mvn
Petty Officer 1st Class
- Joined
- Jul 25, 2007
- Messages
- 204
Background: 2019 Rinker MTX20 with a Volvo V6-280-M/SX drive package. I purchased it at the beginning of summer from a dealer that had it stored for over 2 ½ years with a ½ tank of fuel in it. It had 5 hours on it when I got it.
The Story: First weekend with it, all seemed good. Acceleration was incredible, even with 6 people on board. I had to get used to the very sensitive throttle. I had to increase the throttle friction setting a bit which helped. The next weekend is when the trouble started. I did a single WOT throttle run to see max speed. The tach appeared to almost hit 7,000 rpm. I backed off immediately. No rev limiter, no alarms…..strange. A few hours later, I started to get a recurring alarm as previously posted. Also, Engine Protection kicked in once limiting the throttle. Getting a Rinda scan tool, the code was SPM 4237 FMI 0 which translates to long term fuel trim high, Bank 1 indicating a lean operating condition. Subsequent investigation found a very loose fuel filter so I suspected fuel aeration as the low pressure pump was also gurgling. Changing out the fuel filter and tightening it up, I did not get the code again. I also reset the fuel trim table so the ECM could relearn. WOT indicated 5800 rpm on the boat’s tach but the speed seemed low (43 mph on GPS). Prop was a stock 14x19 4-blade aluminum. I didn’t think too much of it but it stayed in the back of my mind.
I got a 14x20 4-blade stainless to try this past weekend. Handling improved dramatically but the top speed did not improve. WOT indicated 5800 rpm on the boat’s tach. Loading up with 6 teens/adults, we headed out for a day on the water. All seemed to be OK but I found the boat to be sluggish getting on plane while towing. This was not the case on that first weekend. It was able to pop up a skier in no time. Later that day, I went out with my scan tool and did a few WOT runs. Low and behold, the Rinda scan tool showed ~4900 rpm while the boat’s tach showed 5800 rpm. The scan tool also showed max engine load peaking out at 86% to 88%. I did not get a chance to verify the switch setting on the tach…next weekend. I did verify full stop to stop operation of the throttle position sensor so cables are OK. Oil pressure, coolant temps and manifold temps are all good according to the ECM and gauges.
So my question is this…..Assuming the tach is wrong (which would explain the 7,000 WOT reading last month) and its really 4900 rpm, what do I do? I did read the thread on this forum regarding low WOT. I suspect fuel issues. I have been filling up with ethanol-free premium gas to flush the system but could there be a partial blockage somewhere? Any ideas where? I was thinking of setting up a small tank and feeding the low pressure pump to see if it’s a tank issue or an engine issue. I’ll also change the filter again and look at the contents.
The Story: First weekend with it, all seemed good. Acceleration was incredible, even with 6 people on board. I had to get used to the very sensitive throttle. I had to increase the throttle friction setting a bit which helped. The next weekend is when the trouble started. I did a single WOT throttle run to see max speed. The tach appeared to almost hit 7,000 rpm. I backed off immediately. No rev limiter, no alarms…..strange. A few hours later, I started to get a recurring alarm as previously posted. Also, Engine Protection kicked in once limiting the throttle. Getting a Rinda scan tool, the code was SPM 4237 FMI 0 which translates to long term fuel trim high, Bank 1 indicating a lean operating condition. Subsequent investigation found a very loose fuel filter so I suspected fuel aeration as the low pressure pump was also gurgling. Changing out the fuel filter and tightening it up, I did not get the code again. I also reset the fuel trim table so the ECM could relearn. WOT indicated 5800 rpm on the boat’s tach but the speed seemed low (43 mph on GPS). Prop was a stock 14x19 4-blade aluminum. I didn’t think too much of it but it stayed in the back of my mind.
I got a 14x20 4-blade stainless to try this past weekend. Handling improved dramatically but the top speed did not improve. WOT indicated 5800 rpm on the boat’s tach. Loading up with 6 teens/adults, we headed out for a day on the water. All seemed to be OK but I found the boat to be sluggish getting on plane while towing. This was not the case on that first weekend. It was able to pop up a skier in no time. Later that day, I went out with my scan tool and did a few WOT runs. Low and behold, the Rinda scan tool showed ~4900 rpm while the boat’s tach showed 5800 rpm. The scan tool also showed max engine load peaking out at 86% to 88%. I did not get a chance to verify the switch setting on the tach…next weekend. I did verify full stop to stop operation of the throttle position sensor so cables are OK. Oil pressure, coolant temps and manifold temps are all good according to the ECM and gauges.
So my question is this…..Assuming the tach is wrong (which would explain the 7,000 WOT reading last month) and its really 4900 rpm, what do I do? I did read the thread on this forum regarding low WOT. I suspect fuel issues. I have been filling up with ethanol-free premium gas to flush the system but could there be a partial blockage somewhere? Any ideas where? I was thinking of setting up a small tank and feeding the low pressure pump to see if it’s a tank issue or an engine issue. I’ll also change the filter again and look at the contents.
