chrsvo

Hi, wanted to share my experience with a VEMS plug-n-play kit in an installation description and short term impressions.
This is a lengthy post and some of the stuff has been shared multiple times probably, but I am new to standalone EMS and I think describing minutiae could be helpful to others like me.I’ll jump straight to my installation and put some observations/opinions further down.

I bought a PnP package from Peep (raceboy) to hook it up to the existing wiring and mounting the housing under the steering column (I have an 87 924S).

O2 Sensor installation

I had the exhaust off the car to take the old o2 Sensor out, don’t think I could’ve loosened the rusty thing with the exhaust mounted. Just made sure I had the right thread on the new one and proceeded with the cable routing as the sensor needs to be hanging freely in the open for calibration.
I routed the cable going from the vems housing to the sensor under the center console (which I loosened/disassembled for this purpose), down through the shifter opening next to the damping foam. I cut off the plug to avoid damage to the foam (pretty sure with the right tools this would be unnecessary, pictured here with a vacuum hose which I routed through the DME grommet later).


Stupid me connected the cut off cable directly to the sensor not realising the plug had a resistor built in for calibration. This made calibration in vems impossible.
Also, it was set as an LSU 4.9 in the Software stock configuration , but my sensor is an LSU 4.2 according to part number.

MAP/Vacuum line

I wanted to put a rubber line from the hose connector to the throttle body Through the main wiring grommet which is next to the brake cylinder. However, the wiring and grommet were so stiff, there was no way I could get a 8mm rubber line through it. So I took some 4mm OD brass tube I had and pushed it through from the inside. I then connected (stock looking) rubber hose on each end, one going to the housing under the steering column and the other going to a T-connector I added to the vac outlet on the throttle (the one that goes to the fuel pressure regulator).
My back hurts thinking about the hose in the footwell area.


Throttle position sensor (TPS)

There was a throttle position sensor provided, but no adapter (except some flat piece of Alu with some holes in it, I’m guessing that was supposed to act as an adapter). I test fitted the new Tps on the throttle shaft and got an idea how it needs to be mounted. I then cut a 80x45mm piece from 10mm thick ABS, used a 15mm forstner bit to create a recess for the TPS o ring seal and drilled a 10mm hole through the middle. Then I marked the „old“ mounting holes of the TB diagonally on the ABS piece. They were 70mm apart, 35 to the center. I drilled those holes, mounted the plate and then rotated the new sensor back and forth to somewhat adjust it to range and mark the holes to mount the TPS to the plate. The holes were about 25mm away from the old ones (but they are each spaced differently from the shaft!), rotated counterclockwise.

Provided adapter:


Finished adapter looks like this:


AFM delete / IAT sensor

I welded an adapter from a 10mm steel plate with cutouts masked from the AFM to airbox sealing and a 70mm OD steel tube. Also drilled a hole and welded a 12x1.5 nut for the IAT sensor (you can see a bit of the brass nut in the middle of the tube). The welds are pretty bad, I was using a wrong gas.
The sensor plugs into the obsolete AFM connector.



After that, I hooked the battery up and turned the ignition on to connect my laptop via Bluetooth to the ECU. Everything looked ok and I calibrated O2 and TPS sensors using the wizards in Vemstune.
There’s a procedure by Peep how to do the first start, however my car didn’t want to start at first and then only did with opened throttle.
Running terribly and dying at idle.
Peep then provided a stock NA configuration, which, together with some idle screw adjustment, enabled me to run the car.

Idle is still a bit bouncy going 830-880rpm, but that may be issues with air leaks, stuck/leaky ICV, ignition timing or worn injectors.

During a test drive I started to use live tune and will now spend some time on fuel/ignition maps, warmup enrichment etc.

Some notes, experiences, opinions:

• Throttle reaction seems more aggressive vs DME, pulls nicely even when not tuned completely. Sounds "shrillier" when accelerating in high rpm, more scream - less muffled
• I had to set the output for Tach to „P289“ and channel 0 for the cluster gauge to work, this is different for other model years/ engines /wirings
• It’s not (yet) a true PnP product. In my opinion, it should include a TPS adapter, vacuum hose and the right software settings (tach, wbo2 type, fuel requirement) and a printed installation guide. This can avoid hiccups for newbies like me. It would be great if an AFM delete tube could be part of the package as well.
• The MAP connector on the housing should be longer and ribbed. The one on mine only allows for 4x1mm (tpu) line which doesn’t look factory
• I thought the delivery took too long! I know Peep doesn’t do this full time and I appreciate his email help and the involvement in the community but I waited 5 months and was getting pretty nervous having transferred the full price in advance without official paperwork. I don’t expect amazon next day delivery, but a commitment to a delivery date.
• I should have bought the version in the original DME housing (is that even available at the moment?). would look and mount better.
• Bluetooth connection works well, but I had vemstune crash during live tuning more than once. Burn your results to the ECU from time to time while using live tuning
• VE seems high in low RPM/MAP, it idles slightly rich (lambda ~0.97) at 65%. Does this sound ok? Base map provided by Peep has idle VE at 64% by the way...
• How do I tune the ignition map?

H.F.B.

The map, provided by Peep is more or less just a startup map to get the engine running. So fine tuning is necessary.
You can try my old well running Vems config to see, what's different. Don't know, if this works for your as well. But with this map, dyno result was 175 fwhp @ 5917 rpm.

Here is my current ignition map.


