Turbo, RTV, Block off plates, and advice...
 

So I'm having trouble with my car just a month or so before I plan on putting on all the stuff for the turbo. My car now on occasion feels like there's a massive vacuum leak. The trouble is it's intermittent. I recently replaced my EGR valve with a blockoff plate and while I was attempting to remove the gasket from the EGR valve it disintegrated. I used RTV on it and made a pretty good seal. I took it out for a test drive and I noticed that after it warmed up it started behaving like it there was an air leak. I then took it all apart and re-applied RTV more liberally and that seemed to correct my issue.

I then had to park the car for two weeks for a trip out of state. I came back and I started to have these problems again. The temperature has been getting extremely low (down to the single digits) and that's when the problems seem to have started.

I'm curious as to whether or not the RTV is unable to seal properly like it used to and so I should order an EGR valve gasket and re-do it, or if my engine is on the fritz and is in need of a rebuild? I'm going to do a compression test on it tomorrow to see what the numbers are. The last time I did one however my numbers were excellent 115/115 and hit 30/30/30 on each face and that was maybe, MAYBE 8 months ago.

Now more to the point since I am planning on putting the turbo on within the next few months should I rebuild the engine anyways? Just build and port it when I put the turbo on while I prep the engine bay? How much do soft seal rebuild kits go for (as I think that my apex seals are fine)?

The RTV should seal fine if its applied properly and the surfaces aren't warped.

Hard to say what that issue is...

As far as rebuilding before strapping the turbo on - ABSOLUTELY. And unless your engine has been rebuilt fairly recently, you'll probably need more items then a soft seal kit as there will likely be 3 piece apex seals in it. Make sure to spec out all the hard parts....but a coolant o-ring, plus all dowel oring kits from mazdatrix are only a couple hundred dollars. But oil control rings/seals, all springs etc should be measured and replaced if necessary. But in my experience, unless its been fairly recently built or freshened - you'll be in for more then you think.

Hmmm... The RTV was working fine up until the time I left for my trip. It was running a little less than well when I came back, all it did was sit and the temperature changed.
The engine was rebuilt about 55,000 miles ago (about half of that from my driving). It's still pretty recent all things considered and it's previous numbers reflect that. I'm going to be driving it back to my parking lot today and will be able to run some more tests. I'm just putting off doing it because it's balls cold outside

It's having trouble turning on now. It's too cold so I can't really get my plugs out so I can't do a compression test or see the condition of the plugs. It's tending to flood more than not, and runs strong more than not when it actually does manage to turn on. There are instances when it does not run strong and is in need of some fancy driving to keep it from stalling out, but more so than not it runs fine.

What is the problem? Is it the plugs themselves? The temperature? A combination of old plugs, temperature, and flooding? Could my previous symptoms be another aspect of this problem or is it an indication of another problem that I'll need to fix?

Guesses?

Maybe you should adjust the RTek. Temps have been drastically colder in VA the last few weeks.

Also, put new plugs in. I cant stress the value of spark plugs in a rotary, lol...

I would if I could, but the NA S4 RTek 2.1 does not allow adjustment of the cranking map. Beyond that it won't read the fuel map until it's idling, which it can't really do until it's started up.
I'll do that when I put the car in the garage to do the turbo install (either next week or the week after). It's rather annoying right now (and cold for that matter) as I was driving after filling up I came to a complete stop and the car just stalled out, the total running time of the car could not have been more than 7 minutes. I try to restart it and it just won't start, definitely behaves like it's flooded. I plan on doing a compression check when I put it in the garage so I can know if it's in need of a soft seal or more extravagant rebuild.

The plugs themselves are probably approaching 25-30,000 miles on them, which would be about the time for a replacement or at least a very thorough cleaning. Hmmm.... I may even be able to run a compression check when I get up to culpeper. That should be quite revealing.

You doing the turbo install in culpeper? Which weekend....


As for plugs, if you did any tuning on those plugs when you got the RTek, they'll probably need cleaning/replaced... i remember tuning a T2 a while back and after hours of work, it never wanted to start... put new plugs in, and it fired right up. Its usually simple.


I would def do the compression check too though. Even if its been rebuilt, who knows the quality of the rebuild....

Nah, I'm going to be doing the turbo install down in Christiansburg as I'd have access to a lift, tools, and a slew of master welders (or at least certified or self taught welders that have a tig).
I haven't really done much tuning on the car so far. I've dropped the fuel correction down to I *think* -16% or so during the idle range. I've also blocked off the EGR, so I imagine that's the biggest thing going against me right now with the cold air.
Point taken. I really don't know much about the rebuild. I just have a receipt for it and I know that they didn't have any 6PI sleeves in it so I had to put those in. Who knows how they rebuilt it.

I'll be doing a compression check tomorrow and looking at the plugs.

