Do I buy another coil pack as my car vibrates?

[seals_nav]

My VTR is 1.6, Y reg (2001), MKIII...the last model.

I've posted on these forums in the past numerous times about my VTR vibrating, basically when i'm driving the car moves back and forth...sometimes its worse than other times, it happens randomly. When car is stationary it does the same as when driving BUT my rev pointer goes up and down as if the car is gasping for air, sometimes when this happens the car stalls but is rare, the rev pointer settles down sometimes then starts again.

A friend of my friends went in my car and said it could be the coil pack as its very common on the 1.4 engines so it probably is the coil pack on my car, is this what it is.

During 2 services and MOTs the problem has not been picked up, i've had this problem for over 1 year and 6 months, car engine runs fine...does not lose power so its not a misfire.

[Mr_P]

If it was the coilpack it would be missing. Sounds more sensor related to me though.

[seals_nav]

Should that have been picked up in the service or MOT? One thing to note...my engine diagnosis light comes up and when I had my service and it came up on the machine as 'Old CAT', my CAT was replaced with a new one and...same problem, the guy at the service did mention the coil pack, but he finally said to replace the CAT, but I never bothered going back as I was getting fed up.

[Liam_]

Try cleaning the MAP sensor on the front left hand side of the inlet manifold - has a connector heading to it.

Failing that, could be the lambda sensor (green connector), the ICV or coolant temperature sensor.

[seals_nav]

Try cleaning the MAP sensor on the front left hand side of the inlet manifold - has a connector heading to it.

Failing that, could be the lambda sensor (green connector), the ICV or coolant temperature sensor.

Here is a thread with the engine types, mine is the last one (number 3), if you could use the picture in paint and circle each area with a different colour and explain it a little it would be very helpful. Sorry...I have no idea where these parts are on my car as I have very little or no knowledge about car engines.

[seals_nav]

Oops I forgot the link...

http://www.saxperience.com/forum/showthread.php?t=87916

[seals_nav]

Btw...out of curiousity how would a sensor make the car vibrate like that? I thought it would be a mechanical problem.

[Liam_]

http://www.aslr97.dsl.pipex.com/numbers.jpg

1. MAP sensor, disconnect the cable, remove the bolt and give it a clean with WD40 or similar. I rekon this should sort it tbh.

2. Idle control valve, can sometimes cause idling issues. Unplug the connector, remove the torx screws which go into the back of the inlet manifold and give it a clean.

3. Coolant temp sensor, another culprit for idling issues. Will need a replacement if its broken.

4. Pre-CAT lambda sensor. Follow the wire back and lift the red tab on the connector to disconnect. 22mm spanner, penetrating oil and shock it out. Give it a clean up with a soft wire brush and solvent cleaner.

Try 1. and 4. If they don't improve it, there's the crank angle sensor on the front of the gearbox which can be cleaned up (no pics of that unfortunately). Then try 1. and 3. :y:

[seals_nav]

http://www.aslr97.dsl.pipex.com/numbers.jpg

1. MAP sensor, disconnect the cable, remove the bolt and give it a clean with WD40 or similar. I rekon this should sort it tbh.

2. Idle control valve, can sometimes cause idling issues. Unplug the connector, remove the torx screws which go into the back of the inlet manifold and give it a clean.

3. Coolant temp sensor, another culprit for idling issues. Will need a replacement if its broken.

4. Pre-CAT lambda sensor. Follow the wire back and lift the red tab on the connector to disconnect. 22mm spanner, penetrating oil and shock it out. Give it a clean up with a soft wire brush and solvent cleaner.

Try 1. and 4. If they don't improve it, there's the crank angle sensor on the front of the gearbox which can be cleaned up (no pics of that unfortunately). Then try 1. and 3. :y:

Thanks for that, that will help.

[seals_nav]

http://www.aslr97.dsl.pipex.com/numbers.jpg

1. MAP sensor, disconnect the cable, remove the bolt and give it a clean with WD40 or similar. I rekon this should sort it tbh.

2. Idle control valve, can sometimes cause idling issues. Unplug the connector, remove the torx screws which go into the back of the inlet manifold and give it a clean.

