One for the books - first time A4 owner - Pulling Hair!

[Rando1201]

Switch the spark plugs around and see if the problem follows the suspect spark plug.

ex TRUE GRIT

Edit: Buy parts from MMI then you will know you are getting correct parts. +1 on replacing the cap and rotor. The gap between the rotor and the contact inside the cap is critical.

The gap should be .016 right? if the gap is not correct, would it cause extra fuel to not burn off?

[Dave Neptune]

The "rotor" to "cap posts" is not adjustable. The .016" you mention is for what? Depending on which distributor you have the "point gap'' is .025 in the Delco and .018 in the Prestolite. Both of these values are probably worthless as by now the distributor cam is worn out which is why many have gone to the EI. The points need to be set with a dwell meter to get them correct when the distributor cam is worn.

The firing order is the firing order don't vary and be sure it is set properly. double or even triple check.

The spark plugs should get hot as that means they are burning fuel ~~ no heat = no burn. Or the spark is not arriving in order or at the correct time. The cold plug will always be the dead cylinder and after finding that you have a dead one the question is why? Plug wire order, valve adjustment or seating, fuel, dead spark plug, bad wire or no compression.

RE the smoke, it could be just built up carbon loaded with oil burning off from the cylinder being dead. Another cause could be the timing is to advanced or the centrifugal advance is stuck or sticking. Check the c-adv with the cap off by twisting the rotor, it should turn with light spring resistance and the spring right back when released.

Answering direct questions will assist us in aiding your diagnosis and fix.

Dave Neptune

[joe_db]

The firing order is NOT 1 2 3 4. Is that how you have it wired
Also black smoke is a rich mixture, blue smoke is oil, and white smoke/steam can be coolant or a natural result of the wet exhaust. Gaining blue smoke could in the best case mean a cylinder that has some oil in it is now firing and burning the oil when it was not previously burning oil or gas.

[Rando1201]

The firing order is NOT 1 2 3 4. Is that how you have it wired
Also black smoke is a rich mixture, blue smoke is oil, and white smoke/steam can be coolant or a natural result of the wet exhaust.

No the firing order is 1243, but 3&4 were crossed up because I was following that same sequence on the distributer cap. When looking at the cap, the order is sequential.

Also just found my oil was filled up to the last L on the dipstick.

[Rando1201]

The "rotor" to "cap posts" is not adjustable. The .016" you mention is for what? Depending on which distributor you have the "point gap'' is .025 in the Delco and .018 in the Prestolite. Both of these values are probably worthless as by now the distributor cam is worn out which is why many have gone to the EI. The points need to be set with a dwell meter to get them correct when the distributor cam is worn.

The firing order is the firing order don't vary and be sure it is set properly. double or even triple check.

The spark plugs should get hot as that means they are burning fuel ~~ no heat = no burn. Or the spark is not arriving in order or at the correct time. The cold plug will always be the dead cylinder and after finding that you have a dead one the question is why? Plug wire order, valve adjustment or seating, fuel, dead spark plug, bad wire or no compression.

RE the smoke, it could be just built up carbon loaded with oil burning off from the cylinder being dead. Another cause could be the timing is to advanced or the centrifugal advance is stuck or sticking. Check the c-adv with the cap off by twisting the rotor, it should turn with light spring resistance and the spring right back when released.

Answering direct questions will assist us in aiding your diagnosis and fix.

Dave Neptune

Hey Dave I have electronic ignition, The gap I was referring to was the gap on the rotor. I did find out that 3&4 were crossed up. Which I have fixed. I just went there early this morning and found that the oil was overfilled, probably something I did initially.

So to recap I have been running on two cylinders. ( I think) so the backfiring and the plugs getting hot are no longer an issue. As a matter of fact it runs so low at idle I can only feel the vibrations in the cockpit.

Ive also tested the motor in gear, and wow what a burst it can give now.

I didn't have a pump, but I started to remove some oil with absorption pads. The smoke had gone down.

I had also pulled the small black rubber tubing off the exhaust and a blackish liquid came out of it/ (now in my bilge)

[Dave Neptune]

Gude gneus.

The black tube I assume was the water injection to the exhaust. A bit of black water from the exhaust is not a biggie. You probably shook a bit of crap loose from the water jackets.

As far as the "smoke" dissipating, the engine is now burning off what stuck in the offending cylinders. A good run at temp and she should clear up fine.

I have worked on one A-4 that only ran on 2 cylinders for the entire time a dock-mate had the boat. He bought it and part of the deal was to have the engine tuned up however the mechanic that did the work got the wires wrong. He heard I was good with engines and asked me to take a look because he thought it should have more power. I sorted out the plug wires and he was amazed what 4 cylinders could now do.

