T3 megasquirt II conversion

[Devastator]

having the common ground strapped direct to the battery and keeping the rest of the MS as isolated from the engine as possible is IMHO the way to go

I have all my grounds running to a terminal block that is in turn connected to the negative battery terminal by a 10 gauge wire. The TPS signal seems pretty quiet so far.

Mine is wired that way too, only I installed the LC-1 with a wire going directly to the negative battery terminal, (remember that I have a sandrail), in an attempt to "quiet" the TPS signal. Didn't help anything. I'm lucky like that. It's hard to see the TPS signal bouncing around until I go to the ACCEL settings, then it's pretty obvious, until I adjust the sampling rate and the signal masking values. As soon as I disconnect the LC-1, by removing the fuse, the TPS signal is steady as a rock. Anyway, with a friend's LM-1, I didn't have these issues, and that's why I'm posting this information for you. Hope it helps more than it hinders.

[Piledriver]

I forgot to mention all power to the MS and JAW etc is also on a 10 ga wire that runs to/from a relay on the same ground panel, direct from the battery... operated by the ign wire.
(Actually I think it's the std ECU power relay control wire in my case, as it was already under the back seat and it's white, in a T3)

The rest of the electrical system is only seen via the battery...

Maybe your LC1 has some issues?
I think there was a MS board mod to reduce the crosstalk.

[Devastator]

Maybe your LC1 has some issues?
I think there was a MS board mod to reduce the crosstalk.

I don't wanna hijack this thread, but thanks for the info. I'll look into that. I'll also look to see of the LC-1 is wired to the same relay as the MS as I hadn't considered that.

[Max Welton]

More progress tonight. After replacing the left sled tin, and attempting (unsuccessfully) to fix a leak at the coolant temp sensor and replacing the left rear fender, we drove down the road and back about a mile. The LM-1 says we're really rich (9:1 and worse) under throttle, but it does seem to run well.

I have a range of non-FI related things to address, but hooking up the LC-1 will be the next point of interest. Curious to see if the LC-1 agrees with the LM-1. Idle AFR is in the 12-12.5 range according to the LM-1.

Anybody got a suggestion for the CLT leak? I've tried high-temp silicone and ultra-copper thread sealant. No joy so far. I really don't want to JB-weld it in as I doubt it would ever come back out.

Pictures of the CLT back on page 12 of this thread.

http://www.shoptalkforums.com/viewtopic ... T#p1046849

Max

[Piledriver]

Permatex pipe thread sealant. It's an anerobic sealant with good filling capabilities.

I think you give JBWELD way too much credit.

Personally I'd like to try the CHT connected at the intake manifold>head location, as AFAICT that's what most sensitive "warming up" as far as fuel needs. (intake port and valve)

[Max Welton]

Well, I already have a hole in my head (so to speak) so I'll try to make this work.

Do you think the Permatex will handle the heat? I was reading 215º with tonight's short ride.

Max

[Devastator]

Anybody got a suggestion for the CLT leak?

There's a yellow, thicker, teflon tape at my local hardware store, designed fr use with petroleum based products. I've taken a few extra wraps with it on NPT fittings in order to make a good seal with my valve covers.

[Max Welton]

Great. I'll do a little shopping on the way home tomorrow.

Thanks!

Max

[supaninja]

Permatex pipe thread sealant. It's an anerobic sealant with good filling capabilities.

I think you give JBWELD way too much credit.

Personally I'd like to try the CHT connected at the intake manifold>head location, as AFAICT that's what most sensitive "warming up" as far as fuel needs. (intake port and valve)

I'm with max, jbweld would fix that leak, but there would be no removing it ever again...jbweld is some awesome stuff.

[akokarski]

hope sealant/tape will help seal this oil leak. But it's an ntp thread and probably is not getting more than a few full threads in that thin wall. Perhaps aluminum bung welded to the head would seal it up. I know that's a bit drastic, having to take the head off and get it welded.

[panel]

Could you make the hole bigger and then put a reducer in there? Or drill/tap then plug it and put it somewhere else?

[Max Welton]

hope sealant/tape will help seal this oil leak. But it's an ntp thread and probably is not getting more than a few full threads in that thin wall.

Yeah, and the angle probably isn't helping either.

Perhaps aluminum bung welded to the head would seal it up. I know that's a bit drastic, having to take the head off and get it welded.

Assuming I stay with this location, this seems like the best approach.

One thing we did notice last night is that after the test drive, the temp reading from the CLT was at 215ºF. Given the location, that may be reasonable.

But after shutting down for a few minutes then restarting, we saw that the CLT had cooled way down and required a good 30-60 seconds to return to near the pre-shutdown reading. I'm thinking that the oil in the rocker galley drained away after shutdown and uncovered the CLT sensor. I wouldn't mind, but during the time it took for the reading to come back up, the warm-up enrichment was being applied.

But I'm not going to spend a lot of time on the WUE. The engine warms up pretty quick. If neccessary I will disable the WUE function for the time being. I've certainly driven enough dual-carb cars without chokes after all.

I need to plug the leak and move on to the VE table.

Max

[Max Welton]

Filing this under "I need to read the manual more carefully"

Yesterday when I was straightening up the under-dash wiring, and was disconnecting and reconnecting the battery, I made a discovery. After having the ignition (and the ECU) on, when I disconnected the battery, I heard a quiet little *click* from the rear. It turned out to be the injectors. The ECUs injector drivers were staying hot even with the ECU depowered.

I finally found the following note on the "Wiring and Sensors" page of the MegaManual:

You must use a "main relay' that supplies both the injectors and your MegaSquirt® controller, as shown in the external wiring diagram above. When your MegaSquirt® controller shuts down, the injector driver states are 'indeterminate' and might allow current to flow through the injectors. Thus the injectors might stay open and flood the engine if the MegaSquirt® controller isn't powered but the injectors are powered.

I had powered my injectors right off the battery. So when I turned off the engine, the injectors were staying open during the 10 or so seconds it took for the pressure in the fuel loop to bleed down.

This would explain why it started easy the first time and really hard after that. It was flooded.

Max

[Piledriver]

You should have the ~same relay/wire under your back seat I do...
One is on when the ignition is. (on or crank)

I used the $5 fog light relays, but the factory one would work just peachy.

Use the output to power the MS and the injectors/coils, with inline fuses for the injectors and coil(s) 12v as needed.
(the v3/3.57 boards have 1.1a PCT resettable fuses onboard, so the MS is OK)

I used separate relays for MS+JAW and the ignition/coil box, each with their own 12ga direct battery feed.
(I also have a pair of relays I'm not using yet in place)

[supaninja]

Ya that explains the hard stating, you can get those relays anywhere. 30a one should be more then enough.