10 replies to this topic

[HafMan]

Make: Rover
Model: Mini Cooper
Engine: 1275 MPI
Year: 1997

Evening All,

After finding out I have a misfire which I think is just a case of the HT leads being on in the wrong order is cured (touch wood) I did a compression test and these are the results.

Afters 5 cranks:

1st: 215psi
2nd:205psi
3rd:205psi
4th:210psi

I then checked how quickly compression was achieved with 1 crank to check for worn rings.

After 1 crank:

1st:130psi
2nd:130psi
3rd:80psi
4th:130psi

So am I right in thinking I have a worn ring on the 3rd piston?

HafMan

Edited by HafMan, 02 July 2012 - 09:59 PM.

[HafMan]

Well the mini is still cutting out when coming to a stop
So does anyone else have any ideas?
I'm going to be going to be checking for spark tomorrow.

[HafMan]

All cylinders do have spark. got bored so I went out tonight

[Sheikh Pip]

It could be rings, but it could also be the head gasket or a leaking inlet exhaust valve.

[HafMan]

Well I would lean towards a ring or valve beacause i'm not losing any coolant or having on heating issues etc associated with headgasket failure.

[bluedragon]

Squirt a bit of 30w oil into the #3 cylinder and repeat the test. If it's the rings, the oil should temporarily seal it and boost the compression. If it doesn't help, it's likely the valve.

[HafMan]

Squirt a bit of 30w oil into the #3 cylinder and repeat the test. If it's the rings, the oil should temporarily seal it and boost the compression. If it doesn't help, it's likely the valve.

Ill give it a wet test tomorrow. I'm thinking that it will improve on the first crank. Although i'm hoping its just the valve.

[xrocketengineer]

If it is a SPI and the car appears to be running right except that you depress the clutch and the engine dies, then the MAP sensor is not getting a good vacuum signal. Inspect the vacuum lines from the intake manifold to the fuel trap and ECU. With the engine idling disconnect the vacuum line at the ECU and verify it is sucking strongly.
Mine had turned into "chewing gum" and collapsed blocking the flow.

Edited by xrocketengineer, 02 July 2012 - 09:58 PM.

[HafMan]

If it is a SPI and the car appears to be running right except that you depress the clutch and the engine dies, then the MAP sensor is not getting a good vacuum signal. Inspect the vacuum lines from the intake manifold to the fuel trap and ECU. With the engine idling disconnect the vacuum line at the ECU and verify it is sucking strongly.
Mine had turned into "chewing gum" and collapsed blocking the flow.

Hi thanks for the response, I have just updated the opening post.
Its an MPI and it cut out when pressing the clutch in.

[xrocketengineer]

Well my experience with the MPI is next to zero. However, I do a lot of reading about how things work. In most multi point fuel injection systems, the idle speed is controlled by a separate valve and not the throttle. In the case of the MPI it is the Idle Control Air Valve (ICAV). Go to post #40 of the attached thread and open "Workshop_Manual__MPI.pdf". How it works is explained on page 115 of the PDF and how to replace it on page 128 of the same PDF.
http://www.theminifo...ps/page__st__30
I am not advocating its replacement. An inspection might point you in the right direction. Some people in this forum have complained that the plastic body of the valve has cracked.
Its up to you to figure out your next step in your troubleshooting.

Good Luck,

Ivan

[Ruckus]

Hi thanks for the response, I have just updated the opening post.
Its an MPI and it cut out when pressing the clutch in.

I think I might have a similar problem.

(This is with the car warmed up, clutch in or out)
If you give the throttle a tiny blip (on and off quickly revs not going over 1500 ish), what happens?

Mind bogs and drops the Rev's very low and 2 or 3 times out of 10, the ECU won't catch it at all the the engine will die completely?