Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

> 1.8 l-jet fires, but dies within seconds, tried searching :-/
thatguywiththedatsun
post Mar 21 2014, 01:36 PM
Post #1


Newbie
*

Group: Members
Posts: 21
Joined: 21-March 14
From: Memphis, TN
Member No.: 17,144
Region Association: None



I've been looking for a 914 for a few months now, but life has been in the way. I found one last month that seems to be a good starting point, but I'm having trouble getting it to stay running atm. Seems like it's probably the l-jet system being out of adjustment or leaky, faulty sensors, or some old corroded electrical connectors. The question is; where?

I'm getting a buzzing sound with the key turned to "on" which I initially thought was the seatbelt interlock buzzer everyone seems to be so fond of, but upon closer inspection... it's coming from the injectors..? If i unplug the noisy injector, another one starts buzzing. There's no noise from the fuel pump at this time with the key on. The fuel pump relay, and power supply relay on the board were nowhere to be found when I got the car. I went ahead and bought a few new ones to get it back to stock wiring, but I'm really having trouble deciphering the current flow diagrams. (You guys seems to have a reference system to the pins in every connector, or which specific relay you're referencing. Is there a diagram for this somewhere, or are the labels just buried under the grime in this car?) If i hot wire the double relay (86d, 88d?) to the + battery post, the fuel pump will run, but this doesn't change my "start, rumble rumble, die" situation at all. I have a feeling that there is an area in the wiring that has been altered which, if put back to stock, would rectify the problems I'm having... It's just a matter of finding it and fixing it. Any suggestions?

What I have done:
-compression test: 125,130,90,135 - hoping it will improve pending a valve adjustment?
-tested the coil and wires for spark - checks out fine... nice and strong
-tested fuel pressure - 43psi holding steady for several minutes after the test (p.o. said he'd recently had the fuel pump replaced, but didn't mention why (IMG:style_emoticons/default/dry.gif) )
-renewed all the l-jet vacuum hoses and put hose clamps on every connection
-taken care of a few obvious electrical bugs (missing/rusty relays, broken wires, etc)
-checked the head temp sensor spade connection, but where does the other end of that connection terminate on the relay board?
-checked afm resistance. - With key on, if I move the flap by hand, the fuel pump does run, but there is no 1.5 seconds of priming with the key on, just the annoying injector buzz.

Thanks in advance for the help! I'll be much better off if someone could just explain the 'pin 13/relay 74/etc. references to me.

(IMG:http://www.914world.com/bbs2/uploads_offsite/lh5.googleusercontent.com-17144-1395430598.1.JPG)

(IMG:http://www.914world.com/bbs2/uploads_offsite/lh5.googleusercontent.com-17144-1395430599.2.JPG)

(IMG:http://www.914world.com/bbs2/uploads_offsite/lh3.googleusercontent.com-17144-1395430600.3.JPG)

(IMG:http://www.914world.com/bbs2/uploads_offsite/lh3.googleusercontent.com-17144-1395430600.4.JPG)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

