# z31 wont hold idle



## thatkid105 (Dec 3, 2010)

So my 88 300zx n/a wont hold a idle when then engines cold, i pulled the codes and got the fuel temp, cylinder head temp, tps, i fixed all of them and the problem didnt go away. no im getting the idle switch what could be the problem with that, i wasnt getting that until i fixed everything else. once the car runs for a little while it runs fine and will idle at about 1300 rpm 9 ( i set it high so it stay running) but when its cold it will surge between 400-900 rpms for a minute or so then shut off, any help would be great. thanks.


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## CoorsZ31 (May 16, 2010)

Start by checking ALL of your vacuum lines. Will it start back up after it dies? If so, it may be the IACV valve itself. I would take it off and clean it out really well, or maybe replace it.


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## thatkid105 (Dec 3, 2010)

I will do that next week and let you know the results, also does anyone know where the cold start injector is, i have alldatapro and it will not give me the location of said item.


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## CoorsZ31 (May 16, 2010)

The main thing dealing with cold starts is going to be your chts. The fuel temperature sensor plays a minor role. If your chts is bad your going to kill your battery 90% of the time on cold starts.


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## thatkid105 (Dec 3, 2010)

so i cleaned everything, including the throttle body and maf and not one little change, plus they weren't really dirty in the slightest bit, now im starting to think my egr is going out, i looked at my haynes and it said to push the bottom of the egr and it should spring back down, is it talking about way underneath under where the exhaust line attaches to it? if so i pressed it and it will not move, also, how much pressure is suppose to be going into the egr from the vacuum? Im only getting the slightest vacuum from the line, could there be a problem with the pump also?


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## thatkid105 (Dec 3, 2010)

*please help*

Heres a youtube link to my car issue. you cant hear it but it also back fires in either in either the intake or manifold, and it does this until the car is warm, then it runs fine but if i leave it alone and it cools back down i have to do it all over again




[URL="http: :waving:


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## 87z31 (Jun 30, 2009)

That's the same problem I have on my car. I thought it was because I converted my car from an NA to a turbo. I thought the turbo was giving out. Have you had any luck because I too have replaced the fuel filter, chts, fuel regulator, cleaned and replaced aiv on the plenum. Checked vacuum lines and no leaks found yet. What else can we be missing. What parts help with the coldstart that we have not checked yet?


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## 87z31 (Jun 30, 2009)

Ok so yesterday I pulled off the tps and saw that it was all covered in corrosion. I cleaned it right up and put it back together and the car started fine. No more cold idle problems. It is holding strong at 1300 but I still have to tweak it but the bright side is I fixed the idle problem with something as simple as cleaning the tps connector. Hope this helps someone


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