![]() |
|
|
|
Registered
|
![]()
Motor ran fine in my 914 until I changed the fuel lines on the motor and installed stock 915 flywheel for my new 916 trans. I ran through all the bentley book tests.
-Fuel pressure is around 39 lbs -Voltage readings all correct on DME -Unplugged spark plug #1 cable and got spark on external spark plug -Resistance looked good on Reference Sensor and speed sensor -During start I get 3.7VAC on Speed sensor -During start i get between .133VAC-.157VAC on reference sensor It sounds like it wants to start. Click on link below to listen to motor. https://dl.dropboxusercontent.com/u/28794322/Motor.m4a Any ideas?? Appreciate any help at all!!! thanks, Steve in Laguna Niguel, CA.
__________________
Steve 75 914-6GT clone with a 1995 3.6 DME motor, 915 trans with Martin Bott 916 shift kit, MB911 heat exchangers, boxster brakes, etc... Special thanks to Patrick Motorsports for fixing my 915/916 trans and there associated 3.6 conversion parts. |
||
![]() |
|
Brew Master
|
Did you by chance reverse your speed and reference sensor wires? When I installed my engine the P.O. had marked the harness and sensors wrong and had them on wrong. I swapped them and it started.
|
||
![]() |
|
Registered
|
Thanks!! I just tried switching the sensor wires and now it doesn't fire at all.
I am leaning towards the reference sensor pin on the flywheel. I initially broke it off but a local shop welded it back on and swared that it was good.
__________________
Steve 75 914-6GT clone with a 1995 3.6 DME motor, 915 trans with Martin Bott 916 shift kit, MB911 heat exchangers, boxster brakes, etc... Special thanks to Patrick Motorsports for fixing my 915/916 trans and there associated 3.6 conversion parts. |
||
![]() |
|
Brew Master
|
I don't think it's your reference sensor now that I read your post again. If you have spark, the speed and reference are working. How did you test fuel pressure, by jumping the fuel pump? If you've got spark while cranking you need to move onto fuel and air. My guess is fuel.
|
||
![]() |
|
Registered
Join Date: Jul 2013
Location: Munich
Posts: 266
|
Have you tried disconnecting one or two injectors and then tried to start?
__________________
87 911 3.8l |
||
![]() |
|
Registered
Join Date: Sep 2009
Location: North of You
Posts: 9,160
|
Check the brown bundle of ground wires on the drivers side of the intake...
This engine is fuel injected? Do you have a noid light?
__________________
"A machine you build yourself is a vote for a different way of life. There are things you have to earn with your hands." |
||
![]() |
|
![]() |
Registered
|
Thanks everyone for the help!! I bought a fuel pressure gauge and attached it to the test fitting. It shows 39 lbs, when I try to start the motor. I will try disconnecting some of the injectors today and see what happens.
__________________
Steve 75 914-6GT clone with a 1995 3.6 DME motor, 915 trans with Martin Bott 916 shift kit, MB911 heat exchangers, boxster brakes, etc... Special thanks to Patrick Motorsports for fixing my 915/916 trans and there associated 3.6 conversion parts. |
||
![]() |
|
Registered
Join Date: Aug 2008
Location: sectors R&N, SE Pa
Posts: 3,117
|
Quote:
You say you swapped the speed and ref sensors and that it won't start at all. But it wasn't starting at based on the audio clip of your first post. How exactly did it sound different to you. Bentley says you should have a ~2.0 V sine (AC), but your reading seems low. The Flywheel is new and you suspect the reference pin. I think you are on to something here - all relatedto the ref signal and fuel starvation. The wrinkle is your fuel pressure which ok, but the pressure may have gotten up from the ignition switch. I would try jumpering the DME fuel pump relay ON temporarily to see if it fires up.
__________________
Dan '87 Targa Carrera 3.2 - Fabspeed Cat Bypass, M&K Muffler, SW Chip Venetian Blue |
||
![]() |
|
Registered
|
The engine is a totally stock fuel injected 1984 Euro 3.2 motor. The grounds are good. I also tested the grounds and voltages on the DME connector, per the Bentley manual. I need to google noid light. I used a DVM from radio shack for the measurements. It has a nice beep connectivity feature.
__________________
Steve 75 914-6GT clone with a 1995 3.6 DME motor, 915 trans with Martin Bott 916 shift kit, MB911 heat exchangers, boxster brakes, etc... Special thanks to Patrick Motorsports for fixing my 915/916 trans and there associated 3.6 conversion parts. |
||
![]() |
|
Registered
|
Quote:
All excellent suggestions. I won't be able to work on it until this afternoon. I will report back tonight. Thanks everyone for the help!!!
