kyleag89

Hello everyone I recently just purchased my first Nissan ever. It is a 96 maxima GLE V6 automatic. My problem is that it takes 5-8 cranks to start when engine is cold. Sometimes I have to pump the gas pedal to get it running even though I shouldn't have to with a FI engine. Once the engine is warm the car starts perfectly. I have a Haynes service book and have checked everything in the troubleshooting section on cold starts. Here is what I have done:

1- cleaned IACV and checked with meter.
2- replaced CTS with new one and checked with meter anyway at diff. temps and is good.
3- checked air temp sensor with meter= good
4- checked MAF sensor and it was bad according to meter so I replaced it with one from junk yard that checked good with meter. I thought for sure this would fix the problem but NOPE!

So as you can see I have checked everything I know of that can cause a hard cold start and still have no idea whats wrong. My next idea is to clean the T.B but I have to order a new gasket first as no one has one in stock. Its also been 4 degrees here in MD the past week so a little too cold to be messing with my car for hours...

theWalkinator

Check the battery first, weak battery in cold morning usually could cause hard cold start problem, measure the voltage and report back, also check the battery terminals and ground.

CS_AR

Welcome to Maxima.org!

Another possibility is a failing Fuel Pressure Regulator (FPR) that allows fuel line pressure to drop when the engine has been sitting. If the FPR is failing, it will take the fuel pump a few seconds to pump up good fuel pressure when starting after the car has been sitting overnight.

Try turning on the ignition switch to the "on position" and listening for the fuel pump to pump up pressure before you hit the starter. If you cannot hear the fuel pump, try waiting a few seconds in the "on position" before hitting the starter.

Do you have a gauge for testing fuel pressure? A good way to rule out a low fuel pressure problem is to run a fuel line pressure test.

kyleag89

The battery is only 2 years old and is fine. I have about 12.6V with the engine off and close to 14V running. I cleaned the terminals even though they were fine, and added a new ground to the chassis(read somewhere on here that it was a good idea).

I have also already tried the fuel pump thing where I hear it run and let it stop than try to start and it made no difference. I even tried keying the ignition on and off three times to prime the system and didn't make any difference.

njmaxseltd

iTrader: (19)

Make sure the cold idle linkage and plunger is opening the throttle body slightly when the engine is cold. It's located down and to the left under the throttle body.

dwapenyi

iTrader: (3)

Yeah. The fuel pressure regulator. Bad cold starts are the main symptom of a tired FPR.

kyleag89

Thanks guys, I will check the FPR and see if there is any fuel in the vac. hose. If not I will find my fuel pressure gauge and check that. Now only if I could remember where it is...

JoshG

makes sense when you said u have to press on the gas sometimes to start it, fuel to start= has to be fuel related causing the problem.

kyleag89

Well yesterday I took the TB off and cleaned it and popped off the vac line to the FPR and all was dry. I haven't tried checking fuel pressure yet because I can't find a port to hook my gauge up.

dwapenyi

iTrader: (3)

If you've never replaced it before, that means the part is 19 years old. It's a moving part (diaphragm) that wears out over time. Just replace it.

kyleag89

I am trying to check anything I can first before throwing parts at it. Every damn sensor or part for these nissans are expensive and I can't afford to buy 10 things to fix one. From all the research I have done there is a handful of things that can cause a hard cold start. If I were rich I could buy all the new sensors for $1000 and maybe than it would start. All I know is I have checked everything I can think of and it still won't start properly. I'm beginning to think it may need a new ECU. Don't nissans have a lot of ECU issues? I know the sentras do...

CS_AR

Nope. Actually 4th gen ECUs are quite good. If the ECU was bad, the car would not start period.

When I cannot get OEM parts, usually because I make DIY car repairs on weekends, I use BWD/SMP Intermotor brand parts. I only use the Intermotor (top shelf) brand.

Are you familiar with www.RockAuto.com?

kyleag89

I just decided I would check for any stored ECU codes using the screw on the side. My CEL is NOT on but in diagnostic mode its showing a code 0304. I have a 96 so does that mean a misfire or a knock sensor? Also why isn't the light on for it?

dwapenyi

iTrader: (3)

Wow.