3. Coolant temp sensor, another culprit for idling issues. Will need a replacement if its broken.

4. Pre-CAT lambda sensor. Follow the wire back and lift the red tab on the connector to disconnect. 22mm spanner, penetrating oil and shock it out. Give it a clean up with a soft wire brush and solvent cleaner.

Try 1. and 4. If they don't improve it, there's the crank angle sensor on the front of the gearbox which can be cleaned up (no pics of that unfortunately). Then try 1. and 3. :y:

Right earlier I did No 1. MAP sensor, I cleaned it using something called 'Maintenance spray' as I had no WD40, put it back on and drove the car...seems better but i'm going to drive it around for longer and see if its okay as the problem is random and sometimes doesn't happen at a certain drive.

Now...tried to do No 2. BUT I can't seem to romove the 2 screws at the back, I have the correct piece to use but the tool won't get into such a small space.

No 3. & 4. I can't manage to untighten the bolts as I need a really big spanner, will have to get one if car isn't okay.

[seals_nav]

Right earlier I did No 1. MAP sensor, I cleaned it using something called 'Maintenance spray' as I had no WD40, put it back on and drove the car...seems better but i'm going to drive it around for longer and see if its okay as the problem is random and sometimes doesn't happen at a certain drive.

Now...tried to do No 2. BUT I can't seem to romove the 2 screws at the back, I have the correct piece to use but the tool won't get into such a small space.

No 3. & 4. I can't manage to untighten the bolts as I need a really big spanner, will have to get one if car isn't okay.

Right I have some more information:

After cleaning the MAP sensor I have drove my car over 40 miles, the car does not vibrate like it used to, before it used to vibrate alot while driving, now it does not. When stationary it used to also vibrate now I can feel like 10% of the vibrations but is not noticable, I only notice because obviously its my car and its there, before it used to vibrate 80% when stationary...this is just the scale of how bad it used to be and how it is now when stationary.

Another important thing after cleaning the MAP sensor, the car responds much better in 1st gear, also when the car is slowing down (i.e. when I brake) I can feel the car is pusing itself forward, before it never used to.

Another thing i've noticed is when i'm in 2nd gear or higher and the car is doing 5mph or less the car seems its going to stall, if I don't have my foot down on the clutch that is, before it never used to happen, I don't know if thats a good thing or a bad thing.

At higher speeds the car now seems to keep its speed much better than it used to, overall the response of the accelarator is improved. I am thinking of giving the sensor a better clean.

Overall the vibrating/juddering problem has virtually disappeared, it can only be felt when stationary but is so tiny only I can notice it because I know its still there.

[Mr_P]

Basically everything in your last post is normal. Sounds like it was your MAP sensor :y:

[seals_nav]

Basically everything in your last post is normal. Sounds like it was your MAP sensor :y:

I'm glad its fixed now, the car was so irritating to drive before...now its smooth and back to normal, thanks for the help.

[Liam_]

Hmm, at least its improved things for you! I can't really comment on vibrations as i'm poly bushed all round - I can feel every 'beat' of the engine through the wheel if that makes sense haha. If you have it up on the ramps, check the condition of the lower gearbox mount (they are rubber and can go soft over time). There's also a mount for the gearbox under the battery and one over by the ECU.

The MAP sensor measures the pressure in the inlet manifold, thus calculating the amount of fuel to inject. If it was particularly gunked up, then I guess the engine might not have been running as well as it should have.

[seals_nav]

Hmm, at least its improved things for you! I can't really comment on vibrations as i'm poly bushed all round - I can feel every 'beat' of the engine through the wheel if that makes sense haha. If you have it up on the ramps, check the condition of the lower gearbox mount (they are rubber and can go soft over time). There's also a mount for the gearbox under the battery and one over by the ECU.

The MAP sensor measures the pressure in the inlet manifold, thus calculating the amount of fuel to inject. If it was particularly gunked up, then I guess the engine might not have been running as well as it should have.

When I cleaned the MAP sensor some orange stuff was coming off it when I sprayed it, the sensor itself was orange, is it supposed to be that colour?

[Liam_]

Most likely oil mate - with the standard oil breather setup the throttle body, inlet etc. can get really gunked up.

Yeah, it's an orange component in the middle - looks a bit like a thermistor. I guess the smallest bit of crud on that small sensor is enough for it send dodgy readings to the ECU.