75 914/4 2.0 D-jet

At some point today, I'm going to try to start this car. It hasn't run in well over 10 years or more and it has been a long haul.

I replaced the FI harness (thanks to Jeff) with a very good replacement - the original was so brittle you could snap the casing like a dry twig.

I rebuilt and tested the ignition harness.

I have spark, new fuel pump, injectors (according to PO have been cleaned and tested).

Pressure regulator tests OK - OHM readings.

So if I have the following hooked up - electric connections that is

1) CHT
2) Pressure regulator
3) Temp sensors
4) Dizzy triggers
5) ECU / Relay Board

Planning on testing fuel flow first - all new fuel lines (SS through tunnel and rear engine compartment)... to make sure pump is doing it's thing and I have the lines connected correctly.

What else is required to see if this car will start?

Are any of the air lines needed? If so, which ones.

Now I'm off to buy a fire extinguisher before I burn the garage down.

Thanks!

Len

If the smog pump and lines are disconnected, you would need plugs in the heads where the lines connect or you'll have 4 loud exhaust leaks.

Other than that, make sure the motor turns freely, new oil, battery and turn the key

Good luck

Jeff

Edit: if by air lines you mean vacuum lines....then all of them.

I think you are calling the manifold pressure sensor a "pressure regulator". It doesn't regulate. The fuel pressure regulator is the only regulator


Test the mps for vacuum
You'll don't have to have a vacuum gauge for the rough imprecise test of seeing if it has any. Suck on a piece of hose attached and see if it holds for a minute without leak down.

You also have to have the injectors/cold start valve connected and the TPS while you are at it.

Have you heard the injectors click? If they were rebuilt or have been sitting awhile they may be locked up...you can free them by tapping them with a 9V battery. The better test is to verify your fuel pressure with a gauge, then shoot each injector into a jar to check for flow and pattern while cranking.



Using your mouth does not work. Sucking on the MPS port with your mouth only pulls an insignificant vacuum, not anywhere near high enough to test the MPS diaphragm and there is no clear indication of a leakdown. Only use a vacuum pump and the dial indicator will tell you if there is a leak.

I agree that it is not a real test. But if the diaphragm is completely failed. This is a good quick way to roughly detect failure and a junk mps

A test for failure. But not a test for performance or functionality

UGH, as far as I know the smog pump was removed a long time ago. Where exactly are these points where the lines connect? One for each head?

Find everywhere that had a vacuum hose on it, and cap it.

You absolutely must have the hose from the manifold to the MPS, though. The others are "nice to have" but the car can run without themif necessary for testing. But you must plug all of the holes in the manifold and throttle body.

And plug all of the electrical stuff in.

--DD

Two air injection ports on each head. They are just outboard of each end of the intake runners where they bolt to the head.The throttle position switch need not be connected to run. It will actually run quite good without it. The cold start valve is not needed either, unless its 35 dergrees where you are. Get a fuel pressure guage and attach it to the port on the fuel rail where the cold start hose attaches. Cycle your key on and off a few times to build pressure. It should be at 29, or very close. No pressure? No start.

Two for each head, if the pump was removed awhile ago, they should already be plugged. But here is where they are located.

Click to view attachment


Jeff

Len the air injection ports are plugged in the heads...the injectors were cleaned and tested on a Bosch test unit and had a good pattern.

OK, I see these holes in the heads....

Please somebody just shoot me so I have one too!

Are they threaded? I can't see them well enough, but I can't seem to see that they are. Pressure fitted? IDK

How or what do you use to plug them?

Thanks Roger!!!!

So the heads were removed?

Anyway, I'm close to seeing this thing start or go up in flames! HA.

I picked up the seats yesterday. Had them done to look like the originals. They came out really really nice.

Will shoot you some photos soon!

Thanks for chiming in.

Len

I seem to remember that they have the same size/thread as the valve adjusting screw and someone used used ones to plug the holes

Well I have some valve adjusting screws - they are 10X1 but they would fall into those holes if I let go of them.

I heard that also, so I thought I'd give them a go, but they are way too small.

Roger (the PO) said they were plugged - so I have to go with that for now.

So today's attempt - proved non productive.

I know I have good fuel pressure....

I know I have spark.

I did pull one injector, hooked a hose to it and ran that hose into a bottle. No fuel out the injectors.

How important is the timing to get the injectors to fire? Will they fire regardless of the timing, or does the timing come into play.

I understand timing to the point of compression and fuel to start, but will the injectors fire regardless?

....3 prong ground in center of engine!(fires injector's)

That's hooked up.... (again thanks to Jeff B.)

If you have ~30lbs fuel pressure and all FI things are plugged in, you should get the injctors to squirt. Do you hear the injectors click? If not, they may be clogged, even if rebuilt, especially of they sat around for awhile. The cleaning solution can still leave residue that hardens. Try the 9V battery to click them a few times to try to open them up.

Clean, tight connections at the three-prong ground are very important for proper FI operation. I would also recommend cleaning two other grounding points. One is the transmission-to-body ground. Clean the connection on the top of the transmission, the connection on the bottom of the rear trunk and both ends of the ground strap that connects these two points. The other is the grounding point beneath the relay board in the engine compartment behind the driver's seat. There is a cable-to-body ground point there.

Nine volt battery like those that have those snap top connectors?

I read somewhere that when you have ignition on and manually open the throttle you should hear the injectors.

When I try that I don't hear them.

Will try the 9 volt test tomorrow - if I understand correctly.

Transmission to body is good - that I'm sure of.

I'm not sure of the other ground point you mention - will check it out tomorrow.

What connects there? What cable are you talking about?

Minimum.

Power to the relay board, power to the ECU.
MPS needs to hold a vacuum
Grounds at battery, transmission, large ground cluster under relay panel, grounds for all fuel injectors at top of motor, rear upper bolt.

Need fuel pump running when key in on position.
Need cht plugged in
Three wire plug at lower portion f the distributor to activate fuel injectors
Plug at throttle position switch
Spark, which you said you have


That's all I believe you need.

Hey Jeff,

I assume you mean a small 9V transistor battery. Well I just tapped all of the injectors and all I got was a spark at the battery. If I was supposed to hear the injector click, I did not.

Remove the plug from the injector.
Use a AA battery with two small alligator clip leads to plug into the injector.
They should click, loud enough to hear.


If not, pull them out, soak them in Tektron FI cleaner for the night, fully submersed.
Pull them out, dry them off and try again.

Rich