Where do cossie ISCV inputs come from?
Thread Starter
Joined: Jul 2003
Posts: 8,293
Likes: 78
From: Aberdeen
Where do cossie ISCV inputs come from?
I have an issue with my idle speed that I believe is related to the signal the ISCV is recieving rather than the valve being faulty, with the valve being disconnected and the car heated up it idles as normal, with the plug connected to the valve it idles between 1500-2000 rpm, so that would say to me that it is being "told" to do this, when in fact it doesn't need to, so my question is, what governs the operation of the valve?
I see from the diagrams that it has the common black/red wire or positive +12V supply and then another wire wich apperars to be connected to the TPS, like a swithed earth or signal, i think this is where the problem is, but cant really go any further than this.
I see from the diagrams that it has the common black/red wire or positive +12V supply and then another wire wich apperars to be connected to the TPS, like a swithed earth or signal, i think this is where the problem is, but cant really go any further than this.
Last edited by rog; Aug 23, 2011 at 09:49 AM.
Thread Starter
Joined: Jul 2003
Posts: 8,293
Likes: 78
From: Aberdeen
I'm sure I have an issue with my TPS wiring so that would tie in with what you're saying, I am going to replace the TPS connector and section of loom for the TPS, as I have already swapped the actual sensor and it's made no difference.
It's mainly throttle and temperature related.
You are correct, clearly it's being told to open. Check the TPS output first, as yours is 4x4 the output should INCREASE with throttle. You should also be seeing the same voltage at the ECU as you are at the actual sensor connector itself with it disconnected, and it should do as I describe above if there is a difference you could have high resistance somewhere in the line etc.
Martin
You are correct, clearly it's being told to open. Check the TPS output first, as yours is 4x4 the output should INCREASE with throttle. You should also be seeing the same voltage at the ECU as you are at the actual sensor connector itself with it disconnected, and it should do as I describe above if there is a difference you could have high resistance somewhere in the line etc.
Martin
Thread Starter
Joined: Jul 2003
Posts: 8,293
Likes: 78
From: Aberdeen
Cheers, I know the temp input is ok or it should be, new sensors and the SECS shows it to be good also, but alot of fluctuation on the rpm which led me to the problem initially, but now it seems to have gotten worse lately, I will replace the TPS wiring and see if that cures it.
Thread Starter
Joined: Jul 2003
Posts: 8,293
Likes: 78
From: Aberdeen
Update, I replaced the wiring and TPS sensor loom plug last night and it has a marked improvement, however now seems to idle at 1500rpm when warm, and 900 with it disconnected, next plan is to check the TPS voltage and see if it needs adjusted since I technically set it before when the wiring was dodgy.
Thread
Thread Starter
Forum
Replies
Last Post
DixieTheKid
Ford Sierra/Sapphire/RS500 Cosworth
11
Jun 6, 2020 11:20 AM
Russ Payne
Ford Sierra/Sapphire/RS500 Cosworth
1
Sep 25, 2015 08:29 PM