High compression on 98 gst

[my dreamt dsm]

I did tons of search and coming up with weird mix answers.
I'm ready to drop a new evo3 16g in and don't want to worry bout the motor handling the stress.
I got high compression 180-185-190-185.
From my results I read that it maybe due to carbon build up. I did seafom twice in 3 months and a bottle of injector cleaner.
I know service limit numbers and that a perfect motor is close to 178... I never heard/sure if higher is okay???
This was done on a dry test with four seconds of cranking, car fully warmed to operating temp where the rad fans came on already.

 

[bryanwheat]

You will be fine with those numbers.

 

[my dreamt dsm]

I got people telling me that's a healthy asz motor and others telling me I'm screwed. So which one is it .

I'm only going on it as a strong motor because the two previous owners I got it from are old men who took really good care of the car. And when I bought it at 107k it pulled really hard. Just that now it runs really sluggish. I thought it was the clutch so I replace everything clutch related. Then I thought it was the turbo, but there is no shaft play and that t25 has no shaft play at all. So I bought the 16g incase it was the turbo.
So now I'm really confused on what it could be if the motor IS healthy.

 

[bryanwheat]

Well there is really nothing that could be damaged that will cause higher compression. IT is possible that your gauge is reading high, or that the head has been cut down quite a bit. I wouldn't think twice about running it like that.

 

[my dreamt dsm]

You have more green dots then me so I go on what you say

 

[Spoolin4Ever]

Does you car burn oil? In it does that will cause carbon buildup pretty bad. You'd notice it probably though in other ways cause it causes knock and it makes the car run slower and even can cause it to burn valve if it build up real heavy.

But if you're not burning oil you probably don't have much carbon buildup.

When you "seafoamed" what color was the smoke? If it was just white then you're clean. If it was brown black or blue it was burning off carbon. Keep doing it till it sea foams grey smoke only and you know the carbon is cleaned off.

 

[my dreamt dsm]

No oil burning. When I seafoamed the car it was blowing white smoke. Boost leaks are fine. Everything is fine. I just can't seem to put my finger on it if it is the motor or not!

I log my car on a regular base when I drive. No crazy knock. Like 1 or 2 counts but that's about it.

 

[Spoolin4Ever]

Ok...well doesn't the number of times your head has been shaved/serviced as well as the type of HG you are using can affect the compression?

Have you tried more than one compression tester?

 

[my dreamt dsm]

From all the records the previous owner had up to the date I bought it. There is no work for the motor except regular 3000k 3500k mile oil changes.

I only used the tester I had.

From all the records the previous owner had up to the date I bought it. There is no work for the motor except regular 3000k 3500k mile oil changes.

I only used the tester I had.

 

[Spoolin4Ever]

How many miles on the odo?

 

[my dreamt dsm]

It just hit a little over 120k since I bought it 3 years ago.
Oh and driving style is very conservative. I do not floor the car at all. In fact I can't even recall the last time I went pass 50% throttle.

 

[e85_4g63]

Do a leak down test. Also, try a different gauge and redo the compression test again. Does your car still have the stock 7 bolt motor? Are you certain you don't have a 1g 7 bolt non turbo motor in the car? (1g 7 bolt non turbo 4g63's are 9:1 compression, which could be the reason your CT is coming up with those higher numbers).

 

[my dreamt dsm]

I'm sure its the stock 7 bolt!

 

[JusMX141]

How could high compression numbers during a test be a bad thing? If you bought 10.0:1's for a build your compression tester could read 220-230psi.

All the numbers are telling you is your piston rings and valves are sealing very good, as they should be.

 

[my dreamt dsm]

I got an impression from a 4 dot reputation member saying my motor has excessive carbon build up. So I was unease by that thought ever since!

 

[Spoolin4Ever]

Ok so the car runs poorly? I wonder if your timing my have jumped? Describe how it runs, how does it idle? Do you have any other threads on this issue or is this the main thread with it running poorly?

