My PMO ITB Project

[brads911sc]

Thanks Jaime.

Do you have a recommended brand or model of sensor. Have you tried this?

Here is a company that makes several that are good to 500 degrees.
http://www.omega.com/toc_asp/subsectionSC.asp?subsection=C06&book=Temperature

Thanks

Originally Posted by jpnovak

Not all CHT sensors are created equal. Many are based upon a thermocouple wire due to the higher temperatures associated with the air-cooled heads. The thermocouple will require a small voltage amplifier to provide a compatible signal.

Any sensor based upon a thermoresistor or RTD will work just fine but loose sensitivity and resolution at high temperatures. Just make sure you match the sender to the ECU for a compatible setup.

[shbop]

Signing-up. Looking good Brad.

[wachuko]

Brad, thank you for documenting your project. Please, as much as possible, do list the part numbers of what you are using, and if possible, photos of the parts as you did in the first post.

The trick part will be programming the ECU and doing the fuel maps.

I want to do the same with my '83 project. So following your thread closely.

Thanks again and best of luck!!

[brads911sc]

Ok. Received all my electrical components. I will create the wiring harness this weekend and Ill post my progress. Here are some of the parts received.

Here is the ECU. Its Black Aluminum MS-2, V3.57.



Here is the Harness to connect the ECU to the Relay Board.



Here are the Injector Connectors with Pigtails. (EV-1)



Here is the relay board.



Here is the Innovate Wideband O2.



Here is a wiring bundle with labeled wire in 12 foot lengths that all are color matched to the MS Relay/ECU wiring Harness.




More to come!

[brads911sc]

Spent some time wiring the TPS/IAT and Injectors and creating the wiring harness.

Here are some shots... I need to wire the Wideband o2, the CHT (if used), tach wire, engine ground and 12v power... but those will be mostly done in the car...

Here is the TPS/IAT Harness...



Here is a few shots of the middle stages of the Injector Wiring





Here are some shots of the closeup of the completed harness at the injectors...




Here is a shot of the completed harnesses... Turned out pretty good. It will just plug right into Relay Board.




Here is the relay Board. Mostly done.



Next are the fuel lines...

[brads911sc]

Well... here is an update... I've been quiet the last couple weeks with the holidays...

I bought all the fuel lines and related hardware. I will post pics and specs. I am building my own lines using SS Line and AN Fittings.

I removed the distributor and sent it over to Barry Hershon to rebuild it, remove the vacuum advance and recurve it with mechanical advance.

I want to get it back, installed, car running, and the timing set with the CIS on the car because Megasquirt and PMO's are somewhat of an unknown with very few base maps out there and I do not want to have both fuel and ignition ripped apart at the same time. That makes chasing issues and problems all the more difficult...

More to come.

[dfink]

Will jump in on the idle issue. I also have problems getting good idle when cold. Not so much the idle but the idle speed. The idle speed will change on my car several hundred RPM from cold to warm. If I set it to idle good cold it will idle way to fast when warm. If I set the opposite then I have to feather it to keep it running cold. My idea is to install an idle solenoid that will bump the idle when cold then turn off when the car warms up. Holley makes a part and the following link show the part. Should be able to either just use a switch or could wire it to one of the general purpose outputs.

Holley 46-74 - Holley Universal Throttle Solenoids - Overview - SummitRacing.com

[Shaun @ Tru6]

Why wouldn't you just use an MFI filter console with Bosch cold start enrichment valve? Pretty much plug and play.

[jpnovak]

Just install a factory hand throttle on the side of your parking brake. Simple and no programming involved. The issue with a PWM style idle solenoid is where do you connect it to the linkage such that it pushes evenly. The only place is the bell crank at cyl #3. The problem is building a bracket to mount it in that location.

Shawn, The software controls cold start enrichment. You simply tell the computer to deliver more fuel at low engine temps. This amount tapers off as the engine warms up. The problem is that there is no way to deliver extra air to help the engine speed. Early cars have a hand throttle. CIS and motronic both have air bypass systems.

[brads911sc]

The Megasquirt ECU has an input for both the IAT and CHT so i had intended to try to tweak the Maps to help at Idle with a head mounted Temp Sensor (CHT) as well as the IAT. I already have the IAT installed for the Air Temp. I had found several good CHT's. The good ones are about $100 (thermoresistor or RTD type). http://www.omega.com/ppt/pptsc.asp?ref=SRTD-1_SRTD-2&ttID=SRTD-1_SRTD-2&Nav= is a good one that you could cement on the head. http://www.omega.com/ppt/pptsc.asp?ref=PR-20&Nav=temc03 is one you could slide the probe though the fins (may actually work better). There is another pelican who has done this. I remember in my research seeing pics. It probably just doesnt work very well due to the Air issue that Jaime mentions or everyone would do it... so i may skip it and keep it simple and just go with the manual hand throttle. Still have not made a final decision on this part of the install...

