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View Full Version : First Engine Start! (with Video) - Roast my idle sound



mladen
02-23-2023, 03:59 PM
So, that day has come. Beautiful day at that, sunny, 78 degrees.

Had my neighbor over to help, record the video, and be ready with the fire extinguisher, of course :)

We put about 3-4 gallons of fuel in the car. First went through the procedure recommended by BPE, which is to cycle the engine a few times for about 15-20 seconds without a spark or fuel (disconnected the inertia switch). After that it was time to crank for real.

Start 1 (https://youtu.be/NVlMgrIWzNk)
Start 2 (https://youtu.be/De6fSWJ2D-A)
Start 3 (https://youtu.be/ROdSy94yOTg)

It fired up on the first try without issue, though I did this before going through the setup wizard on the EFI. I assume not a big deal since the engine has been dynoed and probably set up already. I did do it before the second start. The main issue is that the idle seems rough. I first had it set at 850, then increased it to 950, but it didn't make a difference between the last two starts, not sure if maybe I'm not completing the setup wizard correctly.

One more problem that came up after the third start, and really got lucky on the timing, and that I had a battery cut-off switch, is that the starter got shorted and started cranking on its own. Again, luckily we stopped it after a few seconds, and it happened when the engine was off (while we were dealing with that coolant overflow at the end). Basically, the starter cranks as soon as I turn on the battery cut-off switch. I checked the ignition switch and went from there, eventually figuring out that there is continuity between the starter power wire and the solenoid power wires. I haven't gotten to fixing it yet, but I'm fairly sure it's because I have the starter power cable sitting on top of the screw for the solenoid. With vibration, it probably just poked through the insulation. Easy fix. Now I have an excuse to take the PS headers off. It will make removing the fuel pressure gauge easier as well.

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Speaking of fuel pressure. On ignition, the pump started and it got close to 50PSI. Once the engine started it was on 60 where I think it should be.

Overall, pretty good day I have to say.

JohnK
02-23-2023, 04:31 PM
Congratulations! First start is always an exciting and nerve-wracking day. Nice to see it come alive on the first try.

jrcuz
02-23-2023, 07:04 PM
Sounds good, great job!
JR

phileas_fogg
02-23-2023, 07:52 PM
Congratulations! Sounds great!

One thing I noticed - you appear to have only one spring on the throttle return. Recommend you get a second spring that nests inside the one you have. It'll make the throttle less twitchy, and most race tracks require dual springs. If you find the throttle is still twitchy, you can move the throttle connecting rod down in the lever arm slot so that it's closer to the pivot rod.


John

mladen
02-23-2023, 10:53 PM
You're right John. I did try with both (kit came with too), but it feltike the linkage struggled. But it definitely feels flimsy now. Will work on it more for sure.

MB750
02-24-2023, 07:51 AM
If you really want to get crafty with the linkage you can set the pivot points and mounting locations along the arm so that initial throttle onset has less of a pull on the throttle plates than heavier throttle does. It's all dynamics of linkage mechanisms.

mladen
02-24-2023, 09:31 AM
I still have some time before body fitting. Do I have to wait for that to be done before I install the side pipe mounts? Right now they're unsupported, which is concerning me a bit since all the weight is on the headers, but I also don't want to install the rear mounting brackets if it needs to be done with the body on to align the pipes to the car.

Mike.Bray
02-24-2023, 10:52 AM
I still have some time before body fitting. Do I have to wait for that to be done before I install the side pipe mounts? Right now they're unsupported, which is concerning me a bit since all the weight is on the headers, but I also don't want to install the rear mounting brackets if it needs to be done with the body on to align the pipes to the car.

I think you can do it before the body is mounted, I did. Pay close attention to the manual and the pictures. You want the bracket tucked up close to the underside of the frame/body like they show. And the rubber hanger pretty close (technical term) to the outer 2x2 RHS and as high as possible. I don't think there's too much wiggle room for mounting this bracket.

phileas_fogg
02-24-2023, 01:22 PM
I recommend you wait to install the hangers, reason being that you don't know how far the support needs to extend to make the pipe fit correctly with respect to the body sides. You won't damage the headers; a buddy of mine ran without hangers at all for several years.


John

mladen
02-24-2023, 01:48 PM
Thanks all!

Small update, the starter issue has been fixed.

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It wasn't just the stud. There are two punctures, small one from the stud and the big one from the little tab which I also left there. I assume it was for a quick disconnect connector. I added one more sleeve of heat shrink tubing as a fix. I'm sure there's no way they can puncture through two of those. Just kidding, I did that, but also added two plastic conduits, and angled the large cable to the side so it's not over the stud.

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John Ibele
02-24-2023, 01:51 PM
Engine sounds great. I'll be interested to see what you're finding about your idle roughness as you move ahead.

I don't have a BP engine (local builder), but after breaking in flawlessly with a Holley carb on the dyno, I've started a few times with the Sniper and it seems to be running rougher / richer with every start. Will be debugging in the spring when its less frigid and I can pull it into the driveway. PM me if you want more background or to compare notes.

Didn't mean to take your post sideways, though - good luck, and congrats on reaching a big milestone!

400BA
02-24-2023, 02:38 PM
Sounds pretty good from here! Watching your build now...

cc2Arider
02-24-2023, 05:56 PM
Papa can weigh in on this, but I think if your self-tuning EFI is running more rich with each session, it is probably an air leak in your header, collector joint, or your O2 sensor bung...

Good Luck,
Craig C

Let us know what you find out :)

mladen
02-24-2023, 07:49 PM
Ran it again today. 4 start overall and the first cycle up to working temperature.

https://youtu.be/usvPTP4wZPE

I set the idle to 950 for now, it was rougher at the beginning but settled well once it warmed up a bit. Water temperature got up to about 85C, and I haven't recorded it but I think the oil pressure was around 60-70psi, not sure what it should be. And the fan definitely kicked in, haven't noted at which temperature.

Oh, and I put ina temporary solution to relieve some pressure on the side pipes :D

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Edit: oh yeah, forgot to mention. The first time I started it today it was suuuuper rough, even when I revved it above idle. Then I remembered that I took the PS header of and put it back on, and that I didn't connect the spark plugs... Oops