Porsche 944 turbo/Injector & Flyback ? (v3.x serialnr 731)
Due to engine failure, I had to build a new one. Found 3.0 litre 16valve Porsche 968 engine as a starting point.
Now with Carillo rods, original forged pistons, cometic 3,2 mm headgasket, wich brings C/R down to 9,5.
Garrett GT35/82R turbo.
Engine harness has been built out of original 968 wire harness, each injector have own wire.
Bosch wasted spark coil pack from VEMS shop.
Racetronix high Z 846cc/min injectors.
Does the harness happen to have some transient diode in EC36/23 flyback connection ?
- if yes, please bypass (short) that transient diode
- injector+ should be direct to EC36/23
- changed v3/731 to 30V flyback (2019-09), injector closing faster and more reproducible (with lower voltage, injectors close slightly sloppily, and not all 4 with the same speed)
- idle will be smoother (injector pulsewidth will be slightly longer)
Trigger : See MembersPage/PeteLeh/PorscheTrigger (132+1)
VEMS: serianr: v3/731 VR/Auditrigger without cam-HALL inverter
Changed v3/731 to 30V flyback (2019-09). Originally Power flyback.
300kpa MAP
LCD&PS2
4ign Driver
- 2006-2009: Firmware 1.1.47
- first: Fuel pressure ok, I get some burning, in combustion chambers, but the engine did not start. Was configured and tuned later, and used for years.
- later firmware upgraded to 1.2.31 (might upgrade to 1.2.38 in 2019), have yet to be tuned.
Wiring has been done by using Porsche 968 engine wire harness, wich is connected to porsche 944 Turbo Engine bay and cabin connectors (very straight forward). Motronic 55 pin connector has been cut away and wires connected to EC 36 and EC 18 connectors. Few extra wires had to put. ( When I ordered VEMS the plans were others, so I did not order it with 55 pin Motronic connector)
Here is schematic of EC connectors with corresponding DME PIN.s
EC 36/ Wire colour/ Object/ DME pin/ Other
1 Gn/Re TPS signal 26 DME Maf sens wir
2 Gr/Bl IAT 33 Tank ventvalv Wi
3
4
5 GND
6 Bk/Wt ICV close 22 Flyback Diod
7 Gr/Bk Inj.1 17
8 Gr Inj.3 35
9 Boost ctrl Flyback Diod
10 Re/Bl Gn/Bl Tacho 6 22Ohm+220uH
11
12
13
14 Ye Clt sensor 47
15 Fuel pump relay- : Please use injector output (injout-E as originally)
16
17 Re/Bl ICV open 4 Flyback Diod
18 Bl/Re Variocam 23 Flyback Diod
19 Gn/Re Inj.2 16
20 Gr/Bl Inj.4 35
21 GND
22
23
24 GND
25 Re/Gn Re/Ye Power 37 Fuse Box
26 GND
27 Br Speed sens 27 Pin 1 Connector
28
29 Ye/Re TPS +5V(1) 25 DME Maf sensor wire
30
31
32
33
34 Br/Ye Coil Pack1 New wire
35
36 Ye Coil Pack 2 New wire
EC18/ Wire colour/ Object/ DME pin/ Other
1 Wt Knoc sens 1 11
2 Shield Knock sens
3 Wt knock sens2 29
4
5
6
7 Br WBO2/5
8
9 Gn/Re WBO2/6
10
11
12 Br Ref sens DME 26 Pin 1 connector
13 Bl/Gr WBO2/1
14 DSUB3
15 DSUB2
16
17
18 Ye/Re WBO2/4
Update:
I got Porsche running and tuned using anvient1.1.44 firmware and megatune. Dynoed up to 400hp with moderate boost, manual boost control. Car had boostcreep and wastegate was chewnged to synapse 60, manually controlled. Then got some kids etc family stuff, so car was left standing for years. Now I have some time for hobby again and started to get car running again. I was not completely satisfied with engine wireloom: too many wireconnections, allthough there were no issues with them. So I built a new wireloom using an other old Porsche 968 engine wireloom as base.
All connections are as abowe, difference is with power wires, wich are as Porsche 968 has: Injectors IAC and variocam solenoid share same wire and fuse, as is in original Porsche. They all also are connected to flyback wire. No separate flybackdiodes in loom. ECU has own fused power source, so has ignition. Boost control not connected.
I triued to start the engine with old firmware and megatune, but had one groundwire wrong, so burned p259 chip. ECU was sent to VEMSSHOP for repair, and got exellent and fast service.
Groundwires were corrected, also all wires checked many times.
Got ECU back, and firmware was updated to 1.2.23.
- Can you check this ? 1.2.23 is weird, 1.2.38 or 1.2.43 recommended
- So I started to configure with VEMSTUNE and tried to start the engine.
- See VemsTuneVersion
First I got decent RPM reading, both tachometer and VEMSTUNE. Injectors were not connected yet. Also fuel pump was priming and got fuelpressure up.
After few runs I lost rpminformation. I connected the fuelpump to EC15/36 to see if p259 chip is working, and fuel pump did not prime.
So I thought the chip is burned again and ECU was sent for repair/upgrade
- it turned out that ECU is ok, to be specific: the "sectrig"="use as primary" setting was configured (most likely accidentally and unknowingly)
- but primtrig was connected to EC36/27 as normally (not to sectrig input) which obviously resulted in 0 RPM reading (and empty InputTrigger/TriggerLog )
- note: Always [report digitally], and request review before sending ECU
- Now checking the wires and sensors again.
Upgrade 1.1.44 => 1.2.x
- Also continue configuration as there are lots of changes between 1.1.44 and 1.2.23
- With newest VemsTune, after "update ini files from web" (see VemsTuneVersion ) after uploading 1.2.38 fw, and
- (using the new, updated VT) upload old (1.1.44 is really old) config to the ECU (File / upload config ; select .vemscfg file), most new variables get filled to default values
- "validate" is needed, and some manual intervention is needed, this is most likely an easier path than