So yesterday I did a compression test. I found a guide on here and followed it to the letter and this is what I got:

 

Cylinder 1 = 70 (drivers side front)

Cylinder 2 = 65 (drivers side middle)

Cylinder 3 = 50 (drivers side back - closest to cabin)

Cylinder 4 = 10 (pass side front)

Cylinder 5 = 25 (pass side middle)

Cylinder 6 = 0 (pass side back)

 

We were confused about this because a TT should be 171PSI with a tolerence of 10% (14-ish psi), so we checked my Black NA:

 

Cylinder 1 = 100 (drivers side front)

Cylinder 2 = 100 (drivers side middle)

Cylinder 3 = 99 (drivers side back - closest to cabin)

Cylinder 4 = 100 (pass side front)

Cylinder 5 = 100 (pass side middle)

Cylinder 6 = 100 (pass side back)

 

Thats still not right and we know that my Black NA is in pretty much perfect order mechanically, so we tested my wifes Celica ST202:

 

Cylinder 1 = 105 (drivers side left)

Cylinder 2 = 100 (drivers side middle)

Cylinder 3 = 98 (pass side middle)

Cylinder 4 = 100 (pass side right)

 

That isnt right either. We then worked on the assumption that my gauge is 80PSI off being accurate, the Celica and black car would be correct and the red one would be at: 150, 145, 130, 90, 105 and 80. Now its obvious that the red one has a problem of some kind, but is it really possible for a new gauge to be 80psi wrong?!

What brand is the tester? Are this warm numbers or cold?

The brand of the tester I don't knoW, it was from ebay for £20. All tests were done with warm engines

I used a cheap tester once on mine and got really low readings, im not sure the cheapies are reliable enough to give a true reading

You are turning this over on the starter arnt you?

Yes I am. I'm going to borrow a better one from a mechanic and do it all again. Hopefully its my gauge being annoying and cheap

Hopefully its my gauge being annoying and cheap

 

Indeed :sweatdrop:.

There is a possibility the gauge is faulty of course, however it could be correct or close to it and all of your cars are lower compression than you thought they would be, provided they are equal or close to it then they will often run just fine, had a customer years ago with 90/ 110 psi spread across his cylinders on a twin turbo and engine ran fine and did not smoke or use oil, it was a genuinely worn engine nothing more, nothing broken unlike your red one, given that no 6 is reading 0 really negates any gauge inaccuracy to be honest, a leak down test would help narrow it down to rings / cylinder or valves though, either way its a strip down job.

 

Jeff

There is a possibility the gauge is faulty of course, however it could be correct or close to it and all of your cars are lower compression than you thought they would be, provided they are equal or close to it then they will often run just fine, had a customer years ago with 90/ 110 psi spread across his cylinders on a twin turbo and engine ran fine and did not smoke or use oil, it was a genuinely worn engine nothing more, nothing broken unlike your red one, given that no 6 is reading 0 really negates any gauge inaccuracy to be honest, a leak down test would help narrow it down to rings / cylinder or valves though, either way its a strip down job.

 

Jeff

 

cool thanks jeff. It does smoke when at idle, but not when under power. Im not driving it at the moment though for obvious reasons! Its not using oil, however we think it might be using water. After warming it up for the compression test it took another 1/5 litre of water in the rad, but its not dripping on to the floor at all. Is that a head gasket on the way out?

You are testing with the throttle bodies wide open arnt you:whistling:

If he has done it correctly the balance bar should still be off and that wouldn't make a difference. If...:shuriken:

Yes I am. I'm going to borrow a better one from a mechanic and do it all again. Hopefully its my gauge being annoying and cheap

 

Not one of those ones in the red case? I got a leak down tester from eBay like that, the gauges failed on first use.

throttles were wide open, balance bar was off, engine was warm. i followed the walkthrough on here. only thing i didnt do was wet the cylinders with oil, but i read that was something to try after...

Yeah that's to test for ring failure in the event of a low reading. My money is on a dodgy gauge. But as Jeff says it does indicate an issue regardless.

Ok so yesterday I did another compression test with a mechanic mates tester (british made, excellent quality etc..) and these were the results:

 

Cylinder 1 = 155 (drivers side front)

Cylinder 2 = 150 (drivers side middle)

Cylinder 3 = 145 (drivers side back - closest to cabin)

Cylinder 4 = 120 (pass side front)

Cylinder 5 = 100 (pass side middle)

Cylinder 6 = 115 (pass side back)

 

They are better than the last test, but the right bank still has a problem. It doesnt seem to be using oil, but while I was working on my black nissan and wifes celica yesterday, we left the red one running away for a couple of hours, It did seem to use a bit of water. we were able to add more water into the system a couple of times. Total added was less than a coke can though. It smoked the whole time (doesnt smoke when you rev it) and seems to jump from 5 to 6 and back to 5 cylinders quite a bit. I played with the coil packs found that its Cylinder 6 (pass side back) that was not always firing...

 

Im not sure what to do now? Im guessing the engine needs a strip down to find out why the low compression and why its not firing?

The thing that strikes me there, your numbers drop in order. The battery was fully charged yeah?

 

It's odd that the whole bank is low. As you say head gasket is possible, however I'd expect to see it leaking from one cylinder to another not between all three. Do you know any of this cars history? Has it had a cam belt change for example, potentially one of the cams is out of line causing this issue. It is also possible the heads warped etc. further diagnostics are required. My first move would be to put the engine at number 1 TDC and count the teeth on the belt with the covers off. Even if it's just the teeth at the top, save you removing the belts and water pipes.

 

Btw the cylinder order goes;

5-6

3-4

1-2

As you look at it. So the right bank is actually cylinders 2,4,6. Just to save confusion when your doing research.

The battery was fully charged. I don't know the history of the car, but ill do what you suggested with the timing belt. Also cheers for the heads up on the cylinder numbers!

Sounds like either a head gasket or can belt. Quite possibly the latter but all seem a bit low anyway.

When was the cam belt done last?

I have looked through the small amount of paperwork I was given with the car and cant find anything suggesting when the timing belt was done. No sticker on the car either. How hard is it to do? Does the engine need to be pulled? same for all the gaskets? Can everything be done with the engine in place?