on the throttle arm should line up perfectly with the socket on the throttle cable when the throttle is resting on the idle stop. Turns out my cable was missing this mark by about 2mm.

I followed the instructions in the Clymer manual to adjust it properly and tested it today. It worked perfectly. No more high idle. Once I figured out the problem (thanks to the help of those on this forum and my Clymer manual), the solution was actually quite easy.

mikeg205
10-06-2014, 05:25 PM
Awesome... love reading about easy solutions!!! :) :D

TallSkinnyGuy
10-06-2014, 06:48 PM
I am really glad I took JimN's advice to check the cable before buying parts (e.g. IAC, TPS). I have also gotten some good value from my Clymer manual. It does seem to assume I know more about engines than I do, but I have been able to fill in the gaps with the knowledge of those on this forum.

JimN
10-06-2014, 07:43 PM
I am really glad I took JimN's advice to check the cable before buying parts (e.g. IAC, TPS). I have also gotten some good value from my Clymer manual. It does seem to assume I know more about engines than I do, but I have been able to fill in the gaps with the knowledge of those on this forum.

The manuals aren't written for end users, they're written for those who have some training and knowledge of the systems. That's the reason they don't start at ground level and teach everything. There are many older service people who were great with carbs, but totally lost when it comes to EFI because a carbureted engine ha very little in the area of electronics and EFI is almost mostly electronics.