8 cylinder front engine iconic vehicle
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By worf
#116767
vely kewl.

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By maddog2020
#116773
looks to be a very well put together kit. My only concerns would be plugging it into a 35 year old wiring harness. the 928 FI harnesses from the S4 and later are really well made, and I've cut apart 4-5 of them. As long as no one ever got into them you should be good. FOE harnesses are not nearly as indestructible.
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By Crumpler
#116801
maddog2020 wrote: Wed Nov 17, 2021 6:21 pm looks to be a very well put together kit. My only concerns would be plugging it into a 35 year old wiring harness. the 928 FI harnesses from the S4 and later are really well made, and I've cut apart 4-5 of them. As long as no one ever got into them you should be good. FOE harnesses are not nearly as indestructible.
Agree fir sure.

I had a terrible time with my S3 FI harness already, and had to rewire most of it. Most distal wires toasted, especially the injector portion. Hopefully the bigger/central portion will hold up.
The FOE harness already replaced with that sexy SeanR product;)


Daddy’s going to savor the flavor this time, I’m taking it nice and slow and doing the homework.
I feel like the my SC install was done short on planning and impulse control. :hitfan:
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By Hey_Allen
#116966
That's a great reference book to dig into. The authors have a good bit of EFI tuning experience, Matt Cramer being one of the people behind DIY Autotune, and Jerry Hoffman is their CEO.
I bought a copy when it first released, as I'd been planning to Megasquirt swap my CIS injected MB 500 SEC (that was rear-ended just before getting all the bits installed...)

Huge amounts of info on MSExtra as well, but much of it is MS focused, even though much is also applicable to EFI tuning in general.
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By Crumpler
#117198
Hey_Allen wrote: Thu Nov 18, 2021 4:53 pm That's a great reference book to dig into. The authors have a good bit of EFI tuning experience, Matt Cramer being one of the people behind DIY Autotune, and Jerry Hoffman is their CEO.
I bought a copy when it first released, as I'd been planning to Megasquirt swap my CIS injected MB 500 SEC (that was rear-ended just before getting all the bits installed...)

Huge amounts of info on MSExtra as well, but much of it is MS focused, even though much is also applicable to EFI tuning in general.
Hey thank you for the link, that is a good resource!

Yes book seems helpful, with plenty of basic theory which is good for me.
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By Crumpler
#117433
TPS install.

Kit came with TPS harness extension, but I have a longer one fairly new one from Roger (Sean?) that I’m going to leave on.
The new TPS has no switch in it, apparently a potentiometer. I assume I will calibrate later with software.
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By Crumpler
#117577
Assembling the top end.
Kit comes with faster response air temp sensor.
I had already upgraded that with the Bosch unit, but for sake of compatibility I installed Peep’s choice.
For orientation, this is last elbow that runs into the MAF boot.

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By Crumpler
#117748
I didn’t but probably should have if I’m going this far.
At the time of order, it sounded more advanced and more $$$$. My thoughts were basic conversion and upgrade to COP later.
I was able to get the new O2 sensor in and system hooked up last night.
I’m assuming I need to configure TPS and probably O2 sensor, and save Peep’s basic configuration before I start it up.

The ECU has Bluetooth capacity, but I was unable to get the PC to find it. So that’s what I will be working on this week, actual computer connection. There is a VGA port as well on the ECU. I also have the SD card logging option.
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By grepin
#118103
I have a VEMS installed on my 1984 928S. I wont say I am an expert at the tuning side but I got it all running with no real issue. To connect I think the code was 9111 (check that) then go into ECU and select the com ports until it works. Mine is com port 3.

Yep calibrate the throttle position and WB02 sensor. There are youtubes on it. One thing that had me confused was that the TPS calibrated backwards. High figure was low and low figure was high IAW the instructions. But it didnt matter. VEMS actually also tells you how to do it when you go into the calibration menu. The beauty is other vems users can share logs and setups easily and you can upload it on your computer or laptop and watch it play back. If yours is supercharged your map will have a larger range than mine so interchangeability wont work. Anyway good luck. Dont hesitate to ask any questions. As I said I am not expert and limited up to a point. However I have been road tuning and think I am nearly sorted.
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By Crumpler
#118141
grepin wrote: Tue Nov 23, 2021 5:34 pm I have a VEMS installed on my 1984 928S. I wont say I am an expert at the tuning side but I got it all running with no real issue. To connect I think the code was 9111 (check that) then go into ECU and select the com ports until it works. Mine is com port 3.

