1998 - 196 Nautique surging under load

[hoopdog]

The problem is when it gets to operating temperature the engine missfires and loses power when the rpm is increased above 2000rpm,the more the rpm inreases from there the more the engine surges and misses and it also has a bad knocking noise which sound like pre-ignition.[i have checked the base timing and maximum advance when the problem is occuring and they are all within specification.
I have followed procedures to test for any fault codes recorded in ECU and there are not any recordings.
i am conserned about the hydralic lifters as i have checked the hydraulic lifter adjustment to make sure they are not to tight.[the lifters do seem inconsistant to adjust as this has been adjusted with shims on 3 occasions, but has never made any difference with the problem.
I have tested the engine management system and fuel system and cannot find any faults.

[Lewy2001]

What type of tester code reader do you have??? Needs to be compatible with the GT40 EEC1V Ford computer. Does it pass the KOEO & KOER tests?

Is the fault intermittent?? Appears you have been chasing these problem for quite some time.

[DanielC]

Let me direct as possible.
What is the fuel pressure WHEN IT IS MISFIRING AND SURGING?

This piece of information is critical!

[hoopdog]

Yep, Fuel pressure gauge was hook up whilst the problem occured and the gauge did not change - 39psi

I have used the Equus 3145 Ford Digital Code Reader whilst on the water and no error codes appear.

[hoopdog]

The fuel pressure does not change when the problem occurs - 39 psi good pressure

[hoopdog]

Yes, fault is intermittent. Seems to do it more when the engine warm rather then cold.

I am using the Equus 3145 Ford Digital Code Reader

[DanielC]

The next step I would take is to find a mechanic that has an ignition oscilloscope. This tool enables the mechanic to look at the firing voltages of the individual spark plugs. The same tool may also have a provision for measuring the length of the fuel injector "on" pulse.

I do not know if the Equus 3145 is able to read that information, it may be with a change of settings.

[hoopdog]

Thansk Daniel,

I will check with my mechanic

[lucky7t]

This sounds like the distributor. Does the dizzy have a module on the front of it? It should be bolted to it and it plugs in on the side.

If it is EEC 4 then it should have a module. These modules are prone to failure. We have bought new ones and the have been bad right out of the box. And your symptoms are exactly what a module would do.

If your module is good and your 100% sure then you need to replace the pickup in the dizzy.

Just my 2 cents

[hoopdog]

Hi ,

I have the Motorcraft Dizzy, module is located on the intake manifold near the flame arrestor. I want to know if you can use a BOSH - BIM032 ignition Module as they are half the price of the PCM module

[pSchwade]

I just encountered a similar problem last weekend - the boat would idle fine, but would lose power and begin sputtering just prior to getting on plane. my first thought was a vapor lock or water in the fuel - so I tried letting it idle for an hour or so, which didnt help. once I got it home I removed the FCC to look for a crack in the high pressure fuel line, but this was also good. I then pulled the low pressure fuel pump and tested its flow rate, it is about half of what it should be - which explains the problem. In the GT40 EFI motor the low pressure fuel pump is constantly circulating fuel through FCC and back into the tank, and the high pressure pump takes what it needs to supply the motor from the FCC - so if the low pressure pump is running at about half of what it should be it makes sense that it would start sputtering when the engine needed more fuel.

one thing that is a little different with my problem is that I can get it to happen on the trailer - at about 5k rmp it will start acting up. it only has to be there for a fraction of a second before it does. so with each new thing i test out I can rev it up real quickly and not need to worry too much about damaging the engine.

As I have said - all that I know at this point is that my low pressure pump is pumping less than it should (I have seen in many places that it should pump about a quart every 15 seconds). I still havent checked to see if it is due to a low supply voltage which would indicate a relay issue or if not than I am going to replace the low pressure pump.

[DanielC]

There is a screen inside the low pressure pump. If you take the nuts off the top of the bracket that the pump is mounted on, you can then unscrew the studs from the pump body. the gasket will probably stick the top plate to the pump.
Here are some pictures.
This is what it looks like after you remove the top plate.

Then there is this smaller plate on top of the rotor.

This is what the pump looks like with the screen removed.

This is the order the parts go inside the pump. Start at the top of the picture. Screen, small plate, gasket, big, or top plate. Do not remove the rotor, or its vanes.

Here is a picture of the pump with just the screen installed.


Of course, be very careful with gasoline, and boats. Check carefully for leaks, and clean up any and all of the spilled gas.
I would suggest you leave the motor cover open, with a fan blowing air through the engine compartment for a few hours to remove any traces of gas fumes.

[hoopdog]

Hi,

Thankyou for the informative and detailed thread.

I actually searched for your thread in the past and have cleaned out the low pressure fuel pump including screen..

I don't think that it is fuel related as I have checked the pressure when the problem occurs and it does not change.

Some days I take the boat out on the water and it runs fine.

I strongly believe the problem is electrical.

I have no idea and am just about ready to sell it

[pSchwade]

I had a similar problem on my 2000 SNOB with GT 40...... and did everyhting that you did and changed my low and high pressure fuel pumps. Still no luck. I too was ready to burn my boat. One day I decided to start the engine on the trailer at night and inspect for leaking spark....... .sure enough one of my BRAND new spark plugs had a crack in the porcelain and it was leaking spark to the engine block that I could not see in the daytime. I replaced the plug and it was fixed. Took me 2 years and about 600 dollars in parts to figure it out !

did you check the plugs?

[hoopdog]

Yeah,

Plugs are new and gap is correct