octanepwr

Hi

I have been doing the plugs on my car (noted one has as much as a 2mm gap), so I am surprised it runs sweet.

However it does idle very low revs when cold (however smooth and no issues). This isn't really an issue as I usually sit in the car at 1500rpm until it has warmed up. Previous owner said it was because it was only at the tuners one day and never got 'cold' so they did not adjust cold idle. When warm it idles at about 1100-1200rpm which is good for a streetported engine, not too high, not too low. I suspect the port has been extended a lot given how it sounds very lumpy.
I was concerned this low idle when cold on premix might foul the plugs, but aside from the gaps being off the plugs look perfect, but I have never let it cold idle without me holding the revs up so don't know! It would be nice to be able to confidently step away from the car when fully cold.

I believe all of the emissions crap has been removed. I assume the carbon canister is still there but yet to get under the car as my jack and stands are too big (for 4wds) so need to buy smaller ones. EGR/air pumps, idle air control valve are gone. There is a plug in beside the fast idle cam which is still plugged in (unlike the odd plug in the engine bay hanging unconnected/redundant) - one plug by the TB water hose and one by the wiper motor/igniter wiring.

It has a single turbo conversion and link G4 storm engine management, therefore I wonder if I actually need the plug in software to adjust this or if I can have a play with the fast idle cam. I can see that while my engine is cold the cam does not touch the other piece and the wax rod is fully in. I do need to check when warmed up if the wax rod actually comes out. I guess the wax rods do wear out too?
OR should the cold idle be adjusted elsewhere? When I play with the fast idle cam I do not see the throttle butterflys change so I wonder if it is even fully connected. Yes I need to remove this part of the manifold as only just got the main intake piece off this evening.
I have never tuned a car with a laptop before so interested to know it this is the approach or there is still hardware to play with to up the cold idle.

Maybe it is just the plugs? But I would certainly think this would effect warm idle too (which is fine). Off idle/any revs it runs perfectly.

Random double throttle question:
I read a thread where people said they removed the double throttle. I would think this unfeasible/not good in my setup stock pri /2200cc sec injectors but removing this would let you run the same pri/sec injectors?
Is this like doing what the n/a guys commonly do with IDAs (no controlled secondaries) as opposed to stock nikkis on carbed n/a engines (often people change them from vac to mech secondaries)?

I am reasonably mechanically minded (and keen) but haven't worked on car like this before so value any input.

Cheers

Rusty 13B

Hi there,

on the fast idle cam - this runs off the coolant temp, so are the coolant hoses to the throttle body still in place? If not - then no amount of fiddling with it will work. I think the software is your best bet. The link will have fuel compensation based on temp, but yes - it will need to be set up. You should be able to pull that idle down too.

Is the plug still on the idle air control valve on the rear of the TB? its a white 2 pin plug. If it is, you would then need to check if the link is able to control this - I am sure it does/is controlling the idle throttle this way. Many people clean this too as they do get clogged up.

The only other, 'manual' idle adjustment is the flathead screw.. on the 'face' of the throttle body, between the 2 lower lugs - you really have to get you head down to see it. The setting is in the FSM.

Double throttle - since you have the LINK it doesn't have the logic to run it, so I am assuming its 'wired' to the open the butterflies fully. It should be - if not, do that!

Hope thats some help - but yes - in these days of laptop tuning, one does need the software to support the ECU, so either you need to get PC Link or just take the car back to a tuner.

All the best. Rusty

octanepwr

Hey Rusty

TB coolant hose still there - I am getting fittings from ENZED to tap a water temp gauge sender into this.

Idle air control valve is completely blanked - no plug either.

There is a plug by the fast idle cam which is connected so I might have a go with adjusting this.

I will check out this screw you mention and maybe have a play.
Will also remove the rest of the manifold and try see what is factory and what has changed, just FMI more than anything.

Yep, double throttle works sweet. Was just curious about people removing it but not relevant to my application.

I wonder if I can find the link software somewhere on the net

Cheers

Rusty 13B

Hi again,

Ah yes - the joys of a new engine/ ecu!

I really think adjusting the cold idle using the 'cam' is too crude. The LINK will have the ability to do cold idle based on inlet air temp/ coolant temp - so I would park that idea and get it properly sorted.

Plug by fast idle cam - is this grey with 4 wires? Thats the throttle position sensor. I don't think playing with that will achieve anything, bar upsetting the existing tune, which is based on the current voltage readout from the TPS as it sweeps through to WOT.

Double throttle - I am curious how this would work, as the stock ECU control it and yours is long gone! Hence it must be wired open - OR the plates may have been removed. Have a look in through the TB inlet to see with a torch.

Software - you should enquire with LINK and see what the cost is. I think that you will find this a useful addition, and may even have extra features will be useful for you in the future. Software is on the LINK website.....not sure if its free...

PCLink Download — Link Engine Management Systems - plug-in & wire-in aftermarket ECU's


All the best, Rusty

Rusty 13B

I can confirm the software is free - downloaded it, and opened the rx7 series 7 base map! It does have the enrichment based on air/coolant temp. You just need a cable to go from you ECU to a laptop.

All the best - Rusty

octanepwr

Scrap what I said about the double throttle - I was confused and now that I actually know what it is it is totally gone - there is only one set of butterflies.

I think I will try the fast idle cam adjustment - assuming it is unlikely to cause me any issues other than adjusting cold idle - it seems like it won't? I can see a number of ways to potentially adjust idle but most of them I think would effect it while hot and cold, and I want to effect cold only.

1) Fast idle cam - cold effect only. It seems turning screw B in opens the throttle some more for cold idle. I will have a play once I get everything back on the car and can see the effects of both screws.

2) The flathead 'bypass' type screw. I think this would effect hot and cold idle so I think I will not touch it given hot is fine. Currently it appears to be screwed the entire way in.

3) A type of throttle stop screw below B of the fast idle cam. Currently this is not touching the fast idle cam part B. I guess your point is also some of these adjustments (number 3 and 4 in particular) would effect the TPS readout permanently which is probably not desirable.

4) This would be similar to 3 above if I adjusted the stop where the throttle cable comes in near that dashpot- hot and cold effected.

I am used to simple bike carbs where for cold start obviously the choke blocks the air intake to richen the mixture and increase the idle. Here the fast idle cam is just like turning the throttle stop up a bit when cold because the ECU controls the fuel, as opposed to 'less air when cold' i.e. choking the intake to get a richer mixture with the same fuel amount to get the revs up when cold. It seems the link ECU is currently not compensating for being cold i.e. making it richer, which as you say is the real problem. If I can get it to cold idle higher though that is good enough as essentially the fast idle when setup will replace my foot for 5-10mins.

Thanks

octanepwr

Oh tempting. I will have to buy a serial cable and have a look. I would not want to screw up the tune though haha!

octanepwr

Ah good to see it is USB actually

Rusty 13B

Your example of your bike is spot on - we can achieve the same through the ECU set up, but, its just a lot more sophisticated!

I would open your engines file when you get it connected and compare it to the series 7 base map from link.
Its under 'fuel'>'post start enrichment'.

Oh SAVE your base (current) map as an original, the open again and re-name the file (put a date as its always useful to know what old and new).

Always important to have the original file at hand should something occur.

Enjoy - Rusty