dan79brooklyn

Hello,

I posted about this a few months ago when it first started.
I would really like to be able to diagnose and fix the problem myself, so I need some advice from you guys...

When it is cold and damp outside the engine often starts and runs on five cylinders. The condition improves when the engine warms up as well as when it is dry outside but I still can feel the engine hesitate and stumble when accelerating. My fuel consumption has also gone up.

I don't have a check engine light on, but I did read the codes and have code 51 Injection valve cylinder 1 I don't know what to look at related to this code, I don't see any external leaks from the injector.

I have replaced the DME relay -NO CHANGE

I unplugged the oxygen sensor -I Need to take it for a drive with it disconnected when it is wet to diagnose further, but I didn't notice a change with the engine idling in the garage-Should I get a CEL with the sensor disconnected? I did not.

I switched the coil plugs and the engine DID run a bit smoother, what does that mean? is it safe to drive with the coils swapped? Do I need new coils?

Are there any other sensors that I should try to clean. MAF, CHT ??

Thanks for any advice. I really want to get the car running well again.

darth

How do you know it is running on 5 cylinders?

elbeee964

Well, it IS saying the injection valve is throwing some weird electrical/connection signs.
Pop the electrical connection off the injector and see if there's corrosion, would be My first inclination. Make sure she's clean and snuggly attached.
Check to see if the problem still exists.
Then, given success and my general predisposition at the time, I might do the others as well as a sanity check.
Then...
...well, then there's a whole slew of fuel/ignition/vacuum/O2 things I'd start checking on in what would likely be the most inefficient manner possible.
Sorry, I'm tapped out.

dan79brooklyn

I did check the injector plug connection on cylinder 1 and it was dry and snug.

The main clue I have to go on is that is is especially bad when the weather is cold and damp.
When I start the engine it fires right up but sounds like a diesel Subaru: rough and uneven and stumbles under acceleration.

Not sure if my tests of the coil and OX sensor helped me diagnose the problem.

If I disconnect the battery does this clear the code? How long does it need to be disconnected for?

Thanks for any further advice.

Looks like I might have to find an 'expert mechanic' (have yet to meet one in the area) to bring it to on the next rainy day....

darth

If I understand you correctly your comment "that it's running on 5 cylinders" is based on the fact that "The main clue I have to go on is that is is especially bad when the weather is cold and damp.
When I start the engine it fires right up but sounds like a diesel Subaru: rough and uneven and stumbles under acceleration." If that's the case then to further diagnose I would pull the plugs and do a visual check of their condition. They should all be beige in color and dry, if they're black and sooty or wet then you may have a hi voltage issue which could be anything from coils/wires and/or spark plug / wires. The fact that it runs worse in damp weather leads me to suspect a high voltage breakdown of the components mentioned. You can mist the wires in the dark and see if there is a lightnening storm. To further diagnose the injector, swap it with another and see if the code follows it.

Bill

Dwane

Dizzy belt?

dan79brooklyn

This thread about poor running related to bad coils sounds very similar to my condition:

https://rennlist.com/forums/964-foru...-on-power.html

I will try starting the car on just one coil and see if it runs.

dan79brooklyn

Car will not start on one coil. Runs the same (tad rough) on just the rear coil. Seems to run the same on both coils as it does on just one.

I have two new bosch coils on order will install next week and let you know how the car does.

jaudette3

Try replacing the injector.

Cheers,
JohnA

dan79brooklyn

I put in the new coils (Bosch Silver made in Brazil).

It still does not start on just the front Coil, but will start on just the rear coil.
What does this mean??

But it does seem to be running well. I will have to wait until it's wet to see if the symptoms return.
I did not detect any hesitation...Will keep you posted.

I checked the caps and both rotors and no sign of any problems there.

boxsey911

D964 has already suggested a broken dizzy belt. As both coils are good (you've replaced them) but it won't run at all on one of the coils, it suggests that the dizzy cap that is supplied by that coil is not providing the sparks to the plugs. A possible cause of this is a broken dizzy belt. To confirm this pull the dizzy caps - if you can spin the rotor arm on the secondary distributor, the belt is broke.

dfinnegan

If the belt is broken then disconnect that coil.
You could do real damage if you drive with a broken belt. Not certain, but very possible.

darth

Dan

"It still does not start on just the front Coil, but will start on just the rear coil.
What does this mean??" It may indicate a bad coil - try switching them and see if still doen't start on the front coil. It may be the dizzy belt but correct me if I'm wrong, but isn't the rear coil connected to the secondary distributor (i.e. the one that is driven by the belt) which would rule out the belt.

"I will have to wait until it's wet to see if the symptoms return." You can simulate wet conditions by spraying a light mist of water from an old Windex bottle or similar, around the hi voltage wires and components and view while in the dark with the engine running. If you see sparks or the engine begins to stumble then you have a hi voltage leakage problem.

There have been a number of bad reports about the Brazilian coils. This is a recent thread "Engine cut out tonight ". It appears the quality control or construction techniques are not quite up to par with OEM. I'd be interested to know the measured resistance between the negative and/ or positive battery terminal and the following 2 points: outer coil case and the coil output. There should be no connection between these points and can be verified with a meter set on the highest resistance setting. This is not a definitive test as it could also be attributed to less than adequate insulation on the magnetic wire inside the coil which allows the hi voltage to leak.

Bill

dan79brooklyn

It's not a broken belt, I verified that the rotor would not spin by hand on the secondary dizzy.

I have a hard time believing that I got a bad coil, especially since the old coil also would not fire the car...Do we know for sure that that the 964 should start on just one coil?

I'm sorry that I don't have a meter nor know how to use one to do more checks.

I will keep you guys posted on how it's running...

dan79brooklyn

Bill is correct the rear coil fires the secondary distributor.

So my car wouldn't start with an old or a brand new front coil that runs to the main distributor?

I'm really not into swapping any more coils I have to say that job was very tight and fiddly for a novice like me.