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 )

> Won't Fire up with L-jet, WTF!!! Update on Page 2 post 35
Black22
post Apr 15 2012, 03:47 PM
Post #1


Senior Member
***

Group: Members
Posts: 886
Joined: 1-November 07
From: Creswell, OR
Member No.: 8,290
Region Association: Pacific Northwest



I have a new 1911 with L-jet. It was formerly a 1.8L stock engine that ran good. Trying to do the break in cycle but have no fuel.

I have spark and air, but injectors won't fire.

I can however jump the relay and get the fuel pump to run. I can also move the flap manually at the AFM and that will also trigger the pump to run with all the stock wiring in place.

I tried all the tests at the manuals.type4.org website. It passes all the tests.
Only one test is questionable though.

** Measure the resistance between ECU plug terminal 20 and system ground at terminal 17. The reading should be 52-78 Ohms. Mine reads 5.9 Ohms. That would suggest the dual relay is bad, so I install a brand new relay and that one reads 6.9 Ohms. WTH?

What am I missing?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
 
Reply to this topicStart new topic
Replies
pilothyer
post Apr 16 2012, 07:25 PM
Post #2


Member
***

Group: Members
Posts: 838
Joined: 21-May 08
From: N. Alabama
Member No.: 9,080
Region Association: South East States



You can determine if the pump is running with the key on start position by looking for voltage at the pump while cranking.....you may need to get a partner to crank the engine while you look for voltage at the pump connector.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Black22
post Apr 16 2012, 08:09 PM
Post #3


Senior Member
***

Group: Members
Posts: 886
Joined: 1-November 07
From: Creswell, OR
Member No.: 8,290
Region Association: Pacific Northwest



QUOTE(pilothyer @ Apr 16 2012, 06:25 PM) *

You can determine if the pump is running with the key on start position by looking for voltage at the pump while cranking.....you may need to get a partner to crank the engine while you look for voltage at the pump connector.


Will do...What will this info tell me (other than if there is voltage present)?
More specifically, what will that point to as suspect?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
pilothyer
post Apr 16 2012, 09:23 PM
Post #4


Member
***

Group: Members
Posts: 838
Joined: 21-May 08
From: N. Alabama
Member No.: 9,080
Region Association: South East States



QUOTE(Black22 @ Apr 16 2012, 09:09 PM) *

QUOTE(pilothyer @ Apr 16 2012, 06:25 PM) *

You can determine if the pump is running with the key on start position by looking for voltage at the pump while cranking.....you may need to get a partner to crank the engine while you look for voltage at the pump connector.


Will do...What will this info tell me (other than if there is voltage present)?
More specifically, what will that point to as suspect?


If the pump runs when you manualy open the AFM flap with the key at the on position, this test will verify that fuel pump will also run with the key in the cranking position. (since it is hard to hear over the starter)
When the ignition switch is turned on it energizes the dual relay which provides battery voltage to the control unit and injection valves. When the key is further turned to the crank position the relay gives voltage to the fuel pump, If the engine starts, voltage continues to be provided to the fuel pump through contacts in the AFM. If the engine fails to start and the key is released to the on position the voltage to the pump is opened by the AFM flap contacts.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
timothy_nd28
post Apr 16 2012, 09:46 PM
Post #5


Advanced Member
****

Group: Members
Posts: 2,299
Joined: 25-September 07
From: IN
Member No.: 8,154
Region Association: Upper MidWest



QUOTE(pilothyer @ Apr 16 2012, 07:23 PM) *

QUOTE(Black22 @ Apr 16 2012, 09:09 PM) *

QUOTE(pilothyer @ Apr 16 2012, 06:25 PM) *

You can determine if the pump is running with the key on start position by looking for voltage at the pump while cranking.....you may need to get a partner to crank the engine while you look for voltage at the pump connector.


Will do...What will this info tell me (other than if there is voltage present)?
More specifically, what will that point to as suspect?


If the pump runs when you manualy open the AFM flap with the key at the on position, this test will verify that fuel pump will also run with the key in the cranking position. (since it is hard to hear over the starter)
When the ignition switch is turned on it energizes the dual relay which provides battery voltage to the control unit and injection valves. When the key is further turned to the crank position the relay gives voltage to the fuel pump, If the engine starts, voltage continues to be provided to the fuel pump through contacts in the AFM. If the engine fails to start and the key is released to the on position the voltage to the pump is opened by the AFM flap contacts.


