rsfire

Hello, well I bought my 300zx turbo with a bad fuel pump, fpr, and one bad injector. I replaced all of those and it ran fine for close to a month, then a few days ago it started acting like it's starving for fuel or something again. When I start if from complete cold it takes idling of 15-20 min or so before I can drive it. If it's already warm it takes 1-10 min it seems. It starts up and idles fine, revs fine for about 10-20 sec, then the rev drops down and feels like it's not getting fuel. It still idles fine, but if i give it throttle it sits at 500 rpm or so and won't rev higher, it kinda backfires out the intake a bit too. Once it warms up it's good to go though, doesn't give me issues until I shut the car off and start it again.
Does anyone have any ideas what could cause this. I'm still getting good fuel pressure to the rail, and it runs just fine after it warms up, so doesn't seem like a bad fuel system or injectors. Maybe cts or thermostat? thanks

Flacster

Might be that your CAS is going bad or the CHTS.

rogerz

chts replace for sure or just test per the fsm but likely the culprit and not terribly expensive. done both on my 85T and 86T much improvement. put a fuel pressure gage in the sytem between the filter and the fuel ring to be sure your fpr is working correctly. what do you mean good pressure at the rail without a gage in there you can't tell squat. good is not a pressure. 30 psi is. check for vac leaks another common problem with an FI engine. do a search on using unlit propane torch to find them.

rsfire

Ok awesome, I'll look into the chts for sure, and check out the cas as well. If either of those are bad does it normally throw a code and show a check engine light? My car isn't showing any check engine lights.
And yes, I've got a fuel pressure gauge tapped in past the fuel filter, before the rail, I'm running 50 psi since I've got a high flow pump and looks like larger injectors, but not entirely sure.
What is the search with an unlit propane torch, I can't say I've heard of that test? Thanks for the advice!

rsfire

Ok, a bit of an update now. I replaced the CHTS, and so far no improvement. The sub-harness does look a little tattered by one end, but I checked it with my ohm meter and got no resistance, so it looks good. I guess my next step might be to look into the CAS, I'll look up to see if there is a way to test it, unless anyone here knows a good way too.
And I'll look up how to do that propane torch test rogerz, i read that too fast and didn't catch that I should look it up haha.
Does anyone else have any ideas that I can look into?

Flacster

Just replace ur dizzy.

rsfire

Ok i can give that a shot. Do you think it could be a bad dizzy, or does changing the dizzy change the cas too? I can't recall if the cas is in the dizzy or below it?

And kinda an update, I have changed the temp sensor and no better. It seemed better for a day or two then it started doing it again. It seems like when the car hasn't been started all day it sometimes will run normally and sometimes will cut out like that. But other than the sometimes it runs fine from completely cold, I have to let the car warm up completely, it won't run right until 30 seconds to a min after the temp is all the way warm. And even when it's hot, even if i just shut the car off and start it right back up, I still have to wait like 30 seconds before it will drive. And now I'm kinda thinking it's running too rich and flooding it out. It smells real rich when it's doing that, tho I don't have a wideband yet so I can't say for sure. But it would make sense if it's fueling for coldstart and it's too much fuel. I do have red-top injectors which from what I've heard are 370cc and my fuel pressure is at 50psi. Though it does seem to run better at 50 than it did at 37. And it looks like my ecu is stock from what I can tell.