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I got my custom TPI conversion done-update- distributorless ignition

That's pretty sweet. :)

What's the deal with the Vortec setup? It has the crank trigger setup in the timing chain cover, could that be a partial solution to some of the stuff you had to fab up, or is there a reason they can't be. Just thinking about this since I have the Vortec short block sitting in my garage for an eventual build.
 
dyeager535 said:
That's pretty sweet. :)

What's the deal with the Vortec setup? It has the crank trigger setup in the timing chain cover, could that be a partial solution to some of the stuff you had to fab up, or is there a reason they can't be. Just thinking about this since I have the Vortec short block sitting in my garage for an eventual build.
Click to expand...
I believe the vortec uses a 4 or 7 pulses per revolution. It wouldn't work with EDIS, but it could probably be used with a GM DIS setup. In fact, one of those might swap in directly for a distributor on a TBI/TPI vehicle. That might be worth looking into. Since I don't use a GM ECM, that swap didn't have any special appeal to me. I probably would have chosen directly controlling 4 coils from the Megasquit first.
 
odin said:
I really have to read this whole thread:eek1:

Impressive:D
I converted my rig to MAF TPI a few years ago and love the response, power, and driveability. Not to mention the fuel mileage increase. 355 roller cam Vortec headed SBC went from 8 MPG highway (with edelbrock carb)to 13+ with the tuned port.
Im using a stock 165 ECM and PROM with a piggyback adapter to eliminate EGR and lower cooling fan temp.

Your setup was ALOT more work than mine.
Is the Megasquirt worth it?
Where do I get started:confused:
Click to expand...
If you are running and already have the ability to tune the ECM, I don't see any reason to jump ship. Now if you are unable to tune and have to buy PROMs, you might find that a Megasquirt conversion is cheaper than getting those tuning tools.

The advantage to MS is that you can change and tune anything. The disadvantage is that you HAVE TO set and tune everything. The base code is supported so you don't have to be a programmer. But if you want to, you can modify the code however you want.

You get started here:

http://www.megamanual.com/index.html
 
It's been running very good and I've had the best idle quality ever with the multiple spark discharge, so I decided to pull the distributor. I was thinking to cut the dizzy below the wide part and drill the top for a new bushing for the shaft to ride in. Some of the holes on the back of the heads are free, so I thought a coil mount could be made to connect to those. While working on it, I decided to take a different direction. I didn't cut anything, but instead used the dizzy body to hold the coil mount.

PICT0062b.JPG

PICT0063.JPG

So the shaft rides in the original top and bottom bushings. It's located in the usual way at the bottom (cam gear rides on a shim against the bottom of the dizzy), and with a snap ring and spacer at the top. I don't like that th engine oil is kind of vented out the top, but this is pretty much how the stock setup works, too.

PICT0065.JPG

PICT0066.JPG

PICT0067.JPG

PICT0068.JPG
 
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I have been second-guessing that snap ring setup on the dizzy shaft. It looks like the shaft is turning inside the snap ring, which will eventually wear it out. Is this a problem or is it OK for the gear to bottom out on the oil pump?

Here's the voltage to the coils:

TEK0022.jpg
 
I dont have the time right now to read through the whole thread, so quick hijack:
can I use the Megasquirt to run a 5.3L I want to put in my S10?
 
Yes. Use all of the sensors and injectors that are already on it and route them to the MS. There is more than one way to do the ignition. It will be batch fire and not sequential injection.

But if you need transmission control, that requires additional hardware and setup.
 
If I took the intake off, could I use an LT1 oil pump drive? What kind of vehicle had a straight up replacement for an HEI? Was it mid-90's truck 4.3L?
 
Blue85 said:
Yes. Use all of the sensors and injectors that are already on it and route them to the MS. There is more than one way to do the ignition. It will be batch fire and not sequential injection.

But if you need transmission control, that requires additional hardware and setup.
Click to expand...

Ya I'd be running it with a T56 so no transmission and I dont have ABS so I thats another computer to not worry about.

Just one more quick question though, would that enable me to eliminate the original ECM on the 5.3L allowing me to save some $$ or does it attach to the original ECM?
 
There is no need for the factory ECM to run the engine. If the egine is throttle by wire, you're probably best off by swapping to a standard throttle body.

This is all you have to wire up, not counting the ignition system:

extwir.gif

These sensors are probably already on the engine. What year is the engine?
 
