Loren's V8 S10

[Loren]

As much as I don't want to call this thing a "project", I guess there's no denying that it is.

So, here's what I've got:
1997 S10, Standard Cab, Sportside Bed
Purchased already swapped with a Vortec 5.7 out of a 1998 Suburban, bored and stroked to 383
Torsen Diff from a Camaro
Mostly stock otherwise

What I've done:
(Okay, *I* didn't do most of this, I've had Joe Brannon and Rob Ledwell do significant work on it because I keep saying "it's not my project, I just want to drive it!")
Replaced Battery
Replaced Radiator
Installed thermostat kit for electric fan w/ bypass switch
Replaced worn out brass distributor gear with proper stock one
Replaced plug wires twice (second time with insulation sleeves)
Replaced engine mounts
Replaced starter
Replaced shocks (cheap KYB shocks "for lowered S10")
Replaced Rear Springs (proper lowering springs with an added leaf for towing capacity)
Replaced front springs (950#, pretty darned stiff)
Replaced lower control arms (stock)
Replaced upper control arms (circle track parts with proper geometry)
Replaced steering box and all steering components
Installed u-joint steering coupler in place of stock "rag joint" coupler (steering still sucks)
Replaced power steering hose
Replaced wheels w/ 1999 Corvette wheels
Installed cheap Sumitomo tires (Stock 1999 Corvette sizes)
Installed wheel spacers (2" front, 3" rear)
Swapped Diff gears from 3.73 to 3.08 (biiig difference, first gear is now useful, highway revs are lower)
Replaced loud-ass dual exhaust with a quieter single exhaust
Replaced O2 sensors
Replaced stereo
Installed hidden trailer hitch kit
Installed flip-down license plate bracket
Replaced most of the external light bulbs
Replaced front wheel bearings
Replaced front brake rotors
Replaced front brake pads (Hawk HPS)
Maybe some other stuff I've forgotten?

So, yeah... clearly this is not a project.

Known issues:
Fuel guage inop
Tach calibrated for V6, so reads way high
ECU tune is crap
ECU can't be tuned to rev beyond 5600 rpm!
Transmission synchros are iffy
Transmission leaks
Cooling Fan control isn't great
A/C inop
Heater inop (bypassed)
Vent controls in dash are messed up
Flaky ABS sensor somewhere
Driver's seat has a hole and missing foam
Reverse lights inop

But, at least is has been starting and running reliably for a while now!

[Loren]

So, the whole point of starting this thread... to discuss the current priorities.

Of course, if the priorities were correct, #1 would be fixing the AC and HVAC controls! (or maybe the ABS, but who needs that?) I really have no desire to do that kind of work, myself. I'll probably get it over to Ledwell at some point and pay him to sort out the AC and some other stuff.

No, what I'm thinking about is ditching the stock ECU and putting a Megasquirt in it. I enjoy doing that kind of stuff.

Here's the deal. It has the stock ECU, which has been reprogrammed for a 1999 Express Van to get the V8 tuning. And I have tuning softwear that lets me mess with it, but it's nowhere near "easy", as I consider the MS system to be. (and MS isn't really "easy", but the tuning software is awesome... and the GM tuning software is very much not) So, it runs "okay", but far from ideal. Bottom end power is annoyingly missing, so it's awkward to launch. Revs hang at 1500-1800 for some unkown reason when you're coasting down to a stop, it doesn't drop to idle until you're below 5 mph. (I think this is what killed the synchros and/or what makes them seem bad a lot of the time) It doesn't engage deceleration fuel cut-off as it should when you're coasting. (makes a big difference in fuel economy, and this thing needs all the help it can get!) And, there's some sort of a hardware limitation that keeps the ECU from revving past 5600 RPM. 5600! And the engine is supposedly built to rev to 7k!

One solution would be to upgrade to a later ECU. Wouldn't be too difficult to do, it's "plug and play" except for the plug itself. (wiring is the same, just have to swap on the correct plug) But, then I'd have to either pay someone to tune it ($$$$) or buy expensive tuning software to tune it myself ($900). That's a lot of money to put into "not a project".

I've been playing with Megasquirt ECU's for nearly 10 years. Pretty comfortable with them. I already own the tuning software. Could put a low-end MS in this thing for under $400! Seems like a no-brainer. I just need to commit to doing it and get it done!

