Couple of questions regarding rpm and knocking sound

[JAC]

I have a couple of questions for you experts.

I took the puma out on some abandoned back roads this morning, and gave it a little push.

If I remember correctly, I read that the VCT make the engine change at around 4200rpm, however, the car seems to change around 4000rpm in first to third, and at around 3500rpm in 4th and 5th. Is this normal? If not, could this be a timing issue that should be addressed when we change the cambelt?

Also, when the car idles, there seems to be a slight knocking sound in neutral, the only way I can describe this is that it sounds like a diesel (maybe that is exaggerated, but its the best explanation I can think of). This goes away as soon as the clutch is pressed. Any ideas?

Finally, and this only happens sometimes, but when coming to a stop in second, sometimes the cars rpm drop so much that it stalls. There is no juddering (I thought maybe it could be a clutch issue), it just sort of dies. It starts again no problem, and this doesn't seem to repeat itself on a regular basis. The normal tickover is at about 750rpm. Any ideas?

Thanks, as always!

 

[Wild E. Coyote]

The VCT on puma is of continuos type, not like Honda VTEC which uses two different cam profiles. And it is turning the cam in advance according to the driving conditions. It is not like switch; if you really want to find out how and when, hook up the forscan to the OBD socket and record it while driving and you will see how the cam advances.

The second simptom would be a sign of master clutch cylinder..

The third. I would first check the idle air valve which surely would benefit from cleaning. That is the valve which is letting the air to the engine at idling when is the butterfly fully closed. You will find it on the inlet maifold, right after the throttle module.

 

[JAC]

Thank you very much Mr. Coyote, that is mighty helpful!

For checking the VCT, I just want to find a Bluetooth OCD that I know will work on this model (I have failed with 2 so far).

For the rest, it is on the list, although below cambelt and brakes

 

[tuonokid]

Hi JAC
If you have a laptop you can use an ELM 327 plug in unit which is probably more reliable. Wild E Coyote got me into this and it cost me less than £7 and works brilliantly. You can also reset your Idle control valve to get rid of the engine stalling (unless it is dirty, or sticking).
Barry

 

[JAC]

Ok, I was thinking of picking up a USB version, but the Bluetooth is nice to leave plugged in and constantly monitor.

I will order the USB version discussed in the other thread (which I believe works well) and leave a laptop in the car (out of sight obviously) until I get it running at its best.

 

[JAC]

BTW, what software do you recommend for windows?

 

[tuonokid]

Hi JAC
I was just looking for a post from 748 (Paul) regarding the software as He's recently bought an ElM 327 which works with his laptop on Windows 8.1. I think if you have a look on the Forscan download page it tells you the software that it's suitable for.
Barry

 

[JAC]

I totally forgot about forscan!

I am so not used to having a Ford, the last Ford I owned was a Ford Sierra V6 (that was my first car), damn I miss that car sometimes.

 

[JAC]

I just orderd this: http://www.ebay.co.uk/itm/390665722455" onclick="window.open(this.href);return false;? ... 26_rdc%3D1

which was recommended in another thread as working on the '97 Puma.

 

[tuonokid]

Hi JAC
Yes that's the one I use and it seems reliable. I had a quick look on Forscan and it looks like all operating systems are catered for now.
Barry