Screeching +Smoke = a bad night.

[enginerd]

Re: Screeching +Smoke = a bad night.

I think I figured it out.

I kinked the breather hose with IAC blocked. The engine could not run. I unkinked the breather hose and the engine fired right up. I removed the vacuum line from the PCV valve. The breather line was still sucking a ton of air in. I'm 99% sure the intake manifold gasket is to blame. Thoughts?

Gasket is here tomorrow. I'm going to rip the it apart once it cools down tonight.

 

[HT32BSX115]

Re: Screeching +Smoke = a bad night.

I think I figured it out.

I kinked the breather hose with IAC blocked. The engine could not run. I unkinked the breather hose and the engine fired right up. I removed the vacuum line from the PCV valve. The breather line was still sucking a ton of air in. I'm 99% sure the intake manifold gasket is to blame. Thoughts?

Gasket is here tomorrow. I'm going to rip the it apart once it cools down tonight.

Yeah. I am not all that well versed in Ancient Ford EFI but any EFI engine will run strange with a severe (intake) vacuum leak because it may increase the fuel flow to make up for the leak (like opening the throttle-plate etc)

The difference here is that I am pretty sure that you do not have either an oxy sensor or other "closed-loop" feedback sensor that could sense a severe vacuum leak OTHER THAN the MAP sensor................

You might talk to a Volvo Penta guy though. That engine is really a Volvo Penta "equipped" engine.

You probably know do have a problem if you ever need to replace your ECM.

3854537 : PART REPLACED BY 3854889

You'd possibly have to find a used one since they don't seem to be available anymore.......A Volvo guy might have a third replacement option. There's still a LOT of these mid/late 90's OMC/Volvo (Ford) engines out there


Yours obviously works so this is only if it failed.

The other choice would be too convert to a carburetor.....or a repower with a Chev Small block (which would require a different flywheel housing etc)

I am amazed that it's so hard to find some Ford EFI parts for a 96 "anything"

 

[enginerd]

Re: Screeching +Smoke = a bad night.

The other choice would be too convert to a carburetor.....or a repower with a Chev Small block (which would require a different flywheel housing etc)

I've thought about what I'd do if the ECU was bad. A few ideas run through my head.

- Marinize and mount a GM genIII/IV truck motor. This would be a huge undertaking...but would be a great engineering exercise. With that said, I'd rather use the boat than engineer it.
- New intake and carbs.
- Replace ECU with a Megasquirt System. MegaSquirt

I am amazed that it's so hard to find some Ford EFI parts for a 96 "anything"

You can say that again. It is unbelievable. The aftermarket mustang market has a lot of solutions to get around it, but at some point enough is enough. I'm even having trouble finding intake manifold gaskets. I'll save that for another thread though.

 

[HT32BSX115]

Re: Screeching +Smoke = a bad night.

I've thought about what I'd do if the ECU was bad. A few ideas run through my head.

- Marinize and mount a GM genIII/IV truck motor. This would be a huge undertaking...but would be a great engineering exercise. With that said, I'd rather use the boat than engineer it.
- New intake and carbs.
- Replace ECU with a Megasquirt System. MegaSquirt

Yeah. That Mega squirt system is pretty cool but I do not know if they comply with USCG requirements.

I always worry about the liability of anything (Non-approved) on a marine engine.........I.E. you're at the lake, with your kids and the neighbor kids......

The boat goes "Boom" and one of the neighbor kids is seriously injured or dies.

The neighbor gets himself a "Slip & Fall" bloodsucking lawyer and in 'discovery' they find out you put non-USCG-approved parts on your boat & they think that's why the boat went "Boom"

It goes downhill from there and you start looking for another mortgage........it gets even uglier

 

[enginerd]

Re: Screeching +Smoke = a bad night.

Good points. I'm hoping the electrons keep flowing properly until I sell the boat.

 

[enginerd]

Re: Screeching +Smoke = a bad night.



Look what I found...I sure hope it was the cause. I should have taken the picture after I cleaned all the rust and paint flakes up.

 

[HT32BSX115]

Re: Screeching +Smoke = a bad night.

View attachment 203781

Look what I found...I sure hope it was the cause. I should have taken the picture after I cleaned all the rust and paint flakes up.

That looks like a pretty good place for a leak!

 

[Grub54891]

Re: Screeching +Smoke = a bad night.

I stopped using them gasket's on the end's of the intakes. Had a few do just that. Now I use the automotive black high temp silicone on em. Just have to let it set for a day to dry well. Never had a problem like that again. What I figured out is when the head's or intake have been machined flat,they sit lower,thus the gap is less between the block and intake. The gasket is to thick and squishes out. Even if it has never machined, I don't use them.
Grub

 

[enginerd]

Re: Screeching +Smoke = a bad night.

Well...the intake manifold gasket wasn't the cause. I swear this boat is cursed. I'm calling a few mechanics tomorrow to see if they can take a crack at it. Wish me luck...

 

[enginerd]

Re: Screeching +Smoke = a bad night.

I haven't given an update in a while. Most local marine mechanics don't want to take a look after I told them everything I did. One mechanic said that he saw this problem on a 5.8L omc once. After hours of being stumped, they found a hairline crack on the lower intake. I took my lower to the local machine shop to have them pressure test it. It tested fine, but they are convinced the upper is the problem. The upper is being pressure tested tomorrow.

I pulled the codes...everything came back good. I'm buying a new fuel pressure regulator tonight. The vacuum line smells like gas now...didn't a few days ago.

I'm going to pull the valve covers to inspect the valves operating too.

Wish me luck. Eric

 

[enginerd]

Re: Screeching +Smoke = a bad night.

Another update...because I find it incredibly frustrating when there is no conclusion to a forum thread.

The upper intake tested fine too. I changed all the vacuum lines. I replaced all the temperature sensors. Still doesn't want to idle, in fact the situation worsened after the latest round of work.

The engine breather tube connected to the valve cover still sucks a ton of air. I'm convinced an internal vacuum leak is causing all these issues. I did the intake manifold gasket twice now, but the problem persists...even with the PCV disconnected.

Any ideas what else could cause an internal vacuum leak? Cracked Head? Head Gasket? Valve seals?

Thanks again...we're inching our way to a rebuild and carbs.
Eric

 

[HT32BSX115]

Re: Screeching +Smoke = a bad night.

Four Winns U17 - Awesome Boat...powered by a finicky OMC Ford.

It's a common "thread" I'm sorry to say......


I sold the distributor and electrical harness etc from my previously installed OMG 460 to a local guy that had a 460 with the infamous OMC "Spitfire" ignition.

It died on him and there were NO parts to be bought to fix it!

I would say that there's not a LOT wrong with the Ford marine engines (unless you can't buy reg'lar repair parts!!)

If you're going to rebuild the engine, AND you have used manifolds and risers, I would want new manifolds and risers on any rebuilt engine.
Ford manifolds are always a little more to buy and are getting somewhat scarce as people move away from ford marine engines.....

That said, now might be a good time to consider going to a 5.7L GM V-8.

You would have to get the different flywheel housing and some other accy's but once installed you'd have a pretty nice setup AND you could also consider replacing your drive with a Volvo DPS.

The addition of a Duo-Prop drive would amaze you with the performance improvement!


Good luck!



Rick