Persistent "Trim Fault" alarm on Smartcraft tach

[skibum]

I've been trying to resolve a very puzzling persistent trim fault error message for 2 seasons now. Last spring, my mechanic installed a brand new Merc digital trim sender and trim limit switch set. Before he left, we ran the Smartcraft trim calibration routine, which worked perfectly. The boat was on land at the time, so we ran the calibration with the key on / engine off. After calibration, the gauge correctly showed the position of the drive on the trim gauge. It also stopped at max trim and required use of the second detent on the trim up switch to get the drive into trailer position. When I put the boat in the water for the first time after he replaced the senders (for the same issue), I got the trim fault error as soon as I started the engine. I can go into Calibration 2 and set it back up, but as soon as I turn the engine off and restart it the problem reappears. I recalibrated it several times yesterday and each time the problem came back every time I turned the key off. I have tried setting it to both "high resolution" and "standard" in Smartcraft. I get the same results either way.

Does anyone have any information on how to set the initial positions of the trim position and trim limit senders? I think that one of them needs to be adjusted (by loosening the screws and turning them a little), but I can't find any documentation on how to do that anywhere. I've considered just moving them a little and retesting, but there must be some actual method of properly setting them up.

 

[bbwhitejr]

I replaced mine on my B3 2 years ago now. I did a lot of research before installing. I replaced mine w/o removing the OD and got it done. To adjust mine, I did it on land as well. I sat my wife in the driver's seat, key on, and had her watch the trim gauge. I trimmed the OD all of the way down and then loosened the 2 screws you mentioned and turned the unit until she told me it was on the bottom. Tightened the screws up and ran the OD to the top and it was off just slightly. Loosened the screws again and moved the unit ever so slightly. "Max trim" as you call it above is actually a measurement of cylinder extension. I cannot remember the measurement, but I had a diagram showing it. I simply extended cylinders to that measurement and turned the disc on the port side until it stopped trimming at the measurement. After that, the trim to trailer function took over.

There are instructions that come with the OEM kit explained adjustments fairly well. If you do not have access to them, try googling the instructions. You want the instructions for Part #805320A03. This is the Merc OEM part number.

Good luck.

Bennett

 

[paulswagelock]

^^^ It sounds like the resistance is out of range. There is a spec on what it should read.
When I did mine, I carefully marked the position and put the new one the same way. It needed a smartcraft calibration, but just once.
Go read the resistance down and fully up. I think you will find one is out of range.

 

[skibum]

There are instructions that come with the OEM kit explained adjustments fairly well. If you do not have access to them, try googling the instructions. You want the instructions for Part #805320A03. This is the Merc OEM part number.

Good luck.

Bennett

Thank you, but p/n 805320A03 is for the standard analog trim sender set. I have the "Smartcraft" digital version p/n 8M0107462. It has 3 wires (red, white, and blue) on the position sender. The trim limit switch is the standard analog 2 wire version.

^^^ It sounds like the resistance is out of range. There is a spec on what it should read.
When I did mine, I carefully marked the position and put the new one the same way. It needed a smartcraft calibration, but just once.
Go read the resistance down and fully up. I think you will find one is out of range.

I thought that I had read somewhere a while ago that the digital version had to be set to read a certain resistance with the drive all the way down, but I can't seem to locate the instructions anywhere. I think it is supposed to be set to something like 15 ohms with the drive down, but I don't know which 2 of the 3 wires I need to measure the resistance on (red to white, blue to white, or red to blue). We did mark the original position on the old sender and we put the new one on in the same position.

It might be time to just loosen the screws, change the position a little, recalibrate in Smartcraft, and try it. I might have to do that a couple of times before I get it right.

Based on the post calibration behavior (before I turn the key off), they appear to be working properly. I think you are correct in that it is just a matter of getting the initial position right before I calibrate them.

 

[paulswagelock]

Do you have the DTS (digital throttle shift) system on your boat?

 

[skibum]

No, I do not.

 

[bbwhitejr]

That is weird as my '06 was Smartcraft as well. As Paul suggests, the one for DTS is different, but the rest are all alike.

Bennett

 

[paulswagelock]

If you do not have DTS, then you need the analog trim sensor not the digital one. If you used the digital one, that is only for DTS equipped engines. I went through this with tech support on my last boat. It had smartcraft but not DTS. A five minute call with Merc tech support set me straight and I purchased the analog gauge instead.

 

[skibum]

Now that is really confusing. I had a problem in 2011. My mechanic replaced the senders like for like, and it worked fine right up until the last 2 weeks of the 2015 season. We replaced it again with the same type at the beginning of last season. How did the same exact sender work perfectly for 4 seasons if it was the wrong part?

