00 Response Monsoon engine slow out of the hole

[jfw432]

I do a lot of slalom skiing and I'm used to having a very firm pull when getting up. The Monsoon engine in my 2000 Response won't do that and it feels more like the ECM is restricting it instead of an actual engine problem. Do these engines have some kind of customized launch control? The engine has loads of power after about 2 seconds but before that it feels like someone rolling the throttle up like they're pulling a 90 year old woman.

My boat has the Acme CNC 13x12 prop and it doesn't have any dings so I can't imagine it's prop related either. Tops out at over 44mph and blows past 34mph so fast we have to help out Perfect Pass so we don't enter the slalom course way too fast.

[justgary]

Your boat should top out close to 50 and maybe a little over 5000 RPM. It could be dirty injectors. It could also be low compression or bad valves. Heck, it could be a lot of things. Plugs, wires, cap, rotor, etc.

Tell us more about it and what you have done already.

[jbower]

Try cleaning the throttle body and spark arrestor

[MadMan]

A sluggish initial response (no pun intended) could be caused by a faulty throttle position or MAP sensor.

[jfw432]

Ok so it sounds like it is an engine issue and not a ECM design characteristic. It's really hot here with no wind even at 9 PM so I'll start digging into it tomorrow morning. The flame arrestor was a little dirty but nothing abnormal... I'll clean it anyway.

There are two sensors on the throttle body. I'm guessing throttle position sensor and idle air controller? The throttle body is a bit filthy. Should I just spray cleaner in there or remove it completely and spray it? Haven't check timing, compression, correct firing order, or anything ignition related yet. Will try to tackle that tomorrow.

Anyway to test the sensors?

Edited July 12, 2015 by jfw432

[jbower]

I typically scrub the throttle body with spray and a old tooth brush

[jfw432]

Ok firing order is correct. How do you time this thing? I see one mark on the harmonic balancer and one mark on the engine. They line up at idle but I'm guessing there is some electronic stuff going on and that's not the real timing.

[jfw432]

Compression appears to be around 190 on all cylinders.

[justgary]

Keep going with the basics. I'm still assuming either dirty injectors or really weak spark because of the general lack of power, but I'm leaning toward the injectors.

If you look under the distributor cap, you'll probably wonder how it runs at all. Change the cap and rotor, and the plugs and wires are probably due also.

You should be able to spray cleaner into the throttle body with the engine running, and then kill the engine and open the butterfly (pull the neutral button) and clean along the edges of it and where it meets the body. Shoot spray into all the little passages and side channels. Wait a few minutes, crank it again, and maybe hit it again with spray at high idle. Personally, I think keeping it clean is a great idea, but you would probably be complaining about rough idle if this were the main problem. Get it clean, and then we don't have to wonder.

It sounds like you have decent tools and skills, so go ahead and test your fuel pressure at idle and at WOT. Even if you have dirty injectors, they need proper pressure to work, so let's check that off the list early.

Where do you live?

[jfw432]

I've rebuilt a few engines but haven't done much with fuel injection. I can do a leakdown check but that will be a last resort as I have to pull the boat out of the water and back it down my driveway which is always a nightmare because I only have about 2-3 inches on either side and it snakes just to make it even harder.

Would cleaning the injectors just be snake oil or should I try to pull them and manually clean them? Also, what is the fuel pressure supposed to be?

[justgary]

I have heard of mixed results with trying to clean injectors, but Bozboat reported a definite performance gain after having his professionally cleaned. I'm probably going to attempt it this winter, but I realize that I can easily make them worse.... Definitely rule out everything else before ripping out your injectors.

You should have a 3 bar =~ 45 PSI fuel system, and it should read that at key on, at idle, and at WOT. If you don't get that pressure, pinch the return line on the regulator to see if it is the pump or the regulator. Without a return, the pressure should rise well above 45 PSI if the pump is good.

[jfw432]

Well I have lots of gauges but apparently I don't have anything to connect to the fuel rail so I'll have to buy that before I can check it. I did clean out the throttle body while it was installed. Hard to say if that did anything as I wasn't being pulled up on a ski but judging by the video, I'm not sure why it feels sluggish on a ski.

I took this with a quick water test. It was choppy so the video isn't real smooth (sorry). Anyway, with just me and not much fuel, I hammered the throttle and it looks like it shoots to 1500rpms, pauses for a quick tick, launches to 28000rpms and then moves on up to about 4500-4800rpms and then backs itself off to around 4200rpms and roughly 44mph. I manually backed it down in the video though.

Lastly, could 87 being affecting it? I assume the previous owner used 87 so I'm running it low and then refilling with 89 but haven't done that yet.

Edited July 12, 2015 by jfw432

[justgary]

It is starving for fuel. Probably a pressure issue.

[Bozboat]

I have heard of mixed results with trying to clean injectors, but Bozboat reported a definite performance gain after having his professionally cleaned. I'm probably going to attempt it this winter, but I realize that I can easily make them worse.... Definitely rule out everything else before ripping out your injectors.

You should have a 3 bar =~ 45 PSI fuel system, and it should read that at key on, at idle, and at WOT. If you don't get that pressure, pinch the return line on the regulator to see if it is the pump or the regulator. Without a return, the pressure should rise well above 45 PSI if the pump is good.