CMax03

iTrader: (3)

Check your water temp sensor.....circuit and ensure that you're getting 5 volts on 1 wire and should have a ground on the other wire (black).... make sure your contacts are clean as possible.

kyleag89

I already replaced the CTS with a new one and checked it anyways with a meter. That was the first thing I replaced/checked as well as checking and cleaning all my grounds. I also added a new heavy gauge ground wire from the NEG batt terminal to the frame.

Anyone help me out with my CEL code?

CS_AR

Knock Sensor.. Check this link out below..

http://vbxmaxima.8m.com/ecudecoder.html

A Knock Sensor code doesn't usually result in a cold hard to start condition.

There are two coolant sensors in the picture below. Which one did you replace? The small one on the left or the larger one on the right?



Here's a video on the ECTS.


Fuel Pressure Testing

Review Page 27 in the EC section of the FSM in the following link.

http://www.boredmder.com/FSMs/Nissan/Maxima/1996/EC.pdf

kyleag89

I replaced the larger of the two sensors.. I know the small one is only a sending unit for the gauge itself. The larger one is the one that talks to the ECU and gives temperature readings that effect the fuel/air ratio. I also checked the old one and the new one with my ohmeter just to make sure I didn't get a bad unit. I checked them at room temp. (70) and then ran them under hot water and the resistance went up accordingly.

So according to my haynes book the only other thing that it could be is the fuel system. I might have leaking or mal-funtioning injectors. My fuel pressure gauge has a crimped on screw adapter so in order for me to attach a "T" fitting I will have to go get some adapters from the hardware store. Why couldn't Nissan just have a standard fuel pressure port on the rail like all my other cars!?

CS_AR

That would have been way too easy...

We're seeing more injector o-ring failures occur these days. That's a good point to consider.

Are you noticing any unburned fuel smell from the exhaust?

kyleag89

I haven't noticed any strong fuel smells from the exhaust but I haven't really paid attention to it either. I will check this today and report my findings. Thanks for your help


CS AR would a bad TPS sensor cause my problems?

surban1

iTrader: (17)

been following this thread and have a question: even though the O-rings, pintle caps or too high fuel pressure caused by bad fpr may allow too much gas into cylinders for the ecu to adequately compensate for, wouldn't you still at least get an o2 sensor code for too rich? if you can "smell gas" out the exhaust, it seems like there should be a code for something??
thanks in advance for any insight.

CS_AR

Personally I didn't receive any codes with a leaking injector. Maybe one misfire code on one of the leaking cyls. A friend of mine lost a beautiful VH45DE due to hydro lock. It blew a hole through the side of his engine block from a leaking o-ring without warning


Sent from my Z998 using Maxima

kyleag89

Anyone have any input on a bad TPS sensor? When I check the TPS its ok but the wide open/closed throttle part of the sensor isn't working properly. Its supposed to have continuity with the throttle plate closed and open all the way and it only has continuity when open.

surban1

iTrader: (17)

I hear what you're saying but it just seems incredible that with all that extra gas (with probably a lot of it leaving the cylinder un-burned) that the o2 sensor wouldn't "pick it up" and throw some kind of code??? with so much excess gas, the o2 doesn't see the exhaust as rich?? I believe what you're saying but I just don't understand why no code when injector is leaking (or fpr causes too much gas)!

CS_AR

Someone else may have received O2 codes on failed injectors, but mine sure didn't. I think that may have been why the dealer couldn't figure out the issue while I paid them over $700 for a misdiagnosis. In my case the NTK O2 sensors were new. The injectors are below.



Check out the other links for recent examples of failed o-rings and symptoms.

As our cars approach 20 years in age, we are starting to see some new fuel delivery issues appear from rubber/plastic parts with age related breakdown. The good news is we haven't had failing injector coils like the Phase I injectors used by earlier Nissans with fuel injection.

https://maxima.org/forums/4th-genera...-age-what.html

https://maxima.org/forums/4th-genera...oded-99-a.html

Now the downstream side effect from too much unburned fuel was cooked/clogged catalytic converters. The cats were obstructing exhaust flow and making the car nearly impossible to start. To diagnose the clogged cat issue, I removed the O2 sensors (while leaving them connected to the ECU) so the engine could breathe. That allowed it to start more normally -- albeit with a miss on #5 from the injector flooding problem.

CS_AR

I found this link on testing the TPS. Maybe it will help.

http://easyautodiagnostics.com/nissa...sensor-tests-1

Here's a video for additional reference.