 

[paulswagelock]

Can't answer that. But I am 100% certain that my 2007 Mercruiser with smartcraft gauges but not DTS used the traditional analog sender /limit per a discussion with Merc tech support, and my current boat with DTS needed the digital version.
i suggest you call them and talk to them directly. Extremely helpful folks. You will need your serial numbers for engine and drive to expedite the answer.

the DTS version is both the trim sender and the trim limit, the second sender on a DTS equipped boat is not used. The ECU limits the trim electronically after the rpm raises to a predetermined level. I remember my discussions with them distinctly.

 

[bbwhitejr]

Here is another twist that you might check...My trim sender was working until I had the engine pulled to replace the oil pan. All wiring was unhooked and then put back after the engine was replaced in the bay. During the work, the shop banged up the trim sensor and now the trim sender/gauge no longer worked either. So...I set out to replace both the sensor and sender. I unplugged the wires from the old ones and carefully marked them so I put the new ones back into the same electrical fittings. Got all done and fought with it working sometimes, not at all, etc. I hooked my multimeter up and it was reading as it should, but nothing correct on the gauge. I did find a wire marked "Analog Trim" and one marked "Digital Trim." When I unhooked initially, the sender was plugged into the 'Analog Trim" and of course, I replugged it into the same wire.

Called Merc and got a Tech on the phone. After about 30 minutes, he figured out it was plugged into the wrong wire. It should have been plugged into the "Digital Trim" wire. After swapping it over, never another trim fault or trim issue. My findings were the same as Paul says above. There are only 2 kinds...1 for the DTS and one without. The one without is plugged into the Digital Trim wire on a Smart Craft System.

Bennett

 

[Mavado007]

Can't answer that. But I am 100% certain that my 2007 Mercruiser with smartcraft gauges but not DTS used the traditional analog sender /limit per a discussion with Merc tech support, and my current boat with DTS needed the digital version.
i suggest you call them and talk to them directly. Extremely helpful folks. You will need your serial numbers for engine and drive to expedite the answer.

the DTS version is both the trim sender and the trim limit, the second sender on a DTS equipped boat is not used. The ECU limits the trim electronically after the rpm raises to a predetermined level. I remember my discussions with them distinctly.

Hi Paul - any idea on : The ECU limits the trim electronically after the rpm raises to a predetermined level - any limit on that rpm level , can adjust it ?

 

[paulswagelock]

Hi Paul - any idea on : The ECU limits the trim electronically after the rpm raises to a predetermined level - any limit on that rpm level , can adjust it ?

I do not remember there being a way to change that through the gauges, or even see what the presets were. Maybe the Merc laptop program allows it.

 

[Lazy Daze]

Hi Paul - any idea on : The ECU limits the trim electronically after the rpm raises to a predetermined level - any limit on that rpm level , can adjust it ?

Mavado, from what you are saying here, it sounds like the system is working as designed. It is not good to operate the drive at higher trim levels with raised RPM's. The ECM is trying to keep the drive safe - defeating that safety feature is not a good idea.

 

[Mavado007]

Mavado, from what you are saying here, it sounds like the system is working as designed. It is not good to operate the drive at higher trim levels with raised RPM's. The ECM is trying to keep the drive safe - defeating that safety feature is not a good idea.

I am agree on that - but if the safety feature knocks in at only 2500 rpm - that is very early as boat is not even on plane than.. i think at cruising speed of 3200 rpm it should be still possible to trim up a bit to gain some speed/ consuming less fuel ?

 

[Mavado007]

Well, we replaced by a 3 wire trim sensor/limit as mine is a DTS system
It takes a while before gauge is showing the trim position and doesn't work at all while boating.
Noticed also the trim limit ( supposed to do the job from 2500 rpm onwards ) not working.
I could still trim up at 3200 rpm. Luckily enough i know how to handle the trim well and know how it works but is not ok.. so i am afraid we need to haul out the boat again to adust the sensor on the drive..

 

[Mavado007]

I do not remember there being a way to change that through the gauges, or even see what the presets were. Maybe the Merc laptop program allows it.

My Technician told me it is preset at 2500 rpm.. what is very early in my opinion as boat is not on plane yet. I think the trimming comes in places once the boat is on plane to adjust position of the boat on the water surface to get less friction ( so gaining a bit of speed or gaining on consumption )

 

[Lazy Daze]

The purpose of the limit function has nothing to do with the boat being on plane or not - the drive and limit function has no idea if a boat is on plane. As I mentioned above, the purpose is to avoid damaging the running gear/driveshaft, etc. Excessive (determined by the Merc engineers, not you or I) RPM at higher trim levels can cause damage.