1975 914 1.8 fuel system help!, 914 l-jetronic fuel system stink Options

[tonymak85]

Ahh were to began. about three months ago I received a 1975 914 1.8l that was in storage for about 18 years. so after changing the oil and draining the fuel system and replacing some fuel line that were in bad shape. A new battery also. I tried to start it and nothing later I determined that it needed a fuel pump. ordered one put it in then it started!! Yes!! I did it......
Then life happen and could not get back to my project for a couple months and went to start it up again nothing.

So as i work on it today this what i have
The fuel pump IS WORKING
The car runs off starter fluid
The EFI regulator is working and right fuel pressure at the rail (IMG:style_emoticons/default/WTF.gif)
The dual relay (ecu and F pump) have power and are working with the key/start position.

All the the sensors are connected and working to the jetronic.



I Turned to the internet and read that 914 l-jetronic fuel system stink.

so I would like some help on this one please guys thanks
(IMG:style_emoticons/default/sheeplove.gif)

[Black22]

AFM and or AFM connection? I'd also swap out to a known good dual relay just for insurance.

[Cap'n Krusty]

Ahh were to began. about three months ago I received a 1975 914 1.8l that was in storage for about 18 years. so after changing the oil and draining the fuel system and replacing some fuel line that were in bad shape. A new battery also. I tried to start it and nothing later I determined that it needed a fuel pump. ordered one put it in then it started!! Yes!! I did it......
Then life happen and could not get back to my project for a couple months and went to start it up again nothing.

So as i work on it today this what i have
The fuel pump IS WORKING
The car runs off starter fluid
The EFI regulator is working and right fuel pressure at the rail (IMG:style_emoticons/default/WTF.gif)
The dual relay (ecu and F pump) have power and are working with the key/start position.

All the the sensors are connected and working to the jetronic.



I Turned to the internet and read that 914 l-jetronic fuel system stink.

so I would like some help on this one please guys thanks
(IMG:style_emoticons/default/sheeplove.gif)

"Stink"? As in "smells bad"? Like fuel? Exhaust? How does that affect the running?

The Cap'n

[timothy_nd28]

Installing carbs is always an option. Do you own a voltmeter? Since you had this running a few months ago, my gut feeling says seized fuel injectors. Do you still have spark? If so, pull one of the fuel injectors and let it spray in a glass jar while turning the engine over. If you own a voltmeter, we can check some vitals.

[tonymak85]

Installing carbs is always an option. Do you own a voltmeter? Since you had this running a few months ago, my gut feeling says seized fuel injectors. Do you still have spark? If so, pull one of the fuel injectors and let it spray in a glass jar while turning the engine over. If you own a voltmeter, we can check some vitals.

I prefer to move forward, not backward with technology. So Carbs. are never an option. At least for me. I would rather buy a mega squirt.
Yes, I have a volt meter, which is how I deduced that the senors are working and the ecu has all of the correct signals ( within the oem specs)

I know that it is possible an injectors to seize or get clogged but all 4 injectors and the cold start at the same time seems highly improbable, the odds alone. . .
And I own a noid light, the injectors are not receiving a signal from the ecu to open.

I know it has spark, because as I stated before, it will run with starter fluid.

So I guess what Im asking is how reliable are the L-jettronics?
What other possible semi-common non starting issues with the 1.8 914.
I had the battery in an out a few times while it was not running.

[JeffBowlsby]

L-Jet is a very solid FI system. Thousands of thousands of cars run it.

Download one of the L-Jet tech manuals from my 'Classic" website, "Tech Notebook" page, at the link in my signature block and go through the simple diagnostics. They include a troubleshooting process, follow it until you find the problem.

[Dave_Darling]

Did you, by any chance, knock one of the wires off the (-) terminal of the coil? The white (sometimes faded to tan) wire that plugs in there tells the injectors when they can open...

Any wires or hoses that are not solidly connected?

Does fuel squirt out of the injectors when you try to start the car? You can stick the injectors into jars and watch...

--DD

[ClayPerrine]

So I guess what Im asking is how reliable are the L-jettronics?

