Thread: Advice on Hard Cold Start

Ok, I'm at wits end with this issue and I'm running out of things to try to fix it....

Car = 92 Sentra SE-R, all pretty much stock as far as the motor goes.

Problem = Car long cranks on cold/cool start (the colder the longer). Most of the time it will just keep cranking until I push the gas pedal down. When I do push the gas pedal its struggles a short time to finally starting. Once started it runs perfectly fine. Restarts seem to be fine as well. I have no other symptoms but the cold start issue. It Runs perfectly fine.

A Little Story of Issue = Car has been sitting since about November-ish over winter and such since i live in the North East. When the car was parked this issue did not exist. It only started when I woke it up this Spring and has been doing it since.

Things Attempted and/or Less Than 2 Years Old =
Things in Blue were done while car was in fine working order prior to waking it up this Spring, Things in Green were done this season already while troubleshooting.
NGK Plug Wires
NGK Laser Plat Plugs
Fuel Filter
Intake/MAF Cleaned
IACV / AAC Cleaned
Stabil for Gas Tank over Winter Slumber
MAF / IACV / AAC recleaned
Throttle Body Cleaned
Fuel Rail Pulled to check for Leaking from O-Rings (None)
All Injectors firing properly
Fuel Pressure Gauge Installed After the Filter Showing 3 Bar Pressure and Holding for almost about 2 hours after turning off engine
TPS / MAF showing correct voltages
Stock FPR Tested working fine
Water Temp Sensor reading proper resistance
All the EGR shit removed testing for Vacuum Leaks (None)
I've put a couple full tanks of gas through her so it's not old gas
ECU Swapped (No Change)


I will update this as I continue troubleshooting, below are some videos. The 2 in the day time were done one right after another. As you can see the more I try to start the closer it gets to firing up. The video at night I added a shot of Consult to see some of the sensor parameters. I also say "Gas" the moment I hit the gas pedal so you can see the effect it has on getting it started.








I'm losing my mind trying to figure this out. My next thing is to borrow an IACV and AAC off a friend to test and see if theres any effect changing those.

is your wideband accurate during the start up process? It is ready very rich 10.x. By you opening the throttle you are adding more air, therefore making the mixture more lean.

Potential causes;
-There is a cold idle mechanism on the de near the passanger side of the intake manifold. Not sure how it works but it may have something to do with the issue
-The IACV might not be opening enough
-Your injectors might be starting to "stick"

Check the distributor, mine did something similar and it ended up being my distributor was falling apart

Like D-Unit said ^^ I have had injectors make the low idle really rough before. The IAC is a little harder to check unless you have a spare laying around to test the difference. As for the distributor failing, I have had 2x go bad but both times it was a no start situation until I replaced them. You might check your fuel pressure and make sure the pump and regulator are doing their job.

I Just put in the wideband in yesterday (the electronics) the bung on my 2ndary interferes with the stabilizer bar on the linkage so i might just use the hole for the AIV on the primary for now to get some kinda reading to see whats happening, but as of now I dont have the wideband sensor in the exhaust. I assume theres no way to really check the injectors sticking unless I had them removed and flow tested? Hate to blindly replace all 4 if they are ok.


As far as it looks the distributor is fine, I suppose that could be the next item on the list to swap and see if it helps. I mean i can get it started adding air so I assumed my spark/ignition was ok. Also warm restarts are fine....



Idle is perfectly fine after when it starts (and when i warm start it), no change from when i didnt have this starting issue. I am grabbing the IACV / AAC (top and the one under the intake mani) off a friend to swap on a try to see if there is a change. That's my next thing on the list. Fuel pressure (noted above) is almost around 40/43 (3 bar) every time. Pump primes everytime and hold pressure after turning car off for a bit. Also I mentioned i had tested the regulator vacuum. No smell of gas in the Vac hose to it and pressure jumps when I remove the vacuum hose like it should.

If you have a scan tool or anything to look at data def check the ect and see what temp it's saying that will def make a hard start/ cold start condition

As noted above, I removed the temp sensor and tested the resistance. I was getting around 2.0 resistance at ambient temps. I put it in 68 degree water and was getting about 2.4 ohms, which FSM says you should see between 2.1-2.9 ohms at 68 degrees, so I think my temp sensor is dead nuts accurate. Also fans kick on and stuff when its warmed up as usually...

The way it's not starting up sounds like a spark issue. Ever accidentally try to start your car with the spark plug wires disconnected? It sounds like that to me

But it does start up when I push the gas and deliver more air (i assume is whats happening). I can also start it after I attempt to start it a bunch of times it will eventually, real weak, but start. Then restart (when warm-ish) but work everytime......if it was the ignition why would i be perfectly fine anytime other than when the car is cold?

Good question. I'd like to see what would happen if the motor was cold and you push started it by popping the clutch.

I have a video of my start up problem when it was the distributor, I'll look for it now