75 1.8 garage find won't start Options

[jhelgesen]

(IMG:http://i184.photobucket.com/albums/x311/jhelgesen/75%20914/DSCN5132.jpg)

I'm trying to resurrect a 75 1.8 thats been sitting for 15 years. (she was hiding in a basement next to the furnace for all that time). Pretty darn rust free as far as 914's go. She got parked for FI issues.

(IMG:http://i184.photobucket.com/albums/x311/jhelgesen/75%20914/DSCN5141.jpg)

I'm trying to get her running again. I've got the tank clean. The fuel pump was cleaned and runs. The fuel injectors have been cleaned and checked, click well. Dual relay clicks when attempting to start. She turns over, but I'm not getting power to the fuel injectors. What to I try next?

Thanks,

[Mark Henry]

Your story is very much like my '74, with mine it was 3 injectors sized/dead. The pintle is moving right? All grounds cleaned? hoses hooked up correct and no leaks? seal on oil fill cap?

[type47]

There is a tool called a "noid" that will verify if you're getting power to the injectors. It's a little light that plugs into the connector to the injector. Try Harbour-Freight for an inexpensive kit. Did you try some sort of starting fluid to see if it would fire on that?

[7275914911]

There is a tool called a "noid" that will verify if you're getting power to the injectors. It's a little light that plugs into the connector to the injector. Try Harbour-Freight for an inexpensive kit. Did you try some sort of starting fluid to see if it would fire on that?

No broken wires at FI Relay Pack??

[jim912928]

another key to the L-jet fuel injection is the Mass Air Flow sensor...this is the that large module that the air box bolts onto. If you take the top cover of the air box off you'll see a big flap that regulates the amount of air entering into the system. It opens up simply by the air being drawn into the system by the engine cranking/running. Key point is it is what triggers things like the fuel pump starting to run etc. If it sticks, power isn't sent to those (I'm guessing you are not hearing the fuel pump running also?). A few easy tests to do (on top of using the noid tool mentioned above):

1. spray a little bit of quick start into the air box...if the car runs for a little bit then you know you are getting spark and not fuel
2. crank the engine and manually push that air flap open on the MAF sensor...if it is sticking and the air doesn't have enough force to open it up on it's own...no power to fuel pump etc. If it starts you know what it is!

BTW.....nice find! That car looks like it is in really great shape!

[ClayPerrine]

another key to the L-jet fuel injection is the Mass Air Flow sensor...this is the that large module that the air box bolts onto. If you take the top cover of the air box off you'll see a big flap that regulates the amount of air entering into the system. It opens up simply by the air being drawn into the system by the engine cranking/running. Key point is it is what triggers things like the fuel pump starting to run etc. If it sticks, power isn't sent to those (I'm guessing you are not hearing the fuel pump running also?). A few easy tests to do (on top of using the noid tool mentioned above):

1. spray a little bit of quick start into the air box...if the car runs for a little bit then you know you are getting spark and not fuel
2. crank the engine and manually push that air flap open on the MAF sensor...if it is sticking and the air doesn't have enough force to open it up on it's own...no power to fuel pump etc. If it starts you know what it is!

BTW.....nice find! That car looks like it is in really great shape!

Actually, the fuel pump is activated during cranking by the double relay, not the air flow meter. During cranking there is not enough air flow to open the flap, so the pump won't run.

Pull the yellow wire off the starter, and turn the key to the start position. You should hear the fuel pump run. If you don't, you probably have a bad double relay. Second, check the wiring to the dropping resistors. They have a tendency to break at the bottom, and then you will lose that cylinder. If enough of them break, then the car won't start. A noid light will verify this real quick. Just pull the plugs off to each injector, and have someone crank the car while you watch the light. It should flicker during cranking.

[stepuptotheMike]

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[davesprinkle]

Another thing to consider -- the Ljet brain requires a signal from the switched side of the coil. If this wire is disconnected, the injectors won't fire.

[jhelgesen]

I have continuity to the resisters and they show about 5.9 ohms on the bench to each one. Wires look good. Voltage to ground showed .2 volts when turned on. Didn't move when trying to start.

Checked the contacts of the relay by a little careful surgery. Nothing melted or missing. Both coils move. Continuity looked good. Tried to trace their paths best I could. I'll see if I can get a new relay on order, will take a few days.

Everything looks to be hooked up.

