So I've been having the same running issue till the car starts warming up as a lot of other people. I had replaced the chts and tested the sub harness in the past with no change. I recently rebuilt the top of the motor since I had to pull a head off anyway to fix a snapped spark plug. In the process I deleted the idle controls and cold start valve after reading most people do it with no negative consequences except needing to hold their foot on the gas a minute or so while it warms up. Well now on the first cold start after the car cools off not only is the original issue there but I have a real hard time getting it started. It'll crank, backfire and stumble a few times then stall. Start stumble and backfire and miss a few times then will run like it used to till it starts warming up (with my foot on the gas to simulate the cold start valve of course) then once warm it runs the best it has since I bought it.

So I guess my question is can deleting the cold start valve make it that much harder to start or am I having another issue and where do you guys think I should be looking for it


i cant post urls but look up Z31 s*** cold start on youtube its a video of me trying to start it tonight after work

Welcome to NICO!

I deleted my cold start and idle circuit but I replaced the ecu with megasquirt, so I have cold start enrichments. On a stock ecu I'd leave the ide circuits in tact, they are pretty simple mechanically adjustable and not prone to failure. The TPS on these cars is also an on off switch, so you giving it pedal at start up might be triggering an accel enrichment while it's already adding a cold start enrichment, so you might be able to dial back the tps but I'd just put the iacv back on.

Thank you! As I was reading what you mentioned about the tps I realized after adjusting the throttle plate for the idle I never adjusted the tps to match to the car never thought it was at idle at all. I adjusted it and started the engine without touching the gas and it started right up then I hit it gas to give it more rpm till it warmed up a little. I'll know for sure in the morning if it definately worked. Though yesterday the time between lunch and the end of the day was long enough it was a little warmer today and may not have fully cooled back off. I may still put the cold start valve back in but I don't know when I'll have time. I appreciate the help

That definately fixed it thank you again