Yep calibrate the throttle position and WB02 sensor. There are youtubes on it. One thing that had me confused was that the TPS calibrated backwards. High figure was low and low figure was high IAW the instructions. But it didnt matter. VEMS actually also tells you how to do it when you go into the calibration menu. The beauty is other vems users can share logs and setups easily and you can upload it on your computer or laptop and watch it play back. If yours is supercharged your map will have a larger range than mine so interchangeability wont work. Anyway good luck. Dont hesitate to ask any questions. As I said I am not expert and limited up to a point. However I have been road tuning and think I am nearly sorted.
Grepin!

Thank you for following. I really do appreciate having somebody who has been through this around. I owe you already.
I don’t think it was wired internally for Bluetooth.
I went and got a serial to USB adapter and the found the ecu on com5. That’s a relief.
Had the same reverse readings in tps calibration too.
All my best, Dave.
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By Crumpler
#118647
Well with further digging I’m not insane.
There is no Bluetooth on this unit because I ordered an SD card logger and they use the same location on the ecu board.

The O2 sensor will heat but not calibrate, just sweeps all over. I checked continuity and power and it looks like the harness is wired correctly. Inversely the supplied NTK O2 sensor appears to have different wire configuration then standard Bosch 4.2 wideband units. I’m hoping its as simple as that.
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By grepin
#118826
Mine had the Bluetooth. My WBO2 came wired already. I cut the pins off and fed it through the firewall. It does sweep around a bit but I managed to get it to settle eventually but it was still a little jittery. I would like to see it settle better as accuracy is pretty important. I will take it for a dyno one day and let an expert do the final tune and I can compare my reading to the dyno. I haven't gone anywhere near the timing side as my car doesn't have any Detonation sensors. I have just relied on the setup as it came from PEEP. I have compared it to a few others and it seems conservative. But that is where power can be won and lost.
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By Crumpler
#118912
Thank you for that feedback, I bought another sensor off the shelf that calibrated (as you described with tiny fluctuations)ok, so bad sensor first time apparently.

Next observation was calibration of battery:
The software was reading 11.8, but 12.2 on the CE panel so I adjusted in software up to proper reading. The software wasn’t pleased because the adjustment value was out of normal reference range (203), but it let me burn changes. Significant?

Yes, the tune. I think SUPER conservative from Peep.
I’m guessing.
I have a knock sensor wired, this currently has a light which signals on a gauge. I need to wire that directly to the VEMS when I’m further in.
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By Crumpler
#119030
Started today, and running.
Super rich even warmed up lambda low but will respond with revs.
I just realized that I while I’m using stock 24 pound injectors, I still have the higher pressure 87fpr on from the Porken chip days. Peep’s config would be for the 86 FPR and lower pressure…
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By hans14914
#119191
If you decide to make a sub-loom for COP, I have distributor blanking plates and there is a mount for Cam Position Sensor on the driver side. You could then do some knock windowing on the ignition. I also have boots to run the VAG 2.0T coils on the stock valve covers.
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By Crumpler
#119262
hans14914 wrote: Mon Nov 29, 2021 4:38 pm If you decide to make a sub-loom for COP, I have distributor blanking plates and there is a mount for Cam Position Sensor on the driver side. You could then do some knock windowing on the ignition. I also have boots to run the VAG 2.0T coils on the stock valve covers.
That sounds incredible, thanks Hans.
That is definitely the long game.
Dave
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By grepin
#120476
Hi Dave,

When you work out a good way to mount your VEMS put up a pic. I haven't looked at it yet. Happy to be lazy and copy some one else. Mine is still sitting on the floor.

Greg
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By Crumpler
#120533
Hey Greg, I sure will, mine is currently in the same position;)

Don’t set the bar high my friend, my climate control lives in the glove box!
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By Crumpler
#120581
I deleted the MAF, since that o-ring junction is a weak link in forced induction. And obviously now redundant with VEMS.
Ok, so let me say this, how great will it be to never have to send a MAF out for rebuilding again?