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Blue85 said:
There is no need for the factory ECM to run the engine. If the egine is throttle by wire, you're probably best off by swapping to a standard throttle body.

This is all you have to wire up, not counting the ignition system:

extwir.gif


These sensors are probably already on the engine. What year is the engine?
Click to expand...

I cant see your picture...

Ya I haven't bought the engine yet so it could be from 2000 or so and up.
 
There is some thought required for ignition. MS does not support Coil On Plug (for more than 4 cylinders) without additional hardware (i.e. much more complicated.) But you could do a waste spark setup. MS can drive up to 4 coils or can work with something like GM DIS or Ford EDIS. So all you would need is a set of 4 wasted spark coils. But this is not a standard MS build, you have to assemble an additional 3 VB921 circuits. This is simple if you are familiar with PCB assembly and such. If not, you might need somebody to help you.
 
Blue85 said:
There is some thought required for ignition. MS does not support Coil On Plug (for more than 4 cylinders) without additional hardware (i.e. much more complicated.) But you could do a waste spark setup. MS can drive up to 4 coils or can work with something like GM DIS or Ford EDIS. So all you would need is a set of 4 wasted spark coils. But this is not a standard MS build, you have to assemble an additional 3 VB921 circuits. This is simple if you are familiar with PCB assembly and such. If not, you might need somebody to help you.
Click to expand...

As far as ignition I think I could have that covered with one of the MSD controller boxes thats meant for a carb retrofit, but will work with EFI still.

http://store.summitracing.com/partd...400122+4294908216+4294924641+115&autoview=sku
 
That would work - MS would just need the tach signal from it and then MSD would have full control of the spark. It seems expensive, but considering that you could re-use the coils (insteading of buying a different set) and save some fab work, it's not a bad solution - assuming it does interface natively with the factory position sensor.
 
I might as well update this thread with other changes on this setup since then.

I wanted to convert to a serpentine belt and since with the way the TPI throttle sticks out of the front of the engine, the more common TBI belt setups aren't compatible. What I sourced is from an F-body. The Corvette setup is a little different.

tpi complete.JPG

I think I got an A/C compressor with the setup and ran it as-is. It would have worked to swap the front pulley and clutch, but my old compressor was noisy anyway. The power steering pumps are all the same, but the reservoirs are different for different applications. Easiest path here would be drop in a pump from a TPI car, but it also works to swap the reservoir and pulley if that's what you have.

Pump comparison front.JPG

One of the nicest things about the serpentine conversion is that it puts the A/C compressor on the PS of the engine where it belongs (since the whole rest of the A/C system is all on the PS and the long A/C hoses crossing over the top of the engine are dumb). This picture is of the old long hoses bent to work temporarily. I remember it took a while to source the correct hoses (I want to say they are for a 1990 Blazer) because once you get into the newer years everybody wants to give you parts for the IFS trucks.

PICT0124.JPG

You'll notice a little vacuum valve mounted behind the A/C pump. This is still in use to bump up the idle speed when the pump turns on. It just bypasses a little air around the throttle. I experimented earlier with using the IAC valve to control it, but at that time, I had no luck with the automatic idle control algorithm. So to this day the IAC is used only for warm up. Other than that, idle is controlled by the throttle stop and this has been fine. Perhaps the fancy will strike me someday to try again with newer firmware.

I got rid of the air pump, hacked up that bracket and put an alternator there, so I have one alternator for the main battery and another for the aux system. I lucked out and one of my used belts from a 3800 engine fit well enough to get everything running. The right size is a little shorter, but I still carry a used 3800 belt as a spare.

PICT0121.JPG

PICT0123.JPG

PICT0125.JPG
 
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Here's where I fought some EFI gremlins a couple of years ago: https://ck5.com/forums/threads/350-lean-on-one-bank-but-not-the-other.334663/

In the end I decided it was a software problem and the math for adjusting the 2nd bank was wrong. I verified signals through the ECU and the hardware is working properly. It's an old firmware and should have been replaced a long time ago, but I haven't gotten around to it because it's been running fine. Basically I gave up on bank 2 O2 readings and have been fueling both sides off the single table, with no issues on multiple long road trips now.

This was reinforced when I got new headers and new O2 sensors (the old sensors are still frozen in the old headers, hanging on the wall, actually) and everything worked the same.
https://ck5.com/forums/threads/got-...eaders-pics-inside.323418/page-4#post-3973094
 
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