The L-Jet system is VERY reliable. My wife's 914 has 350,000 miles on it over 28 years, and all on the L-Jet injection. Starts up everytime, hot, cold or anywhere between.


To check the system. Start with the Injectors. Get a Noid Light. You can get one from Wal Mart for 14 bucks, or a whole set from Northern Tool or Harbour Freight. It plugs into an injector connector, and will flash if the injector circuit is firing.

If the noid light doesn't blink when cranking (check all the injector plugs), then check the power feeds to the injector plugs. On each plug, you should see positive voltage. Use a meter, not a test light. If you don't see positive voltage, check the condition of the wiring on the dropping resistors. They are in a silver can mounted on the battery tray support. They are prone to breaking wires inside them. If the center wire breaks, there is no power to the injectors.

If you do get positive power, then check the grounds on the engine case. Go to the passenger side rear of the engine. Under the intake runner there is a 3 spade connector ground point. You will probably need an inspection mirror to see it. Check that all the wires are connected, and that none of the spade connectors have broken off the wires. Age and engine heat makes them brittle.

As was said before, check that there is a white wire with a single spade connector connected to the negative side of the coil. If this wire is missing from the coil, the noid light won't flash.

Verify that the boot between the throttle body and the air flow meter is on, and that it has it's electrical connector hooked up correctly. You cannot run the engine without the air flow meter connected. Any air leak in a L-Jet system will cause very poor running or no start at all.

Do those things and let us know what you find. Oh.. and (IMG:style_emoticons/default/welcome.png)

[r_towle]

Walk through this.
Before you do, make sure you have 12vdc to the coil at start.
a few things I would try based upon your condition,
Check all the rubber vacuum lines and especially the large rubber intake boot for cracks.
Ljet requires no leaks at all in order to start. The vacuum of the engine opens the flapper door in the AFM to get the pump working and if you have even a minor leak of outside air, the door won't open, you get no fuel, and the car won't start.

To verify this, you can remove the a
Large AFM rubber intake hose at the AFM and stick a pencil in the AFM to hold open the units flapper door which will turn on the fuel pump. If you do this with the key on, you will hear the fuel pump start.
If you do it for a while , you WILL hear the fuel pump change tone as the fuel pressure gets up to normal pressure.....if you don't hear that tone change, you have a fuel delivery problem, leak, blockage, out of fuel etc...
The pump will change tone from a higher pitch free running pump to a lower pitch sound once it hits normal pressure....then the pump is working harder. It's fairly easy to hear.

Vacuum lines, intake boot, injector seals, intake runners, gaskets and hoses...., valve adjustment, valve cover gaskets, head vents if you have them, oil filler cover gasket and o-ring in cap.
All of that can and does add unwanted air to the system that will make starting damn near impossible, and super hard to tune up.
Fix all the air leaks and old hoses.

L-jet is a rock solid system with many cars still using a modified version of that system even today.
Two ways to measure air, with air flow or air pressure.
L-jet is air flow and it is not only simple, it's super reliable once you fix the air leaks with new rubber hoses.

You mention the car has been sitting for a while, well rubber wears out and cracks....so fix and replace what it bad.
You can replace everything with new EXCEPT the large rubber intake hose...that is NLA,
So be gentle with it, and remove it to look at it, the crack will be underneath at the turn in the hose in a place you cannot see with the hose in the car. some rubber goo, cement, tape , caulking all wil do the trick to seal up the hose while you look for a replacement.

http://manuals.type4.org/ljet/

[timothy_nd28]

Installing carbs is always an option. Do you own a voltmeter? Since you had this running a few months ago, my gut feeling says seized fuel injectors. Do you still have spark? If so, pull one of the fuel injectors and let it spray in a glass jar while turning the engine over. If you own a voltmeter, we can check some vitals.

I know that it is possible an injectors to seize or get clogged but all 4 injectors and the cold start at the same time seems highly improbable, the odds alone. . .

