It's important to have everything sealed up now that the engine is running. (Congrats btw, I've been watching this thread for a long time) Even though our cars run off of a speed density system, it's important that everything from the throttle body blades to the combustion chamber is sealed. The throttle body meters air flow and not having a sealed system changes that metered air flow which makes boost leaks and can cause idling to do weird things. If you're fouling spark plugs like that, you either have a serious amount of extra fuel, or completely improper timing and having an aftermarket ecu, it's very possible to have both. If timing ends up being accurate compared to what the ecu is doing, then it's probably down to fueling. It would also be a good thing to look for consistent sparking between every single spark plug either with a spark plug tester or the timing light.

As far as fixing plugs, they're basically never the same once they foul. What we do on our farm trucks are hit them with a wire brush, shoot some cleaner on it, and hit it with a propane torch to burn off whatever is left and that helps with our old trucks to get them by, but I probably wouldn't rely on it for such a demanding application.

 

Thanks for the nice words!

I should install these 4 remaining nuts on the UIM... I swear everything else is tight and as it should! Engine is street ported, single turbo... with base map on the Power FC. Of course I would like to have the car in good shape before sending it for tuning, otherwise they'll have to fix what's not working first... and I wouldn't like it.

Spark plugs get heavily fouled, as you can see on the picture. But, they don't smell like fuel, and when I try the unflooding procedure, there's almost no fuel coming out of the combustion chambers (I flooded the car too many times to know when there is fuel, and when it is flooded).

Timing light subject comes back again... I'll have to see how it works I guess...

I've got 12 spark plugs here, almost new... I do not like the idea of buying more spark plugs

Here is my actual strategy: I'm assuming that my actual problem is too much oil everywhere (in UIM, LIM, engine), because PCV valve was connected incorrectly. It constantly ruins my spark plugs (and stops the engine). I need to start the engine and make it run for at least 10 minutes, to clear all the oil.

 

PCV valve looks correctly installed to me. The valve is effectively a check valve. Should be able to blow through it but not suck. The direction it should face is: the engine should be able to suck on the oil fill neck but not blow into it.

This is a picture from my 93.

Matt

 

The PCV valve I think is for only certain load and conditions, there's also the vent (pointing down) that normally goes to the primary turbo inlet, which is simply filtered air.

Considering you had a big oil mess and that one nipple is capped I think it's worth keeping it open for now. Long term get that catch can installed. If the nipple is just left open air it will eventually make a mess but just sitting in the garage and idling it won't be that much.

I'm baffled why the spark plugs are fouling THAT badly after a fairly short run time.

Dale

 

Have a wideband? Looked at AFRs at idle at all? Stock primary injectors? If they’re not, is the tune set for bigger injectors?

Matt

 

Agree. Sounds like you have an overly rich idle mixture

 

I just deleted that PCV valve... And the oil mess is no more.


2 possibilities here:

1. Rebuild oil (including transmission oil in combustion chambers)
2. PCV valve

I cannot tell which one was the cause of the oil mess.

There was even some kind of deposit this afternoon... But I found a nice way to clean them.

I have a Wideband, yes and no. I would say no, I have to change the sensor! All injectors are stock, I'm running PFC base map.

At this point, I've got to agree.

1. Gas tank is draining faster than ever.
2. Black smoke coming out of the exhaust.

Engine is in a stable condition now. It ran for at least 24 minutes today (2 x 12 minutes). I am able to start it, get it to idle at 1,400 RPM. Here are my actual issues:

1. Hunting idle.
2. Black smoke.
3. High idle.

If I set the idle too low via idle screw on the TB, it dies, and that's when spark plugs get pitch black.

I also did a major mistake today. I realized I did not fill enough coolant. Temperature gauge went high. I went to remove the cap right afterwards (while it was still hot), and no coolant came out (!!!). Ouch. I managed to add about 5 quarts (mainly by filling coolant directly in overflow tank though). I wasn't proud. Do you guys think it could have broken the new OEM coolant seals? I couldn't smell coolant at the exhaust (could only smell gas).

3 minutes after it happened, peak water temperature on the PFC Commander was 107°C (right when I stopped it, it was at 103°C).