I have a spare TB and j-pipe assembly that I can devote to this project luckily. There is an aluminum coupler around that three inch pipe JB welded and then some drei bond to top coat junction.
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By grepin
#120885
Thinking about your over fueling did you set up your req fuel under engine setup in VEMS or leave it as it came. Hit F1 when in the menu and it will explain it. Mine is set to 14 ms with injectors that flow about 220cc (from memory). If yours has bigger injectors I think the time should be a lot less. Sorry some of this stuff is already getting a little hazy.
Also under tuning - acceleration enrichment I have been informed to use pressure based instead of acceleration based.
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By worf
#120927
grepin wrote: Tue Dec 07, 2021 6:22 am Thinking about your over fueling did you set up your req fuel under engine setup in VEMS or leave it as it came. Hit F1 when in the menu and it will explain it. Mine is set to 14 ms with injectors that flow about 220cc (from memory). If yours has bigger injectors I think the time should be a lot less. Sorry some of this stuff is already getting a little hazy.
Also under tuning - acceleration enrichment I have been informed to use pressure based instead of acceleration based.
Also consider injector latency (dead time.)
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By milrad
#120951
Crumpler,

Here is a little inspiration for you as you work through all this engineering/tuning. This is my rebuilt 89 GT on the dyno yesterday. Lower two lines are from a stock 90 S4.

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Keep going, it will be worth it in the end! And good luck buddy!
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By worf
#120959
milrad wrote: Tue Dec 07, 2021 2:36 pm Here is a little inspiration for you as you work through all this engineering/tuning. This is my rebuilt 89 GT on the dyno yesterday. Lower two lines are from a stock 90 S4.
That is a nice chart! :drink:
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By Crumpler
#120980
milrad wrote: Tue Dec 07, 2021 2:36 pm Crumpler,

Here is a little inspiration for you as you work through all this engineering/tuning. This is my rebuilt 89 GT on the dyno yesterday. Lower two lines are from a stock 90 S4.

Image

Keep going, it will be worth it in the end! And good luck buddy!
Wow.
That is completely awesome sir!
That curve is amazing.
I know you put a ton of work into it, I’m thrilled that it paid off.
Can you set up a thread or share the high lights?
What all went into the rebirth of the Gretchmobile?!
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By Crumpler
#120983
grepin wrote: Tue Dec 07, 2021 6:22 am Thinking about your over fueling did you set up your req fuel under engine setup in VEMS or leave it as it came. Hit F1 when in the menu and it will explain it. Mine is set to 14 ms with injectors that flow about 220cc (from memory). If yours has bigger injectors I think the time should be a lot less. Sorry some of this stuff is already getting a little hazy.
Also under tuning - acceleration enrichment I have been informed to use pressure based instead of acceleration based.
worf wrote: Tue Dec 07, 2021 12:29 pm
grepin wrote: Tue Dec 07, 2021 6:22 am Thinking about your over fueling did you set up your req fuel under engine setup in VEMS or leave it as it came. Hit F1 when in the menu and it will explain it. Mine is set to 14 ms with injectors that flow about 220cc (from memory). If yours has bigger injectors I think the time should be a lot less. Sorry some of this stuff is already getting a little hazy.
Also under tuning - acceleration enrichment I have been informed to use pressure based instead of acceleration based.
Also consider injector latency (dead time.)
Thank you guys.
I did mess with the req_fuel and flow rates.
Also tinkered with IAC PWM.
Also injector ramp settings.
That got the lambda close to one.
But, as it stood I had bigger injectors and a higher FPR so thats when I started to address the hardware side. Thank should have it up and running tomorrow.
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By Crumpler
#121413
Hey Greg, the TPS…

Always been inverse readings on calibration.
Now it calibrates and reads position fine until I actually start the car.
Then I’m reving and it won’t read position.
Have you seen this phenomenon?
My eye is twitching lol.
I’m going to email Estonia tonight.
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By hessank
#121471
I'm just wondering if you were sent the wrong TPS.
TPSs are made for Left & Right sides. I learned that from John Speake (JDS Porsche).
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By grepin
#121592
Crumpler wrote: Thu Dec 09, 2021 9:48 pm Hey Greg, the TPS…

Always been inverse readings on calibration.
Now it calibrates and reads position fine until I actually start the car.
Then I’m reving and it won’t read position.
Have you seen this phenomenon?
My eye is twitching lol.
I’m going to email Estonia tonight.
No I haven't seen that. Its always just read inverse. I did ask PEEP once but didn't get a reply. Sometimes you get a reply and sometimes you dont. I will add that its only the calibration figures that read in reverse. The throttle position on the VEMS display has always looked normal.
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By Crumpler
#121692
Ok, once again I’m not crazy, derangement but not clinical insanity.
I’m addition to the tps not reading position the throttle was sticky at WOT, which was consistent with both throttle bodies I had tried.

