Low Compression - Cylinder 4
 

hi, I'm after some thoughts and advice about my 2006 Hawkeye WRX 2.5

At 100,000miles it developed a misfire, MIL light (P0304) and high oil consumption. Cyl 4 spark plug was oily. So off it went to Zi Motorsport, Wrexham for a rebuild.

I wasn't fully happy with it when it came back (slight wobble at idle) and a further couple of MIL incidents (P0304) - but no obvious cause. Same code after I swapped the coil and plugs between 2 and 4. But no codes for the past few months.

They were a bit vague about what was wrong. Rings and bearings replaced and valves lapped in as part of the rebuild.

Now, 5000 miles after coming back, I have a full misfire on no.4 (P0304), oil consumption is not excessive, no. 4 plug smelt of fuel when removed. A cold compression test shows 100psi on 3 cylinders, but no.4 is down at about 20psi

Zi don't appeared interested and are suggesting perhaps an ignition or injector issue has caused the problem. I would thought that would have be obvious when they opened it up i.e signs of lean running/detonation or bore washing.

So now I'm stuck looking at another rebuild (possibly just one of the heads) assuming its a valve rather than a piston problem. I don't feel inclined to use Zi again, although I can't prove they did anything wrong with the rebuild.

Any thoughts of a good place to take it somewhere in the sussex/surrey/kent area?

Any idea of the likely cause - valve, spring, tappets....

Slowboy racing at brands hatch. Been using them for a long time.

Sorry to say but you should have not accepted it back if it wasn't right and been straight back onto them.

do you know what components went into the build?

Thanks for the slow boy recommendation, I hadn't come across that name previously.

yes, I regret not doing more when I got I back and when the light reappeared. But it did seem generally OK and nothing these past months. Things are further complicated by the distance involved to Wrexham.

Did you pay via credit card ?
You may have some recourse that way.

Paid by bank transfer :-(

Second slowboy. Just had my secondary air pump taken off and mapped out. Going back in may for a remap

Secondary air, Yes my valves failed so I had them replaced, then the motor failed, but got it rebuilt with new bearings. Removing it all and switching of the diagnostics would seem to have been a better bet

Andy Williams - Williams motor sport built my 2.35 and is Based near Queensferry North Wales

Use best; Finch motorsport Northampton

☝️☝️☝️☝️☝️ what he said☝️☝️☝️☝️☝️

Something cant be right, I have a 2007 wrx 2.5 and my compression test ive just done was 158,158,148,146 and its on 120k those are really low numbers.

Yep, my 2007 wrx hawk 2.5 mid 140-mid150 on all with 105k on it, warm engine when tested

Any other recommendations in the Kent/Sussex/Surrey/Hampshire area? Slow Boy has gone quiet on me after saying he could take the car in a few weeks ago

East Kent Subaru. Richard Nicholls is spot on. He won't mess you around!

An Update. Rich Nicholls at East Kent Subaru sorted it for me - thanks for the recommendation Kandaris. He found a burnt out exhaust valve on cylinder 4. He suspected that Zi didn't lap it back in properly, so now the engine is running well

However, I'm now experiencing another problem - clutch release bearing noise.

Zi changed the clutch during the rebuild at 100k miles (removed the original one). At 105k miles when the engine was acting up, the clutch release bearing also started making a noise, so it was replaced at the second rebuild by EKS. Now only 1k later, the noise is coming back - so it's gone back to EKS for another investigation. This time he is looking at the clutch, the bearing and the fork. Any other ideas why this could be happening?

Yes. You let zi touch your car. They are complete cowboys. I would not even let them wash mine. I found out that my car had been mapped by them before i had it. Got a map check and it was a bag of ****e running lean, getting det and not boosting properly. All good now. They have recently been taken to court for selling an evo that was mostly rust and should not have been on the road. Im from wrexham there was a big thing in local paper about them and traiding standards (i think)were tellin any unhappy customers to contact them. Google them you will see

Indeed, I'm using Zi.

Selling a car like this doesn't suggest a professional service https://news.wrexham.gov.uk/car-buye...nd-in-vehicle/

You found it then. That was probably one of there better cars. They have had 5 hawk sti's for sale for nearly a year and they are all complete dogs. As for remaps dont get me started
Get on to trading standards about the work the did on your engine the fact that it only lasted 5k miles speaks for its self. hardly quality workman ship.
Did they give you any kind of warranty off them for the work the did .