I know it sounds crazy, but it had happened twice this year already. You revealed a new piece of information to this puzzle, lacking voltage to the injector circuit.
You do have spark, I'll assume that you do have the white wire attached to the negative post on the ignition coil. You also have fuel, as you already verified pressure at the fuel rail. So we need to check the continuity of the limiting resistors and fuel injectors.

We can do this all in one simple test. You will need to pull off that big plug on the ECU. After you pull the ECU plug off, grab your voltmeter. With the negative (black) voltmeter lead, attach this to the negative post on the battery. Now with your positive meter lead, probe pins 14-15-32-33 on the ECU plug with the ignition switch turned to "on". You should see 12vdc on each pin.

12vdc is sent thru the dual relay to the dropping resistors. From there, the voltage goes thru each fuel injector coil then up to the ECU. Pins 14,15,32,33 is the end of the train. Checking voltage on these pins verifies the FI electrical loop.

Since you will have the ECU plug off, go ahead and check the resistance between pin 13 and ground. This is your temp sensor, which will also cause a no start condition.

[Woody]

Are the injectors injecting? Are they fouled? That's where I would look.

[timothy_nd28]

Taken from the Ljet manual that the Capn' emailed me

[Cap'n Krusty]

Walk through this.
Before you do, make sure you have 12vdc to the coil at start.
a few things I would try based upon your condition,
Check all the rubber vacuum lines and especially the large rubber intake boot for cracks.
Ljet requires no leaks at all in order to start. The vacuum of the engine opens the flapper door in the AFM to get the pump working and if you have even a minor leak of outside air, the door won't open, you get no fuel, and the car won't start.

To verify this, you can remove the a
Large AFM rubber intake hose at the AFM and stick a pencil in the AFM to hold open the units flapper door which will turn on the fuel pump. If you do this with the key on, you will hear the fuel pump start.
If you do it for a while , you WILL hear the fuel pump change tone as the fuel pressure gets up to normal pressure.....if you don't hear that tone change, you have a fuel delivery problem, leak, blockage, out of fuel etc...
The pump will change tone from a higher pitch free running pump to a lower pitch sound once it hits normal pressure....then the pump is working harder. It's fairly easy to hear.

Vacuum lines, intake boot, injector seals, intake runners, gaskets and hoses...., valve adjustment, valve cover gaskets, head vents if you have them, oil filler cover gasket and o-ring in cap.
All of that can and does add unwanted air to the system that will make starting damn near impossible, and super hard to tune up.
Fix all the air leaks and old hoses.

L-jet is a rock solid system with many cars still using a modified version of that system even today.
Two ways to measure air, with air flow or air pressure.
L-jet is air flow and it is not only simple, it's super reliable once you fix the air leaks with new rubber hoses.

You mention the car has been sitting for a while, well rubber wears out and cracks....so fix and replace what it bad.
You can replace everything with new EXCEPT the large rubber intake hose...that is NLA,
So be gentle with it, and remove it to look at it, the crack will be underneath at the turn in the hose in a place you cannot see with the hose in the car. some rubber goo, cement, tape , caulking all wil do the trick to seal up the hose while you look for a replacement.

http://manuals.type4.org/ljet/

Actually, George has the intake boots. The ones he has are, IIRC, for 75s. Rich mentioned the necessity of having a perfect seal at the oil filler cap, with BOTH rubber gaskets in good shape. Any other vacuum leaks will cause a no-start condition, as well. This is the FIRST thing to check!

The Cap'n

[hqbibb]

Let me mention one thing that is L-jet specific that people often overlook.
Being a sealed system, vacuum leaks are deadly, and a non-obvious one is the oil filler cap seals. It's easy to get it on a little cocked, and that will cause you trouble.

As will the cork gasket at the base of the oil filler, the hose connecting the oil filler to the intake elbow, the auxiliary air valve hoses, etc. Basically go over all the vacuum hoses with a fine tooth comb. After sitting a long time, they can become brittle, and crack when you pull them off.

I just reinstalled the L-jet on my 914 which did 200,000 before being put in storage almost 20 years ago, used original FI parts & injectors, and it fired right up. I did replace every vacuum hose in the engine compartment.

Hope it helps,
Henry Bibb