I think it was RTS that sent his injectors off to be cleaned and that made a big difference for him at higher rpm. Mine probably need cleaning.

[justgary]

I think it was RTS that sent his injectors off to be cleaned and that made a big difference for him at higher rpm. Mine probably need cleaning.

Oops, bad memory. Thanks for clearing that up.

I think the main impediment to cleaning them is the need for a jig to pump cleaner through them while you electrically open the solenoid. I don't know how long you can safely hold the solenoid open, but it shouldn't be too hard to set everything up.

[justgary]

By the way, do the fuel crossovers on the top of your engine have rubber hose segments, or are they just steel lines? I'm talking about the lines that link the left and right fuel rails. The lines should have rubber segments in them to correct a fuel hammer issue common in that model.

[Bozboat]

Oops, bad memory. Thanks for clearing that up.

I think the main impediment to cleaning them is the need for a jig to pump cleaner through them while you electrically open the solenoid. I don't know how long you can safely hold the solenoid open, but it shouldn't be too hard to set everything up.

I watched a couple of YouTube videos where they hook a small battery to the injector and use a syringe of cleaner to squirt through. I would hate to mess one up as the replacements look expensive Edited July 12, 2015 by Bozboat

[justgary]

Exactly. As long as you don't burn out the solenoid, odds are that you won't make it much worse. I just worry about getting one partly clean and then having it hang open because a piece of crud is stuck in the needle.

A test jig with a pressurized rail would let you look at the spray pattern.

[grandude]

The main thing about cleaning the injectors is typically removing the debris in the inlet port of the injector itself. I've helped a few friends do this and it's usually the first three injectors on the inlet side that catch the most sediment. Just remove the injectors and have a fresh can of carb cleaner with the straw available to spray out the inlet/top of the injector. First order is clean the inlets, you might do this over a clean plastic ware container so you can track your results at the end. The injector will open on a pulse from a 9 V battery. If you really want to go to the extra effort you could build a injector pulse activator with a 9 V battery, a momentary on button, some wire and some small female spade connectors. My friends set up also uses a syringe body with piece of hose the same size as the top of the injector without the O ring. The tip if the syringe has a carb cleaner straw attached. He typically cleans the inlets first, then sprays carb cleaner thru the injector by pulsing the momentary button. It seems that the inlet cleaning is by far the most productive of the whole process. I really need to learn to post pics.

[jfw432]

Ok so fuel pressure is between 39 and 41 psi at idle, 40 psi with just the key on, and it swings wildly and quickly between 28 and 42 at 3000rpms in neutral. At 1800rpms its dead on 38psi. Bleed down after turning the engine off is golden...read 46psi when I shut it off and was holding at 46psi for 10 minutes with the key off.

I'm gonna change the inline fuel filter by the tank. Are there any other filters which could be clogged?

There is a small section of rubber hose, maybe an inch long between the rails on the front and back.

[MadMan]

Ok so fuel pressure is between 39 and 41 psi at idle, 40 psi with just the key on, and it swings wildly and quickly between 28 and 42 at 3000rpms in neutral. At 1800rpms its dead on 38psi. Bleed down after turning the engine off is golden...read 46psi when I shut it off and was holding at 46psi for 10 minutes with the key off.

I'm gonna change the inline fuel filter by the tank. Are there any other filters which could be clogged?

There is a small section of rubber hose, maybe an inch long between the rails on the front and back.

You should monitor the fuel pressure while the problem is occurring, while it's backing itself down.

The fuel pressure regulator tries to maintain 3 bar (45 psi) across the injectors. It does this by referencing the vacuum in the intake manifold. So you should see 45 psi at key on with engine not running (might have to cycle the key on/off a few times to build up this pressure) and wide open throttle. At idle and part throttle cruise (vacuum in the intake) the fuel pressure will be less. This is normal. If you connected a vacuum gauge, the vacuum + fuel pressure should equal 45 psi.

87 octane might detonation, which the MEFI would detect through the knock sensor. It would then pull back timing to stop the detonation, causing power loss, but protecting the engine.

[justgary]

So it sounds like you are getting things figured out, and that you have the correct crossover lines on the fuel rails.

[jfw432]

So much for figuring it out today. Went to go pick up a Wix 33033 fuel filter and they gave me 33003 which is the plastic version. Back to the store tomorrow...

[jfw432]

Ok so I got a hold of the Wix 33033 which is what BakesOnline sells for these boats. The pressure jitters go away, the engine stays at 4800 rpms and doesn't back down, but the hesitation out of the hole is actually worse now. Not sure if I never tried before but there is a hesitation with any medium to heavy throttle increase regardless of rpms or speed.

Fuel pressure at idle is a steady 45 psi. Fuel pressure after shutting the engine off is 46 psi and holds. Pressure at fast idle is pretty steady around 40.5-41.5 psi and no longer bounces around wildly. I left the engine cover up and watched the fuel pressure during the hesitation periods and it jitters a little more than fast idle but it still only between 40-42 psi.

Still think it's clogged fuel injectors? It's hard to tell if it's really a lean hesitation or a rich bog. It sounds more like it's lean but feels like it's rich with the way it just clears and takes off.

[justgary]

Did you test the regulator by pinching the return line?