On the way up it ran like complete crap (RTek registered lean, though I was definatly spewing fuel in the exhaust pipe and doing back fires and flames). Will look at the condition of the plugs and report back come morning. Hopefully it won't be so F'ing cold this time.

Okay, so I checked compression on both rotors. I'm getting around 50-60psi on each face and a total compression of 100+psi (using piston compression tester) both front and rear.

I pulled the plugs and they're a little fouled. One of the leading plugs isn't looking too good as the piece in the middle has been warn away compared to the other one (not as pointy). When I pulled them however I noticed the first had alot of oil and and seemed well lubricated (front). When I pulled the second (rear) I noticed it had alot of oil and fuel mixture in it. I don't know why it's flooding on the rear when compression is so high.

Any thoughts on why a very good compression engine is flooding out?

(As a side note, I'm only able to secure trailing plugs right now. Would putting those in the leading position affect anything?)

So I got a full set of plugs (at least I ordered a full set; both leading and trailing). Ended up only getting 4 leading. No biggie. I look at the gapping for the new plugs and I realise why my engine's been running so crappy lately. My spark plugs are definatly shot more than a dead zombie corpse on a marine base.

The elctrodes on the old plugs have been melted/warn away to almost just little blobs/spikes. Couple that with the amount of carbon on them and I think I know why the plugs only worked the way they did. I'm very surprised by how well the car ran. I'll replace the plugs tomorrow to see if that remedy's my problem.

On a side note will running a full set of Leading plugs pose much of a problem? I'm planning on putting the car in the garage and putting on a turbo in the next week (it'll be down for a month or so). I'm of the thought that it won't be a problem since the plugs themselves are a cooler plug and will take to the additional air and heat without much of a problem.

I run leading plugs all around. I have ever since I did the turbo swap with no emissions.

No ill effects. It actually runs a whole lot better that way.

Alright so I swapped in the new plugs. It seems to idle much better now, but while I was letting it idle I tried to blip the throttle (it was idling fine just prior to this) and it ended up dying on me. I couldn't get it to restart, it seemed quite lathargic when attempting to turn over.

I won't know too much more about the current state of affairs until after I start driving it around more. At least I feel like it'll be able to get me to the garage without problem.

The leading plugs are hotter. 7 heat range in the leading vs. 9 in the trailing

I've run all 7's in some of my N/A DD's before.....never been a problem.

Are you running all leadings? or all trailings? Never tried all 7's in a boosted (even stock boosted) 13B before....interesting.

Thanks for the clarification about the plugs.

I'm still having trouble with the engine dying after a little while. I'm going to try to hunt down a vac leak (if there is one) and see if that solves my problem. If that doesn't work I'll just tear into the intake again and remove the EGR Block off plate and clean up the mounting one last time and install it. I may go out and purchase a gasket maker compound or something instead of the RTV red.

Have you checked your injectors yet? They may be old and leaking...

Wait, I can't remember now. Been a while since I changed them!

They were cleaned awhile ago. I don't think an old and leaky set of injectors would only misbehave when operating temps were reached. could be mistaken though.

Are you sure its the engine and not electrical issues? Weak alt, etc?

If the idel is not lopy (like 1500 to 3000, back to 3000, etc) its probably not a vac leak. Pull the new plugs out now and see what they're like just after running for a while. Also, check the fuel filter...

I'm pretty sure I found a vac leak. I checked the vac too on the RTek and it was only pulling in 5inHG. Normally I pull in 11+inhg at idle. The rear securing bolt on the LIM had sheared, and while running it condensation had developed on the engine. The condensation got sucked into it, and that opened up the passage way. Forcing me to cool the engine back off which developed more condensaiton in the vac leak which froze again blocking off the vac leak. Repeat until vac leak was found.

At least that's my theory. I really won't know until I replace the UIM and test out the idle again.

Don't take this the wrong way, but 11 inches of mercury is LOW for an N/A engine especially.

My 1/2 bridge with monster exhaust ports would pull 13in/hg idling!! :lol:

(I don't know if the ports have been ported on this engine or not. So they might, they might not) I'm of the thought that I have alot of little vacuum leaks going on. When I rid myself of the emissions crap I imagine that I'll eliminate alot of the vac leaks. I'll have to double check the actual numbers when I idle again.

alright, i put it all back together and it idled fine until it warmed up to operating temperature.

I'm still only pulling 5.8inhg according to the RTek. It's got to be quite a big vac leak as I've checked compression and both rotors are fine. The only thing i've changed would be the egr block off plate though i'm hesitant to mess with it until I remove the emissions (Or it warms up).

Anything else I should check?

I checked the condition of the new spark plugs, still look good. Rear rotor tends to flood when the vac leak presents itself.

Honestly, vac leaks are either there or they arent, cold or hot. The vac numbers sound low, which isnt good. Its hard to get accurate compression checks with a piston tester, but I'm thinking you may want to do another comprsesion test when the engine is hot and see...

