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914World.com _ 914World Garage _ L-jet question

Posted by: bd1308 Nov 18 2005, 09:33 PM

I have a few questions:

What does the ECU plug-in look like?

are the pins that plug into things like the D-jet ones?

can i convert a D-jet relay board to accept a L-jet injection system?

I'm real confused here.

b

Posted by: Gustl Nov 19 2005, 12:50 AM

IIRC Andy used to have a D-Jet engine with L-Jet on in - so he should know

Posted by: Mueller Nov 19 2005, 12:59 AM

QUOTE (bd1308 @ Nov 18 2005, 08:33 PM)
I have a few questions:

What does the ECU plug-in look like?

are the pins that plug into things like the D-jet ones?

can i convert a D-jet relay board to accept a L-jet injection system?

I'm real confused here.

b

L-Jet does not need the relay board like the D-jet does

Most of the connectors are the standard Bosch connector

4 of the connectors shown are the L-Jet connectors, the other 2 odd ones are GM Weatherpak

user posted image

Posted by: bd1308 Nov 19 2005, 05:51 AM

okay...so standard plugs. Which would make sense.

GM Weatherpak....found on chrysler Jeep 2.5 /4 engine.

how would i power the L-jet brain? Can i get around using the dual relay....I only hear bad things about that relay.......

b

Posted by: ejm Nov 19 2005, 07:19 AM

Unless you want your fuel pump running whenever the key is on (not a good idea) you are going to need a relay. Most problems with the dual relay can be traced to poor connections. We can help if you are installing and troubleshooing the stock relay and wiring. With a custom design you are on your own.
my .02

Posted by: Mueller Nov 19 2005, 09:50 AM

QUOTE (bd1308 @ Nov 19 2005, 04:51 AM)
how would i power the L-jet brain? Can i get around using the dual relay....I only hear bad things about that relay.......

b

you don't "get around" the relay, you look at the circuit and substitute 2 Bosch or 2 standard square relays.

I'd have to look at the wiring schematic again, it's been awhile, so you need to find out that when the flapper opens, is the signal suppling ground or positive to the relay to activate it?

Ed, do you know if the fuel pump gets energized 1st, and it completes a circuit to activate the injector relay?

or

does the injector relay activate 1st and it trips the fuel pump relay?

or

both at the same time (this is how my Link fuel injection works)

Posted by: ejm Nov 19 2005, 04:38 PM

Both of the relay coils always go to ground. When the key is turned on 15 power from the ignition coil enters the relay at terminal 86c, contacts close and supply power to the ecu and injectors thru 88b and to the contacts in the afm thru term 88a. The fuel pump runs when the afm contacts close and supply power to term 86b or when starter term 50 is energized and power enters the relay at 86a. So the ecu and injectors get power before the fuel pump.

To substitute a standard relay would require adding a diode (internal to the stock relay) so the afm contacts don't energize the starter and supply constant power to the cold start valve and thermotime switch. At least for a moment until they burned up.

The stock relay can be had new for less than $60.