L-jet help!, testing ECU Options

[eg914]

Is there anyone in the Sacramento, CA area with a running L-jet car? Are you willing to plug my ECU into your car to see if it works? I have a '74 with a pukegressive carb, and a box of L-jet parts. I think I have everything but the fuel pump, but I don't know why the PO removed the FI for the carb. I would hate to install everything only to find that the ECU was bad. Let me know if you can help. I live in Elk Grove, and work in Rancho Cordova.

Thanks

[lapuwali]

The chances the ECU is bad are almost nil. It's much more likely the PO simply switched because he couldn't "tune" the EFI (no need to, but some people never learn, or because he blamed some other problem on the EFI, or he mistakenly thought he'd get more power.

The most common failures on L-Jet are wiring related, followed by one of the temp sensors, followed by fuel pump failure. Actually, the No. 1 problem is a misinformed owner messing with things they don't understand, and doing things like opening the air meter to "recalibrate" it. Way down the list are things like ECU or injector failure, which is usually the first place most people look for failures.

You can test the fuel pump easily by (briefly!) connecting it to power and see if it makes noise. Don't leave it connected too long w/o fuel running through it. There are published specs on what the temp sensors should read using an ohmmeter (Google). Wiring just requires careful checking for broken or corroded connections.

If the top has been taken off the air meter (look for marks on the screws), be suspicious, and figure a PO messed with it, and most likely didn't do it any good. If it's still sealed, use it.

[Trekkor]

If you do decide to reinstall the L-Jet, make sure you replace ALL the vacuum hoses. Test ALL the temp sensors and use new seals for the injectors and the intake runners. Then, and only then, will you have a fighting chance.

L-Jet is super touchy to vacuum leaks. The gasket on the oil filler cap needs to seal tight or it won't run right.

And...FYI: Albert Correia, who runs a very fast 914 in the Bay Area a/x's, has the Webers off his old 2.0 on his 1.8 without any adjustments and it makes loads of power on the stock cam.

I've seen it, heard it and ridden in it first hand, so the carbs vs. stock F.I. debate will rage on.

I like carbs better ( right now ) because problems are almost always related to dirt in a jet. Where F.I. problems usually prove to be a little more complicated to track down. ( and $$$ ) (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

That said, I had zero problems with my D-Jet on my 2.0 FOUR, zero problems ( after tuning ) with my Webers on the 2.0 SIX I run now and nothing but problems with my L-Jet on my '75 1.8.

And you can borrow my spare L-Jet ECU from a '74 if you want.

KT

[eg914]

Thanks for the answers. The ECU has a rebuilt sticker on it, so it made me wonder about it's status. I have checked the harness for continuity, and all is good. I have also checked any items I could find ohm values for. The car sat for a while before I got it, and the air flow meter has a rough/sticky spot at about 3/4 open. This may have been the reason for the switch. Is it possible to open the AFM up and fix this? What sealant would you recommend to make the bottom to body air tight?

Thanks again, for this and all the answers I have found over the last 1.5 years through searches. This site makes working in this car a lot easier.

[Trekkor]

I've got a spare AFM, too. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

KT

[eg914]

Trekkor, thanks for the offer on the ECU and AFM. I will keep you in mind if I run into any trouble. I still need to replace the tunnel fuel lines before changing the fuel pump, as the plastic is very brittle in the engine bay. It may be a bit before I actually make the change (time is tuff to come by), but I want to get ride of the single carb before winter. Was the trouble you mentioned with L-jet due to the age of the components, or some other cause?

[Trekkor]

I replaced near everything gasket, seal or hose wise.
New cat as well. Tested everything. Could't pass smog.

Car's exempt now. Long sold, parted and junked (IMG:http://www.914world.com/bbs2/html/emoticons/headbang.gif)

Prolly coulda just lowered the fuel pressure now that I look back at it. (IMG:http://www.914world.com/bbs2/html/emoticons/idea.gif)

KT

[Dave_Darling]

QUOTE (eg914 @ Jul 3 2005, 08:49 PM)

... the air flow meter has a rough/sticky spot at about 3/4 open.

Could be a warped flap. Most of them have a spring-loaded valve in the flap, but sometimes that isn't enough to let a backfire go through without causing damage. A big-enough backfire can warp the flap in the meter, which can cause it to stick.

Not sure what you'd use to seal it back up after you opened it. But any time you mess with the relationship between the return spring and the flap's shaft, you've altered the air/fuel relationship and you will probably have a lot of tweaking to do in order to get it right.

--DD

[bd1308]

QUOTE (eg914 @ Jul 4 2005, 12:02 AM)

but I want to get ride of the single carb before winter.

well i'll pay for you to box it up and send it to me (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

[eg914]

Britt,

Sorry for the delay in responding, been a busy week. I will let you know when I have the injection working, though it may be a couple of months before I have everything together and time to install. At that point if you want the carb and manifold I will make arrangements to get them to you. Be warned, this is FAR from optimal for a flat engine. Horrible when cold (below 50F), wants to die. The electric choke opens too fast, then closes while the engine is parked an still warm, can you say "hard to start"?

Thanks to all for the responses.

[bd1308]

a little project for me..... (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)