74 Crank, no run FI probolem?

galto · 12-17-2003, 12:08 AM

Bought a 74 914, the story behind it is way longer than I want to get into. Anyway, it cranks over but won't run. Timing seems OK
I am thinking that it is a FI problem.
Not sure about the wiring in this car. (It’s integrity or if it is hooked up right)
How I was testing it was removing the ECU, a component, plugging a probe into the harness side of the component plug then looking for where it comes out on the other side of the ECU plug.

Example
1.) Remove injector 2 from harness
2.) Insert voltmeter - plug into right side of plug
3.) take + voltmeter probe and look for where it comes out on the ECU plug.

I believe that only one pin should be active, I may and most likely am wrong (As this is far from the case)

I bought
Bosch Fuel Injection - Engine Management
Porsche 914 4-Cylinder 1969-76 Haynes Shop Manual
Porsche 914/4 and 914/6 Handbook

From pelican parts, don't have the capital as of this time to invest in the factory ref. manual... but one day...
are any of these good?
Is the Hanes manual better than some of the books I have bought from them before in which I get some kind of generic wiring harness that I have to figure out anyway?
All-data didn't have anything for my car:-(

One more thing, do I have D-jet K-jet or L-jet
a 1.7 1.8 or 2.0? I think it's an L-jet 1.8?

Anyone help is very much appreciated

AND NO, I AM NOT PUTTING IN CARBS!
I hate-love FI as where I just don't love carbs.

jmargush · 12-17-2003, 01:58 AM

I had a similar problem with my 1.8. It turned out to be a harness problem that some of the insulation had pulled away and some of the wires were shorting out.
Might try moving the harness around while someone cranks it to see if there is any change. Or it could also be an ECU problem.

But if you have a 2.0 it coud be fuel injection trigger points in the distributor.

Where is the air cleaner located? that will help determine if it is a 1.8b or 2.0

jim912928 · 12-17-2003, 04:51 AM

galto, I just got a 1.8 Ljet running, went through everything on the FI. The LJet, if you have that, is alot different in how it works and how to troubleshoot than a Djet. See the pic below, which is of a 1.8 with Ljet. Easiest way is to note the air cleaner box to the side, then the air flow meter (silver box thing with a black sealed cover on the top), then an S tube with 2 hoses attached, then the throttle body.

If this is what you have I can walk you through alot of good diagnostics to see if you are getting fuel and if the FI is triggering.

joes · 12-17-2003, 04:52 AM

Does it have an air flow meter? Go to Pelican parts site and look at a picture of a 914 1.8 AFM.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Question number one--are you getting spark? Have you verified this? Take a spare spark plug and plug it into one of the plug wires. Tape it so that the threads are grounded to the fan shroud or some other ground. Have an assistant crank the starter while you look at the plug. Do you see sparks in the little gap?

Question number two--do you have compression? Hook up a compression tester and see. Make sure that the valves are adjusted, as well.

Question number three--do you have fuel? You can unhook the injectors from the manifolds while still leaving them connected to the fuel lines and electrical wires. Stick them into glass jars. Have an assistant crank the starter while you look at the jars. You should see fuel squirting out of them in pulses--not dribbling.

After that, the only questions left are "How much fuel?", and "when does the spark happen?"

--DD

Va914 · 12-17-2003, 09:06 AM

I have always been told this when attempting to get a non car running.

If the engine cranks and sounds okay cranking, cars need 3 things
- SPARK
- CORRECT FUEL/AIR MIXTURE
- SPARK AND MIXTURE AT THE RIGHT TIME.

If you have the above it should run, rough but it should run.

I know there are other things that could cause problems but they are things you should have checked..

Cheers
Kerry

galto · 12-18-2003, 08:38 AM

It does have spark, do not know about timing.
So next time I get to work on the car, find #1 TDC on C, make sure the distributor is pointing to where it should
Sounds like it has compression, but to be sure does have spark.
Have an extra intake set w/ injectors. Will hook up the fuel rail to that to test. (Don't want to replace the injector seals)
Tape it to a 2L bottle should reduce fire risk, right?
Anyone know of a good L-Jettronic trouble shooting guide?
Found some for the D-jet but not the L-jet.
I believe it may be a FI problem because the previous owner stated such, but then again he couldn't get it running.

What should be hooked up? The last owner did a bit of a hack job and didn't put back much of the intake. Guess that's why it's my project car.
Anyway, thank you very much everyone for the quick response

galto · 12-18-2003, 08:40 AM

It looks just like jim912928's
Thus it is a 74 1.8 L-jet?

jim912928 · 12-18-2003, 09:45 AM

Yes it is an l-jet then. So, try this (good info I received from another 914'r here...so I'm parroting which I just went through!...and now mine runs like a dream!