The TPS sensor was binding on the Throttle plate arm at WOT. It looks like the 3D insert is not strong enough material to not slightly twist.

It may be that action was causing it to uncalibrate sensor, and don’t know, but I will check continuity and resistance on the sensor itself.

https://youtube.com/shorts/7dw-7nclmr4?feature=share

My next move is probably to use the 3D insert as a pattern to fabricate an aluminum spacer.
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By Crumpler
#121724
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Here’s the insert off the car. You can see the warped edge. I don’t know if from heat or force, I’ve never really worked with this 3D material.
Doesn’t seem like the future, at least in combustion engines. ;)

I know I’m probably making a big deal out of it, but I had a throttle hang open at the track one time and it was a pretty shitty experience lol.
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By Crumpler
#121894
hessank wrote: Sun Dec 12, 2021 9:02 am What is the make of the TPS?
Good to know for a replacement as well
Hey Fred, it is a Delphi ss10993.
It looks like compatible with Bosch 0280122003

I’m testing mine, the resistance changes as I move position but no idea if I’m in spec or not. Numbers look reasonable.
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By Crumpler
#121954
Wondering if the insert is even correct for 85/86 and this tps sensor. ;)
I copied the thickness based on 3D insert, but actually the thickness should be 3mm less to fit correctly on the TB arm. So fabricated a thinner steel insert and finally normal and smooth throttle action.
Yay. What’s another three hours of my time. :banghead: :rolleyes:
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By hessank
#122310
" ..... What’s another three hours of my time.... "

So it becomes a labor of love plus you'll know all its weak and stronger points :beerchug:
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By Crumpler
#122516
Thank you comrades.
The Bosch tps mentioned above is an exact match for the record.
Peep returned email, says the original insert should fit, also for the record.

Car is up and running.
After warm up cycle done,
I’ve been messing around with AFR at idle. Playing with fuel req and injector ramp. I’ve got actual AFR to equal target AFR at idle. Right now it will go above target when rpm’s increase. SC factor of forced air, I’m guessing.
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By Crumpler
#124225
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Update on progress.
AFR dialed in.
Next issue seems to be IAC. Or I need to adjust VE numbers at lower RPM.
After warm up in closed loop, I will get a dramatic stumble in rpm’s, if I come off throttle quickly.
Attached is screen shot of log, it may not be legible, but it goes like this: goes lean with increased tps, then bounces rich with rpm drop. IAC duty increases, lambda increases, rpm increases.
I have adjusted IAC PID numbers and it was better ie not killing engine. The duty cycles and response looks like Idle control valve is working.
It occurred to me last night to adjust idle screw on the TB. (S3 has that adjustable bypass port).
The cold start idle was 640’s and I adjusted up to 790’s, I did not have time to run it into closed loop function yet so I don’t know what the brain will do with it yet.
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By Crumpler
#124230
grepin wrote: Tue Dec 07, 2021 6:22 am
Also under tuning - acceleration enrichment I have been informed to use pressure based instead of acceleration based.
I’m going to look at this now too.
It’s interesting to look at spark in real time on the log, there is a ultra short decrease with increased tps position, which I think is the tip in enrichment but I don’t know enough about it yet.
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By hans14914
#124258
Just a thought, but does the bi-directional 85/86 IAC have anything to do with it? Most IAC are just a single-direction with return spring. It may be that the VEMS is either not configured for or wired to do the bi-directional valve. In which case, you may need to sub out the 87+ valve which is the more traditional style.

I haven't really played around with VEMS in the last 10 years, and all my previous projects were Audi, but If I was wagering a guess, it's that valve format giving you issues.
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By Crumpler
#124564
hans14914 wrote: Fri Dec 24, 2021 1:22 pm Just a thought, but does the bi-directional 85/86 IAC have anything to do with it? Most IAC are just a single-direction with return spring. It may be that the VEMS is either not configured for or wired to do the bi-directional valve. In which case, you may need to sub out the 87+ valve which is the more traditional style.

I haven't really played around with VEMS in the last 10 years, and all my previous projects were Audi, but If I was wagering a guess, it's that valve format giving you issues.
It makes sense to me.
In attempt to rectify issue:
1. Changed bypass port settings on TB
2. Acceleration enrichment, pressure based, no difference.
3.IAC/TPS follow enabled, no difference.
4. IAC PID’s no difference.
5. Disabled ign idle control, worse.
6. VE adjust lower rpm’s, no difference.

