# 1980 Rabbit 1.6, CIS - Starts then Dies



## TreVW (Oct 25, 2011)

*When I got it, it wasn't getting any spark, and most of the ignition components tested bad(hall sender, coil, ICM). So I started systematically testing and replacing components.*
- New(re-manufactured) distributor
- New cap & rotor
- New plugs and wires
- New ignition coil
- New ICM
- New fuel pump and filter
- New(re-manufactured) fuel injectors
- New cold-start valve
- New thermo-time switch
- Cleaned out the whole fuel system (flushed lines, replaced lines as needed, re-built fuel distributor)
- Re-did the vacuum system -- replaced hoses, put everything back to how it was supposed to be, I think (there were bolts and screws plugging ports and nothing looked like the book)

*After all that, it will now start up about half the time, and run for 2-5 seconds, and dies faster when I give it any throttle input. Here's what I'm thinking as far as possible causes:*

The frequency valve is not functioning as of now (no buzzing). It was buzzing when I brought it home, and then stopped working. I wiggled the wires next to the plug, which made it work in short bursts, now it doesn't work at all. I replaced the connector on the valve itself, but no change. 

The "Fuel Injection Power Supply Relay" is what controls that function, if I'm correct. None of the relays on the panel match the part numbers that I've found for the relay(171906381 => 7M0951253), and neither do any of the relays I have laying around.

Any electrical troubleshooting is difficult, because a PO made a rat's nest of the relay panel.

Possibly a large vacuum leak? Maybe around the intake manifold, idle screw, throttle body, etc?

Incorrect fuel pressure? Even after all of the fuel system work I've done, still leaving this open as a possibility, as I haven't been able to check the fuel pressure with a gauge yet.


Air Flow Sensor not adjusted properly? 


*Any other possibilities? Maybe (hopefully) some simple solution I've over-looked? *


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## erty67 (Feb 23, 2010)

sounds like a vac leak. I had the same symptoms and one of the ports on the intake was wide open.


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## GDR (Sep 25, 2000)

*After all that, it will now start up about half the time, and run for 2-5 seconds, and dies faster when I give it any throttle input. Here's what I'm thinking as far as possible causes:*

*Thats sounds like a bad ignition switch. Its usually the "RUN" position that goes bad.The car is running with the fuel supplied from the cold start injector which ONLY operates in the start position.


Do you hear your fuel pump running in the run position? It should run for about 5 seconds in the RUN position with the engine not running.* 

The frequency valve is not functioning as of now (no buzzing). It was buzzing when I brought it home, and then stopped working. I wiggled the wires next to the plug, which made it work in short bursts, now it doesn't work at all. I replaced the connector on the valve itself, but no change. 

*Run positive power to the valve direct from the battery. If it works then you have to back track to find out where your power problem is. The negative side controls the duty cycle*

The "Fuel Injection Power Supply Relay" is what controls that function, if I'm correct. None of the relays on the panel match the part numbers that I've found for the relay(171906381 => 7M0951253), and neither do any of the relays I have laying around.

*The original one was metal and has dual power out prongs. I jumpered the relay panel and run a standard Bosch relay with a single power out prong.*

Any electrical troubleshooting is difficult, because a PO made a rat's nest of the relay panel.

*lol. The original wiring already looks like a rats nest. Look for burnt pins on the back of the panel. If you see any burnt pins I highly recommend you replace the panel.*

Possibly a large vacuum leak? Maybe around the intake manifold, idle screw, throttle body, etc?

*It will just run poorly and you can hear large leaks. But this is for a cor that runs good before the leak happened.*

Incorrect fuel pressure? Even after all of the fuel system work I've done, still leaving this open as a possibility, as I haven't been able to check the fuel pressure with a gauge yet.

*You need to check system and control pressures before doing any work. You will actually save money in the long run buying a cis pressure gauge and a duty/dwell meter for cis lambda. When you go see a Doctor the first things they check are heart rate and blood pressure. * 




Air Flow Sensor not adjusted properly? 

*Plate height is easy to check and set. I've never had a problem with this.

Your mixture setting could be way out of wack so try one turn at a time to see if you can get it to run. Just remember your starting point and try up to 3 turns total in each direction.

You can adjust the mixture setting to get a car to run with just about any combination of system and control pressures. But once you change/correct one of these it can be too far off to get it running long enough to adjust.* 


*Any other possibilities? Maybe (hopefully) some simple solution I've over-looked?

Wiggle the fuel pump relay.
*


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## TreVW (Oct 25, 2011)

Finally got it to run last night! It ended up being a bad fuel pump ground, and the pump just wasn't producing enough pressure. Wired it directly to the battery for now(is this bad in any way?), and it runs great now. :thumbup:

Edit: I have the fuel pump switched, rather than going through the relay. I know that this could pose a problem if I were to get into an accident and a fuel line broke, but other than that is there anything wrong with this setup?


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## TreVW (Oct 25, 2011)

I came home last night, and as I walked by the rabbit I heard a buzzing. . . opened the hood, and somehow the frequency valve was working. With the ignition off. Hm. 

Any ideas as to why it would be doing that?:what:


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