A few questions after engine refit (V6)

[Salad-Dodger]

Since the refitting of my V6 back into the 190 I have only used it to commute to work last Thurs/Fri.

Today I thought it was time to give it a proper run. We went down to Headcorn (Kent) from Maidstone and the outside temperature was about 27 degrees so a good day to test for any overheating.
Running on open roads it ran about 88 degrees but climbed into the 90s as soon as we got into stationary traffic.

Using the on board temp reading I could see that in standing traffic the temp would rise to 100 and the fan would come on. It stayed on till the temp dropped to 95 and the fan switched off. As long as we were in standing traffic this process just repeats itself.

Now I know I have a two speed fan and I replaced the resistor when I did the engine job but as yet I haven't seen the other speed. Am I missing a slower speed here or a higher speed that I'm never lightly to see?
The only other thing is that the idle speed is only 500rpm. I'm going to start some research on this subject but for now, I was wondering if someone on here has any idea as to how I can increase it a bit. Some have said I'll need a T4 session to do this but but everything I had on my old engine was just swapped over to this one so I'm a bit puzzled as to why the idle is so low. I'm missing that Whoosh!! on start up if you know what I mean! Steve

[SD1too]

Am I missing a slower speed here or a higher speed that I'm never lightly to see?
Your slow speed seems to be working just fine. You might hear the fast speed when you use the air conditioning on a hot day.

... the idle speed is only 500rpm ... any idea as to how I can increase it a bit.
It's set by the ECM according to running conditions so I don't think that you can, even with T4. Are you relying on the car's instruments when you say it's 500 rpm?

Simon

[Salad-Dodger]

Thanks Simon.
I am indeed using the dash read out but only as the only evidence available! But it is quite a lot lower than it was with the other engine.
I may remove the TB and just have a look. There's no servicing as far as I can see. The butterfly is shut on the stop and the engine relies on the bi-pass for its air just like all the other engines today that use a bi-pass.
I know I'm going on about that "whoosh" when the engine is started. This happens on a lot of engines that use this bi-pass system. The thing that always crosses my mind is that when starting from cold its not a good time to be revving above 2k, but that's just me and way I think! I have a V8 in my XK8 and this does the same when it starts....Whoosh!!
This V6 almost dribbles into life. I'll get the TB off and report back. Meanwhile, I'll get in touch with a few Mechs that I know who used to work for the rover network to see what they have to say. Useful lot sometimes! Steve

[SD1too]

I am indeed using the dash read out but only as the only evidence available!
Mine doesn't indicate the expected idle speed either. I've also had a long standing problem with the idle speed occasionally 'hunting'. IACV service is on my list of things to do. ;)

Simon

[Salad-Dodger]

This is one of my pet-hates of these systems Simon, where it doesn't matter how much work you put in, you never get a nice regular idle. Can't remember when I last had one of those! And I have four cars!

One thing you can count on though. If the mixture deviates too much, it won't be long before that engine light comes on which will probably be down to the lambda sensor, due to too little or too much fuel.

This is a bit of a pain for the earlier cars as a great number of them aren't able to be plugged into an OBD2 scanner at home.

Being an old f**t I still rely on what I hear and not too much on the evidence of text or RPM readout. After all, you need to have it useable. You can bet that with the idle as low as it is, when I get the air-con re-gassed, it may just stall when the switch is pressed unless the ecu does something. I'll get that control valve off later in the week and get back on it. Steve

[Mike Noc]

If you really want a rock steady idle get a diesel. ;)

[Salad-Dodger]

No ta.....had enough of paraffin cars!!

[minimutly]

The reason you wont get a steady idle is because the ecu is cycling the mixture rich/lean, its to get the cat hot enough to work. Also the lambdas used in these old cars is a narrow band, and only works on a narrow band.
When its cold its smooth right? High, due to the ecu opening up the iac valv, but smooth nontheless.

[Salad-Dodger]

Yes, I see what you mean. When I first started it, I ran it for about 20 mins up and down the street till the engine light came on. The codes indicated a failed knock sensor, a multi-misfire and a post-cat sensor. I just changed the knock sensors and, as expected, the other codes went away. All down to the knock sensor. I've driven it about for a few days now and its more or less behaving itself apart from the idle which is at 500rpm. Its not the end of the world, but I'd prefer it was at 700. Steve