__________________
Steve 75 914-6GT clone with a 1995 3.6 DME motor, 915 trans with Martin Bott 916 shift kit, MB911 heat exchangers, boxster brakes, etc... Special thanks to Patrick Motorsports for fixing my 915/916 trans and there associated 3.6 conversion parts. |
||
![]() |
|
Registered
Join Date: May 2002
Location: St Louis
Posts: 4,211
|
Quote:
Any chance some contaminants got in the fuel hoses?
__________________
Rick 88 Cab |
||
![]() |
|
Registered
Join Date: Aug 2008
Location: sectors R&N, SE Pa
Posts: 3,117
|
Quote:
I've seen though, that sometimes if the speed/ref sensor signals are there, the FP doesn't turn on. Maybe it is because no FP power was easier to diagnose - that led me to that thought. (and the fact / smoking gun that the flywheel was recently changed, and the OP did mention good spark on #1). That stuff aside, my bad if I threw anyone off track - espec'ly fetus. I would love to know more about the DME. +1 fuel contamination (b/c of the fuel line work too)
__________________
Dan '87 Targa Carrera 3.2 - Fabspeed Cat Bypass, M&K Muffler, SW Chip Venetian Blue Last edited by steely; 05-17-2015 at 11:23 AM.. |
||
![]() |
|
Registered
Join Date: May 2002
Location: St Louis
Posts: 4,211
|
I am also interested in the DME electronics, From what I've learned from the FRWILK website the reference sensor is used one time and then the DME counts teeth off the flywheel. FRWilk also says there is some crude frequency synthesis to get the angular resolution required for spark timing between teeth (see DME math)
Sal Carceller has disassembled the code and maybe he knows.
__________________
Rick 88 Cab |
||
![]() |
|
Registered
Join Date: Feb 2014
Location: Lomita, CA
Posts: 2,696
|
Quote:
starting. Once the engine is running the ref sensor can be disconnected. The DME ECM always knows when TDC re-occurs by counting the speed sensor teeth. This is a good test to determine how good the speed sensor's signal is. If the engine eventually dies, the speed sensor is weak.
__________________
Dave |
||
![]() |
|
Registered
|
It runs!!!!!!! But I don't know why. I put everything back the way it was. Traced the sensor wires to make sure they were going to the correct sensors. Tried to start the motor again, same symptom as the recording. Then I disconnected two of the three injector plugs on the distributor side. The one in back was being a butt head. Then I tried to start the motor again and it started!!!! Then I shut the motor off and plugged in the middle injector plug. Then started the motor again. It ran a little better!!! Then I shut the motor off again and plugged the #1 injector back in again. I thought it must be the #1 injector, but the motor started right up again.
Has anyone seen this before? I guess next step is to reseat all the injector plugs and wiggle wires to see if I can make it happen again. I did go to Harbor Freight and bought a noid kit, but I didn't need it so far. Motor runs great so far. Now I just need to adjust the clutch and tweak my home grown 916 shifting linkage and get insurance for the car. It's been apart for over 2 years, with fixing the hell hole and installing the 916 trans. Thanks again everyone for the help!!! I was ready to tow it to a shop, but I am tight on funds right now and didn't know how I was going to pay for it.
__________________
Steve 75 914-6GT clone with a 1995 3.6 DME motor, 915 trans with Martin Bott 916 shift kit, MB911 heat exchangers, boxster brakes, etc... Special thanks to Patrick Motorsports for fixing my 915/916 trans and there associated 3.6 conversion parts. Last edited by fetus; 05-17-2015 at 09:37 PM.. |
||
![]() |
|
Registered
Join Date: Aug 2008
Location: sectors R&N, SE Pa
Posts: 3,117
|
Quote:
__________________
Dan '87 Targa Carrera 3.2 - Fabspeed Cat Bypass, M&K Muffler, SW Chip Venetian Blue |
||
![]() |
|
Registered
Join Date: Aug 2008
Location: sectors R&N, SE Pa
Posts: 3,117
|
This is great - although I agree it would be nice if you knew exactly what the prob was so you don't get a surprise later. Congrats on getting this far.
__________________
Dan '87 Targa Carrera 3.2 - Fabspeed Cat Bypass, M&K Muffler, SW Chip Venetian Blue |
||
![]() |
|