Another N52 swap attempt!

[hoveringuy]

Heat.

Our cabin heat like most engines comes from engine waste heat. Unfortunately, the N52 is efficient and doesn't have as much waste. One of the benefits of the electric water pump is that it can be de-coupled from engine speed for extra efficiency, so our pumps only run at like 5% until the engine is warmed-up and then it will run on demand which in a lot of cases is only 20%. 80% is moving a LOT of coolant!

I found initially that I was getting almost no cabin heat.

There are two different ways to run the heater core inlet. One is the way that LukeJ did it by tapping the engine outlet directly:


The other is by tapping the radiator, which pulls slightly cooler water but has somewhat less obtrusive routing.



One of my solutions was to have Nando up my minimum pump speed to 40%. The downside is that the motor takes a bit longer to warm-up, but I get enough flow at all times for cabin heat.

Another solution I considered was to use an auxiliary pump that most new cars have for exactly this reason. I played with one off an A series Mercedes and it worked well but I never installed it It could go on either the core inlet or on the outlet side to pull coolant through (so you could mount under the radiator...). It would need to be triggered somehow when you needed heat. Maybe power to the heater core valve?

The OEM solution is that the comfort module communicates and coordinates with the ECU so that when heat is selected it bumps-up the pump speed, so there's a geek solution out there somewhere....

[Striker01]

The other is by tapping the radiator, which pulls slightly cooler water but has somewhat less obtrusive routing.

I chose this simply because I think it looks cleaner.

Another solution I considered was to use an auxiliary pump that most new cars have for exactly this reason. I played with one off an A series Mercedes and it worked well but I never installed it It could go on either the core inlet or on the outlet side to pull coolant through (so you could mount under the radiator...). It would need to be triggered somehow when you needed heat. Maybe power to the heater core valve?

I also like this idea, especially if it’s as simple as activating a relay with the heater core solenoid power. A little more complex but would save some wear on the water pump and let the engine warm up quicker. I need to think on it.

[Striker01]

Progress is slow, exhaust mid section is off for coating and waiting until after the new year to get my front panel and plastic bumper painted, earliest they can get it done.

I did get my fan wired up. Used 2 5-pin relays to isolate the PWM module from the fan side when AC is turned on. Reading up on how it works I was worried that having a constant ground available, if I just spliced both stock power wires together, would mess with how the PWM works. I can activate the fan with protool but won't be able to test the AC portion for a while. If it ends up throwing codes I'll cross that bridge when I get there.



Also got a box made for the IVM. ECU Wiring will have to be tucked up better or I'll have to modify the trim piece above the glove box to get the trim to fit, maybe both. I don't want to move forward with that or with putting seats back in until I get my ECU flash issue sorted.



No on to a super frustrating issue that I can't figure out, thought it was solved but I was wrong. Hopefully someone here can walk me through this flashing stuff, it's beyond me.

22RPD sent me a new flash to get rid of a couple DTCs and try to get water pump working for heat. I went to flash it and can't get it to work. The flash fails "unable to erase ECU" error at 1:13 every time I try. If I try a full flash instead of quick flash it does the same thing at 1:07.

It seems like the flash they sent for the EKP flashing after I changed to a bigger K line gauge wire was a fluke, I've probably tried 100 times in the last 10 days. I have tried the bimmergeeks expert k+DCAN cable and Jordan, 22RPD, sent me one of theirs. Same result with both.

I have tried 2 different laptops. Both are using the same FTDI driver dated July of 2021. One is a windows 11 home machine and I'm not sure what my son's is but it's less than a year old.

Flash tool can see and read the ECU and clear the DTCs but the flash isn't working. Latency is set to 1MS and I've tried standard 9600 baud, 4096 and 2048. Same result for all, COM1.

I really don't think I have a wiring issue in the car, protool can see live engine data and activate all the peripherals on the egine and the flash tool can see ECU and clear codes.

Charger was hooked up while attempting and voltage stayed around 12.6 for the entire process.

I'm at a loss here, if anyone has any advice I'm all ears.

Cleared codes before attempting.



This result every time, with the exception of the 1 time it worked, weeks ago.

[Striker01]

I'm reluctant to make this post but if my embarrassment can save someone else a headache then I guess it's worth it. I've been chasing my tail for quite a while with the issue of not being able to flash my ECU. Last night Steve suggested I make a bench harness to try in the warmth of my house, instead of a cold garage. Super idea, wish I would've thought of it earlier. My old xbox 360s power supply was a perfect match.



Anyway, while the ECU was out I noticed that some of the pins were pushed back into the ECU. The connectors were kinda hard to secure but I didn't think much of it because I assumed I'd used the right pins when I shortened a few wires. Wrong! Here is what I happened to glance at it while it was out. All the wires I shortened and the whole X60001 connector were messed up.



The pin, Digikey P/N A123797TR-ND, is the correct one for the IVM connections but not the ECU. The ECU has wider blades but I didn't even look, they locked right into the connectors and I assumed they were good.

ECU pin on the left, replacements from digikey on the right. I searched digikey for a while looking for the correct pins without any luck so I just ended up soldering some pigtails from a spare harness, not ideal but it will work.



Pulled the pins back out of the ECU with needle nose pliers and attempted another flash.



All seems to be good now!! Another lesson learned the hard way with this project.

[hoveringuy]

The more people do the swap, the better we get at it!