Dave Neptune

[Rando1201]

Gude gneus.

The black tube I assume was the water injection to the exhaust. A bit of black water from the exhaust is not a biggie. You probably shook a bit of crap loose from the water jackets.

As far as the "smoke" dissipating, the engine is now burning off what stuck in the offending cylinders. A good run at temp and she should clear up fine.

I have worked on one A-4 that only ran on 2 cylinders for the entire time a dock-mate had the boat. He bought it and part of the deal was to have the engine tuned up however the mechanic that did the work got the wires wrong. He heard I was good with engines and asked me to take a look because he thought it should have more power. I sorted out the plug wires and he was amazed what 4 cylinders could now do.

Dave Neptune

Yea, I am so excited about how damn clean it runs now. Well, hopefully, once I reduce the amount of oil in the system the smoke will clear out more. I had to come back to my home office to work, got some out with absorption rags.

One more thing while I have you. So I can't get the cover plate for the mechanical fuel pump to stop leaking. I bought it brand new from you guys or from moyer, not sure if you are associated. Would this have any effects on my engine?

[Dave Neptune]

No the cover plate would have no affect other than covering the hole. I've not seem them to be a leaking problem. May have a bad gasket, a warped plate or a chip in the block where it seals. Remove and inspect once you get another gasket. Did you put the gasket on dry or with a sealer?

Dave Neptune

[Rando1201]

No the cover plate would have no affect other than covering the hole. I've not seem them to be a leaking problem. May have a bad gasket, a warped plate or a chip in the block where it seals. Remove and inspect once you get another gasket. Did you put the gasket on dry or with a sealer?

Dave Neptune

OK yes, I installed it with the gasket that came with the part. It was still leaking, then I made my own gasket, it was still leaking, initially, I used high temp gasket maker. Then after I made my own I did not use a sealer.

I also used stabil in the fuel. Could that cause any issues?

[JOHN COOKSON]

One more thing while I have you. So I can't get the cover plate for the mechanical fuel pump to stop leaking. I bought it brand new from you guys or from moyer, not sure if you are associated. Would this have any effects on my engine?

Call Ken @ MMI about the leaking cover plate. He may have some ideas.

The forum and MMI are not financially associated. MMI sponsors the forum as a courtesy to the A4 community.

ex TRUE GRIT

[Dave Neptune]

No issues with the stabilizer just stay within recommended dosage.

There has to be a gap or an imperfection between the cover and the hole. A careful visual inspection and feel may yield something. Don't use silicone based sealants on old oily cast iron as it will not "stick". Use something sticky like Permatex #2/

Check to see how the plate "seats" on the hole flange once cleaned. It should not rock around and the plate should cover the entire "hole". Look for a chip in the block side or a warped cover from overtightening possibly.

Dave Neptune

[Rando1201]

No issues with the stabilizer just stay within recommended dosage.

There has to be a gap or an imperfection between the cover and the hole. A careful visual inspection and feel may yield something. Don't use silicone based sealants on old oily cast iron as it will not "stick". Use something sticky like Permatex #2/

Check to see how the plate "seats" on the hole flange once cleaned. It should not rock around and the plate should cover the entire "hole". Look for a chip in the block side or a warped cover from overtightening possibly.

Dave Neptune

Alright thanks Dave.

[Rando1201]

Hey guys I removed oil I still have blue smoke i did see some smoke coming out of the reversing gear and the oil smells pretty gassy

[Dave Neptune]

You probably got some fuel to puddle on the pistons when the float was sticking. That fuel will run past the rings and join the oil. How much did the oil go up? And a little fuel mixed with the oil will smell for quite a while.

Might just change out the oil for piece of mind then run her for a bit.

You may need to set the timing after playing with the distributor. To much advance in the timing can cause additional blow-by and smoking. And be sure the c-advance is functioning first then set the timing.

Dave Neptune

[Rando1201]

You probably got some fuel to puddle on the pistons when the float was sticking. That fuel will run past the rings and join the oil. How much did the oil go up? And a little fuel mixed with the oil will smell for quite a while.

Might just change out the oil for piece of mind then run her for a bit.

You may need to set the timing after playing with the distributor. To much advance in the timing can cause additional blow-by and smoking. And be sure the c-advance is functioning first then set the timing.

Dave Neptune

Gotchya. Ok I just changed the oil. Still same issue. Still a little slick. I did remember that when I originally replaced that plate I took the push rod out. Then later I reinstalled the pushrod . There was a little damage on the plate where the dimple is on the plate. .

I'll start checking the others you have listed. I also noticed, just by luck that the exhaust seems to have a pinhole leak. A little piece of debris on the exhaust started moving when the boat was running