So, Will It Run?
Back to Part 7
Spoiler: It runs! But first...
The drivetrain install went fairly smoothly. If you've removed/installed one of these, you realize it's really not so bad of a job. I hate, hate, hate the concept of removing a drivetrain to repair something (Lotus manual for changing the oil: Step One, Remove the Engine) but the 914 is really not that hateful. A couple wires, a couple cables, the eight (yes only 8) drive axle bolts, and the whole thing is held in by four more bolts. I used to laugh at Edd China casually removing a drivetrain on a car to do some work on it but after watching him remove the 914 drivetrain in an episode (Season 9, Episode 5, worth the watch) I'm kinda with him there (and I use his "drop on my toolbox and raise the car off with the lift" trick). Yeah, it's a pain in the butt to a certain degree, but the amount of time you save having things right there in front of you and accessible makes it so much morez betterz....anyway...the bro-in-law and I had the drivetrain installed in an hour or two, including beer (exact time lapse unknown, mostly due to "including beer"). The next couple of evenings after work I was tidying up stuff like wiring, hoses, cables, axles...and I spent some effort installing a Tangerine Racing rear-mounted oil cooler (took a little engineering but job done).
Firing up a car for the first time can be stressful. There could be fuel failures (leaks, failed components) electrical failures (sparks from bare or improperly-terminated wires) -- or worse, both (top tip: fuel leaks and sparks in combination are bad, m'kay?) So I kinda did it in stages.
First, I pulled the fuel pump relay and briefly connected the battery ground wire then quickly removed it, listening for sparks...nothing. Then did it again, slightly longer...nothing. So then I screwed it together and looked all around for heat, sparks, hot wires...nothing. Good so far.
Then I went in the car and turned the key on and off quickly...nothing. Turned it on for longer...nothing. No sparks, no noise, no hot wires...so far, so good.
So next I turned off the key and inserted the fuel pump relay and turned the key on. The fuel pump ran for two seconds which is exactly what was supposed to happen. That told me that the Microsquirt ECU was getting power and properly controlling the fuel pump. So what could possibly go wrong...?
I wanted to next test for fuel leaks so I cut the top off of an older relay I had to use it as a jumper switch. Once the top is revealed you can push down on the solenoid and it'll engage the relay. I installed it in the FPR slot and used a piece of paper to keep it on so I could measure fuel pressure and check for leaks. I was surprised to find that the stock adjustable fuel pressure regulator (FPR) would only screw up to 36psi...I was hoping it would go higher. The injectors I chose were spec'd flow at 3 bar/43.5psi so I really wanted it to be there, but I figured 36 wasn't that bad so I went with it.
3/28/22 Update: I eventually installed The Dub Shop's 3 bar Bosch FPR, cores the fuel pressure nicely.
Everything was set and checked. I got the bro-in-law to bring over some tasty local Connecticut beers for "the unboxing". We got my two fire extinguishers in key locations (by the garage and exit doors) and we jumpered the fuel pressure relay and let it build up and checked for fuel leaks. None. All set.
So, armed and ready, we cranked over the car and let's see what'll happen...
I'll be damned if that thing didn't actually fire right up! Well, "right up" is a bit of an exaggeration, but not much: the first time I cranked it we got a "pop!" from it but no start...but the second time it fired up with some throttle and I could keep it running.
The damned thing actually started. It started! With oil pressure! I was so ready to have to troubleshoot wiring, pump, oil, ignition, injector, whatever problems. But nope, all the homework paid off. No one was more surprised than me.
Yes, my bro-in-law took a "start up video" (he's a Honda guy, into that engine start up video thing) but I hate the way I look in it so you're just gonna have to YouTube search it for yourself. But I did have another beer.
(Edit: eh, screw it: https://www.youtube.com/watch?v=tc_WD-302Oc)
It actually started...damn. With no problems...I impressed myself.
.
.
.
.
.
.
Well...except for one little minor miniscule silly nothing-not-a-big deal problem: the car, once running, wouldn't shut off with the key. It would start, it would run, but when I turned the key off...nothing changed. Regular noises continued. I had to pull the fuel pump relay to get it to stop. Somewhere in my electrical design was a flaw. Either the alternator was still powering the system or I failed to accomodate an unintentionally-latched relay and the car was running on the alternator. I pored through my "CAD" wiring diagram ("Cardboard Aided Design"), doing some FEA ("Ffffffriendly Everything Analysis") to figure out my "fale".
But what was it? The T4-I relay panel pin that I'm powering the Microsquirt with is the same pin/circuit that powered the D-Jet system and it was used for both the D-Jet ECU as well as the coil and injectors, same as D-Jet. I was kinda stumped.
But that left me with two questions: why did it not do this with the D-Jet system, and how am I going to fix it? On the first question, the only thing I can figure is that between the old D-Jet ECU, coil, and injectors, that maybe they pulled enough amps collectively such that there wasn't enough flow through the dash lamp to adequately power it all so it died. Because otherwise, it's the same exact wiring design that was used for the D-Jet system.
TDC - Top Dead Center, the firing position for #1 cylinder
CPS - Crank Position Sensor, also known as CAS, Crank Angle Sensor
TPS - Throttle Position Sensor
MPS - Manifold Pressure Sensor
IAT - Intake air Temperature sensor
CLT - Coolant temp sensor
AFR - Air-Fuel Ratio
FLAPS - Friendly Local Auto Parts Store
FPR - Fuel Pressure Regulator
Back to Part 7
Spoiler: It runs! But first...
