Printable Version of Topic

Posted by: George H. Nov 12 2007, 03:14 PM

OK

here my problem,

I'm trying to use my previously functioning L jet system to break in my fresh rebuild, before i switch to an sds system. fyi I had removed everything from the engine bay for paint so everything is a fresh reinstall. which I'm sure is where my problem lies.

I have spark, compression and fuel pressure, but no fuel coming from my injectors.

I have checked my wiring over and over, and believe i am correct.

I ,for the sake of argument, am a neophyte at best when it comes to this so any and all direction is appreciated.

my ???

what causes the injectors not to fire ?

is there a spot on the net that actually shows ( pics, diagrams)of the fuel injection harness connections?


Where do I begin to test to get this system up and running?

I would switch to sds, but the switch will be easier with the engine timed and able to idle as i work out the initial bugs.

Posted by: ejm Nov 12 2007, 03:44 PM

The single white wire from the FI harness to terminal 1 on the coil is a must have....

Posted by: Brando Nov 12 2007, 03:47 PM

What kind of ignition system are you running?

In stock configuration the injection system recieves it's RPM info and trigger from the points in your distributor. Without the high voltage pulse from the points it will not trigger.

Now, there are ways you can trick it into working. IE: On MSD setups your run a stand-alone coil that runs in-line with the ignition switch lead tot he points and trigger wire for the ECU.

If you're using a stockish (read: 035, 009, etc) distributor with the magnetic pickup, you can still attach it to the coil negative lead and it will work.

Now...

Do you have all your wiring hooked up correctly? Is the Air Flow Sensor hooked up correctly? Do you have any large vacuum leaks? Is the ECU recieving voltage appropriately? If you are running a stock distributor with points, is your timing and dwell set correctly?

All of these things make or break L-Jet working properly.

Check and report back to us

Posted by: George H. Nov 12 2007, 04:46 PM

check

Posted by: George H. Nov 12 2007, 04:54 PM

mallory





I believe so..




I believe so



fresh (new) tight hoses everywhere




I will check voltage when i get home



timing should be in the ball park to get her started

Posted by: Cap'n Krusty Nov 12 2007, 04:58 PM

Double relay there and functional? Yellow wire plugged in to the correct tab in the relay board? The Cap'n

Posted by: jim_hoyland Nov 12 2007, 05:01 PM

George,

Is the yellow wire attached to the relay board ? I assume you put gas in the tank??


Attached image(s)

Posted by: Brando Nov 12 2007, 05:20 PM

George, can you please elaborate on your Mallory ignition?

Posted by: SLITS Nov 12 2007, 06:22 PM

Resistor pack installed with no broken wires?

Posted by: George H. Nov 13 2007, 12:07 AM

yes to the yellow wire to proper location

yes to fuel ( boiled tank all new lines )

resistor pack all wires are connected

double relay installed, unable to prove functional
have another relay that I'm picking up at my shop now to swap out and see

I've been using the search function most of the evening and reading the many sites or pages that the captain has recommended before.and i can see that i need to expand my electrical testing tools

so i have decided if this doesn't work ( swapping out the relay) then I might as well just pull all of the L jet and install the sds system that i planned on using in the long run



Brando , Mallory unilite and original coil at this moment. I will be swapping out the coil with promaster E coil and the Mallory ballast resistor during the sds install.

Posted by: George H. Nov 13 2007, 12:09 AM

Neophyte ???,


but where do i check the ecu voltage?

Posted by: Brando Nov 13 2007, 01:16 PM

I was asking if it was getting power. 12V trigger lead, Yellow wire on the engine bay fusepanel.

It should be working if everything is hooked up correctly. Could be a bad ecu? When was the last time this system was installed and working properly?

Posted by: Jeff Bowlsby Nov 13 2007, 04:13 PM

Here is a link to an L-Jet manual.

http://members.rennlist.com/914_collectibles/zRareDoc06.pdf

And here is a link to a draft L-Jet wiring harness diagram. I have better drawings, but they are not on the website yet:

http://members.rennlist.com/914_wiring_harnesses/

Posted by: Jeff Bowlsby Nov 13 2007, 07:27 PM

I deleted this post...answered my own question

Posted by: George H. Nov 14 2007, 12:36 AM

well the first problem has been found

broken and frayed wires going to TTS

wires under rubber boot where broken


Brando, it has been a about a year since the system was in use, but it did work fine

but heck the PO said he had the engine rebuilt, i do believe he had the engine worked on

because i had to replace the case from where a rod had punctured it

anyways everything keeps directing me to install the sds and go from there

I have another harness, but i believe it is from a 75

off the top of your heads is this going to be compatible?

thanks for the links

Posted by: Jeff Bowlsby Nov 14 2007, 12:47 AM

The 74 and 75 harnesses and ECUs and AFMs were different and not compatible. Check to see if the AFM connector on your harness has the same number of contacts as your AFM.

Posted by: George H. Nov 14 2007, 12:57 AM

I don't know why I even asked that I have read that a hundred times on here

Posted by: jim_hoyland Nov 14 2007, 08:53 AM

Any Update ?

Posted by: slackin' at work Nov 14 2007, 09:42 AM

Im still not sure how you are triggering your injectors with the Unilite.

Posted by: sunnyvale Nov 14 2007, 11:51 AM

Check the cylinder head temp sender isn't open circuit.

Ground the sender wire if so, add a 2k or 3k ohm resistor depending on how cold it is.

Posted by: Brando Nov 14 2007, 12:08 PM

Same here.

Posted by: George H. Nov 14 2007, 12:19 PM

Same here meaning what exactly? you can switch the stock dizzy with the unilite on L jet

won't be switching out harnesses till thurs