3.6 conversion 1st start issue

[racerx9146]

Hello

Thanks to all the info on this BB my 3.6 conversion to-do list is finally getting short.

I will confess my conversion it into a 914-6 but its a fairly rare conversion in the 914 world and most of this knowledge is here so excuse my trangression.

I attempted 1st start last night. Its a 91 964 conversion. Custom wiring harness by me. I have spark and I have some fuel as there is a start attempt. I did rebuild the dizzy so in short everything has been touched. I have a cel light that is working properly. I can hear DME relay turning on with ign. and pulsing under crank.

tiThere is a small start attempt so some gas must be getting though. Tried it about 10 times (letting starter rest) Result was very consistent with video

Take a look a video and let me know where i should spend my time 1st.

3.6 startup - YouTube

Tonight I was going to measure fuel pressure and then recheck firing order I guess. (no fun in a 914)!

thanks Daron

[Joe Bob]

Andy who runs the 914world site has a 3.6 in his 914 BTW....

As to the video, it seems like it wants to start.....have you tried a shot of ether into the intake? If it catches and fires it is a fuel supply issue. What fuel pump are you using?

The DME relay? If it clicks and continues to click during the starting cycle the 12volt power to the DME is fluctuating. That was my problem once.

[racerx9146]

appreciate for the advice, I will look closer at the DME relay tonight as to whether its turning on/off during cranking or holding steady. From reading other threads I was under the impression it will pulse during the cranking procedure but that assumption might be incorrect.

I am using a factory 964 pump/filter

I am aware of the 914world (3 or 4 conversions there but not much troubleshooting and I prefer the maturity level over here at Pelican.

thx. Daron

[Jaskas]

What about driveblock ? I had it inmy ecu...

[JeremyD]

intake leak? You have all the proper stuff plugged? I'd do the ether.

How bout your flywheel sensor? the DME has to see the flywheel moving before it will turn on the fuel pump.

[Tom '74 911]

Hi Daron,

When I did my 3.6L conversion I remember having an initial no-start issue that I had to work through. It ended up being wiring related. I had wired a +12V (I think it was from the fuse box to the DME) that was hot with the key turned to the "ON" position. It wasn't, however, hot when the key was in the "START" position, so when I turned the key through "ON" to "START", it went cold and there was no power to the DME and the engine wouldn't start. It took me a few days of troubleshooting as I was SURE I had wired everything correctly! Swapping that wire to another location in the fuse box that was hot when the key was turned to the "START" position solved the issue.

It's more than likely something simple that was just overlooked!

Best of luck w/your troubleshooting,
Tom

[wildcat077]

I had the same issue as Tom when i attempted my 3.6 conversion startup ... had a conversion harness wire connected to the fuse panel with 12v with key on but only 5.6v when cranking,i moved the wire down the panel where i had 12v with key on and 9.8 volts cranking.
It fired right away ... with open exaust ansd scared the crap out of me !

Sure hope you get to enjoy the rewards of your conversion soon,it's well worth it

Cheers
Phil

[racerx9146]

Thanks for all the replies...Hi Tom have not seen you in quite a while!

So got home and did some troubleshooting...

the 2nd stage of the DME relay seems to be firmly engaged when cranking...checked voltage and listened to relay...

Car runs on ether just fine, so I guess firing order/static timing is okay

No immobilizer on the 964 I believe

I think since I have spark and some fuel delivery that crank sensor is probably okay.

Tried running fuel pump manually, no differance....

Soo I rigged up my old fuel pressure tester. 60lbs at the rail while cranking.....

so that's too high, should be around 36-40 I have a brand new fuel regulator, then I remembered I got the fuel pump off EBay so I checked the part number, it's for a 964 turbo which has CIS still I believe.....

So could too high a fuel pressure cause a no start? I guess the injector solenoid has to be strong enough to over power the pressure at the line or am I nuts here?

Thanks Daron

[jpnovak]

output pressure will be governed by the regulator, not the fuel pump. I don't think that is your issue.

Have you used a noid light or Oscope to check that each injector is firing? How long did the engine sit between being pulled from its former home to the key turn on the 914? It is very common for these injectors to stick closed. Try tapping them with a blunt object while cranking to see if they free up. You have to free up dried fuel.

[Joe Bob]

I still have my CIS pump in my SC.

[racerx9146]

Yup I thnk you are right, just checked the Bently and Porsche Motronic runs at 60 lbs unlike BMW and others....

I had the injectors professionally cleaned but they have been sitting a year.

will try the injector tapping next.

[racerx9146]

Folks

thanks for all the assistance and replies. Stuck injectors takes the win. I did A little tap tap and the story changed immediately.

I did have the injectors professionally cleaned but that was a year ago. So I almost got a perfect conversion 1st start but not quite. I did not run it long since now I have to go drop some large $$ on a oil cooler system and some kind of exhaust that will clear my Wevo 915. My neighbors love me here at 8:00 PM in suburbia with no muffler.

All my senders/gauges work and we seem to be charging. Tach does not work but I half expected it to not be compatible with ECU output.

Here is the vid my 7 year old took before bedtime!


Thx for the help, Daron

[wildcat077]

It's alive

Cheers
Phil

[Tom '74 911]

Glad it was an easy fix!! Enjoy!

[racerx9146]

Below is my Wiring Diagram. I am not sure if the resolution will get downsized by the upload to the forum but if you need a higher rez version IM me.

The wiring diagram is 914-centric but many of the concepts will carry-over. I assembled this from the many diagrams others have uploaded here. I like playing in Visio!

So always referance the factory diagrams, this diagram worked for me, it may not work for you, use at your own risk.

thanks Daron

[jpnovak]

Great News that its running!

Are you still using the 914 transmission or did you do a 915 swap. Maybe even a G50.

Would love to see more on your build. I went with a Suby ej20TT in my 914 project.

[racerx9146]

Another question. Does it matter which coil/ignitor is connected to which distributor?

My intellect says not but that usually is wrong!

thanks Daron

[1976 TN Porsche]

Lets see some Pictures.