The drivetrain install went fairly smoothly. If you've removed/installed one of these, you realize it's really not so bad of a job. I hate, hate, hate the concept of removing a drivetrain to repair something (Lotus manual for changing the oil: Step One, Remove the Engine) but the 914 is really not that hateful. A couple wires, a couple cables, the eight (yes only 8) drive axle bolts, and the whole thing is held in by four more bolts. I used to laugh at Edd China casually removing a drivetrain on a car to do some work on it but after watching him remove the 914 drivetrain in an episode (Season 9, Episode 5, worth the watch) I'm kinda with him there (and I use his "drop on my toolbox and raise the car off with the lift" trick). Yeah, it's a pain in the butt to a certain degree, but the amount of time you save having things right there in front of you and accessible makes it so much morez betterz....anyway...the bro-in-law and I had the drivetrain installed in an hour or two, including beer (exact time lapse unknown, mostly due to "including beer"). The next couple of evenings after work I was tidying up stuff like wiring, hoses, cables, axles...and I spent some effort installing a Tangerine Racing rear-mounted oil cooler (took a little engineering but job done).
Firing up a car for the first time can be stressful. There could be fuel failures (leaks, failed components) electrical failures (sparks from bare or improperly-terminated wires) -- or worse, both (top tip: fuel leaks and sparks in combination are bad, m'kay?) So I kinda did it in stages.
First, I pulled the fuel pump relay and briefly connected the battery ground wire then quickly removed it, listening for sparks...nothing. Then did it again, slightly longer...nothing. So then I screwed it together and looked all around for heat, sparks, hot wires...nothing. Good so far.
So next I turned off the key and inserted the fuel pump relay and turned the key on. The fuel pump ran for two seconds which is exactly what was supposed to happen. That told me that the Microsquirt ECU was getting power and properly controlling the fuel pump. So what could possibly go wrong...?
I wanted to next test for fuel leaks so I cut the top off of an older relay I had to use it as a jumper switch. Once the top is revealed you can push down on the solenoid and it'll engage the relay. I installed it in the FPR slot and used a piece of paper to keep it on so I could measure fuel pressure and check for leaks. I was surprised to find that the stock adjustable fuel pressure regulator (FPR) would only screw up to 36psi...I was hoping it would go higher. The injectors I chose were spec'd flow at 3 bar/43.5psi so I really wanted it to be there, but I figured 36 wasn't that bad so I went with it.
Everything was set and checked. I got the bro-in-law to bring over some tasty local Connecticut beers for "the unboxing". We got my two fire extinguishers in key locations (by the garage and exit doors) and we jumpered the fuel pressure relay and let it build up and checked for fuel leaks. None. All set.
So, armed and ready, we cranked over the car and let's see what'll happen...
I'll be damned if that thing didn't actually fire right up! Well, "right up" is a bit of an exaggeration, but not much: the first time I cranked it we got a "pop!" from it but no start...but the second time it fired up with some throttle and I could keep it running.
The damned thing actually started. It started! With oil pressure! I was so ready to have to troubleshoot wiring, pump, oil, ignition, injector, whatever problems. But nope, all the homework paid off. No one was more surprised than me.
Yes, my bro-in-law took a "start up video" (he's a Honda guy, into that engine start up video thing) but I hate the way I look in it so you're just gonna have to YouTube search it for yourself. But I did have another beer.
(Edit: eh, screw it: https://www.youtube.com/watch?v=tc_WD-302Oc)
It actually started...damn. With no problems...I impressed myself.
.
.
.
.
.
.
.
.
.
But what was it? The T4-I relay panel pin that I'm powering the Microsquirt with is the same pin/circuit that powered the D-Jet system and it was used for both the D-Jet ECU as well as the coil and injectors, same as D-Jet. I was kinda stumped.
After some basic diagnostics, I discovered that this circuit was still hot when the key was turned off...but it shouldn't be, it's fed by the ignition switch. And that circuit is dead when the car isn't running...normally. It gets powered by the original "power relay" which supplies power for everything in the engine compartment. I pulled the power relay and the car died. I pulled the fuel pump relay and the car died. I pulled the plug at T4-I and the car died. I pulled the alternator plug at the relay panel and the car died. So the alternator was keeping those circuits powered up. But how...?
I'm not gonna bore you with the troubleshooting details, but I took a guess that the alternator/GEN light on the dash was involved, somehow. So I removed the GEN bulb from the back of the gauge, started the car, turned the key off...and the car died. So, electricity was back-feeding through the alternator warning lamp and keeping the electrical system energized! Incredible that that small amount of amps ran the entire system!
And as for how I'm going to fix it...the answer was "a diode". Specifically, a solar panel diode I had laying around in a tool box. I added it to the D+ wire from the alternator and all is well. I just won't have overvoltage notification (a very rare failure).
But the damned thing runs. How about that?
So on to Part 9: "What About Tuning??"
But the damned thing runs. How about that?
So on to Part 9: "What About Tuning??"
TDC - Top Dead Center, the firing position for #1 cylinder
CPS - Crank Position Sensor, also known as CAS, Crank Angle Sensor
TPS - Throttle Position Sensor
MPS - Manifold Pressure Sensor
IAT - Intake air Temperature sensor
CLT - Coolant temp sensor
AFR - Air-Fuel Ratio
FLAPS - Friendly Local Auto Parts Store
FPR - Fuel Pressure Regulator
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