Cool, good to know that. He has already stated earlier that when he depresses the AFM flap, the fuel pump does indeed turns on. So the fuel half of the dual relay seems to work. I think the next step would be trouble shooting voltages on the dual relay that feeds the Brain (ECU). Looking at the schematic, I would keep the dual relay in their electrical sockets and check pin (88z) to gnd. It's tied directly to the battery, and you should have 12vdc at that terminal at all times. If you have power at that pin, then go ahead and turn the ign switch to the on position and check pin (88b) to gnd. Again you should have 12vdc with the key switch on. If this is the case, then continue to the Brain ECU connector. Check pin 10 on the connector to gnd, (with the ign on). You should have 12vdc. If you have power there, then put your red multimeter lead on pin 10 on the ECU connector, and put the black meter lead on pin 5, then pin 16, then pin 17. Those last 3 pins are all grounds, you should have 12vdc on each. If you have voltage on everthing I just said, then I think your brain is faulty.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

Posts in this topic
Black22   Won't Fire up with L-jet   Apr 15 2012, 03:47 PM
pilothyer   The L-Jet system doesn't pressurize the fuel l...   Apr 15 2012, 03:52 PM
Black22   Alright, I checked it out a little more after the ...   Apr 15 2012, 10:18 PM
falconfp2001   Alright, I checked it out a little more after the...   Apr 15 2012, 10:56 PM
falconfp2001   Alright, I checked it out a little more after th...   Apr 16 2012, 12:04 AM
CrashDown   Youve got waaaay more patience then me for that st...   Apr 15 2012, 10:59 PM
76-914   Youve got waaaay more patience then me for that s...   Apr 16 2012, 12:25 PM
Dave_Darling   No trigger points in L-jet. It goes off the ignit...   Apr 16 2012, 09:25 AM
Black22   No trigger points in L-jet. It goes off the igni...   Apr 16 2012, 11:00 AM
pt_700   while not l-jet, my 1.7 had the same issue - no si...   Apr 16 2012, 01:40 PM
Black22   I saw an ad in the classifieds for and ECU. Do th...   Apr 16 2012, 02:00 PM
pt_700   i'd search around as i seem to recal seeing a ...   Apr 16 2012, 03:19 PM
tim_nd   Mine didn't start up at first. Same issues yo...   Apr 16 2012, 02:11 PM
Black22   Mine didn't start up at first. Same issues y...   Apr 16 2012, 02:58 PM
tim_nd   I believe you, I'm sure the dbl relay is good....   Apr 16 2012, 03:05 PM
tim_nd   2 more silly questions. Is the yellow wire attach...   Apr 16 2012, 03:41 PM
Black22   2 more silly questions. Is the yellow wire attac...   Apr 16 2012, 03:50 PM
pilothyer   Have you checked the temp sensor? Do you have a w...   Apr 16 2012, 04:08 PM
Black22   Have you checked the temp sensor? Do you have a ...   Apr 16 2012, 04:54 PM
tim_nd   You have fuel pump action, while depressing the AF...   Apr 16 2012, 05:04 PM
Black22   You have fuel pump action, while depressing the A...   Apr 16 2012, 05:51 PM
pilothyer   You can determine if the pump is running with the ...   Apr 16 2012, 07:25 PM
Black22   You can determine if the pump is running with the...   Apr 16 2012, 08:09 PM
pilothyer   You can determine if the pump is running with th...   Apr 16 2012, 09:23 PM
tim_nd   [quote name='Black22' post='1667731' date='Apr 16...   Apr 16 2012, 09:46 PM
Black22   [quote name='Black22' post='1667731' date='Apr 1...   Apr 16 2012, 09:59 PM
Black22   Cool, good to know that. He has already stated ...   Apr 17 2012, 10:02 PM
Black22   [quote name='pilothyer' post='166768...   Apr 16 2012, 09:55 PM
tim_nd   Correct operation of the double relay would be zer...   Apr 16 2012, 08:24 PM
Black22   Thanks, I'll have to test it again. I have th...   Apr 16 2012, 08:30 PM