I did it when the engine was hot. It had just been shut down from operating temp to get the readings.

Just out of curiosity, is there a test I can do to see if I have a coolant seal going? Maybe what I'm seeing in the rear rotor isn't fuel but leaking coolant... Is there any test I could do to see without breaking open the engine?

I"m leaning more and more everyday to my coolant seal letting go. It makes sense as the car dives fine one minute and as soon as it warms up it runs like it's on one rotor. I think the rear coolant seal is letting go, hence why the plugs are continually soaked when I check them when the problem occurs. I also have a rather large plum of smoke when I start the car when it sits and feels like it needs to clear it's throat.

Does that fit the symptoms pretty accurately?

It's a possibility. You could possibly have an injector that's getting stuck open, too, but I haven't witnessed that before, I'm not exactly sure how it would manifest itself.

I think I may just go ahead and pull the engine and order an overhaul kit. I'm fairly certain that the apex seals, oil rings, and other seals are fine on the car, just my rear coolant seal has gone to crap.

I think the only sure way to check to see if I have a seal failure (without taking it to a shop and pressurizing the system) would be to check it with a bore scope through the exhaust ports. I should be able to see a majority of the engine through that. At least from the locations of when the full cycle of the rotor.

what kind of temperature are we talking

Which temperatures?

The recent temperatures outside were around 30F or as low as 7F. The temperature when the car starts behaving like it's got a vac leak is 173.8F.

I data logged a recent trip to Radford VA when it happened and this is what I have:
(I adjusted the idle to be high so I wouldn't stall out--when the symptoms occur the car idles at about 1200-1500rpm. When the symptoms are not there the car idles at 2000-2500rpm)

At 3478RPM I see:
7.2 Lbs/min
3.0 inHg
AFM Air Temp is 34.2F
Intake Air Temp is 42.1F
Injector P/W is 8.73ms
NB O2 is 0.03 Volts
Coolant Temp 173.8F


I can pull some of the logs I've taken of the car during the symptoms if it would help.

I'm waiting on a garage to open up before I do any more testing.

What color is the smoke on startup?

Coolant seal is a possibility, although, your engine temps should rise if thats the case (unless the car dies before it gets a chance to). Have you had issues w/ coolant level in the radiator lately?

My level in the radiator drops on occasion, but it can be accounted for by the crappy universal recirculation tank I installed to get me through this as it tends to be a little leaky. I have noticed more condensation build up in the filling neck of the oil and in the ventilation hose... The oil itself still looks good (golden brown/black not milk chocolate). Also the fluid in the radiator is pretty clear but there is some strange contaminates that seem to be sticking towards the fill port (black in color). The color on start up is white (at least from what I can tell). It looks similar to regular exhaust but hangs around longer in a bigger plum.

On a side note, I have details on when the engine was installed and by who. The engine was installed by Wayne's Imported Automotive and as far as I can tell was completed on Aug. 6th 1997. They list an entire engine as a part for a cost of 2150 and has the part number of E008-99-008R which I think means it's a re manufactured engine, maybe rebuilt, but I doubt that shop knew about it.

As a side note to discussion is 1997 late enough in the game to have the newer 1 piece Apex seals in it or would it contain the 2 piece Apex seals, or is there just no way to tell until I look at them through the exhaust ports/ break open the engine?

Just break open the engine and look at what's needed and not needed. That would tell you the condition of the engine much better than just guessing. It's better to be sure and make sure you get things right the first time. It's also much cheaper.

If I had a little extra money I would in a heart beat. But I don't so I'm only trying to buy what I need to.

I'm going to be tearing down the car tonight and inspecting the exhaust ports to see what's up. I should know alot more by then.

Alright so I checked the rear rotor. It's not coolant. It's just alot of gas. so much so that it was pushing it into the thermal reactor and half way down the exhaust. It was just a heavy gas mixture with some oil mixed into it. When I checked the coolant it was perfectly clear without and any obvious change in color. The oil looked like oil and not milk chocolate.

So what could cause a huge vacuum leak on the rear rotor? So much so that it effects it at operating temperature?

Well if you said it was fuel coming out, then its probably a stuck injector and not a vac leak at all.


Also, a side note on your engine info. 2150 sounds a bit "cheap" for a reman engine installed, even back in 1997. Remans are tagged and you should be able to see this tag on the front cover area (if looking from the front, it should be visible near the CAS and below the alt, tucked in a little), or possible on the rear iron on the drivers side.

Either way, if you dont see a tag, I'm betting on it being a used motor, bought from a salvage yard and installed. Not that its a bad thing, just something to consider. You may have more miles on that engine than you think...

The only tag I've seen on the engine so far is a stamp that read FR97 on the rear rotor housing. 2150 was just for the engine itself. Not for the install. I don't think it's a reman from Mazda as it has hymlar used (I believe the FSM calls for crisco or some other lubricant to install the water seals).