cold start issues!! **ISSUE HAS BEEN FIXED**UPDATE

[dsastr_clan]

Hello, I have a 1990 z32 NA, car has been converted to manual about 3 years ago, motor has been rebuilt, runs strong, rebuilt about 2 years ago. It is my daily driver. I treat her well, oil changed on time or when im bored and have nothing else to do. Maintenance has always been provided to her, I recently have been experiencing some issues that are really pissing me off!!!

The problem aroused this winter, i'm getting bad cold starts, the car cranks forever, takes a few cranks for her to come back. I always need to hit the gas pedal for her to fire up in the morning or 45 mins after she has stopped running, but it really depends on the weather. Some days when it isnt cold she starts right away.

this is what i have done so far to try to trouble shoot the issue:

replaced the temp sensor (the one with 2 wires)
replaced the fuel filter
put a brand new fuel pump
replaced battery terminals
replaced the fuel pump relay
replaced the FCU fuel control unit
replaced the PTU and deleted sub harness
replaced both catalytic converters
checked most of the wiring connectors and made sure there isnt corrosion.
checked for fuel leaks and air leaks.

none of these have changed any of the symptoms!!! once that the car fires up it runs super strong and idles fine! I cant think of anything else, im about to give up! do you guys have any ideas? please help

[nissanfreak12]

Have you checked for codes in the ECU?

A few things come to mind when having issues with cold starts;

Fuel pressure regulator
Fuel damper(still on the fence about this one)
Fuel injectors
Spark plugs
Test Coil Packs

Have you checked compression in the engine? How cold are we talking about when you have starting issues? What viscosity of oil do you have in the car?

[dsastr_clan]

Have you checked for codes in the ECU?

A few things come to mind when having issues with cold starts;

Fuel pressure regulator
Fuel damper(still on the fence about this one)
Fuel injectors
Spark plugs
Test Coil Packs

Have you checked compression in the engine? How cold are we talking about when you have starting issues? What viscosity of oil do you have in the car?

checked ohm and fuel injectors click with screw driver they are good.
forgot to mention that sparkplugs where replaced and gapped the coils work as well

how do i check the fuel pressure regulator ?

[nissanfreak12]

Hook up a fuel pressure gauge tester, run the car, you should be at 36psi(or very close to it +/-2psi). Unplug the vacuum line, it should jump up about 10 psi.

Leave the gauge hooked up, when you shut off your car, does the gauge drop dramatically? Or does it take a while to drop?

[t.mcginley.jr]

When you put the new coolant temp sensor in, did you put anything on the threads (like teflon or RTV)?? If so it will not read correctly.

[nissanfreak12]

He still never said he checked for codes.

Mr Jr, I always forget that. Did that to a CTS on my jeep, man what horrible mileage I got for a few weeks till a light bulb went off.

[dsastr_clan]

i havent checked the codes sir, i will get to it over the weekend, honestly i doubt the codes are gonna tell me what it is. the cars runs strong, idles smooth. Its just the stupid cold start thing. No teflon on the temp sensor either.
ill do the gas pressure test over the weekend too.

I did clean the throttle bodies and had to adjust the TPS to .45v, then realized that the throttle cable screws were set too high, so i adjusted that as well as the icva, this somewhat made it better but not sure till the car is fully cold. Will check back in the morning.

[dsastr_clan]

hello there, so i was out troubleshooting stuff in the Z, i was inspecting the fuel temperature sensor for corrosion and i started to smell gas fumes. i dont see any gas but i can smell it. Im posting a picture of the area where the gas smell came from, in the picture,I have just replaced the black hose, and the blue hose is thick silicon hose, my question is if you guys know about any other fuel hoses hat i cant see but that run around this area?

what do you guys think??

here is the pic:

[t.mcginley.jr]

One reason you're probably smelling fumes are because those are NOT fuel hose clamps. The ones you're using are cheap hose clamps that won't be able to get tight enough before they break. I do see one correct on in the top left of this pic. You need to be using these:

http://www.z1motorsports.com/imagemagic ... page=popup

Z1 sells them in pairs, or you can go to any u-pull-it/junkyard and grab a handful from any Nissan. Also, are you sure all of that hose is "fuel injection" hose and not just fuel hose. It needs to be rated at at least like 50 or 60 psi (most fuel injection hose is alot higher than this, but that's the bare minimum). Alot of parts places will just give you "fuel hose" which is only rated at like 10-20 psi.

If you still smell fuel after using the right clamps and/or hoses, it could be leaking fuel injectors.

[dsastr_clan]

One reason you're probably smelling fumes are because those are NOT fuel hose clamps. The ones you're using are cheap hose clamps that won't be able to get tight enough before they break. I do see one correct on in the top left of this pic. You need to be using these:

http://www.z1motorsports.com/imagemagic ... page=popup

Z1 sells them in pairs, or you can go to any u-pull-it/junkyard and grab a handful from any Nissan. Also, are you sure all of that hose is "fuel injection" hose and not just fuel hose. It needs to be rated at at least like 50 or 60 psi (most fuel injection hose is alot higher than this, but that's the bare minimum). Alot of parts places will just give you "fuel hose" which is only rated at like 10-20 psi.

If you still smell fuel after using the right clamps and/or hoses, it could be leaking fuel injectors.

do you think this could cause my cold start issues? i kinda feel that it may be because my fuel system gets depressurized when is cold...lmk what you guys think. I'm going to replace all hoses and refresh the clamps (with the fuel clamps) ive seen them at Napa, today after work.

it about 29 to 30 degrees where im at.

[dsastr_clan]

i noticed that the fuel dampener was dripping fuel from the vaccum hose when i pulled the balance off to check on the injector connections for the 20th time, not sure if it was supposed to do that, but i replaced the fuel dampener and the fuel pressure regulator and now the car fires right up!! and drives even better than before!! i just needed to give this update since it seems that a lot of people are having this issue on this winter, hope it helps!!

i have been having this issue since the begining of winter and nothing feels greater on earth's face right now!