2004 225 EFI - 4900 RPM max + idle issues

[willijd712]

I apologize in advance for the length of this post. I've been struggling with getting this engine right for a long time and have a lot of data to share!


2004 225 EFI S/N 0T961276
Boat is a 23ft proline center console
Current Prop - 15x15p Enertia
Idle water pressure - ~1.0psi
WOT water pressure - 16.37psi (Note: This is actually at 4900rpm)
Smartcraft connection to Lowrance HDS displays
12" set back manual jackplate
electric trim tabs


History and the problems:


Problem 1- Idle has been intermittently troublesome. Sometimes it idles ok, but sometimes (mostly after a run) it idles rough and dies. When this occurs, I have found that pumping the primer bulb will either prevent it from dying or can help it restart. This is not a constant issue, though.


Problem 2 - It will not rev beyond 4900 rpm unless it is trimmed up to where prop blows out.


Problem 3 - The fuel flow rate seems very high (to me). From idle to about 1400 rpm it is normal at ~1.5-3 gph. It spikes to ~13 gph at 2500 rpm. At 3500 rpm and up to 4900 it is ~23-25 gph. I first saw this on the Lowrance displays, but have since confirmed it with Diacom software.


I bought the boat used and it seemed to run ok for 4 or 5 trips. The idle issue was severe and was the first issue to occur. I attempted several trips on the water where I was never able to make a higher rpm run because I couldn't keep it running at all. That led me to this site and to get past that point I performed a lot of the items below. All the fuel system work seemed to greatly improve the issue of keeping it running. It was after this improvement that I found I had problems 2 and 3. With the 19p Mirage prop that was on it originally, it struggled to get on plane and then maxed out at 4500-4600 rpm. (Note: I do not remember this being an issue before the "problems" started) I tried various props and have gotten that max rpm up to the current 4900 with the 15p Enertia. It gets on plane better, but still not great. When coming down off the higher rpm range there is a strange anomaly where it will do a very brief surge in rpm/power. It's weird to describe - sort of like the reverse of a missing cylinder. It's a drastic increase that lurches the boat forward, but it's extremely brief (less than a second) and ONLY occurs when reducing rpm. It will do this 3 or 4 times depending on the rate of deceleration. To me, it feels like for that brief point the engine is running "right" and in all other times it’s not at full power.


Additional data and what I've done so far:


-Drained fuel tank
-installed all new fuel lines & new primer bulb (using Don's recommended types)
-disassembled and cleaned VST (I used an ultrasonic cleaner)
-rebuilt diaphragm pump
-sent intake and injectors to Integrity injection for cleaning/testing and installation of TDS reeds (Don, my intake was in an igloo cooler with plastic belt strapping around it if you remember that!)
-replaced all check valves in oil lines and so on
-replaced poppet valve
-installed ONE redundant ground from CDM plate to battery terminal point on block (don't know if the second one I've read about applies to this engine)
-New plugs (QL77CC set to 0.040 using wire gap tool)
-new plug wires
-pulled powerhead and drilled out idle relief holes (but there was actually minimal clogging here)
-water pump rebuilt
-engine mounts replaced


-Warm engine compression numbers: all within 2 psi of 113 psi.
-Plugs all look slightly wet but no indications of fouling at any point. I've examined them many times and this is consistent whether after idling on water hose or on the water after running.
-spark gap tester on all cylinders set at 0.040 indicates good spark strength (I ran this coil test using Diacom software)
-fuel pressure: originally had problems here but after cleaning the vst and regulator it stays at 40-42 psi after key on and while idling (on hose in yard), and after 60 seconds or so it drops to 38 and then seems to hold for quite a while. On the water test is coming this weekend, hopefully.
-I use the quickleen/quickare mix
-I get my fuel at the busy spots in hopes of better freshness
-all hose connections are either radius tie wraps or stainless pinch clamps
-both cylinder temps read 113F at idle and stay around 120-130F at higher rpms


I know I’m probably forgetting to add some things here…


All of this has been done either per what I've read here, or per the service manual. I have tried to be very disciplined and thorough in following all the recommendations on this site and every detail in the service manual. This includes using OEM parts, with one exception. I used a Sierra pulse pump kit. Per some other posts on this site, I will be changing that to a Mercury kit just to be safe. Because everything appears to be within spec otherwise, yet it still isn't right, I recently purchased the Diacom software.


Using the diagnostic software has been enlightening to say the least! I have run all the tests it will allow for my ECM and all check out ok. However, in the recording files I have noticed the following items that don't seem right to me. Items 1-4 are examples of what *might* be data glitches and not real issues.


Item 1 - The TPS data occasionally indicates a spike from the normal reading to anywhere from 8 volts to as high as 16.88 volts (VERY brief spikes that don't show a change to rpm or any other numbers).
Item 2 - Engine RPM data occasionally indicates a spike to 14,000 rpm. This spike in the data points does not align with the above spike and doesn't make an audible change to rpm.
Item 3 - Fuel flow occasional spike to 45 gph. Same comment as others - they are not occurring at the same time.
Item 4 – Spark advance has a single spike in one instance that reads 1045.81 deg! Yes, that is one thousand forty five degrees. It’s a single point, but nonetheless I’m sharing it.
Item 5 - The TPS voltage at idle is 0.69 volts in some cases. In others it is 0.74 volts.
Item 6 - The spark advance at idle is sometimes positive 4 deg, but in some cases it's as much as negative 6.44 deg
Item 7 - There is one file where the spark advance runs at about 20 deg at 1650 rpm, then later WHILE DECELERATING holds at a flat line of 28 degrees for the entire range from about 3000 rpm down to around 1700 rpm, where it abruptly drops to 23 deg. There is a lot of time in the range above 22 deg, which is stated as the max for this engine in the service manual.