Black22   Sorry! My quote separating didn't go as pl...   Apr 16 2012, 09:56 PM
tim_nd   Good to hear that you have voltage at 88b. Now ch...   Apr 16 2012, 10:03 PM
Black22   Good to hear that you have voltage at 88b. Now c...   Apr 16 2012, 10:07 PM
tim_nd   Cool, that sounds great. Now check pins 14 to gnd...   Apr 17 2012, 10:16 PM
Black22   Alright....where to continue from? 1911 with L-je...   Apr 22 2012, 02:16 PM
914itis   Deleted   Apr 22 2012, 02:22 PM
dlee6204   L-Jet doesn't have trigger points   Apr 22 2012, 02:23 PM
dlee6204   You should only have 12V to 88c when the engine is...   Apr 22 2012, 02:26 PM
Black22   Doug, I don't have that ground wire in your la...   Apr 22 2012, 02:30 PM
dlee6204   Um, not sure :confused: Its been a while since I...   Apr 22 2012, 02:35 PM
dlee6204   I skimmed through the rest of this thread but if I...   Apr 22 2012, 02:39 PM
Black22   3 NOS injectors 1 that was previously on engine ru...   Apr 22 2012, 02:45 PM
pilothyer   3 NOS injectors 1 that was previously on engine r...   Apr 22 2012, 05:47 PM
Tom   Mike, How many wires do you have going into the...   Apr 22 2012, 02:56 PM
jim_hoyland   The dual relay has a brown ground wire. Usually at...   Apr 22 2012, 03:07 PM
Black22   The dual relay has a brown ground wire. Usually a...   Apr 22 2012, 03:11 PM
Black22   6 wires. One at each terminal listed on the diagra...   Apr 22 2012, 03:10 PM
Tom   I admit that I don't know L-jet. I see you ha...   Apr 22 2012, 03:27 PM
Black22   I admit that I don't know L-jet. I see you h...   Apr 22 2012, 03:37 PM
dlee6204   Doug, I don't have that ground wire in your l...   Apr 22 2012, 03:29 PM
Black22   [quote name='Black22' post='1671369' date='Apr 22...   Apr 22 2012, 03:38 PM
dlee6204   Well I'm out. It seems like you've alread...   Apr 22 2012, 04:05 PM
Black22   Well I'm out. It seems like you've alrea...   Apr 22 2012, 04:10 PM
jim_hoyland   IIRC you can circumvent the dual relay by groundin...   Apr 22 2012, 04:11 PM
kg6dxn   Need a L jet manual? https://docs.google.com/file/...   Apr 22 2012, 04:37 PM
pilothyer   Mike....I had this identical problem with my 75 1....   Apr 22 2012, 05:29 PM
tim_nd   Check the resistance on the ECU plug between pin 1...   Apr 22 2012, 06:07 PM
Valy   I would check 1. Does the injector get a pulse? i...   Apr 22 2012, 06:22 PM
Tom   Mike, Reading over your thread again, it sure s...   Apr 23 2012, 10:18 AM
ClayPerrine   My suggestion. There is a white wire in the L-Je...   Apr 23 2012, 10:30 AM
Black22   My suggestion. There is a white wire in the L-J...   Apr 23 2012, 11:56 AM
Cupomeat   Sorry you are having this much problem with L-Jet,...   Apr 23 2012, 11:54 AM
Tom   I can tell you are really frustrated! Been th...   Apr 23 2012, 12:25 PM
Black22   I can tell you are really frustrated! Been t...   Apr 23 2012, 01:19 PM
jim_hoyland   :popcorn: Any progress ?   Apr 23 2012, 05:18 PM
Black22   :popcorn: Any progress ? Didn't get to it...   Apr 23 2012, 07:46 PM
Qarl   Don't give up. You will get it... And in the ...   Apr 23 2012, 08:17 PM
Black22   Don't give up. You will get it... And in the...   Apr 23 2012, 08:57 PM
ClayPerrine   Get one of these : Noid Light Plug it into your...   Apr 24 2012, 02:21 PM
dlee6204   Bump :boing: Did you ever find the issue and g...   May 20 2012, 06:01 AM
Black22   Sorry to leave everyone in suspense. It is running...   May 20 2012, 09:03 AM
dlee6204   :Qarl: :trophy:   May 20 2012, 09:21 AM
Tom   So glad to hear this Mike. I have found many tim...   May 20 2012, 01:36 PM
Jaydebeers   Have a Double relay question. Trouble shot no curr...   Dec 7 2015, 10:58 AM
76-914   Have a Double relay question. Trouble shot no cur...   Dec 7 2015, 01:53 PM


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: 2nd April 2026 - 07:56 AM
...