my low budget dream car build

[ian c2]

If it helps you feel better , you’ve pretty much rebuilt a whole car in less time than it’s taken me to remove a windscreen .




And I still haven’t got the windshield out

[wout]

Good luck and hang on Chris!!! Been there many times but still very happy I didn't sold my (problem-) baby when I thought about it after the 1000th failure...

Wout

[Focker]

Hey Chris, I used a diesel repair shop to have my injectors cleaned. 3 day turn around and they were all matched. Cost was $25/injector with new baskets and o rings.

[chrisbalich]

Originally Posted by ian c2

If it helps you feel better , you’ve pretty much rebuilt a whole car in less time than it’s taken me to remove a windscreen .




And I still haven’t got the windshield out

It really doesn't. But thank you, none the less.

Originally Posted by wout

Good luck and hang on Chris!!! Been there many times but still very happy I didn't sold my (problem-) baby when I thought about it after the 1000th failure...

Wout

Thank you. I'm doing my best.

Originally Posted by Focker

Hey Chris, I used a diesel repair shop to have my injectors cleaned. 3 day turn around and they were all matched. Cost was $25/injector with new baskets and o rings.

Thanks. I called SouthBay Fuel Injector (in Long Island, NY) and they sent me a set of refurbished and flow-matched 30lb injectors for $29 each. They arrived ~50 hours after I ordered them.


Which brings me to today's post.
Kelly texted me yesterday just after lunch that USPS had delivered my new injectors. The ECU, now equipped with upgraded injector drivers, was sitting by the stairs. It looked like everything was coming up roses.
1700 came and I left work. I got home ~45 minutes later, changed clothes, gave Kelly a smooch, and headed down to the garage.

**Jump-cut to mini flashback**
Sunday on the test drive of Mike's Jeep, something rattled off the truck and jingled down the road. I didn't see anything and figured it was a screw/bolt/nut/unimportant bit.

**jump-cut back to story**
I open the drawer that contains my allen keys and all my wrenches.
"Where the fork are my allen keys?"
*finds 4mm and remembers last time they were used was to attempt to tighten the mirror on Mike's Jeep.*
"Son of a bush. Honey! I'm going for a quick bike ride. Back in a few minutes!"
*Airs up tires on MTB and pedals down the road to where the jingling occured just a few days prior.*
*Finds allen keys on side of road...missing two...one on bench at home...looks more closely at side of road, miraculously finds other allen key.*
I jam them all in a pocket and return home feeling that maybe the universe was back on my side.

Once home, I removed the two screws that secure the fuel rail above 4-6. A gentle nudge and I'm awash in 93 octane. :facepalm: I clean up what fuel I can and swap the injectors.
Wash, rinse, repeat for 1-3.
Flashlight and fire extinguisher at the ready, I primed the fuel system to check for leaks.
No leaks, so I primed it again to make sure there were no bubbles and things would go smoothly.
Still no leaks.
Push the car out into the drive (so it can burn without burning down the house) and jump in.
It fired right up. No leaks, no drama. It actually fired up easier than it has in weeks.
I hooked up TunerStudio to take a look at my numbers.
PIG RICH
Don't care. It's not popping or doing anything weird, so I set off on a drive. It runs rich the whole time, but it runs strong. NBD, I can re-scale the VE map to account for what difference there is in the injectors.

If I stopped the story here, it's a success story. Alas, my automotive sagas are Sisyphean more than they aren't.

I went in and had dinner with Kelly and then back out to see what I could do about the ultra-rich VE map. (I was cruising at ~11.0 AFR)
Car still warm, back out onto the road. The VE map seemed pretty a-ok above 16% throttle, so I leaned it out below that.
It started popping and stumbling again after about 90 seconds.
WHAT
THE
FORK
It's getting dark by this time and I'm 10? 20? miles from home on a 2-lane country road I absolutely don't want to break down on. So I stop again, fatten it back up and head home. It's happier, but still just dumping fuel into the cylinders. As I drive, I'm trying to wrap my brain around what I've missed. I've got spark. It pulls like a freight train at high throttle input. Pulls hard all the way to 7k. It's not a spark problem.
I've clearly no shortage of fuel. Were the fuel pump failing, it'd go way lean up top, not when I crack the throttle or just tip-in.
The ITBs are most sensitive at minimal throttle input. That's where I'm having trouble.
***I remember at this point that I'd raised the idle ~200rpm right before this whole thing went to poop.