Posts in this topic
thatguywiththedatsun   1.8 l-jet fires, but dies within seconds   Mar 21 2014, 01:36 PM
Chris H.   Timothy_nd28 is the man you need to speak to, and ...   Mar 21 2014, 01:47 PM
timothy_nd28   The injector buzzing sound is very intriguing to m...   Mar 21 2014, 02:14 PM
Cap'n Krusty   Unplug all of the injectors. Key on, plug them ba...   Mar 21 2014, 02:28 PM
thatguywiththedatsun   I'll be in the garage in the next few hours, a...   Mar 21 2014, 02:30 PM
thatguywiththedatsun   Email address is xxxxxxxxxx@gmail.com. One chance ...   Mar 21 2014, 02:31 PM
timothy_nd28   2 manuals sent to your email address. I would re-...   Mar 21 2014, 02:38 PM
Dave_Darling   Here's a link to a diagram of the FI wiring ha...   Mar 21 2014, 04:17 PM
thatguywiththedatsun   Very useful tests! What I originally thought w...   Mar 21 2014, 08:09 PM
thatguywiththedatsun   Wait a minute.... You said pin 13 to ground. Lol, ...   Mar 21 2014, 08:49 PM
timothy_nd28   Yep, pin 13 on the ECU plug to engine ground. The...   Mar 21 2014, 09:45 PM
thatguywiththedatsun   Man, you are good with this stuff. I'll try to...   Mar 21 2014, 09:57 PM
69telecaster   While I don't really like Rivieras, that car l...   Mar 22 2014, 07:40 AM
jim_hoyland   All the above info is very useful; I have on occas...   Mar 22 2014, 12:21 PM
thatguywiththedatsun   Interesting. I read 0V on 14 and 15, and I have no...   Mar 22 2014, 06:57 PM
thatguywiththedatsun   I'm not crazy about the weird cloth seats myse...   Mar 22 2014, 07:08 PM
Jeff Bowlsby   That's a standard 1974 1.8L FI harness. You c...   Mar 22 2014, 08:53 PM
thatguywiththedatsun   Man, I'm stupid. Okay, after testing the corre...   Mar 22 2014, 11:00 PM
malcolm2   Man, I'm stupid. Okay, after testing the corr...   Mar 23 2014, 10:00 AM
timothy_nd28   Good, what was your reading from pin 13 to engine ...   Mar 23 2014, 12:51 AM
thatguywiththedatsun   3.5k ohms   Mar 23 2014, 01:43 AM
timothy_nd28   Great, just wanted to verify that you weren't ...   Mar 23 2014, 09:30 AM
davesprinkle   Oh yeah, the old "leave the AFM disconnected...   Mar 23 2014, 12:41 PM
Chris H.   Yep met too. Runs terrible with that thing off do...   Mar 23 2014, 12:46 PM
davesprinkle   Yep met too. Runs terrible with that thing off d...   Mar 23 2014, 03:02 PM
thatguywiththedatsun   [quote name='thatguywiththedatsun' post='2014655'...   Mar 23 2014, 05:55 PM
malcolm2   That's my problem... I don't have the fa...   Mar 24 2014, 08:32 AM
thatguywiththedatsun   All injectors fire a nice even spray pattern with ...   Mar 23 2014, 06:55 PM
timothy_nd28   So far so good. Now with your multimeter set to o...   Mar 23 2014, 11:16 PM
jim_hoyland   As an aside: By grounding # 1 ( forward left spade...   Mar 24 2014, 07:06 AM
thatguywiththedatsun   No buzzing from the injectors during the spray tes...   Mar 24 2014, 06:48 PM
timothy_nd28   How far away do you live from Clark? It would be ...   Mar 24 2014, 06:57 PM
malcolm2   How far away do you live from Clark? It would be...   Mar 24 2014, 07:53 PM
thatguywiththedatsun   Not sure. I'm in Memphis. I did see a '74 ...   Mar 24 2014, 07:23 PM
timothy_nd28   If it can be had for under 5 bucks, maybe.   Mar 24 2014, 07:24 PM
timothy_nd28   Pin 6 and 9 on the ECU plug show the total resista...   Mar 24 2014, 09:32 PM
malcolm2   Tim, did you give him the ITINERANT link? http://...   Mar 24 2014, 09:44 PM
timothy_nd28   Black22 found that link, all good stuff. :beer2:   Mar 24 2014, 10:08 PM
thatguywiththedatsun   Oohlala. Definitely my cup of tea. I'll probab...   Mar 25 2014, 12:54 PM
thatguywiththedatsun   No dice, gentlemen. Got the afm responding reasona...   Mar 28 2014, 05:16 PM
Valy   I bet it dies because the fuel is cut at the injec...   Mar 28 2014, 05:37 PM
timothy_nd28   Okay, so some further tests you can do. On the (+...   Mar 28 2014, 07:42 PM
timothy_nd28   One last test, in addition to pin 88d being jumped...   Mar 28 2014, 08:03 PM
malcolm2   so what ever happened here? Did you buy a new AFM...   Apr 20 2014, 09:34 AM
thatguywiththedatsun   Once again, other stuff got in the way. I'm po...   May 2 2014, 02:24 PM
thatguywiththedatsun   Bought a rebuilt afm from fuel injection corp. Sam...   Mar 12 2015, 08:00 PM
thatguywiththedatsun   Bringing a thread back from the dead here I know, ...   Feb 22 2017, 02:07 AM
Tjmrfe   Bringing a thread back from the dead here I know,...   Feb 23 2017, 05:14 PM
Root_Werks   ECU failure is uncommon....used to be. Maybe as t...   Feb 24 2017, 09:09 AM


Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 6th May 2024 - 12:52 AM