With that, I can tune it any which way I want to. Rev limit wherever the hell I want. Tune for power at full throttle. Tune for economy at light throttle. Fix the idle problems. Control the FAN with the ECU rather than an external controller.

[Loren]

So, if you wanna geek out on Megasquirt stuff for a minute...

The currently available options are the top-end "MS3 Pro", which is totally not my style. (I'm cheap) The MS3x (which is awesome, very powerful, and not TOO pricey at around $700), the old school MS2 (pretty capable, and under $300), the even older school MS1 (more limited capability, cheaper, but I ain't goin' there), and the Microsquirt (around $340, and is essentially a condensed MS2).

For this project, because I have to keep the stock ECU in the system (it controls the gauges, ABS, and who knows what else), I want to keep things small. Also want to keep things simple and cheap. The Microsquirt should be just the thing. It's VERY small. It has all the capability of an MS2, which is plenty for what I need here.

Major limitations of the Microsquirt are:
- only two fuel channels, so I have to do "batch fuel", which is fine
- only four spark outputs, so I have to do "wasted spark"... but the engine is already running a coil & distributor... which only requires one spark output
- not a lot of extra outputs to run things like a boost controller, etc... which I don't need, anyway

Doing a "piggyback" or "parallel" installation, the stock ECU stays in the system. I'll splice into most of the sensor inputs that I need. (for some reason, word is that I can't share the temp sensors, so I'll have to fit coolant and intake temp sensors) And I'll completely hijack the outputs to ignition and fuel injectors. So, essentially, the stock ECU will "think" it's in control, but it won't be.

The whole thing will take right about 16 connections to the wiring harness. A few hours work. From there, it's all tuning... and that's the fun part!

[AScoda]

Umm, what's the discussion?

Deux it.

[twistedwankel]

Guess next season's M car is accounted for. Wow. Fun to watch.

[Loren]

Guess next season's M car is accounted for. Wow. Fun to watch.

Oh yeah, the other problem I left out. Oil pressure dips under hard braking. Probably something to do with the choice of oil pick-up and oil pan. I'm experimenting with putting more oil in it to see if that will solve it.

Need to get that problem fixed before I can autocross it.

And autocrossing it isn't really "the plan"... but, I'd like for it to at least be an option.

[jreid1000]

THIS IS GETTING EXCITING!

[twistedwankel]

Oh yeah, the other problem I left out. Oil pressure dips under hard braking.

You actually have the time to watch your gages while autocrossing? Whoa. You just aren't pushing anything yet. My Mazda oil needle doesn't move at all if there is any pressure whatsoever. Maybe you need a Mazda (what they don't know) gage? Oh, and since when do you "hard brake"? Not buying any of this yet.

[Loren]

Oh yeah, the other problem I left out. Oil pressure dips under hard braking.

You actually have the time to watch your gages while autocrossing? Whoa. You just aren't pushing anything yet. My Mazda oil needle doesn't move at all if there is any pressure whatsoever. Maybe you need a Mazda (what they don't know) gage? Oh, and since when do you "hard brake"? Not buying any of this yet.

Doug, I promise you no amount of trash-talking or other bullshit is going to turn my Chevy S10 into a Mazda.

That said, I never "noticed" the oil pressure gauge, but I did notice the stupid "check gauges" light that comes on when this occurs. Big bright yellow light that stays on for 5-10 seconds after whatever gauge reading causes it. Say what you will about GM, but that's a pretty cool feature.

I've taken exactly 3 autocross runs in this truck. And that's where I first noticed the "check gauges" under hard braking. Experimented with it on the street after that, and found that it was oil pressure that was dipping (to zero). Like you, I'd have probably never noticed, otherwise. But, I'm very glad to know about it!

The good news: I played with it while driving around today, and I couldn't get the oil pressure to dip. Apparently running a full quart over indicated "full" (with the unkown oilpan and oil pick-up, and the unknown oil dipstick) did the trick. I'll do some more testing to verify, of course. And maybe I'll take a couple runs in it at the next Classic?

[AScoda]

You can go all uber-baller:

https://www.diyautotune.com/product/ms3 ... -ultimate/

A mere $2,049.00

[Loren]

Not gonna do it, Drew!

But, my plan is coming together. I did some more research last night and this afternoon.

