Taking the plunge, 1.8 liter FI Won't Stay Running Options

[knuckledrgr914]

I am a new 914 owner and have just started trying to get it road worthy. It is a '74, 1.8 liter, and fuel injected. Now for the noobie question...

After running the car around the neighborhood, I came home with a fuel leak. I found one of the hoses, leading to what I assume is one of the injectors, was split open. I replaced the hose which stopped the gas leak.

Now comes the problem... My car now fires, runs for approximately 40- 50 seconds, and then quits. It does not matter if it is just idling, or if I am giving it some juice... It just quits. I turn the key off, turn it back on and it will fire again after a couple revolutions!

Any idea why changing out the bad fuel line would cause this behavior? As you can tell, I am just learning the mechanics of the 914 so be kind and send lots of pictures (of how to resolve the problem that is (IMG:style_emoticons/default/ohmy.gif))

Thanks in advance,
Brad

[Cap'n Krusty]

Look for vacuum leaks, the most common problem with L-jet cars like yours. Be sure BOTH seals in the oil filler cap are there and in good condition. BTW, you DID use 7.5mm metric FI rated hose, right? Next is to determine the state of the tuneup stuff. Points (physical condition, gap, dwell, and timing), the cap and rotor, the air and fuel filters, the spark plugs, and, MOST IMPORTANTLY, the valve adjustment. A well tuned car is a happy car. Use only genuine Bosch electrical parts, although NGK spark plugs would be OK.

Best of luck! The Cap'n

[knuckledrgr914]

Look for vacuum leaks, the most common problem with L-jet cars like yours. Be sure BOTH seals in the oil filler cap are there and in good condition. BTW, you DID use 7.5mm metric FI rated hose, right? Next is to determine the state of the tuneup stuff. Points (physical condition, gap, dwell, and timing), the cap and rotor, the air and fuel filters, the spark plugs, and, MOST IMPORTANTLY, the valve adjustment. A well tuned car is a happy car. Use only genuine Bosch electrical parts, although NGK spark plugs would be OK.

Best of luck! The Cap'n

Thanks Cap'n... I did in fact use FI rated hose. Not 100% sure if it is 7.5mm metric though. I got it from a local Porsche dealership here in Boise, Idaho.

I will indeed look for vacuum leaks. Any tricks to finding them?

Brad

[jim_hoyland]

If you don't mind spending $30 or so, buy a vacuum gauge. Install a T to one of the smaller vacuum lines entering the plenum; than a small hose to the vac gauge.
As you make changes or replace hoses, you can monitor the vac.

I bought a VDO vac gauge and it came with a metal holder which easily mounts inside the engine compartment on the targa top holder nuts ( right side). I also mounted an in-line fuel pressure gauge. Whenever I have an engine problem, I can quickly determine whether there is a vac leak or fuel pump problem.

Watch out for the small hoses, try bending them between your fingers, if they break, you found it. There are other possible places for leaks.

Jim

[Spoke]

Sometimes vacuum leaks can be found by spraying carb cleaner on suspected parts. If the engine changes speed when an item is doused with cleaner, then you've located a possible leak.

[angerosa]

I have a 74 1.8 too but it's carbed. These guys are right. It's not from replaing a bad fuel line. This a is a different problem. Get use to it. Replace cap, rotor, plugs condensor, points, set timing and see if still hapens. And stop buying parts from the porsche dealer. Especialy things like fuel lines which are generic. Welcome to the 914 world.

[jimkelly]

the guys on speed channel said to spary propane into the suspected area - if there is an engine rpm change - you found the leak - their way, similar to yours.

Sometimes vacuum leaks can be found by spraying carb cleaner on suspected parts. If the engine changes speed when an item is doused with cleaner, then you've located a possible leak.

[jesiv]

(IMG:style_emoticons/default/welcome.png)

If you want to be sure... I went through this last year with my 75 914. I spent thousands of dollars chasing this and other issues with l-jet fuel injection. What I learned was the quickest and most permanent fix is to renew all the rubber and gaskets in the fi system, replace the cylinder head temp sensor, really inspect and replace if necessary the elbow. Also, make sure you have the hoses routed and connected correctly.

The moral of this story is to make sure every vacuum hose and connection is good.


As the captain said check the rubber gaskets in the oil filler. Also, in addition to the two rubber gaskets there is a hidden rubber o-ring as well. Of course once you have all the hidden gaskets be sure to replace the oil filler cork gasket as well.

Good Luck and Welcome to 914 World!

Regards,

James

[knuckledrgr914]

Thanks to all who responded to my post!!!! Your help is much appreciated... I actually picked up a '70, '72, and two '74's in a package deal so I am sure I will be asking for much more advice in the future!!! Hopefully going to throw a Subi motor in one of them.

On a different note... I saw a post about using a BMW fuse box in place of the existing Euro fuses. Can anyone tell me if I have to use a 7 series BMW fuse box or will any newer style fuse box work?

Thanks again!!!

Brad