Here's a picture of my bench harness. It's literally just the big power and and ground wires, plus two signals on the X60002 plug. Wakeup signal on pin 1 (power, again) and the K-line on pin 2.

Power supply was $8 on Amazon.

The OBD plug also gets power and ground, plus the Kline, and you're in business.

Is is super-duper handy!!

Striker01 Resetting pushed-pins basically makes you an avionics tech now!

[Striker01]

The more people do the swap, the better we get at it!

Striker01 Resetting pushed-pins basically makes you an avionics tech now!

So true about more people. I've had a bunch on hindsight is 20/20 moments for sure! That's part of the reason I try to post my mess ups, don't want someone else to deal with the same issues; they'll have plenty of their own without repeating mine.

I don't want to be an avionics tech. LOL

I tried to be methodical with the wiring process, now I'm stuck with some splices I tried really hard to avoid. Even if I had the right pins, I didn't leave enough slack to re-pin them and I'm not ordering new engine harnesses to change it all.

The pins 1355556-1, the medium ones won't fit into the connectors, they are just a little wide. I'm going to try and find the right one and post it. We need one in between the small and medium I ordered, unless digikey sent me a bag full of the wrong pins. Possible but very unlikely. Here is a picture compared to the correct ECU pins.








This is what I ordered.

[projectJTv4]

I'm reluctant to make this post but if my embarrassment can save someone else a headache then I guess it's worth it.

...

All seems to be good now!! Another lesson learned the hard way with this project.

Thank you for sharing!

[Striker01]

Car is back on the ground for the first time in over a year. I forgot how low these things sit. My plan was to drive it around the block yesterday after I got the exhaust on but I realized I should probably get rid of the rust on the seat feet so my new carpet doesn't end up rust stained like the old one. Remflex flange gaskets seem to have cured my exhuast leak at the headers and an impact to the slip joint clamp seems to have cured one at the rear slip joint.

Still working on the heat situation. I can feel the heater inlet pipe is hot but my heater valve solenoid doesn't move, it is getting 12V when I turn the dial to cold so I guess I get to drain the coolant and check it out. Seems odd that it would fail with the solenoid extended but who knows. Any thoughts on just bypassing it?

Can't wait to get the front end put back together and drive this thing!!

[adam.nonis]

You have the patience of a saint. I couldn't wait to drive mine around the parking lot. Just to have it move under its own power. I was working the throttle in my hand while steering and shifting. 😂


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[Striker01]

You have the patience of a saint. I couldn't wait to drive mine around the parking lot. Just to have it move under its own power. I was working the throttle in my hand while steering and shifting. 😂


Sent from my iPhone using Tapatalk Pro

That’s awesome! I’m getting antsy myself now that the exhaust is done.

I’m pretty patient but this thing is trying me.

Figure it’s easier to sort the heater without seats. I’m sure everyone here can guess what I did wrong. 🙄. Still not sure why the solenoid isn’t opening. Going to mess with that after work.

[Striker01]

Finally have heat. Like most people were probably thinking, I had the hoses switched. Why the valve is on the output side of the core doesn't make sense but whatever, it's fixed.

I took the heater valve out and apart. I have the URO version. It had a little gunk from sitting for over a year and one of the connector screws for the solenoid plug was a little loose but other than that looked fine. Cleaned it up, re-installed and it works now. Maybe trying to force coolant backwards through it had some affect, who knows.

22RPD's updated tune keeps the water pump running at all times like I requested and the heat works great. I tried to test my fan but the warmest I could get the coolant was 105C, guess that's not hot enough to turn on the fan, just cranks the water pump higher. I can activate it so I'm sure it's good. I'm thinking of adding a resistor to the coolant gauge line like Garagaholic did for his N54 build. At 100ish C the guage is in the middle or just past, never got that high before the swap.

Interior is cleaned up and installed, ready for the first drive tomorrow!! Wanted to go tonight but without headlights it's probably not a good idea.

Got some aluminum tubing, intake tube is the next project on the list, I want it moved near the ABS module. Need to order a few small things that vanished in my garage over the last year but other than that I'm running out of stuff to do. paint work on the front parts is what I'm waiting on to finish getting it back together.

Wiring tied up and ready to drive!



I missed this driver's seat!! Also wanted a ZHP shift knob since I got my first E30, I figure my car is worthy now.

[Striker01]

Finally got to drive it today! Car pulls hard and sounds good! I'm sure it'll be even better when I get the hood on.

Put about 10 miles on it. Few slow laps of the neighborhood to test everything and check for leaks then some good rips on back roads. Just a few drips of coolant from the radiator outlet. I adjusted the hose and clamp and it seems good now, will keep an eye on it. Clutch grabs just off the floor so probably needs another round of bleeding. Ibooster seems to work fine, brakes feel about how they did before; from what I can remember. Not an on and off switch like I've read somewhere. Poly mounts added significantly more NVH, might need to bump up the idle a bit, shakes the whole car when coming to a stop and dropping to idle. 3.73 dif is too short for the car now, will get something longer at some point.

Unfortunately my cruise experiment didn't work out, doesn't work at all. I don't know if the ECU needs a bus signal from one of the other missing modules or what, pretty disappointed but knew it was a long shot.

Pretty weird seeing the coolant temp needle go from midpont, or just above, to the mark below when I started driving it a little harder.

Drove it to my brothers house and left it, need his TIG skills for the intake. Got the filter in a better position just need to figure out some kind of support for it.

Overall, super happy with it. Almost to the finish line!