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76S&S
07-26-2010, 09:35 AM
I've searched the threads but didn't find my exact issue, so looking for a little diagnostic help.

Boat: 2002 xstar with the LTR 330 (I think)

Issue: Yesterday after over an hour of run time, on some occasions when going back to pick up a fallen rider, when either reversing or just going to neutral the rpms would rise to 1,000 or so. One a couple of occasions it surged to well over 2,000 and then leveled off at 1,000 again. (Normal idle is around 600 - 700). The check engine light came on a couple of times but not every time that it idled around 1,000 rpms. I could turn the engine off and immediatlely fire it back up and it would idle fine.

Appreciate any insight that anyone might have.

JimN
07-26-2010, 10:14 AM
I've searched the threads but didn't find my exact issue, so looking for a little diagnostic help.

Boat: 2002 xstar with the LTR 330 (I think)

Issue: Yesterday after over an hour of run time, on some occasions when going back to pick up a fallen rider, when either reversing or just going to neutral the rpms would rise to 1,000 or so. One a couple of occasions it surged to well over 2,000 and then leveled off at 1,000 again. (Normal idle is around 600 - 700). The check engine light came on a couple of times but not every time that it idled around 1,000 rpms. I could turn the engine off and immediatlely fire it back up and it would idle fine.

Appreciate any insight that anyone might have.

Scan it for codes. Do you have Perfect Pass, or anything like it?

76S&S
07-26-2010, 10:43 AM
thanks for the reply Jim. Is there a way I can check for codes without a scanner? And yes it does have PP.

JimN
07-26-2010, 10:45 AM
thanks for the reply Jim. Is there a way I can check for codes without a scanner? And yes it does have PP.

Physically disconnect the PP from the throttle and see if it stops surging. If it doesn't, contact EngineNut to find out if a regular scan tool can be used, or if a diagnostic computer is mandatory.

76S&S
07-26-2010, 10:54 AM
will do, thanks

any possibility it is something like the IAC?

JimN
07-26-2010, 11:30 AM
will do, thanks

any possibility it is something like the IAC?

It's possible but logic dictates that everything else should be eliminated as a possible cause before replacing anything. PP is connected to the throttle, so it's a potential cause. Once the codes have been scanned, it will/should eliminate the MAP and TPS as possible causes, too.

The MAP being bad usually causes it to respond to throttle position changes slower than normal and a bad TPS may cause similar issues- this is a potential cause for your issue, so if you increase the throttle position verrrrry slightly, it may clear up.

The TPS tells the ECM that it's idling (2% or less throttle position) or not idling (more than 2% throttle position). Once it's not idling, about the only thing the TPS is needed for is +/- throttle position changes (Delta) of ≥ 20. + Delta indicates 'acceleration enrichment' and - Delta indicates 'deceleration enleanment'. A TPS that is faulty for a long enough time or returns no voltage will usually result in a code and the ECM will default to 12% throttle position.

76S&S
07-26-2010, 12:11 PM
Thanks JimN, it's great having people like you on this site!

76S&S
08-04-2010, 08:47 AM
JimN, it appears that this just might be much less of an issue that either one of us originally thought. Got the boat out the other day and it was immediately idling high, which it has never done on startup. I opened up the cover over the engine and wiggled the throttle arm (butterfly, what ever it should be called) and realized that the spring wasn't pulling it all the way back against the idle adjustment screw. A little WD and working the throttle and I never had another idle issue for the rest of the day.

JimN
08-04-2010, 09:17 AM
JimN, it appears that this just might be much less of an issue that either one of us originally thought. Got the boat out the other day and it was immediately idling high, which it has never done on startup. I opened up the cover over the engine and wiggled the throttle arm (butterfly, what ever it should be called) and realized that the spring wasn't pulling it all the way back against the idle adjustment screw. A little WD and working the throttle and I never had another idle issue for the rest of the day.

Good to hear that it may be fixed, but use something other than WD40. That has cutting oil in it, like what's used for cutting threads, etc and it will cause the metal to wear. Use something like TriFlo. Use carb cleaner to get the WD40 out of the pivot.

76S&S
08-04-2010, 04:09 PM
Good to hear that it may be fixed, but use something other than WD40. That has cutting oil in it, like what's used for cutting threads, etc and it will cause the metal to wear. Use something like TriFlo. Use carb cleaner to get the WD40 out of the pivot.

Will do, thanks Jim