Suzuki Club UK

Ok so finally got round to buying a compression tester and doing a compression test. Results below.
Measured in PSI.
WIDE open throttle.




After some further testing it appears as though my budget compression tester underreads by around 60psi.

Meaning my results are:
1 = 160psi
2 = 160psi
3 = 150psi
4 = 160psi

From what i've read this is ok for an engine with around 80,000miles on it.

Where to go next?
TPS?
Exhaust leak?
Lambda?
ECU?

A leak from the exhaust manifold will throw the O2 sensor reading off and cause it to run rich, that is well worth investigating, a new O2 sensor would be a good investment too.
How did you determine that your compression tester was out by 60psi?

Rhinoman wrote:A leak from the exhaust manifold will throw the O2 sensor reading off and cause it to run rich, that is well worth investigating, a new O2 sensor would be a good investment too.
How did you determine that your compression tester was out by 60psi?

Rhino. I used my air compressor with a high quality pressure gauge. Connected both gauges to the compressor and ran it up through various pressures.

I will order a new lambda sensor. Would a leak from the exhaust manifold cause issues like this?

160 is low but ok, my 410 engine is 175 on all 4. And it's done a lot more miles!

Changed lambda tonight. Seemed to make a slight improvement.

Think the next step is to seal the exhaust leak from manifold. And to peform the TPS test and adjustment.

After that I am out of ideas.