Fresh MS1 v3.0 install. Runs, but a couple questions

[calpoly-z]

After almost 2 years of a semi completed MS1 v3 box sitting on my shelf I finally got the time and extra income to actually finish building and install megasquirt on my 77 w L28ET. I must admit I am in love with my car once again. Motorcycles had stolen the attention away for the last couple years, but now that it runs and drives like it's supposed to the Z will get much more of my attention.

 

Anyway, on to the reason for the post. First let me list the specs:

 

MS1 v3.0 w 29y4 code

New wiring harness from DIYautotune wired through its own fuse panel

GM open element air temp sensor from DIYauto threaded into bung welded onto J-pipe just before throttle body

Stock CHTS

LC1

240sx TPS (I also have the throttle body that I will install when I get an intercooler)

82-83 distributor w/ CAS

MSD triggered by megasquirt

310cc low impedance Supra injectors w/ stock resistor pack

 

All of that is on a .5mm overbored and balanced 81 L28ET w/ stock T3

 

I've got the car running pretty well now, but I was bit curious as to the temperatures those of you running the cylinder head temp sensor are seeing. I haven't had a chance to take my own measurements of the sensor so I plugged in Mobys values from the sticky into EasyTherm and followed the instructions to get those values into MS. Now for some reason I'm seeing around 215 F whenever the motor is warmed up and running. It never seems to get any hotter than that even under load, but it never really gets any cooler when cruising. I think Ive read that the cylinder head reads about 10F higher than the coolant, but my coolant temp gauge sticks around 180 for the most part. Do I just have it calibrated wrong?

 

Also, I'm noticing a huge amount of heat soak in my intake temps after shutting the car off. For instance, when I start the car 10-15 minutes after shutting it off at operating temps my MAT will read about 140F and it can be 5-10 minutes or more of driving (light load) for it cool back down to around 100F. This seems like an excessively long time and I'm worried I don't have good placement of the sensor or maybe it's not far enough into the airstream. The car also runs pretty rough after these hot starts.

 

I'll post some datalogs soon when I get a chance.

 

Thanks guys, I never could have done this without the people and information on this board

[xxjoeyxxeb]

Hi,

I don't have much help for your post, but I was wondering if you're still near SLO. I am still at Poly, and starting an engine swap soon. PM me or email me at jcloutie@calpoly.edu

[mario_82_ZXT]

215 is what I saw with a bad radiator and normal coolant.

 

With an MSA 4 row and water wetter, I see about 195 with a 180 deg thermostat. Friends with aluminum radiators see much closer to their thermostat value.

 

On the heat soak, what I normally do is after hard driving, making cracking the hood but at the very least, leaving the electric fan on. Where is the IAT located?

Mario

Mario

[calpoly-z]

I've been running an aluminum radiator for years without any issues so i don't think it's a cooling problem. Plus my coolant gauge reads right in the middle, though it is probably about time for a coolant flush. I'm thinking its more likely I screwed up the INC file or didn't import the file to the right place or something. I'll try again tomorrow if I get a chance.

 

IAT sensor is mounted in J-pipe just before throttle body.

 

On another note, I was looking through one of my old datalogs, and is it normal for the WBO2 sensor to oscillate at idle? It just seems like if the idle is pretty stable and pulse width and timing aren't changing that AFR would be more constant. Granted it is only +/- a couple tenths.

[evildky]

did you calibrate for the datsun CHTS with easy therm? mine doesn't nromally get that hot

[calpoly-z]

I tried to calibrate to the CHTS using Moby's values in the install sticky, but I may have screwed up somehow. I'll try again tonight with my own resistance readings.

 

As I drive the car more I'm beginning to notice a few more little issues. Mainly that at light load, low throttle cruising I sometimes get a bit of jerkiness. Is this due to my overrun settings?

 

I think I have it set to initiate over 1700 rpm and less than 25kPa and when thottle is around 25 (this is about 4-5 points higher than my closed throttle value because it tends to vary a bit around 20 +/- 3).