Please help me get her running (74 1.8 stock) [Repost from Rennlist]
 

I own a stock (original fuel injection) 74 1.8 914, it was my first car and for many years my daily driver, but then one day it wouldn’t start. I had another car and a fiancé so I let it sit in the garage. My fiancé became my wife and four kids and tens later it’s still in the garage. So now I’m fixing it. But I’m stuck, and I could use some help. The car doesn’t start at all.

This is what I’ve done.

Fuel: I drained the gas (yes I let it sit in the tank for all those years) took the tank out and had it cleaned and coted. Sent the plugs out and had them cleaned, new seals, flow tested and repaired (one of them leaked down)

Fuel Injection: I have a pressure gauge inline, just before the driver’s side fuel rail (under the air box). When I crack the engine the gauge reads around 60 psi and then drops to around 10psi. I’ve check the injector’s connection with a circuit test light and the light pulses as the engine cranks. Pull the sparkplug and there is faint smell of fuel.

Based on this I think the fuel system is operational

Ignition

New: Sparkplugs, points, coil and condenser. When I turn over the engine I get a good spark jump from the plug wire to the case. Plug wires are old but show very little resistance. Plug wires are plugged in according to diagram from repair manual.

Based on the fat spark I think the ignition is operational.

Head temperature sensor: I removed this from the car and tested resistance. Measured 1.7K at 70F. Put the sensor in the freezer for around 10min. Measured 3K ohms and then rapidly decreased to around 1.7K. Manual says that sensor should read between 500-2500 ohms, and should be at 2500 ohms at 68F. Is the sensor bad?

I can’t really think of other things to test. Every so often I charge up the batter so the car cranks well, but not even a sputter of a start.

Please give me some ideas; I’d really love to get her started again.

Have you checked for vacuum leaks?

I assume its a D-jet?
If you have fuel and spark it should do something.
How long does the gauge stay at 60psi? It should be reading about 29 psi. That is what your regulator is suppost to be set to. Does it stay above 30psi while your turning it over?

Vacuum leaks are very important I agree. But it should still be trying to kick over some.

Stock FI for a 1.8L is L-jet. Mine is down too. I'll be watching this thread.

I thought fuel pressure should be something like 29psi?
I'm not familiar with L jet, so I could be wrong.

did you re-connect the wires on the coil correctly? fuel pump relay on l-jet is a common problem 10 psi seems low. did you try starting spray to verify she will fire up

ok, I didn't know. I have a '74 2.0 w/ d-jet.

spark, fire, compression= running

You have spark
Rent a compression tester from local parts store
Wire fuel pump direct and let it run full time and try that.

Have you replaced the fuel filter? It may be all gummed up from the old fuel. The L-jet has a cold start injector (at least the 912E has one). Is yours functional? Did you get it cleaned?

Fran

I agree + CHT, will not start without the CHT

"One day it wouldn't start." Have you considered this? Remove passenger seat. Locate box with thick yellow wires running into it. Disconnect battery. Then snip the two wires. Peel back the insulation wire nut them together. It is a Seat belt interlock. 1974 Cars won't start unless your seat belt is buckled. When the module fails, car won't start. You can replace it $, or bypass it. I would think the module would have failed years ago, but just in case...

I haven’t checked for vacuum leaks because I don’t think this will keep the car from starting. I think vacuum leaks would cause it to die, and idle/run poorly.

10 PSI is the residual after the pump stops, I'll go back and check it maybe 60 psi was wrong.

I did replace the fuel filter, and I made sure it's going the right way.

I ordered a new CHT, but it's not here yet, the temp sensor was in the car and connected while I was doing my trouble shooting.

Will the engine crank if this is the case? I thought it would just click, like the battery was dead. I'll check it.

Fuel pressure should be 35psi. How long after running the starter does it drop to 10psi? Pressure regulator may be shot.

http://www.bowlsby.net/914/Classic/zTN_Man08.pdf

Read..

Mine use to bleed down pretty quick after I shut it off.
As long as you have 20-30psi while cranking it should start.
U said u had spark.
The vac lines u can replace later. It should be tryin to start even with bad vac lines.

Fuel pressure drops off immediately, holds steady while pump is running, then drops off when pump stops, holds at 10psi till it slowly leaks down. I've never timed how long it takes but, it's long enough I don't stand there and watch it.

Talking this over with a guy at work he theorized that the connections to the ECU might need to be cleaned. Has anyone ever seen this to be an issue?

He thought something like this would be good.

Amazon.com: CAIG DeOxIT D100 Power Booster Metal Electric Connection Cleaner, Enhancer, and Lubricant: Musical Instruments

Thanks: I'll go through this, is the 914 L-Jet exactly the same as the 912s?

Similar enough for you to diagnose. The main difference is that the 912E motor is a 2.0 whereas you have a 1.8.

Fuel pressure should not drop off immediately. It should hold in the lines for a while. This could be a bad fuel pump check valve or the fuel pressure regulator.

Check to be sure you have the inlet fuel line connected in the proper routing. If you connect the inlet and outlet (return line) backwards the car will not run. Fuel line loop should run inlet, injector rails, regulator, return line. don't ask me how I know...