Ford EFI cooling: Way to cold... (SOLVED sorta)

[MasterGoa]

You may remember this thread about my adventures
in finding why my engines are in limp mode, except
for 3 weeks in the middle of summer.
Thread here:
http://forums.iboats.com/volvo-pent...ce-ford-based-efi-v8s-1993-1996-a-622323.html

Well, after EXTENSIVE testing of all fuel injection related, the issue is
that the engines never get hot...

The right engines stays in the vicinity of 97F, including the exhaust manifolds.
The left engines goes up to 125F...
This is measured with a DeWalt pro quality IR thermometer...

I have changed the t-stats this spring, so they have 30 hours.
They always seemed cold. I though my temp gauges where faulty,
but they are on the dime. WAY TO COLD!

So what to do? Those engines are OMC, but they have the same
engines and especially t-stat housing as the Volvo counterparts.

Could the bypass hole have grown over time to let too much water
pass by? I will remove the housings tomorrow, but I would appreciate
some guidance...

I have no idea what to do...

(PS: Water temp is 65F...)

 

[500dollar744ti]

Re: Ford EFI cooling: Way to cold...

Re: Ford EFI cooling: Way to cold...

What temp thermostat are you running?

 

[MasterGoa]

Re: Ford EFI cooling: Way to cold...

Re: Ford EFI cooling: Way to cold...

new Volvo 160 on both engines...

 

[BRICH1260]

Re: Ford EFI cooling: Way to cold...

Re: Ford EFI cooling: Way to cold...

I had a similar "underheating" condition in my Volvo. Turns out the thermostat bypass hole was clogged with rubber impeller pieces. Once the hole was unplugged, it began to heat up near normal operating ranges.

 

[MasterGoa]

Re: Ford EFI cooling: Way to cold...

Re: Ford EFI cooling: Way to cold...

Oh really?

This is very interesting, as I though my bypass would have grown
in size and provided too much water...

Life is ironic sometimes...

Thanks for the tip!

 

[MasterGoa]

Re: Ford EFI cooling: Way to cold...

Re: Ford EFI cooling: Way to cold...

Interesting...

Closed loop and open loop cooling systems have
bypass holes that do the opposite:

Closed loop (car with coolant) has a bypass hole
to recirculate coolant in the engine whereas
open loop as a bypass to take fresh water and take it
straight to the exhaust cooling hose and back in the lake...

The more you know!

 

[MasterGoa]

Re: Ford EFI cooling: Way to cold...

Re: Ford EFI cooling: Way to cold...

Well, I was finally able to do a complete ride without issues in 65F water today:
The t-stats were simply installed on an uneven surface...

I have not cleaned the surface where the t-stats sits, thinking
the rubber oring that holds it there would seal it off...

I uninstalled the t-stat housings and had the guy
from the marine clean and buff the t-stats mating surface...

Now both engines are in the 140-150F range...

I will order new housings during winter, but at least now,
I can see the temp gauges very close to where they should be

BTW the bypass holes were clear, but I did notice that pressure
takes a long time to dissipate when I turn the engines off...

Oh well

 

[MasterGoa]

Re: Ford EFI cooling: Way to cold...

Re: Ford EFI cooling: Way to cold...

Dang, I spoke a little too soon.

The situation HAS improved but there are still
episodes where the engines run rough again...

So it went from bad to intermittent...
The water is getting colder though...
Gauges were both pretty much at 140
which is a bit low.

Welp, lets try new housings

 

[MasterGoa]

Re: Ford EFI cooling: Way to cold...

Re: Ford EFI cooling: Way to cold...

Well, did testing today by installing garden faucets at the raw water inlet
of the t-stat housings.

EUREKA!!!

Reducing the flow of water to the t-stat housing brought both engines to the 160F range
and I did a 1.5 hour ride today consuming only about 10 gals and hearing the engines
just super smooth!!!