 

I have been following this post for a while as I was having issues starting my car after a rebuild, I replaced the stock computer with a Power FC, changed the fuel pump as it wasnt getting to max pressure. Still couldnt get it to start, I had a couple explosion noises like you mentioned but wouldn't start up.

After reading that you had 1 dry plug and 3 wet plugs after checking the plugs when it flooded it made me realize I was seeing the same thing. Then just yesterday I saw that you were able to start the car after changing plugs so I did the same thing and mine started right up and idled!

Thank you for your persistence and posting everything you have went through with your car. It has really helped me out with my own car. I hope you get everything working right and get back on the road.

 

Only way to know if the coolant seals are good is to pressure test it. I got my car slightly above 100 C on the power fc when a heater hose busted on me. Over a year later and its still kickin. I also regularly see it above 100 C during the summer after shutting the car off after a drive and coming back to it.

In the video it sounds like you have a nasty exhaust leak somewhere.

 

Haha wow, that's nice to read! But hey, to me, spark plugs looked so clean and new! So wrong...

I'm very scared of doing the champagne test. Especially because it doesn't seem to be quite clear. It seems like everybody got bubbles in there. Some people remove the water pump belt... I don't want to sound a false alarm.

I don't think it was super hot. It's 15°C outside here (59°F). Ran for 12 minutes at 1,600 RPM. Cluster water temperature gauge is what scared me the most.

Exhaust leak is right after the turbo (between turbo and wastegate). I need a new V-Band clamp and it is not so easy to find locally. I'll look for that tomorrow.

 

Since it was running with no load, it's possible that no damage was done as long as those were the actual coolant and engine metal temperatures - 107C is not that hot. However, since no coolant came out when you opened the cap, you cannot tell what the temperature of the metal was. So it's not conclusive whether damage happened or not. The good thing is that you weren't running it hard, so you may have escaped w/o damage since running with no load will not super-heat the metal like running hard. Also, running rich as you were will lower the combustion chamber temperatures.

As said above, you'll have to pressure test to know for sure if the coolant seals are intact. For any possible other damage, you may need a compression test, but, IMO, that can wait until after you run it a while.

 

That's what I was thinking too... That gauge couldn't have been accurate. Am I sadly right to assume that it could only have been higher than 107°C? I have searched and I'm not the only one disliking the popular "Champagne test". I have seen that tool on Pineapple Racing website. Is it what I need? It is fairly priced at $43.95 + shipping.

But for compression test, I do not quite understand that part. I'm not even worried about it.

I've got to ignore the overheating issues that I had today. The main concern I've got to work on now is black smoke. It's running way too rich right now.

 

Yeah it could have been hotter than you knew. I was gonna mention my car idles weird until the coolant is decently burped. Could be why your idle is high and strange.

If you fill it with coolant and it doesn't come out the tailpipe as steam when you run it, you're probably ok. Pressure test is conclusive.

 

Right now, as soon as I put my nose at the exhaust pipe, I almost faint and my eyes hurt. It smells too much like gas right now, can't smell nothing else.

I am not sure why the engine is running that rich, I don't have many ideas... Is it already time to send the car for a tuning session?

 

When you have a major water seal failure, it doesn't make you wonder what's happening. It's clouds of white smoke and coolant fill alarm all the time. Even a small leak will trip the coolant sensor with fair regularity. If you're not mysteriously losing coolant, then 95% you're ok.

Did you reset the PFC tune before you re-did the rebuild?

 

Alright I like to read that this morning. Yes, I reinitialized the PFC, so I lost my previous tune.

 

I really doubt you did any damage to the coolant seals. The engine is just idling under load so the temperatures in the combustion chamber are very low. It's a whole 'nuther thing to have it driving with load on the engine. Coolant seal failure takes a lot of time and the fact the seals are new are in your favor. I wouldn't get too wrapped up in it, just move forward.

Big thing here now is why is it running so stupid rich. Some questions -

1. PowerFC? Stock map?
2. MAP sensor hooked up? No check valve in the line to the MAP sensor? (Stock there's a small filter, I've seen people think it was a check valve and put one in there)
3. Water temp sensor hooked up and reading properly?
4. Do you have an air pump? If not, is O2 feedback turned off on the PowerFC?
5. Coil pack harness and plug wires hooked up right?