VEMS 944 Ignition Map

VE-Table depends on your injectors. Here is my old VE-Table with the stock injectors. Currently I'm running Bosch 0280155759 (Volvo) Injectors, so the current VE-Table is different.

chrsvo

interesting, those are indeed very different numbers from the base map.

what was your setup for these maps, stock 2.5 8V?
is this VE table more on the rich or lean side?

H.F.B.

Nearly stock 2.5 8V. It was a bit head work done.
The VE table is more lean at idle and lower load.

tempest411

Is there ANY stand-alone that actually works properly out of the box on a stock NA? It seems that all of them, and not just for our cars, require endless tinkering/dyno time to get working properly.

Raceboy

How is it endless tinkering? The map I provided to Chris was tuned on the dyno (152rwhp) and it drives nicely. Engine likes lambda 0.97 so what is the problem?

Regarding delivery date, I was a bit overwhelmed with orders and during summer also had my house construction going on at the same time. Can't say it is normal but sometimes happens.

Regarding settings, there are just way too many models etc and sadly one works for all does not cut it and some calibration (like TPS and WBO2) is needed by customer! With instructions and youtube video tutorials this should not pose a problem and so far it has not.
P.S. "Stealth" is still a no cost option. It offers better packaging but makes for more difficult future upgrades.

V2Rocket

Curious about the tps - my kit came with a tps that required no adapter and plugged right in.

But that was 4-5 years ago.

there can be some tweaking based on individual cars to get it all right but vems software makes that easy to do as needed.


Congrats on the best upgrade you can make for a 944.

aussie944cab

I kinda agree with the OP, Not exactly PnP but if it is something you're planning to do then you should expect a few bugs/issues, I found Peep to be great in dealing with my issues, and I was having real time messaging via facebook when installing mine, made my S2 run a lot better, can't wait to get it fitted now I've gone supercharged

suf.agent

Nice thread

Bought my PNP kit year ago, but only now preparing for first start
Have same TPS in my kit, decided to cut throttle shaft and made silicone seal, rebuild throttle so oil won't flood new TPS sensor.
Also made bushing for wasted spark coil:



Made separate hole for MAP:



What's benefit of Volvo injectors? I thought of changing stock one's to something more modern, but havent yet spent time on discovery.
Is there any noticeable improvement? Better idle, fuel consumption, etc?

chrsvo

looks good! I’m ok with my adapters/cable routing for now but maybe in the future I’ll change things.

When you look up horsepower/injector size estimations, the NA injectors are already on their limit. In general, injectors perform best at an 85% duty cycle, so even stock cars may benefit from bigger injectors.
As I want to increase head flow and use a mild camshaft soon, the bigger Volvo injectors are a must.

Another thing I’ll definitely do in Vemstune is to half the req_fuel time and double the numbers in the VE table. Because they go to 255 theoretically, limiting the values to 100, 120ish is using only half the possible resolution.

H.F.B.

4 hole pintle vs. 1 hole pintle injectors are always an improvement. This means better fuel atomization, so better cold start, idle, part throttle behaviour, fuel economy and driveability.
With the 4 hole injectors I could reduce VEMS start, afterstart and warmup enrichment significantly.
Apart from that, a modern engine management system and modern injectors are a nice package IMHO.

Edit: Found this pic.

chrsvo

Update: I had trouble with the car when cold, it basically died almost instantly below 60 deg C coolant temperature.

I suspected the IAC and I think it was the reason as it stays running once I made these settings:

This is for a late 8V NA with the 3-wire IAC. All changes by me differing from the "Stock config" (provided by raceboy / Peep) are red.

Under Idle Ignition Advance:
Control Setting: disabled

Under PWM Idle Control:
IAC PWM Frequency: 200 Hz
Max PWM Duty: 100%
Min PWM Duty: 0%
IAC close delay: 1s
Power Off IAC after close delay: Enabled

Dual Solenoid:Enabled
Idle Solenoid Output: INJGroup
Idle Solenoid Channel dual: 6,i7

Under Idle Reference Curve / Idle Air valve reference position:
Deg C / RefDC %
-40 / 0
-15 / 3
-7 / 8
2 / 20
15 / 31
30 / 43
40 / 52
53 / 68
73 / 85
106 / 89

-> basically an ascending line from 0-90% RefDC. I think this should be the other way round and the solenoid channel further up should be inverted, but same difference, right?
Stock setting was a more or less flat line - so it was either not set up correctly at all or the early 2-wire ICV works very differently.

Here are my cranking, afterstart, warmup enrichtment curves, although I think these are not as important as the right IAC setup.


Other changes to the stock config (not sure if I mentioned):

Under Outputs -> Tach
Tachometer Channel: P259
Tachometer Channel: 0
Tachometer Divider: Custom
Tachometer Divider: 17

Before this, the tach wouldn't work - and even now, it's bouncy when I step on the throttle - I'm wondering if a wrong signal fried some electrics in it.

edit: here's my config attached, it's also pasted raw here: https://pastebin.com/JY4h3USd
924S-stock.zip

throttle is a bit jerky when cold, and it needs optimisation, but it's staying on when started cold it's what's important!

tempest411

What a PITA dealing with that. That should've already been configured for you, or at least the setup information should've been provided.

chrsvo

Well it’s annoying but inevitable when installing a standalone EMS it seems.

however, I hope Peep takes this info as feedback and includes the changes for future customers.
My guess is that 99% of his customers are turbo owners.

By the way I had to tweak the IAC curve a little, keeping it a bit more open at lower temperatures to keep idle above 800 RPM

V2Rocket

Another interesting thing, because my VEMS setup was made for a 2-pin ICV. (not the aux air valve that came stock on early 944).