Originally Posted by jpnovak

Just install a factory hand throttle on the side of your parking brake. Simple and no programming involved. The issue with a PWM style idle solenoid is where do you connect it to the linkage such that it pushes evenly. The only place is the bell crank at cyl #3. The problem is building a bracket to mount it in that location.

Shawn, The software controls cold start enrichment. You simply tell the computer to deliver more fuel at low engine temps. This amount tapers off as the engine warms up. The problem is that there is no way to deliver extra air to help the engine speed. Early cars have a hand throttle. CIS and motronic both have air bypass systems.

[Jeff Alton]

Can you not make corrections with oil temp and air temp? That is all I use to get good idle cold and warm. My car idles about 100rpm lower when cold, but it does not take much time (1 min maybe) to be idling perfectly. I have not bothered to try to optimize it anymore as the car is heading to the track only in the spring.

Cheers

[brads911sc]

Jeff,

Do you have a pic of what you did with the breather port?

I was thinking the now unused Thermotime switch port but many thought that it wouldnt work effectively. have you effectively used it for this purpose?

Im in the same boat. Doesnt need to be perfect, just wanted alittle more precision than Air only.

Thanks

Originally Posted by Jeff Alton

Can you not make corrections with oil temp and air temp? That is all I use to get good idle cold and warm. My car idles about 100rpm lower when cold, but it does not take much time (1 min maybe) to be idling perfectly. I have not bothered to try to optimize it anymore as the car is heading to the track only in the spring.

Cheers

[Jeff Alton]

I can take a pic in a bit for you. I don't use that location, although I have a sensor in it. I did the two locations to test them as no one could tell me which one would give more accurate oil temp readings. They both read the same......

All you need is sensor that has a value that changes as your motor warms then you make changes based on the change in value. It could be oil or CHT that you use for warmup maps.

[dfink]

Originally Posted by jpnovak

Just install a factory hand throttle on the side of your parking brake. Simple and no programming involved. The issue with a PWM style idle solenoid is where do you connect it to the linkage such that it pushes evenly. The only place is the bell crank at cyl #3. The problem is building a bracket to mount it in that location.

Shawn, The software controls cold start enrichment. You simply tell the computer to deliver more fuel at low engine temps. This amount tapers off as the engine warms up. The problem is that there is no way to deliver extra air to help the engine speed. Early cars have a hand throttle. CIS and motronic both have air bypass systems.

I had a hand throttle. Modified one of the heater levers as I no longer have heat. It worked OK but my connector broke and I just never got around to making another one.
As for idle speed differences mine has more of a 300 rpm difference. I however am horrible at tuning so the entire issue is likey that I just don't have things set right. As for a warm up sensor I just used the original head temp sensor.

[jpnovak]

Mine idles about 400 rpm lower than when warm. The hand throttle is a must. Especially since my car idles about 850-900.

Jeff is correct, there just needs to be some indication of a "warm" engine. It does not even have to be very accurate. Make sure you use a location that is tied to a large metal object. Mounting on a cooling fin is not enough. Also choose a location that is free from air currents that will prematurely cool the surface compared to the sub-surface temperature readings.

I wish I had the CHT sensor mount machined into my SC heads. That would be the best indication but not absolute.

As far as setting warm-up maps this is easy but will require a fairly well tuned motor. You just start the car when cold and look at the engine temperature vs AFR. Simply let the car idle for warm up and adjust the fuel trim to get about a 12.8 AFR or whatever your personal mixture target is. You might also need to adjust the after-start enrichment to get a bit more gas for those cold starts. Think of this as the electronic equivalent of pumping the gas pedal with carbs for initial start.

[Jeff Alton]

Ok,

I am not familiar with Megasquirt, I use a different system. The "temp" reading when cold is not important as long as it is considered "X" value. The temp reading when at "operating temp" is the same as long as it is "Y" value. You should be able to change maps starting at X and ending at Y with many steps in between in which you can tweak fuel and advance if you chose......

Cheers

[Jeff Alton]

Here is the pic of the breather cover sensor. Like I said earlier, I only mounted this one to compare it with the factory gauge and the sensor in the timing cover. All read the same give or take a few degrees. No one was able to provide any conlclusive info as to the best place to mount the sensor so I mounted them in both places to put the issue to bed. So depending on one's situation, they can rest assured that both locations will work fine.

Here is a pic of the sensor that I took 10 mins ago. It is a standard GM style oil temp sensor. Please pay no attention to the dirt in the pic, I had just finished cutting out the the seat base and firewall area of the car and had not blown the debris away!




The throttle return spring and throttle linkage in the corner of the pic is the custom stuff I fabbed up for my Jenvey ITB's.

Cheers

[78SCRSMAN]

Any plans to soldier the electrical connections?
Great thread, thanks for sharing.

[Jeff Alton]

Proper crimp connectors and shring wrap. Solder can have a tendencey to crack under vibration....

Cheers

[brads911sc]

there are three wires that are soldered to the relay board... the rest are proper crimps and shrink tubing and the wrapped in the wire loom shown.

Originally Posted by 78SCRSMAN

Any plans to soldier the electrical connections?
Great thread, thanks for sharing.