1. first lets see if the fuel pump works. It will not turn on until the air flap opens...so, take off the air filter stuff, turn on the ignition, then push open the air flap (you can see it when you take off the air cleaner). You should then hear the fuel pump turn on. If you don't, you either have a fuel pump problem, fuel pump relay problem, or power to the fuel pump.
2. If you do not hear it run, while the flap is open (shove a screw driver in there) and go check the power to the pump..make sure it is getting 12v...if it is and the pump doesn't run, then you have a fuel pump problem.
3. If the fuel pump is working, let's make sure the injectors are firing. Easy test is to turn the ignition on, take off your distributer cap, make sure the points are closed..then (using a non-metal instrument or finger) open and close the points. On every other open/close you should hear the injectors clicking. If they are not clicking, pull an injector wire off an injector and check it for voltage. These will show always on on both connectors (when the points open/close they break the circuit..but it is too fast to see on your voltmeter). You should get somewhere between 8-12 volts at the injector when testing.
If they are getting power, and they are clicking...we can go the next step. (you can email me if that would be easier).

galto · 12-18-2003, 10:05 AM

Not a bad idea. Will do that.
Thus don't need to reconnect everything (vacum lines)
Don't remember if the fuel pump works, but I think it does.
Good tip about the injectors firing (the clicking noise)

Dave at Pelican Parts · Dave at Pelican Parts's Garage

If there are holes in the intake, the engine will never run right. L-jet EFI relies on having ain intake that only lets air in through the air flow meter. Any air that gets in elsewhere will not be measured by the AFM ("unmetered air" or "false air") and will cause the mixture to be lean. A very lean mixture will not ignite.

1.8s hate vacuum leaks...

--DD

galto · 12-21-2003, 03:38 PM

Fuel pump does not put anything out... EVER no 2 second pump, nothing. removed from harness and it worked fine.
Was no power to relay...
disconected wiring harness at relay, no connection at ECU
I don't think the timing is right either. Could not find notch on the impeler fan when the rotor was lined up with the notch in its housing.
Engine hood pull cable broke. 's' tube intake fell apart when I took it off. Vacume hoses look like they have had better day. How much extra work would it be to redo the fule lines while I am at it? Should I be doing this with everthing in the car or should I remove the engine.
And to top it off, I lost the screw for testing the fuel pressure line
(The one removed to check fuel pressure)
Anyone know what size that is? It looks like a 6mm, what is the pitch is?
Or even better, where in the world do I find one of thoes little brass things?

Thanks everyone.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

I don't remember what size the bolt is.

The rubber boot and the vacuum lines being in poor shape likely explains the no-start condition. They were probably leaking like a sieve. And 1.8s really hate vacuum leaks.

The lack of timing mark is probably due to your not looking hard enough. If you don't have a sprained neck, you didn't have your head far enough into the engine bay to see the timing mark. (I'm kidding, but only by a little bit!!) The marks are on the very rear part of the fan, and are generally covered up by the fan shroud except where the notch in the shroud is.

--DD

galto · 12-21-2003, 07:58 PM

Well, it did end up with me on the back trunk looking for the mark... with a flashlight and someone else turning the wheel
Didn't turn with the flap opened with a screw driver either.
Will the ECU tester work with a dead/toatsted/shorted harness?
Could the bad harness kill the controler?
Harness was at one time suppourting the entire engine under the prev. owener. An engine mount was not tightened to spec.
Also very scarry that the 74 has a 75 ECU...
Think I should replace the ECU and harness after testing every component attached to it. Any sugestion as to where I should start?

bowlsby · 12-21-2003, 08:51 PM

The 74 and 75 L-Jet cars had 2 different ECUs...they are different and have different pin-outs onto the FI harness. No wonder it wont start. Its essential that you get all the right parts for your setup. For instance one year has a 6 pin AFM, and the other year has a 7 pin AFM, and there are other differences, which are not interchangeable.

The 74 and 75 1.8L cars also have 3 different FI harnesses and they too are wired differently and not interchangeable.

I can test and verify your wiring harnesses for proper function and make any repairs it may need to be serviceable. Contact me directly at bowlsby@aol.com and be sure to see my 914 wiring harness website at the link below my signature.

Jeff

galto · 12-22-2003, 10:01 AM

Wiring harness is dead, already tested with the wirng diagrams.
Has both opens and shorts. Lookin just to get a new one w/ECU

Alfred1 · 12-22-2003, 10:46 AM

This page http://persweb.direct.ca/aschwenk/TroubleshootingtheLJetronicSystem.htm will help you troubleshoot your L-jet system.

jim912928 · 12-22-2003, 11:05 AM

Galto,

In my gathering of parts in restoring (just started) my 75 1.8l, I purchased an almost complete FI system from a 74 (have S tube, intake runners, wiring harness, injectors, fuel rails, ECU, 6-pin air flow meter and other misc. parts). They are all pretty clean but not sure if all is working. I was told they were taken out of a working car. Not sure if this helps, but I may have a mostly complete FI system if you decide you need on.

galto · 12-22-2003, 04:02 PM

I tried the test at http://persweb.direct.ca/aschwenk/TroubleshootingtheLJetronicSystem.htm

The components for the most part are OK, just that the signa does not get through the wiring harness in most cases PLUS the ECU is the wrong type for the car. Anyone know about replacing a wiring harness and ECU as a unit, do I need the vin or just the number of pins on the air meter?

bowlsby · 12-22-2003, 04:11 PM

Get the EXACT harness and ECU correct for your car, or it will not work. Is the harness toast or can it be repaired?

The AFM pins are one clue, but check all other branches to be sure they are the same, especially the ECU connector. You might try HP House in Redwood City...the 1.8L harnesses are very HTF because there were not that many made, and there were 3 different configurations.