Dale

 

Alright yes I'll just ignore that overheat... I agree, the main issue now is the (very) rich mixture.

1. Power FC freshly reinitialized.
2. MAP sensor with brand new filter from Mazda, correctly hooked up.
3. Water temperature reading correctly on the PFC Commander.
4. No air pump, I've got no clue if o2 feedback is turned off, I didn't change anything on it since I reinitialized it.
5. Coil pack harness connected properly, however I connected the ground cable just under the rear nut, where the coil bracket attaches to. I am not sure if that's where it is supposed to go.

 

I would go in and disable O2 feedback. That's probably not the whole problem but it's not helping. It's super easy to do on the Commander.

Vacuum line hooked up to the fuel pressure regulator? Stock fuel pressure regulator?

The coil pack harness, if it has a ground it's the original one, the newer design doesn't have a ground wire. I don't think it really matters where it is grounded, it is normally going to a nut/stud that holds one of the coil packs down.

The coil pack harness has a big 4-wire connector that connects to the main harness, then the very last connector farthest from that 4-wire connector should be on the coil nearest the firewall. I worked on a car once that had the harness plugged in backwards - the last connector on the harness was on the coil pack closest to the front of the engine. Engine ran WEIRD and took me forever to find that.

Dale

 

The fouled plugs (and smoke) could also be attributed to oil in the intake. If you removed (and hopefully capped) the PCV, recheck your plugs and see if they are still fouling (of course starting with them clean). If they are still fouling, it's probably due to a rich mixture.

There are a ton of posts on hunting idle. Think that's a general trait of the PFC, or it could be a vacuum leak. You can mess with the idle air screw under the TB which also help with a rich idle. If you can't get it stable, you may want to do a smoke test.

The good thing, it idles, so you're halfway there

 

Not sure if it's been covered yet, but if you still have your thermowax rod on your stock throttle body and there's no coolant getting to it (It's the highest point on the coolant system which is why you fill the system from there) it's gonna stay at a high idle and mess with your TPS readings and your throttle body should not be messed with until you have proper timing, the engine is warm, and the thermowax rod has shut the throttle blades properly. The factory service manual has good literature on how it's supposed to react and gives some good base settings on the thermowax system in the case it's out of adjustment and such.

 

Vacuum line hooked up to the stock fuel pressure regulator.

Coil pack harness verified and plugged in correctly.

I disabled o2 feedback - car never started today. I re-enabled it - still no luck.

I played a lot with that idle air screw on the TB, to prevent the engine from dying.

Fouled plugs because of oil in the intake - that's exactly what I thought too! At first, yes... But now, I don't think there is anymore oil in the intakes (engine ran about 30 minutes since I had the problem).

I didn't know that! There is coolant running in the TB, but I was planning on bypassing it in a near future.


Today wasn't a good day. Engine never started, tried 4 times, with "clean" plugs each time. Sad, yesterday, I manually stopped the engine... A few explosions, but very far from idling. It gets flooded easily. I added some transmission oil in each leading hole, without any change.

I'm pretty sure the spark plugs are the problem. I'm gonna do a "level 2" cleaning tomorrow. My "level 1" was: let them sit in starting fluid for an hour. Tomorrow, I'll use a wire brush, that's my level 2.

I can't afford using 4 new plugs each time I start the car to troubleshoot the issue. I'm thinking more and more that this could be a good time to send the car via tow truck to the nearest rotary shop (80 miles ride, they are VERY reputable in Canada).

 

Get a timing light and make sure it's firing at the right time. You shouldn't be fouling plugs so easily.

 

I searched on that. I understand there's a little tab on the timing wheel in front of the engine. But, where is it supposed to be when the light comes on?


Today is a better day.

O2 feedback disabled. I cleaned the plugs using a steel wire brush, and the engine started. Ran for about 15 minutes. I stopped it manually. Smoked a little bit at first because of transmission oil. It still smokes (blue?) but it is much better than it was. I am able to stay in the garage while the car is running (still got some headaches afterwards though).

I think this video sums it all. It really seems like the car's idle is 1,600 RPM (and as you can see, it is fairly solid at 1,600 RPM).

I'd like to repeat it: engine has been street ported. But a vacuum of 12 inHg at 1,600 RPM seems a bit low?

 

Damn... that sounds like bridge port..