Is it possible that these data spikes in items 1-4 are simply glitches in the recording process? Data rate limits perhaps? Or is it possible that I have an ECM problem causing ALL of these issues? They (data spikes) do not align with each other and don't appear to be causing any other data points to change.


At 4200-4500 rpm it rolls along seemingly ok, yet is burning 23 gph! My boat is admittedly heavier than a typical bass boat, but it seems that this is abnormal per my research on similar boats. Nothing I do to engine trim, trim tabs, engine running height, etc. has improved these fuel burn or max rpm numbers.


I am at a point where I'm stuck and don’t know what to examine next. Based on these data files, I am now suspicious of the ECM. I have multiple data recordings available I would be happy to share with the experts on this, if necessary! I would need a little guidance on preferred way to send them, though.

Many thanks in advance!!

[Savage]

Dude can you narrow the question down......that's a novel. Lol

[willijd712]

Ha! Yes how about this...

I've done all the basics and everything now checks out. I am seeing erratic readings on the data logs from diacom and it still doesn't seem to be running at full potential. I don't know what to check next. Would these observations indicate a possible ECM problem?

[kls2020]

Thats quite a laundry list of problems . Looks like the ECM controls the spark and fuel mixture for that motor so it would be worth it to get that tested and eliminate it as a problem . You didn't mention the battery voltage or charging system but a faulty (noisy ) regulator can wreak havoc with any electronic components or system . I was thinking about the symptom were it straightens up briefly when decelerating and made me think maybe the detonation sensor is sensing a knocking due to too much timing advance for whatever reason . This would retard the timing and increase the fuel flow to eliminate the detonation resulting in less power . When you then reduce the throttle the timing would be backing down the timing and when the knock stops the timing and fuel mixture would return to normal for that throttle position /RPM .
I'm probably wrong shooting in the dark but good luck with your engine...

[Gamblinman]

I feel for your issues. I think I would part this outboard out and find a used or new outboard. You could spend a lot of time and money chasing this further. Too many problems all at once to diagnose any one issue accurately.

[willijd712]

UnfortunatelyI have been close to that same decision more than once lately. I'll be checking out the charging system idea above over the weekend since that's something I haven't looked at yet. At least for noise and current output - the voltage appears to hold steady (in the data log graphs).

[kls2020]

I looked at some Diacom softwear video's on YOUTUBE and if there is anything that would help to pinpoint any problem(s) with your motor that should do it . This may be a dumb question but are you certain you are using the right adaptor cable for your particular motor ? The reason I ask is because you have outlined show so many problems occurring . Manufacturer says using the wrong cable can give you bogus engine readings .

[EuropeanAM]

Timing and Spikes:

Possibilities include RFI Interference from a bad plug, bad wires, OR Diagnostic Software Glitches OR PCM problem.

DEFINITELY get that pulse pump rebuilt properly, with an OEM kit, before going any further. Some of your complaints are pointing to it as the potential culprit (and you definitely need to address that OBVIOUS problem FIRST).

[willijd712]

Thank you for the responses so far. I've finally made some real progress!

Last weekend I spent time with the diagnostic software. I eventually found that my throttle percentage was only going up to 89% in forward direction, but 100% in reverse.
Similarly, my TPS volts were starting at about 0.68 volts but were only reaching 0.75 volts when returning the control to neutral.

After checking all the throttle connections and adjustments I found two issues. The idle stop was out of adjustment and was not returning to the point where it makes contact. This was a simple cable adjustment. I think I had gotten the setting off at some point while doing all my other work. This immediately fixed my TPS voltage - it starts at 0.58 volts and returns exactly to this number every time the shifter is returned to neutral.

The 89% max throttle item took me longer to find. It ended up being the way the control was mounted to the helm!! The front adjuster screws were loose and the whole box was tilted forward. It was preventing the throttle cable from being fully extended in the forward direction. After I aligned it properly and tightened everything the throttle % runs smoothly from 0%-100%. I know this would have been obvious to a professional, but I never dreamed I was short on range in that location.

In the several hours that I had the diacom software running I never once saw another spike or weird number like I had the previous weekend. I think those were anomalies related to where the cable was sitting? As Don suggested it could have been RFI interference. I don't remember where I routed it that time but this round I zip tied it in a position I knew was clear of the noisy electrical items. I wouldn't have solved these issues without the software, so in my opinion it was worth the investment.

Today I removed the Sierra pulse pump parts and installed the OEM (Quicksilver) kit. There was a noticeable difference in the plastic disc valves between the two kits. The ones in the Quicksilver kit were a larger diameter and were a more flexible material. My assumption was that this *should* improve the performance at the reduced vacuum levels during idle (which has been my other primary trouble zone). I put the water hose on and ran it at idle for what was the NICEST sounding and smoothest 15 minutes of run time this engine has had since I've owned it! I am absolutely ecstatic over the recent progress.

I will be lake testing it this weekend to see how the top end changed. That control box adjustment was probably the only reason I couldn't ever get it past 4900 rpm. I may have finally gotten this one beat!! I'll report back soon...

[EuropeanAM]

Sounds like you're on the right track.