"I bet those GD throttles are out of sync."

When I got home, I pulled it into the garage. It's full dark in late May, so I knew it was late. Still idling, I prop open the decklid, grab the sync-tool from the tool chest, and unceremoniously remove the 1-3 rain hat.
#1 - 3.75
#2 - 4.25
#3 - 5.25
"MFer"

I shut it down, closed the garage, and went inside. Too late to be messing with that loud car or I'll never hear the end of it from my forking neighbors. Have I mentioned that I hate living near people? Society and civility are scams. I digress.

When I get home tonight, I will re-sync the ITBs and see if that fixes the problem I've spent too much time and too much money to fix. I suspect it will. That's often what happens to me. I throw a bunch of money at a problem whilst mashing my head into a wall only to find out later the real fix was nearly free and would have been right in front of me if I had another set of eyes on the problem.

Ever been so tired of fighting your car you consider a plastic 964 manifold with one TB and exorbitantly expensive EFI just to ensure the thing runs right? Because I'm right there, right now. I hate the sh!+ out of my car right now and there is little to be done about it except fix it.

[jeff951nj]

Sounds like you and the car need another small getaway to Joe's and the Burg for a little R&R.

[chrisbalich]

Originally Posted by jeff951nj

Sounds like you and the car need another small getaway to Joe's and the Burg for a little R&R.

If only I weren't driving it 2000 miles next weekend ripping around the mountains of WV.

At the rate this car is taking years off my life, I will be spending a week this winter with Joe to sort it out and get it on a dyno.

[jpnovak]

These kind of projects always take years off your life. And you will swear you will never do another one. And then you do...

Glad you found a sync problem. Should give you more confidence about going on your trip.

[chrisbalich]

I re-synced the ITBs last night.
Turns out, when I adjusted the throttle stop to increase the idle I wrecked the sync. Not sure exactly how/why that works, but the car is much happier than it was the days prior.

I still get some lean pops, but I did some logging and some smoothing of my VE map last night.
What I'm not sure about is why the car runs progressively worse once the AFR gets above 12.5.
This car needs to go on a dyno with a pro. In the interim, I'm just going to have to run it richer than ideal and change plugs and oil on a 3k/6k interval.

I didn't get to drive it to work this morning as it's supposed to rain all day...of course it did not rain omw into work. But no more rain this long weekend, so I'll get to see where I'm at by weekend's end.

[Quasimoto]

Still doing Ruchlos then?

[chrisbalich]

Originally Posted by Quasimoto

Still doing Ruchlos then?

I think so?
As long as I can get it to run well, AFRs be damned, I'll be there.

[Jonny042]

I had no end of trouble with tuning the MFI until I gave up chasing AFR's and concentrated on what the motor likes. My motor doesn't seem to respond to anything over 12:5 either.

It's probably worth a bigger discussion, but these cars seem to like a much richer AFR than ideal. I'm sure there are many factors but it must have to do with the fact that richer than ideal mixtures burn faster.

Unless you can find a pro who knows aircooled cars you might be better DIY'ing the tuning in the long run.

[Jonny042]

PS - I should add, not sure where you are having the most trouble, but even at light cruise I'll get a slight stumble at anything in the high 13's. Of course I'm not running vac advance and I'm sure that would help, but just trying to add an FYI point.

[jpnovak]

So... If you are having trouble running leaner than 12.5 you need to add more timing. A rich mixture is slower to burn - up to a point.

General rule of tuning is that to run more lean, you need to add more timing. This rule especially holds at light load and cruise. This is why you see Motronic (3.2 and 964) cars with lots of light load timing. In some cases, higher than 40 BTDC.

Increase the timing at light load and see if that helps you increase the AFR to run more lean.

And yes, Always give the engine what it wants... In some ways you tune by feel/sound.

[chrisbalich]

Originally Posted by Jonny042

I had no end of trouble with tuning the MFI until I gave up chasing AFR's and concentrated on what the motor likes. My motor doesn't seem to respond to anything over 12:5 either.

It's probably worth a bigger discussion, but these cars seem to like a much richer AFR than ideal. I'm sure there are many factors but it must have to do with the fact that richer than ideal mixtures burn faster.

Unless you can find a pro who knows aircooled cars you might be better DIY'ing the tuning in the long run.