Open loop no issue, gradual decrease tps in closed loop no issue.

I have however heard from Peep, he doesn’t think the bi-directional IAC is a factor.
I ordered a 87’ IAC (Lowe’s) from Germany just in case. They are pretty hard to find apparently.
I guess the shipping time will give me time to figure out the knock sensor installation.
If 87-95 IAC is the move then I need to wire it to the ECU independently, the S3 is set up as the three pin harness. I also need to find room under the pipe organ, it’s mentioned that the 87-95 IAC is bigger then the earlier valves.
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By hans14914
#124684
I can lend you one if that helps. You could use any IAC and just plumb it remotely. On my supercharger stuff, I am using a Hitachi valve from a Ford 4.6 application.

Since you are keeping the stock harness, I would just build a small extension harness with the 3-pin male JPT on one one, and a female 2-pin JPT on the other. That way you can keep your harness stock, and if someone figures out the 85/86 valve, you are good to go.

Which three pins does Peep have connected on the VEMS to the IAC?
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By Crumpler
#124705
hans14914 wrote: Mon Dec 27, 2021 8:28 am I can lend you one if that helps. You could use any IAC and just plumb it remotely. On my supercharger stuff, I am using a Hitachi valve from a Ford 4.6 application.

Since you are keeping the stock harness, I would just build a small extension harness with the 3-pin male JPT on one one, and a female 2-pin JPT on the other. That way you can keep your harness stock, and if someone figures out the 85/86 valve, you are good to go.

Which three pins does Peep have connected on the VEMS to the IAC?
Hans, thank you so much for the lifeline on this one. I owe you.

So, I traced pins from LH harness this morning.
LH pin10 IAC/ICV Close.
Goes to
VEMS ecu 36 port, pin 6 (injectorGch64)

LH pin 23 IAC/ICV Open
Goes to
VEMS ecu 36 port, pin 17 (injector14ch128)

Third pin, assuming ground, could not read where that hits specifically on the on pin out map I have.
It looks like all grounds run into a community soldering point in Peeps harness then into VEMS at different pin locations, if that makes sense.

I appreciate the offer on the IAC, mostly I needed specs or replacement models for one I could find compatible on this side of the pond. So I will shop for what you mentioned. Thank you again.
Best, Dave
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By hans14914
#124711
Referencing this page on the VEMS documentation:

https://vems.hu/vt/help/v3/v3_idle_pwm_hardware.html

Is the "Dual Solenoid" option enabled and the "Idle Solenoid Output / Channel" set to Dual?

If so, make sure that the pins you discovered for open and closed are mapped correctly to the IAC Dual Solenoid in the output configuration. It may also be worth reversing the pins in the output map just in case they are backwards.
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By Crumpler
#125785
Ok, one step closer.
IAC issue hopefully resolved.
I never did get the bidirectional 86 unit to comply, but did wire the 87 in and adjusted all the software settings.
I used a free 12v pin on the LH harness side and pin 8 on the ec36 side as ground output to 87 IAC.
Then of course that didn’t work, and I pulled the ecu out and started bench testing with the IAC lock function in the VEMS software.
I could not get any frequency on the IAC signal pin in question. I had used a different pin then Peep but it was still in the injector grouping.
I really could not have done this without Chris(Shifted), who had heard that pin six was the only one in that group that had the diode set up to signal the IAC. He also answered about 500 texts. Not published anywhere I could find, but he was right. Went back to pin six and frequency matched whatever Hz I picked on VEMS.

Then using a boroscope with video feed next to my laptop, I stated trying to calibrate the IAC, gate movement to duty cycle. Pretty tedious plugging in numbers at each frequency.
The best curve was actually at 45Hz for some reason. I was going into this thinking 100Hz.
Matching gate opening to DC via the IAC lock function Min DC 39 and Max is 90 DC. This is close but not the same as the 27 and 80 dc that I had researched.
So there is a curve, but it’s not linear which I’m not crazy about. 50% open is 80DC.
Anyway, hopefully it’s enough to keep the rpm’s from falling off a cliff.
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By Crumpler
#128257
Adjusted IAC reference curve with new RefDC.
Target idle now achieved.
VEMS bug: you can’t burn numbers unless you drag the data points on graph. Entering numbers in cells does not work.
Hoping since we are talking about it, that VEMS tune is not end of life software. Last update was years ago. Sigh.

Excellent graphic!

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