However, I did catch a debris in one of the faucets, of course, just opening it
resolved the situation where the port engines when up to 190F and into SLOW mode.

Just a 1 minute trawl brought everything back to normal...

However, the strange thing is how little raw water (60F) the engines
needs to run at the right temps...

Using a 1inch faucet on each engines, and those faucets need 8 full turns
to close, I only needed between 1/4 and 1/2 turn to keep the engines perfect...
That's right, only about 1/8 inch equivalent hose...

So there you go... I still cannot believe how little
water these engines needs while running perfect...

So I will probably use smaller faucets and strainers
to keep everything perfect all year round...

So unless t-stats sold by Volvo for those engines are all
way to limp to keep pressure, I guess that is my only option...

I never would have though...

NOTE:
While trawling at 12kph and 1400 rpm, closing the
faucet completely required 4 minutes for the engines to go over 170F!!!
4 minutes!!! Wow...

 

[djpeters]

Re: Ford EFI cooling: Way to cold... (SOLVED sorta)

I have been following your thread as I love do-it-yourself troubleshooting and things. Glad you got them to run good again!

 

[MasterGoa]

Re: Ford EFI cooling: Way to cold... (SOLVED sorta)

Thanks.

I am so relieved myself as I was going crazy trying to find why they ran so good for just a short while...

Never though it would be cooling...

At least after checking everything else, I know it is in perfect running order...


Still, I find it hard to believe that this is the setup from the factory...

I still feel I may be missing something, but for now, a water strainer and valve
will make me enjoy this boat to the fullest...

To think I was ready to rip out the MAP sensors lolll

 

[MasterGoa]

Re: Ford EFI cooling: Way to cold... (SOLVED sorta)

So I have confirmed the symptom: Overcooling ruins fuel consumption!

Having said this, the boat is coming out next week-end so I will search in
the winter for a solution to maybe fit a more recent t-stat housing on these
engines and keep them at adequate running temps...

If not, i will experiment with sealing the t-stats with rubber seals
at the mating surface... What I ride it has been!

 

[500dollar744ti]

Re: Ford EFI cooling: Way to cold... (SOLVED sorta)

So I have confirmed the symptom: Overcooling ruins fuel consumption!

That's generally the case but on EFI engines it REALLY ruins fuel consumption.

Glad you are well on your way to getting the right temps.

 

[MasterGoa]

Re: Ford EFI cooling: Way to cold... (SOLVED sorta)

Thanks.

Indeed, EMFM (limp mode) on these Ford engines
turns it into an alcoholic lolll

Chocking the water inlet is not the solution though,
so I will search for an alternative during the winter...

The mechanic at the marina suggested a cork
seal under the tstat seat to be 100% sure...

But for now, next year! The boat is coming out next weekend...

Thanks all for your help!

 

[MasterGoa]

Re: Ford EFI cooling: Way to cold... (SOLVED sorta)

Well, it's THAT time of the year...

Before the long sleep, I took a pic and video of the engines:

OMC 50FI starting, pair (302 Ford EFI) - YouTube

You can see the tstat housing as well...

Happy winter!

 

[MasterGoa]

Well, I was able to finally fix my issues!

Without changing any parts, I disassembled the therm housings and installed
cork gaskets I made from 1mm think cork blank sheets.

I used an Olfa circular cutting tool.

Now both engines go up to 150F and I see when the terms open up.
Gas consumption went down to a minimum, so I am very eager to
get back at the helm this week end!

For anyone with the same issue, use a wire brush on a drill
to clean the thermostat mating surface and the O-Ring groove.
Then, put the cork gasket on the termostat and push the thermostat
only the mating surface. Using a large flat blade screw driver, push
down on the thermostat, compressing the gasket, while twisting the
O-Ring into the groove.

Worked perfectly and was very inexpensive...

Now, I have another problem: My engines being optimal, I have
a lot of prop slip

Happy boating season to everyone!