KBlair

Needing to know if the L-jet EFI system used in the 83-84 US cars is a sequential or batch controlled system?

KBlair

Here is a link to a VW site, which has some manuals online for L-jet (with and without Lamba).

<a href="http://www.conservatory.com/vw/manuals_nyx/" target="_blank">http://www.conservatory.com/vw/manuals_nyx/</a>

Enjoy!

Incendier

Per the L-Jet manual, p. 15, "all the injection valves in the engine open and close at the same time"..."The injection cycle of the L-Jetronic is selected so that for each revolution of the camshaft half the amount of fuel required by each cylinder is injected twice"

The injectors are powered in fours (1,2,5,6 and 3,4,7,8), and ground-side triggered in pairs - 1/5 (pin 15), 2/6 (pin 33), 3/7 (pin 32), 4/8 (pin 14).

HTH

BrianG

According to the Probst book on Bosch FI systems, the first Jetronic system capable of sequential injector control is the ML.3 or L Motronic (third generation). In the 928, Motronic was first introduced in the "S4" model. So certainly, the earlier L-Jet is batch pulsed. This reference does not say if the "S4" 928's Motronic FI system was batch or sequential pulsing.

KBlair

Thanks guys, I'm trying to determine if the Megasquirt DIY ECU will work in my shark. It is for a batch controlled EFI system, so it looks like it should work.

Incendier

Oh man...I have to say, that Megasquirt, despite the laughable name, appeals to every instinct I have. Thanks for the point-out.

No more barn-door AFM...

KBlair

I know what you mean James. Imagine being able to tune the car while it is running.

If you are really serious about this we should work together on it, considering we have the same platform.....

Incendier

On further review, it looks like the closest thing to a direct hook-up I can imagine, least for power, coolant temp, injector control, and the fuel pump.

Have to plumb an air temp sensor into whatever intake tract replaces the AFM, add a TPS, and figure out how to control the Aux. Air regulator and cold start injector off of one solenoid. Outside of the idle system, kid stuff.

Cool! Next, forced induction...uh, sorry, that's already been beaten to death.

Yeah, man, I'd like to chase this down. I've done enough rewiring of the beast to hopefully be of some help, and I have a few sources that might be able to help on fabrication, parts, etc.

KBlair

You've obviously went farther down this road than I have, only had my car for a few months and hven't really done anything to it since purchase. You caught me off-guard with the Aux air regulator control and cold start injector thing.

As far as parts, they are cheap and I may even be able to wrangle a few freebe's (you might be able to as well if you happen to be in Schaumburg, if you catch my drift).

I've fabbed a few PCBs before but nothing as elaborate as this one.

Any specific thoughts at this point?

Incendier

Hey:

Grab me off-list at _jim@yahoo.com, lest we torture the whole list with this

If anyone else is interested, let's form a little brain trust to hack through some of the issues.

Er, that's a small-in-size brain trust, not a trust of small brains. Or, it may be just that...

WallyP

As far as I know, ALL post-CIS 928 systems are batch-fire.

KBlair

No prob.

KBlair

In case anyone else is interested, here's the link to the MegaSquirt DIY ECU

<a href="http://www.bgsoflex.com/megasquirt.html" target="_blank">MegaSquirt</a>

BC

Please guys - Keep this and anything you do with this ON LIST. This is what this place is for. Are there any options for controlling the ignition as well?

Incendier

The system is designed to be a fuel control only; the designers wanted to keep from getting bogged down in feature bloat. The only interface is the tach signal from whatever ignition control unit you have, so if finer control than the stock unit is desired, should be no trouble to go to an MSD or Jacobs setup.

Speaking only for myself, I'll be happy to keep the topic alive on list, but the discussion it would take to get this running would create the mother of all threads. Could we agree to a digest format?