355 owners only! More data samples needed! Anonymous poll!

I understand where you are going and your hypothesis is a good one. You probably have considered what I say next. First is are we are sure that even with the low gauge temps you are in closed loop? There is a hierarcy of factors that set the fuel , coolant temp being one factor. But is it a big enough factor to see the effect you are seeing with damage like dead cats from wrong A/F ratios? third? why doesn't the primary feedback, the upstream 02 sensor especially with its confirmation from down stream 02's correct for, or significantly over-ride, the errant coolant temp especially if a hierarcy is in play? Fourth, when these cars are raced they live at wide open throttle. The cars run in open loop with no where near the correct mixture control that is possible in closed loop. How can we explain the near complete lack of engine destruction of the 355 challenge fleet from this whole cat death, valve guide, header triad vs. the many problems seen in the streetcar fleet under much less stress and sometimes very low miles?

 

Not sure if this gives us anything but my secondary air system also stopped kicking in after driving the car. I think it was kicking in because engine would cool off enough. Not sure but now it only kicks in I think during warm up. I would always hear it when pulling up to stop lights after cruising about 5 gear in town up to a stop light. Not positive because did not clue in at the time but my engine temp was probably at 6. Grant

 

but what does fatbillybob = ?

 

Sounds more like the temperature gauge isn't reading 100% accurate. Brand new thermostats aren't THAT prone to failure.

I'd be curious to see what an IR thermometer reads at the top/bottom of the rads.

 

My initial findings are that my cruising temperature is unchanged after replaceing both coolant temp sensors (gauge sensor, ECU sensor) and the thermostat.

Prior to replacement it would sit at the #6 level on Goth's scale. As of my long drive on Sunday it is still sitting at #6 on the scale. This is on a 10 mile drive on the freeway after being fully warmed up. Outside temp is about 40F, low humiditiy and the heat on low in the car.

 

Thanks for following up Steve. I'm still having temperature issues with my car. It's in the shop now having a 360 pump put in. I asked them to replace the thermostat and to take a look at the rest of the cooling system to see if I need anything else done while it's there.

When the temperature is less than 80 or so outside my car gets just below 7 on the scale when moving over 40 mph. When I get to a long stoplight after driving for a while it will sometimes go as high as 13. When we test is at idle in my driveway or the shop it's stays at a little over 10.

 

The only time my car hits 10 on the scale is in the summer sitting in traffic for long periods of time. 80F plus outside and it will kick the fans on at 10 and pull it down to around 9 an then the fans turn off. Once back up to speed the temp will continue to drop to 6 eventallly.

 

Just reading back through this thread and remembered this advice Goth gave me. It turned out that the switch on one of my fans was failing. It eventually triggered a CEL that the shop said indicated that one side of the engine was hotter than the other. They replaced the switch and I haven't gotten any temps over 13 since.

As I said in the post above I'm still a little concerned about the swings in temperature I'm seeing from 7 to 13. Maybe I'm just worrying too much.

 

Steve where did you get the thermostat mine I got seems to be ok.

 

Goth, first off, that is not correct. I have a 98 F1, assembly number 28459. The parts diagram states the oil temp sensor was valid until assembly number 29613.

Ferrari F355 M5.2 (1996+) Parts : Table 17 - LUBRICATION SYSTEM

See photo. I'm still trying to figure out were it's wired to, I've not yet traced it. Of course there is no oil temp gauge (I plan to add one)

Second, this thread and your efforts are awesome!!!! I believe my car is always between 8 & 11 but I'm going to follow your exact procedure next drive and will post.
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Dave,
This newbie thanks you for resurrecting this thread. I would have been completely ignorant about this issue. And Goth, another thanks for posting it.

 

Just to add to the importance of the engine temperature and accuracy of the sending unit
The engine ECU has in the area of 65 functions that are based off the coolant temperature

I am now changing changing mine every major service and check the calibration before installing a thermostat and coolant sensor

 

Is the 86C degree 328 thermostat that fits the 355 Ferrari part number 128991?

 

In town 10, tearing it up on highway 7-8

 

8.
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Looks like temperature follows a normal distribution with one outlier!

 

Did the test mine sat at 7

 

Tested and she stays at a solid 8 here in California with temps in the high 70's. I have noted that in traffic, she will jump to around 10, but the fan kicks in and she runs about 9 on a warm day if I am driving normally (for me 80+). I have driven her on cold days, when she runs at 7 for a while, but that is very unusual.

 

did I miss something? Now that this thread has lost steam...what was the purpose of this poll?

 

Randy, it's all spelled out in the thread - you should read the entire thread.

 

Great thread Goth. Would it be best to drive with a obd scanner telling you the actual temperatures, rather than, relying on the dash temp gauge. Want to get a accurate reading.

 

Today I went for a long drive with my scanner reading temp info live. The scanner was showing very different info from the dash gauge while highway driving.

Scanner was between 179.6 and 195 with most readings consistently in the 181 to 188 range. There were a few dips to 177 degrees, but things were quickly reversed back above 179.

I was driving around 70 to 80 mph and outside temperatures were 55 to 60 degrees ambient temperature.

When going slower (40 mph), the scanner had a similar range in the 183 to 188 range for most the time.

Stopped, scanner read 194 and fans kicked in about 192

The dash gauge was all over the place, but mostly below the line to the left of 190 while driving.

Also, the markings / ranges on my gauge don't match Goth's chart. His seems to have more levels / lines on the gauge than mine

See picture below. The scanner was reading 183 degrees when this photo was taken.
I'm thinking my thermostat is fine, but the temp sender has failed.
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I want to update the results I have experienced for others benefit.

Due to the above scenario, I replaced the thermostat (GT Car Parts), the thermo sensor, and the thermo sender. Huge pain in the azz!!

I took the car for a drive with the OBD scanner running. It was cold outside (mid 30s). These new parts made a big difference. The scanner showed temps mostly between 185 and 188 at all times. 60mph to 95 mph. The lowest I saw was 183. This compares with running in the upper 170s before the changes. Turning on the heat made little drop in temperature.

I boiled the old thermo and new thermo side by side on the stove to test. The old thermo was opening before the new thermo, thus coolingthe engine too often.

The dash guage was confirming the OBD numbers and stayed in the "good" range of Goth's chart.

Hope this data helps.

Skipp

 

While moving, about 50 degrees. Another pic while idling for a while. Never goes over 190, even while idling in 90 degree weather. Oil shot for reference at 50 degree and idling for a bit.
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