This should be all I need:
Microsquirt
T-fitting to put a second Coolant Temp sensor on the head
Hijack the Intake Temp Sensor, as I don't think it will be a problem for the stock ECU that's not controlling anything to not have it. (and if it's a problem, I can add another IAT easily enough.
All other sensors can be shared with the stock ECU. (Cam and Crank Position, Throttle Position)
There's already a wideband installed, I just need to find the output wire.

That should be it. I need to research the wiring, and hope that all of the wire colors haven't faded into oblivion. But, the rest should just be cutting and splicing wires.

[twistedwankel]

I had a defective oil level sending float in a Ford, in a Miata and in an RX8. The last one cost me a new oil pan assy....moan. None of them was accurate but were scary all the same. I remember a couple SCCA guys running a Japanese pickup for years in mod class. The Vettemeister used to run a lowered lead sled once or twice?

[Loren]

I had a defective oil level sending float in a Ford, in a Miata and in an RX8. The last one cost me a new oil pan assy....moan. None of them was accurate but were scary all the same. I remember a couple SCCA guys running a Japanese pickup for years in mod class. The Vettemeister used to run a lowered lead sled once or twice?

My Spitfire lost its engine due to a pinhole leak in a 30-year-old oil pressure sensor. Technology just can't be trusted!

[Loren]

Update. Okay, not really. I've made no actual progress!

But, I've done some research, and come up with a plan. That's a start.

The first part of the plan is that I promised myself that I won't actually start this project until I've divested myself of the parts car that's in my garage.

The rest of the plan... pretty much this:

Microsquirt S10 Wiring.pdf

(200.97 KiB) Downloaded 436 times

I want to wire the MS in so that it can function and monitor to be sure everything is going to work before transferring control. If I do it right, I can then take the 10 wires that matter (the ones that are being CUT rather than spliced into... the 8 injector wires, ignition control wire, and idle control) put them on a connector so that I can switch back and forth between the MS and stock ECU by just switching a plug.

[Loren]

The good news: I played with it while driving around today, and I couldn't get the oil pressure to dip. Apparently running a full quart over indicated "full" (with the unkown oilpan and oil pick-up, and the unknown oil dipstick) did the trick. I'll do some more testing to verify, of course. And maybe I'll take a couple runs in it at the next Classic?

I was almost convinced that I'd fixed this problem. It's definitely a LOT better than it was. But, get into full threshold braking... yep, the oil pressure still dips.

I may try another half quart of oil. Don't think I want to go more than that. Otherwise, I'm half way thinking about just running it. The only other option is to pull the engine to remove the oil pan and figure out what I need to do with the oil pickup. Before I do that, I think I'll have an oil analysis done. And then I'll put some good synthetic oil in it.

Still waiting on me to get the parts car out of the garage before I start the Megasquirt project.

[Tim_M]

Have you done an oil change on it and filled it with a known quantity of oil? (with filter...not sure what a 98 Suburban holds)

What does the idle do when you hit the brakes-if sub idle speed-could possibly illuminate the low oil pressure light?

Someone could have mixed and matched the pan and pickup...think if folks did a swap they wouldn't of made such a basic mistake.

Cool Project!

[Loren]

Have you done an oil change on it and filled it with a known quantity of oil? (with filter...not sure what a 98 Suburban holds)

Yeah, I think I put 5 quarts in it, and that put it on the full mark. It all made sense until I started noticing that it loses oil pressure under hard braking. With the extra quart in it, it only does it under VERY hard braking.

What does the idle do when you hit the brakes-if sub idle speed-could possibly illuminate the low oil pressure light?

It does idle on the low side (I guess not low for a big V8). Somewhere around 750. But, it doesn't actually go to idle until 5mph. (one of the annoyances that made me want to go Megasquirt) It actually hangs at around 1200 until you're almost stopped.

Someone could have mixed and matched the pan and pickup...think if folks did a swap they wouldn't of made such a basic mistake.

Yeah, my money is on wrong pickup, OR simply leaving out some baffles. It was built more for street/strip use. Hard braking probably wasn't much of a concern.

Cool Project!

Thanks!

So far, it's proven to be entertaining to drive on the street, and capable of towing without issue. That's primarily what I wanted. Oh, and reliability seems to be getting better.

[BrilloHeadBen]

Installing an Accusump would be less labor than installing a new pickup. I think you can get the basic kit for under 300 bucks these days.

[Loren]

I hadn't thought of that. Hmmm...

[twistedwankel]

$300 is the new $30.