Fuel pump runs when attempting to start, got voltage at the pump and can hear it running.

No fire when I sprayed starting fluid in the system and tried to crank.


(IMG:style_emoticons/default/welder.gif) Hi Mike!!! Happy to be here.

[jim912928]

Clay...info I got was from a Porsche mechanic who helped me get my 75 l-jet sorted. The AFM completed the circuit (according to him) and it needs to open just enough to allow the pump to run (relays, afm etc are all in the loop). He was dead on as the test we did with him there was open it alittle and behold..the pump started. His explanation was porsche did this so as not to have fuel being dumped in without air. I'm no expert here but this came right from a Porsche mechanic and he demonstrated the fuel pump not running when cranking and the flap close...and the fuel pump ran when opening it slightly. I saw it with my own eyes. Maybe the 75's are different but that is what I saw.

Now, back to this issue...you said you used starter fluid with nothing happening. You should have gotten something here since the fuel delivery system would have been bypassed. Is there spark/sufficient spark getting to the plugs? You said that you could hear/feel the injectors clicking...do you smell fuel? Have you tested to make sure the fuel supply lines have not been accidently hooked up in reverse?

[jhelgesen]

Next step I'll check the coil and plugs.

When I said injectors clicked, that was testing on the bench after they were ultrasonically cleaned.

I tried starting with the vane of the afm open, no change.

Fuel lines are clean and correct direction. Fuel filter is not blocked.

[type47]

It should be easy enough to put an inductive timing light on a spark plug wire, crank the engine and look for flashing out of the timing light. Either that or take a spare spark plug and one of the plug wires and ground the threads of the plug and crank and look for spark. Sounds like you have fuel and no spark.... You can do a visual of the cap and rotor and verify the wires are connected in correct firing order in the distributor.

[messix]

point gap/dwell?

[davesprinkle]

point gap/dwell?

I agree. Sounds to me like you don't have a functioning ignition system. And remember, if the coil isn't getting switched, the Ljet ECU ECU won't trigger the injectulators.

So no spark AND no fuel.

[jd74914]

I too am thinking you don't have a functioning ignition system which as previously said results in a non-functioning injection system.

Try starting the car while jumping the + side of the coil with a wire coming directly from the + terminal on the battery. This jumper ensures your ignition/injection system is getting power. If your car starts the problem is with your ignition switch.

Just make sure you try starting immediately after jumping the coil or you could fry your points.

[jhelgesen]

Timing light shows no spark....lets see what I can find now....

[jhelgesen]

Can't get power to the ignition. Jumpered a wire to the + side of the coil, nothing. Even tried a spare coil.....

[jhelgesen]

Put in new points tonight. I now have power at the coil. Plus side on at start, other side flashes on my test light. Timing light shows spark at each plug wire, but slowly.

I put my test light on one of the injector plugs and it showed constant on at start.

Not showing power at fuel pump now.

Tried jumping 12v to the fuel pump, got fuel circulation noises at the regulator, would not start still.

Now that I have spark, I'm wondering if I have something wired wrong, or if the relay is now bad. Bosch platinum plugs are installed, figure I'll put some standard plugs in too.

[r_towle]

Back up. Pardon me if I am brief...
We need to extablish that you have a functioning system.

Remove large hose from throttle body and AFM.
Turn key on to run position.
Stick finger in large hole of AFM and open the flapper door.
Does the fuel pump come on then...with all standard wiring? (no jumpers)
If no, check fuel pump relay...the smaller relay pack next to the tubular relays for the injectors.

Post a pic and someone should be able to point to the relay for you.

Second
When key is on, you should see 12VDC on the middle pole of the tubular FI relay pack.

Third, open up the distributor cap, remove the rotor and look at the advance plates. We have been finding the small ground strap that connects the advance plates has seen better days...sometimes it looks good but it sucks. weak wire= weak spark.
Also, your coil may be suspect.

Lastly...
Go to the store and buy four baby food glass jars.
Empty them and clean them
Pull all four injectors and while leaving them hooked up to the fuel rail, place the ends of the injectors into the glass jars.
Remove the high voltage wire that goes from the coil to the middle of the distributor cap.
Turn over the car for 30 seconds.
See how much, if any, fuel you have in the glass jars. It should be the same amount.

RIch

[jhelgesen]

Good plan Rich, thanks, I'll start again.