That makes me feel much better.
Like 20T better.
What AFR are you hitting at WOT?

Originally Posted by Jonny042

PS - I should add, not sure where you are having the most trouble, but even at light cruise I'll get a slight stumble at anything in the high 13's. Of course I'm not running vac advance and I'm sure that would help, but just trying to add an FYI point.

Same.

Originally Posted by jpnovak

So... If you are having trouble running leaner than 12.5 you need to add more timing. A rich mixture is slower to burn - up to a point.

General rule of tuning is that to run more lean, you need to add more timing. This rule especially holds at light load and cruise. This is why you see Motronic (3.2 and 964) cars with lots of light load timing. In some cases, higher than 40 BTDC.

Increase the timing at light load and see if that helps you increase the AFR to run more lean.

And yes, Always give the engine what it wants... In some ways you tune by feel/sound.

I'm in the ballpark of 31-32* at freeway cruising. Once that gets above 12.5-12.7, it gets unhappy.
I think what I'll do is move my AFR targets down .5-.75 and tune to that. Then, I can lean it out and add timing once the darn thing runs like I want.

I may send you my AFR target table and ignition table this weekend for a quick perusal. Let me know if you see anything glaringly wrong?

[jpnovak]

Chris,

I assume you have confirmed that your timing read on TS is the same as pulley marks with timing light.

It could also be that deadtime and/or voltage corrections for injectors is off. This has a greater effect than most think.

What is your pulsewidth under cruise? I try not to allow a PW that is 2X deadtime if possible. At this point you may experience surging and weird issues if the deadtime is not near perfect.

[Jonny042]

Originally Posted by jpnovak

So... If you are having trouble running leaner than 12.5 you need to add more timing. A rich mixture is slower to burn - up to a point.

General rule of tuning is that to run more lean, you need to add more timing. This rule especially holds at light load and cruise. This is why you see Motronic (3.2 and 964) cars with lots of light load timing. In some cases, higher than 40 BTDC.

Increase the timing at light load and see if that helps you increase the AFR to run more lean.

And yes, Always give the engine what it wants... In some ways you tune by feel/sound.

For some reason I had in my head the leaner mixture burns more slowly and thus the need to start the combustion process sooner?

I think Chris and I are in the same place, timing-wise. I have a max of about 32 degrees in the mid-range, tapering down to 30 degrees at the torque peak. I have no means to determine load with the system I have (no vac advance) but am thinking of adding one back in. Maybe adding a 123distributor so I can map timing to vacuum.

My car seems to like closer to 12:1 for best power although that's seat of the pants at this point and not really what I'm spending most time on these days.

[chrisbalich]

Originally Posted by jpnovak

Chris,

I assume you have confirmed that your timing read on TS is the same as pulley marks with timing light.

It could also be that deadtime and/or voltage corrections for injectors is off. This has a greater effect than most think.

What is your pulsewidth under cruise? I try not to allow a PW that is 2X deadtime if possible. At this point you may experience surging and weird issues if the deadtime is not near perfect.

JPN,
The timing is good.
Deadtime is set to .634 as spec'd for the injectors.
IDK the PW at cruise. I'll have to look when I get home. I'll look at the voltage correction as well.

[Jonny042]

Originally Posted by chrisbalich

That makes me feel much better.
Like 20T better.
What AFR are you hitting at WOT?


Same.


I'm in the ballpark of 31-32* at freeway cruising. Once that gets above 12.5-12.7, it gets unhappy.
I think what I'll do is move my AFR targets down .5-.75 and tune to that. Then, I can lean it out and add timing once the darn thing runs like I want.

I may send you my AFR target table and ignition table this weekend for a quick perusal. Let me know if you see anything glaringly wrong?

As Jamie said, you should be able to add lots of timing at part throttle and that might smooth it out and make it more responsive, too. I think your plan to lower the target is good. Theoretical max power is, what? 12.3 or so?

Sheesh. I should read up on this stuff a bit more.

[chrisbalich]

Really wishing I'd braved the rain and driven the car to work today. I'd have the laptop with me and could post my timing and AFR target maps so we'd have actual info and not just me approximating.
I also did a log last night right before I got home. I could actually pull the PW at cruise.

It all becomes homework for tonight.

[Jonny042]

Last random thought, I promise. At part throttle cruise and my lack of timing, I'll get lean stumbles even at 13.5:1. I didn't think that was even possible but it seems to be so.