[Mk2] [Turbo] MR2 turbo rebuild

[ringslayer]

Hi Guys,

just rebuilt my gen3 3sgte, but idles bad, it misfires on idle, although I get no codes from the ECU, checked for all connectors to be attached, etc. but can't seem to find it.

I also did a compression test, giving 9 bar or 135 psi on all four cylinders, but with the throttle body wide open it gives 3 bar more, almost 175 psi. Did someone else have a similar experience? IACV blocked?

Thanks!

[abovetherim]

First off you should be WOT when compression testing so 175 seems about right and if it is within 10 or so between cylinders then all good.

Start with simple things like vac leaks. Plug leads in right order. Coolant bled properly. TPS set correctly. All injector plugs on well. Vac lines in correct places with any valves the right way around? Fuel pressure good?

Is the ignition timing close to where it needs to be?

Are you positive the cam timing is correct, timing marks at 1 tdc line up with the crank pulley at 0 Deg?

[pbmr2]

first bet would be an air leak. anything from a cracked idle valve to duff intake gasket to injector O-rings etc.

is the vacuum piping at the rear of the intake all correctly plumbed?

mef sensor can be a git when they go, best search on how to test them as not had the pleasure yet.

is the vacuum hose for the FPR still good?
The one way valve for the brake booster hose still working?

good luck

[ringslayer]

ok, so further testing was done, but still couldn't get it right.

Compression is as follows after 5-6 cranks:

155, 160,160, 160 PSI

I cleaned out the IACV, which made my idle a lot better, but engine is shaking still slightly. Popping seems to have stopped

Pressure tested for boost leaks/ vacuum leaks all eliminated.

very small leak at downpipe, just in front of o2 sensor, could that be the cause?

[markstevieandmads]

my bet is timing is out

[ringslayer]

cam timing or ignition timing?

[androo007]

cam belt timing i'd have thought. check it hasnt slipped a tooth

[ringslayer]

I'll check it again this week. taking the rocker cover off to be 100% sure

[Ryan S]

Check ignition timing with a timing light first. It's easy to check and easy to adjust. Before you start taking off the rocker cover. Could just be a few degrees out.

[ringslayer]

checked everything

cam timing is dead on, as well as ignition timing

also pulled the ECU and checked for leaking capacitors, but looks as clean as a whistle

I'm out of ideas... Cylinder leakage test was also less than 20%, so that's ok.

Any other ideas?

[Ryan S]

HT leads on in the right order? You have compression and ignition and timing. That only leaves fuelling.

[ringslayer]

ok, I'll check the fuel pressure regulator. Something else to test or known to go wrong?

[ringslayer]

HT leads on the right order, all new ignition components;

I also seam to have a very small leak at the dp and turbo gasket, could this cause such issues? I will be changing the gasket this week...

[Ryan S]

HT leads on the right order, all new ignition components;

I also seam to have a very small leak at the dp and turbo gasket, could this cause such issues? I will be changing the gasket this week...

na i doubt that would cause this issue. Deffo worth checking fuel pressure. Did you replace the king lead? I know you said you've replaced everything but I've seen this be overlooked in the past on here and more often than not it has been the culprit. make sure the coil is earthed properly too. Possibly check the coil wires for continuity.

[ringslayer]

king lead was also replaced, I did notice the car running a lot better with the TPS sensor unplugged, however it then wouldn't idle below 1200 rpm. I did check the TPS a while ago and it was withing BGB specs...

pulling the plugs one by one made difference, so it's running on 4 cyl, albeit rough.