Chilicharger665

iTrader: (2)

Ok I didn't do the magic funnel thing because I didn't have the time, but did manage to "burp" the engine as much as I could by jacking up the front. It drove the 100 miles to get home and to work and it didn't overheat so I guess it worked? It did pick up a new problem though. Now it refuses to go into full boost when I floor it. It will just sit at 80mph and sputter and not go any faster. My boost gauge shows full boost, but the car goes nowhere...

I unleashed hell when I replaced my spark plugs and wires apparently.

Savington

iTrader: (31)

Have you compression-tested yet?

hochkis

What gap are you running on the new plugs?

Joe Perez

iTrader: (8)

I am no has understand?

As Sav suggests, this is probably a good time for a simple compression test. That'll give you an excellent indication as to how everything survived the experience, and perhaps a little peace of mind.

Beyond that, I'm afraid I can't quite understand what you're trying to describe above. Are you saying that the car feels like it's producing less power than before? This is not a symptom which I would typically tend to associate with having overheated the engine to a degree not sufficient to cause significant (and obvious) damage.

Chilicharger665

iTrader: (2)

I apologize, the way I worded things makes no sense. When I floor it, the rpms sit in the same spot and the car just sputters basically. The boost gauge shows a max of 12 psi but I feel no extra forward motion. This came into play when I tried to pass a car and it wouldnt accelerate any faster so I obviously couldnt pass. I can accelerate at half throttle with no sputtering but thats not fast enough to pass either.

No I havent compression tested and I have no idea how to do that. Do I need to go buy something?

Chilicharger665

iTrader: (2)

I got them from Trackspeed and the page said they were pre-gapped so I put them straight in. Trackspeed Engineering
I got the BKR7E-11's.

hochkis

Id pull the plugs and gap down to .025 and try again. Sounds like spark blowout.

curly

iTrader: (25)

Sounds like water injection caused by a blown head gasket. When you over heated your engine, your head most likely warped. It probably drives ok out of boost, but when you enter boost it's blowing past the head gasket that's no longer sealed great with the warped head, compressing the coolant, and pushing it into the cylinders. If you take your spark plugs out, you most likely have very clean piston tops if you shine a flash light on to them. If you look at the bottom of your oil cap, you might see a milky residue, that's the water thats in your oil steaming off and condensing on the cap. And you could probably drain you coolant or look under your radiator cap and see a milky brown coolant if it's real bad.

Not all of these signs will be present with every blown gasket, but I'm sure you'll see one of them. The symptoms you're describing is enough to tell me what's up. I've been wrong before though.

For the compression test, you simply replace your spark plug with a pressure gauge, and crank the engine over with the starter. The gauge will measure the compression your piston is capable of. I think the tolerance for that is 160-180psi or something like that.

hornetball

iTrader: (4)

You sound like a super-noob. You need to be patient with yourself. You've got a lot to learn. Here are random thoughts:

1. You should not be driving a turbo-Miata unless you wrench on it yourself. Prior experience is highly recommended -- but not mandatory. Expect learning pain if you're new. Don't get frustrated with yourself. Fortunately, Miatas are easy to work on, rugged and forgiving. If you had a BMW or MB, your car would be headed for a junkyard right about now.

2. A turbo-Miata should not be your only car. It will be down from time to time for maintenance and to satisfy your "mod" bug. By the way, what you did here -- driving 5 miles without a water pump -- would have brought any car to its knees, modded or not. It sucks now, but in a couple of years it will be a funny story.

3. Pick up a copy of "Mazda Miata MX-5 Performance Projects" by Keith Tanner. Easy to read and great illustrations/pictures. It will help get you going on basics like changing the timing belt/water pump, pulling the head, etc. I've been doing this a long time, but I still like to see pictures before starting something whenever possible.

4. To do a compression test, do the following:
-Buy compression tester at parts store. They're inexpensive.
-Make sure battery is fully charged.
-Remove all spark plugs (while you're at it, check gap -- .025 is what you want on a turbo car unless you've modded to run COPS -- that will be less than the manufacturer's pre-gap). As you remove the plugs, take a look at them and sniff them. Are any of them discolored, wet or smell like coolant? Can you see or smell coolant in any cylinder?
-Screw compression tester into 1 spark plug hole at a time to test a cylinder.
-For each cylinder, sit in the driver's seat, press the throttle pedal to the floor and crank at least six times. Your engine will spin more quickly than usual because you've removed your spark plugs and eliminated engine compression. If you watch closely and you have coolant in a cylinder, you may even see it shooting out of the spark plug hole.
-Return to engine, write down the compression reading from the tester, and move tester to next spark plug hole. Repeat.

5. Other signs of blown head gasket:
-Rough running (like Curly mentioned). In my case, I've had rough running at idle/low throttle and good running at open throttle before. Symptoms can change depending upon where and how the head gasket has been breached.
-Coolant smell.
-Milky oil (like Curly mentioned). Again, not always present -- requires a path between a coolant passage and an oil passage.
-Oil in coolant. Same as before, not always present.
-Coolant being consumed -- low radiator level. Almost always present.
-White smoke (steam) from exhaust. Present in severe cases.

6. Recommendation -- do the compression test and regap the plugs. If everything looks normal (even compression across all cylinders), then drive it and be watchful for other symptoms. In particular, be checking the level and condition of your coolant and oil before each drive.

hornetball

iTrader: (4)

Oh, BTW, welcome to the hobby!!

rleete

iTrader: (21)

Excellent post, Hornetball.

mc85

iTrader: (1)

Did your boost issue only come up when you replaced the plugs and wires? And it ran fine immediately after the overheating issue?

Keep us posted on the compression test. The procedure is fairly easy and can be applied to other cars.

Chilicharger665

iTrader: (2)

How do I make the gap smaller on my plugs? I pulled them all and theyre all about .035. It was recommended to go down to .025 so how do I do that?

I am also about to do the compression test and Ill let you know how that goes.

Joe Perez

iTrader: (8)

Holding the spark plug in your hand, with the ground electrode facing down, tap the ground electrode against a flat surface lightly to close the gap up.

hornetball

iTrader: (4)

Here you go:

hornetball

iTrader: (4)

BTW, I like to put my plugs in a bench vice and SLOWLY/GENTLY press the electrode in to the proper gap. Gives a bit more control than tapping, but either way is fine.

Chilicharger665

iTrader: (2)

Ok counting the cylinder closest to the radiator as 1 and counting back towards the driver the results are 1 - 125, 2-115, 3-125, and 4-140.

Chilicharger665

iTrader: (2)

So is my engine healthy or on its way out? What is normal?

Joe Perez

iTrader: (8)

The service manual says:

Ideal = 192 PSI
Minimum = 135 PSI
Max differential = 28 PSI from highest to lowest.

These numbers assume the following:

1: You remembered to hold the throttle plate fully open during the test.
2: Your battery is sufficiently healthy to achieve 300 RPM while cranking.
3: You had all four plugs removed during the entire test.

Chilicharger665

iTrader: (2)

1. Throttle plate was fully open
2. Battery seemed to have no problem crankibg. Is there anyway to check the rpm reached?
3. All 4 plugs were removed.

I did some more searching on here and I did not know the engine was supposed to be warm so do I need to reinstall everything, get it warm, and repeat?