strange knocking noise above 2,000 rpm (5.0 efi 95')

[bruceb58]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

Thats the problem, there isn't anyone around here certified for OMC. I barely have a dealer I can get direct parts through.

Well, you are in luck as far as your drive is concerned since you basically have a Volvo SX. The fuel injection may be another matter.

 

[Don S]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

Carefully check the firing order of the plug wires. Ford EFI engines can mask a couple of crossed wires and sound fine, most of the time.

 

[perna00]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

Ironically, when I first got the boat, it wouldn't rev over 3k rpms. I checked out the firing order and he had two of the wires crossed. I rewired them and it eliminated the rpm limiting. I was reading about the outdrive and it says that if the universal joint is misaligned or worn, it can cause a knocking noise under load. I can't see it sounding like a miss like does, but I'll fix the drive first and see.

 

[perna00]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

. . . And so the problems continue. I pulled the lower unit off and found two things:

It looks like there is a small hole on the bottom of the unit which I found out is actually a bleeder hole to drain water. I was able to clean it out to fuction properly. The other problem is that the outside casing around where the seal goes for the water inlet is missing. It looks like someone might have used a screw driver to pry the unit from the transom and broke a slight bit off. It doesn't effect the groove for the ring but it does have metal missing. Maybe I can reform it or seal it.

On the good side, there was plenty of grease still inside (water mixed) without any damage to the U-Joint. It doesn't have any play at all. That's good for parts but not the answer to my misfire. Since water has gotten into the u-joint boot, other than the basic replacements of water seal, o-rings, gasket, and shift cable grommets? Should I pack new grease into the bearing just inside of the opening (shown in the picture)?

 

[bruceb58]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

What does your gear oil look like? That looks like emulsified gear oil all over the place.

 

[perna00]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

I'm going to check it out today. Yeah, there was quite a bit of grease/oil/water that leaked out of the ujoint bellow boot. It was white/green in color. You can see it in the top picture in the bottom hole. From the amount of oil that came out, I'm betting the yoke seal (or yoke itself) is bad. I'll check it today. This boat is starting to not look like the deal I thought it was going to be when I bought it. . . And I still have to figure out the backfire!!!

 

[perna00]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

Well, the yoke is in fact worn into. Just enough to have to replace it. That is where the gear oil entered the bellow. I've got a list of parts to replace now. I can't seem to be able to find the shift cable grommets anywhere. Mine were destroyed and I don't see them in any parts lists.

 

[Don S]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

I can't seem to be able to find the shift cable grommets anywhere.

Which outdrive do you have? Not sure what you mean by shift cable grommets.

 

[perna00]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

It says omc cobra outdrive but the book lists all my parts out of Volvo sx. They are two small grommets that goes into the housing around the cable. Mine is the version that has the tube going through the back of the boat so it doesn't have the large cable boot like in the rebuild kits. They are about the size of the rubber caps on a brake caliper protecting the bleeder. Here is a pic of the damaged ones:

 

[Don S]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

Those aren't drive parts, they come with the cable. Not sure you can even buy them separate. You might check with your local boat shop, I know when I replaced cables I saved the old ones if in good shape, and used them quite often on cables that were missing them.

 

[perna00]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

Thanks for the info Don. I'll have to check out Marine West or similiar for them. At least I have my old ones to take with me (or what's left of them).

I got all my parts ordered and am playing the waiting game on getting everything back together. Well, the drive will be up to par, now I just got to figure out the engine. Somebody said that it sounds like a sticking valve. It doesn't make any sense at all to me. Another guy said it might be a crack in the distributor cap. . . sounds like it is worth a shot.

 

[perna00]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

I believe I might have finally found my problem. I took off the cap and rotor (told it was new by previous owner) and found quite a bit of corrosion and wear into the metal with arching evidence. I changed out the coil, cap, and rotor. I'm about 90% sure that was my misfire issue. I'll update when I test it out.

 

[perna00]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

So I tested out the boat today. Unfortunately, the backfire was still an issue. I changed every ignition component except for module and wire. I also noticed that there a slight up/down in rpms at idle (I think the IAC valve needs cleaned). I'm starting to think even though a mechanic said the fuel pressure was reading properly, I think I'm going to hook up the gauge and test it under load. Now that I think about it, the "marine mechanic" said he took it out himself. How could he run it under load and check the fuel pressure? Don't you need to see where you're going too?! I'm starting to lean toward the fuel system now.

!!! And to end the day, I found out the alternator was bad as the boat stalled after it drained my battery completely. I had a 2nd that made it to the dock and out of the water. This is getting worse every time.

 

[perna00]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

Another update, I found the belt got loose and was slipping to cause the charging problem. I'm taking the boat out tomorrow to troubleshoot more. I read that sometimes the distributor's bearing will get loose and cause the spark to miss. I was told if I hook up a timing light and check the timing, the spark shouldn't move more than 2-3 degrees reguardless of rpm. Is this an accurate test?

 

[perna00]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

Time to take the boat out in a little bit. I found out from trouble shooting in my driveway that the low pressure pump was getting pretty hot (almost too hot to hold on to, but barable). I bought another one thinking I found my problem and it does the same thing. Gets pretty hot to the touch. The high pressure pump doesn't get that hot but it whines. . . then again, all high pressure pumps on automotives I've worked on whine decently loud even through the tank. I had the cover off of the engine so I also sprayed some carb cleaner around gaskets and didn't find any leaks. I even took the IAC (idle air control valve) off and cleaned/lubed it. It did seem to lower my rpms slightly afterwards. Maybe it was partial closing instead of all the way from sticking? This boat is going to run like new again by the time I get it right. . . well, it should, half the engine will be new parts. :facepalm:

 

[perna00]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

well, I tested it. No success. It still has the random miss above 2,750 rpms. The only odd things are the the low pressure pump (new) gets very hot, the high pressure pump whines very loudly, and when I slightly pushed the test port on the high end to bleed out a little gas, the engine almost stalled. Maybe not enough fuel on the top end? I'm posting a video of the whining to see if it is odd in this category. Advice?

 

[bruceb58]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

Sounds to me like you need to do a fuel pressure check at all RPMs. You also may want to run on an external tank to get any tank issues out of the equation.

 

[perna00]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

I'll try the external tank. I completely drained the in-boat tank but it would be nice to take the option out of the equation.

 

[dubs283]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

the high pressure pump whines very loudly

a loud whine in an otherwise quiet electric pump indicates either impending failure, or air in the system

like bruce says, run an external tank to eliminate tank/line issues

 

[perna00]

Re: strange knocking noise above 2,000 rpm (5.0 efi 95')

If I hook up an external in the driveway, will the pump quiet and cool down or does it need to be under load?

Did you see my other thread with the pump video? Is it definately too loud?

Here is the link to the video of it whining: http://www.youtube.com/watch?v=ml4DW4uM63o&feature=youtu.be