Hunting on idle and smoking when up to temp

[JEBB4]

So another week another issue with the Lude..

So I swapped the injectors and she runs good on the VTEC ECU now but when fully up to temp she is hunting on idle and smoking like it's over fuelling...

I have had to put the h23 coolant sensor in as the original h22 one broke when moving the engine

Is there a difference in the coolant sensors between h22 and h23?

I'm also running the FITV valve off the h23 as I swapped the entire throttle body to eliminate an air leak causing the same hunting issue on idle which was fixed while using the h23 p14 ECU but has now returned with the h22 p13 ECU..

Both the coolant sensor and the FITV valve worked fine on the h23, is there a difference between h23 and h22 on either part?

It feels as if it's a fuelling issue related to coolant temp as it starts to surge and smoke when cruiseing at full temp...

Any help or ideas on this muchly appreciated guys, just want the thing to run properly now

@Drax I remember you had a similar issue with yours when I met you, did you fix it?

[wurlycorner]

Are you sure the coolant is properly bled and not drawing in air from somewhere?

[JEBB4]

Are you sure the coolant is properly bled and not drawing in air from somewhere?

Yeah im pretty sure there's no air locks in the coolant system unless there's a small one at the FITV valve

If so how would I get it out? It's a possibility as that section is a small series of pipes and may not budge easily if there is air in there, but it's been driven for a week or so like this and I'd of thought it would be out by now..

I have also had ago at checking for air leaks around the injectors and inlet by spraying brake cleaner around with no positive signs of an air leak..

[NafemanNathan]

If there was a chance of lots of little air pockets in the cooling system they might not have been large enough to really cause any effect before, but they could have bunched up together by now, creating one larger air pocket that would be causing the engine to surge when up to temp.

Park the lude facing up a hill. Remove the radiator cap and rig up the top half of an old Coca-Cola bottle (sealed around the radiator neck). Then let the engine heat up. Give both the rad hoses a good old squeeze throughout. That should dislodge any trapped wind.

[JEBB4]

If there was a chance of lots of little air pockets in the cooling system they might not have been large enough to really cause any effect before, but they could have bunched up together by now, creating one larger air pocket that would be causing the engine to surge when up to temp.

Park the lude facing up a hill. Remove the radiator cap and rig up the top half of an old Coca-Cola bottle (sealed around the radiator neck). Then let the engine heat up. Give both the rad hoses a good old squeeze throughout. That should dislodge any trapped wind.

Ahh I know what you're getting at Nafe, we have a proper coolant funnel for that exact job at work but I didn't have time to use it when I last filled the coolant..

[Drax]

My hunting issues were 2 broken fitv's and 2 broken intake manifold gaskets ... Yes, 4 times I had hunting issues

[firstlude]

i had this very issue when i first started up my h23 after the head rebuild, was fine till it warmed up them hunting like pig , persistence in topping up and bleeding the cooling system fixed it, on the h23 there is a bleed screw in the alloy coolant pipework , i thought it must be trapped wind as the amount of coolant i put in was no where near what its capacity was , once bleed running sweet as

[JEBB4]

My hunting issues were 2 broken fitv's and 2 broken intake manifold gaskets ... Yes, 4 times I had hunting issues

Wows I bet that was a total annoyance, but your persistence payed off!

i had this very issue when i first started up my h23 after the head rebuild, was fine till it warmed up them hunting like pig , persistence in topping up and bleeding the cooling system fixed it, on the h23 there is a bleed screw in the alloy coolant pipework , i thought it must be trapped wind as the amount of coolant i put in was no where near what its capacity was , once bleed running sweet as

Ahh that's quite interesting to hear, I will definitely be trying to flush the coolant system properly first... Cheers.

The only thing that is throwing me is that it only started since I've swapped the injectors and ECU

[JEBB4]

This may solve all my issues

https://www.ebay.com.au/itm/151293461946

[JEBB4]

Little update on this..

So me and my bro had a look, we tested the coolant sensor, started at around .600 ohms but wasn't completely cold, then went up to aver .900 ohms when up to temp.. Couldn't find the correct specs on the net for this but we think it's working fine..
Next we took the PCV valve out and clamped the pipe letting the engine breath to atmosphere and it stopped hunting, great we thought it must be the PCV but I swapped that and coupled it back up with a new hose for it and the faults still there..
So it seems to be an air leak of some sort, it's just getting a slight bit too much air from somewhere..

Any ideas shout

I do have a small exhaust leak by the manifold somewhere but I am in doubt that this could effect the o2 sensor that much but then it only takes the PCV pipe to be blanked to allow it to idle properly..

I think I will try fixing the exhaust leak next just to eliminate that, luckily my stainless manifold arrived today