MS3 Pro Conversion

[smurfbus]

Oh, well. It blew the main fuse again and now idle valve and tps were not even connected and vref fuse was out. sensors were powered of a separate 5V output. sensors have clean 5Volts. I also power the pump and injectors externally now. It just shut down of low rpm just like last time and about the same time running before that 1300 sec to 1500 sec. If the fuse blowing is from vref short how does the main fuse blow now with the vref fuse out and sensors powered externally? What else blows main fuse?

[smurfbus]

Now I have spare 500mA fuses. On test run I found out cam sensor is not functioning correctly and gives an error. Could that blow a fuse if settings are for full sync? I switched to semi seq for now with 6squirts/alternating.

I have 14 spare fuses now and 100 coming from china. I hope its not heat related as then these spares would not help fast recovery from cut out.

[willtel]

When you mention that you are using a separate 5v output is that 5v sensor power still coming from the ECU? Just making sure you aren't trying to feed sensors 5v from another source.

[smurfbus]

MS had no fuse for the 5V so yes external 5Volts as I did not have spare fuses. Car worked like that for 20 minutes.

Today I installed the wiring back to how its shown in ms3pro manual. Two new fuses and pump/injectors from one relay and MS from another. MS feeds the 5V now and TPS is connected again. PUUF goes the main fuse. Removed TPS connector and put in new fuse and after that managed to drive an one hour test drive. I hope this all was mostly because of the bad TPS. Although at one point it did blow the main fuse when TPS was disconnected but after that I rewired the vref and installed good insulators over the unused wires.

I got the bad TPS from GSF and it also came with wrong adaptor kit which Albert did not make right so I had to improvise with a tap/drill and a bolt to make the rod long enough. Had to run autotune to get the AFRs in check but now its pretty good with MAP AE only. I really hope this was the end of fuse problems but I will continue to run the car for some time the MS case open. I hate it when I need to pull over to do any troubleshooting in dark and traffic.

['76 911S 3.0]

Can you post a diagram of how you have things wired up? I'm slightly confused as to why the 5v has a fuse on it. You should not need a fuse on the 5v as that is internally regulated by the ECU.

A system diagram, or power distribution diagram at the very minimum, would be very helpful in diagnosing this issue with you.

[smurfbus]

There is an internal fuse for 12V and 5V inside ms3pro. They are 500mA and blow easily if there are any shorts on vref wires. Bad TPS or ICV are most common sensors that can short internally and cause fuse POP. No wonder my TPS was funky. I should remove it and test the resistance but now that the car drives I rather just drive it : )
My only concern is why it popped the main fuse when the TPS and ICV both where disconnected (with no 5V fuse)?

I have it wired just like the ms3pro manual shows.

BTW my off throttle is now much better with MAP AE only than it ever was with TPS AE. Only thing I miss is overrun but its not bad either as those cells are around 16AFR.

[philip j]

Hey John, how you doing with temp control driving your car in this cooler weather? Always had a problem with mine, with my current system, where driving in cooler weather/warm up cycle kicked in on cooler mornings, and made for a really rich drive... Philip

[Jim2]

Philip, what temp does your cold enrichment reach value zero?

[philip j]

Hi Jim, about 118*. car stumbles if I bring it down before its warmed up, but when driving on cold mornings engine temp is only about 90*and intake air is 50-60*

[jpilcher]

Hey Phillip

Mine does run richer on cooler mornings until it gets to operating temp. I need to adjust CLT/MAT values. I am still running Bosch single wire CLT sensor. Car warms up quick.i am out of Warmup within 3 minutes in most cases.

[philip j]

Originally Posted by jpilcher

Hey Phillip

Mine does run richer on cooler mornings until it gets to operating temp. I need to adjust CLT/MAT values. I am still running Bosch single wire CLT sensor. Car warms up quick.i am out of Warmup within 3 minutes in most cases.

John, on a cold morning, what is your engine temp when warmed up while driving? I have my CLT clamped to cooling fins on cylinder number 1. Even after I have warmed up the engine in my garage to about 130*, once on the road, it drops to about 90* bringing on fuel enrichment. I think I may move the CLT to the back of the engine by the oil pump as Chris Carol does... Philip

[Jim2]

Philip, I have my fuel enrichment tapered to zero by 60 degrees C. Three 911 installs and haven't seen a need for added enrichment above this temp.

Of course you will need to correct your RPM fuel values as they are currently being messed with by enrichment up to your quoted 118.

[smurfbus]

Philip, you might want to check your sensor calibration in boiling water and if its still between the fins. Hard to imagine cylinders dropping to 90F after they are warmed up unless the sensor is in direct airflow and not in between the fins.

[philip j]

Originally Posted by smurfbus

Philip, you might want to check your sensor calibration in boiling water and if its still between the fins. Hard to imagine cylinders dropping to 90F after they are warmed up unless the sensor is in direct airflow and not in between the fins.

I just changed my sensor, the new one gives the same readings as the one I took off...

[jpilcher]

Originally Posted by smurfbus

Philip, you might want to check your sensor calibration in boiling water and if its still between the fins. Hard to imagine cylinders dropping to 90F after they are warmed up unless the sensor is in direct airflow and not in between the fins.

Hi Phillip

I still have to check the clt temp, I will do that this morning. My sensor is located on cylinder number 3 cooling fins. A hole was drilled and tapped, and sensor was threaded into hole. Your problem might be a function of the location.

[jpnovak]

There is too much airflow to clamp a "clt" sensor to that fin location. It will always show cooler than actual due to location and convection cooling.

[philip j]

Originally Posted by jpilcher

Hi Phillip

I still have to check the clt temp, I will do that this morning. My sensor is located on cylinder number 3 cooling fins. A hole was drilled and tapped, and sensor was threaded into hole. Your problem might be a function of the location.

Thanks John, this also seems like another good location... you didn't happen to get a pic if the installation?

[jpilcher]

I'll see if I have one.

[jpilcher]

Hi Phillip

Sorry couldn't find a picture of sensor. It is screwed into the fins, so it is partially shielded from direct exposure to fan.

Regards

John

[kenikh]

Here's mine. It's drilled and tapped into the cam tower.



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