 

[jrohner]

First time I've heard someone worried about having good compression. I had maybe 100psi in my 2G; I would've traded you.

 

[Spoolin4Ever]

First time I've heard someone worried about having good compression. I had maybe 100psi in my 2G; I would've traded you.

Except if you read the thread you will see he says it runs bad in someway which is why he tested it.

Just that now it runs really sluggish. I thought it was the clutch so I replace everything clutch related. Then I thought it was the turbo, but there is no shaft play and that t25 has no shaft play at all. So I bought the 16g incase it was the turbo.
So now I'm really confused on what it could be if the motor IS healthy.

Yeah it's also somewhat confusing post because initially you say you are testing it because you want to upgrade, to an EVO316G, then a few replies down you say it is running sluggish.

Have you done your plug wires and plugs lately? Do the plugs once a year and the wires every 3-5 years.

 

[my dreamt dsm]

Except if you read the thread you will see he says it runs bad in someway which is why he tested it.



Yeah it's also somewhat confusing post because initially you say you are testing it because you want to upgrade, to an EVO316G, then a few replies down you say it is running sluggish.

Have you done your plug wires and plugs lately? Do the plugs once a year and the wires every 3-5 years.

Oh, my fault. I tested compression because I wanted to check the motor to see if it was HEALTHY to put the turbo on. I did the basic maintenance, new pcv, new thermostat and mods up to date. Disregard the intercooler on t25 part. Problem was before I put in the intercooler.
I might have to check timing. I'll be doing some search on that tonight.

Idle is fine. 750rpm on the dot. I can't describe it. Car just runs sluggish for the past 2 years. I'm starting to wonder what it is... o2 sensor check out within parameters on evoscan, Knock count isn't a concern. Boost leaks are none.

 

[And_44]

Like mentioned above could check wires and make sure plugs are gapped right. Fuel filter been changed recently? TPS numbers correct?

Have you changed fuel suppliers. I notice both my cars run dfferently on different suppliers. So my 300m gets Safeway or Citgo because it runs smoother and better (its my DD so cheap is my goal for fuel on it), but the Talon only gets Shell, Citgo, Valaro, or 76.

Have you checked fuel pressure? Maybe try a fuel pump rewire to get some extra juice to the engine and pump.

Sorry, just trying to think outside the box.

 

[my dreamt dsm]

I got new ngk plugs and wires. Problem still exist. I will check timing tomorrow!

 

[Delta2Echo]

I got new ngk plugs and wires. Problem still exist. I will check timing tomorrow!

Have you checked the plugs and wires to make sure they are getting spark? Just because you replaced them, doesn't mean they are working properly. If you test them, and they aren't all getting spark 100%, it's probably a bad coil pack. But I don't think they go bad all that often.

 

[bryanwheat]

Have you checked the plugs and wires to make sure they are getting spark? Just because you replaced them, doesn't mean they are working properly. If you test them, and they aren't all getting spark 100%, it's probably a bad coil pack. But I don't think they go bad all that often.

Well the car does run so it is getting spark.

 

[shampoo]

Ever think that maybe you got used to the car?

Just tossing it out there.

 

[my dreamt dsm]

Ever think that maybe you got used to the car?

Just tossing it out there.

I thought of that many times. But yeah, the car just doesn't pull as good as it use to.
When I drive on regular street, say 40mph is the speed limit. I would get so tired of the t25 spooling to fast that it pulls everytime I try to get to 40. One day, like 2 years ago I launched the car at 4K rpms and ever since then. The car doesn't pull as hard as it use to.
That's when I started to replace all clutch related stuff thinking it was a slippage issue. I replace all cooling sensors and radiator stuff thinking it might be running to hot. I pulled a compression test and the motor seems fine. It just bugs me that if the car isn't running good. How come I don't have a check engine light. So yep. Unsolved mysteries of this dsm.
Oh and timing came out okay also.
Next is I will try to rewire the pump and see if that helps. Some searches I've been looking at, op's say it miraculously cure their car.