SR20DET warm up problem...

[SRJesse]

Hey Guys,

I have been registerd to SilviaAustralia's website for a while. I

am in the USA and finally registered for this hoping that most

people would know similar problems. I recently completed a 1992 sr20det motor in my 1990 240sx.

Until now, everything has been fine. First the exhaust gasket

went bad, then the cat. There is also a problem when I start the

car when its not warmed up. If I press on the gas pedal it seems

to want to stall out on me, and will continue to do this unless I let

the car idle for about 3-5 minutes. Someone on the Australia site

said that it could be a dirty Air Flow Meter. I honestly have no

idea what that is, so any other suggestions would really help me

out. Thanks alot in advanced.

[Daunttless]

if I had to venture a guess I'd say the aussies were right. : ) MAFs are a common problem. : ) Good luck!

[SRJesse]

Can you please explain to me where the MAF is and how to clean it? Thanks alot

[1991240xs]

also could be a thermostat stuck wide open..that was the problem on my ka-

[chrispy]

hey where abouts in NJ are you from?

[SRJesse]

I am in southern NJ, you? I was talking about an SR20DET not a KA, so I am not sure if that would be the case. Thanks guys

[S13240]

Not to be an a**, but you installed an sr20 into your car and don't even know what and where the maf is?

[chrispy]

i live about 2 secs awat from philly.

[SRJesse]

I know what and where the MAF is, just never cleaned one before so I wouldnt know how to go about doing that. I know they can be expensive so I dont want to clean it and ruin it. Any suggestions of how to clean it? Thanks

~Jesse

[Daunttless]

carb cleaner/intake cleaner/throttle body cleaner, anything like that can be used to clean your mafs. You may also want to check the grounding wires as that tends to be a problem for Nissans across the board.

[chrispy]

are you guys sure it is the mafs and not a fuel problem? I know that when a car first starts that it supplies the engine with extra fuel. then once it warms up it leans it out a bit. so maybe you are not getting enough fuel to the engine. did you ever upgrade your stock fuel pump?

[Daunttless]

Very good point Chrispy, I thought he said he had upgraded the fuel pump. My bad. You may wish to check that as well. : )

[I H8 UR DSM]

unplug the MAFS w/ the car cold, and start it...if it runs fine, then plug the MAFS sensor back in, (with the cars still running) and see if the problem returns...(the car starts to studder, or stall)...(if you have the MAFS unplugged you cannot rev the car above about 3000rpm, or drive it w/out it being ****ty...)

I had the same/similar problem when i first got my SR running, and it turned out to be the MAFS....thats what i would suggest to try first.

[SRJesse]

No I never replaced the stock fuel pump, but I thought that the 300zx pump was an upgrade and the stock one should work fine. I took apart the MAF today and everything seemed to be clean. I will try it again and take some carb cleaner and wipe it down. Thanks for all the input.

[SrSLeePeR]

Try the Fuel Filter...You NEVER know....Mines is like that too...It doenst start that great and bogs in the beginning...First I found out it was the ground wire, so I relocated it and got it working better but it still kinda bogs a little. changed the fuel filter and everyhing starts up fine like a normal car now...BTW, I have a 300z fuel pump but I havent installed it yet..Do you know how to? Can you please tell me..Thanks..

IF you have AIM, my SN is JaiBeRT7o2 or you can e-Mail me at [email protected]

-ThaNKS

[SRJesse]

When I put the sr20 in I relplaced everything to give it a full tune up. Spark plugs, fuel filter, oil, oil filter, belts, everything!!! Thats why I am still wondering what it could be..... Thanks for all the input.

[I H8 UR DSM]

if u do what i told you, you can then add *checked the MAFS* to your list of what you've checked/replaced.

[SpeedRacer1]

What are you idling at currently? Also, when you gave it the tune up you didnt use any KA parts did you?

[SRJesse]

I have checked the maf and everything was fine. No I didnt use any KA motor parts!!!

[1991240xs]

you still didn't say you checked the thermostat...they can go bad and get stuck open..not letting your engine get up to heat..very cheap part...-

[jrpimp269]

if your car has a hesitation problem when you press the gas, or shakes and stuff when you accelerate, you might want to check the distributor or spark plugs.

[Daunttless]

There isn't a distributor on a SR20...

[SrSLeePeR]

SR20DET's are Direct Ignition... no distributor...

[hurddawg]

you still didn't say you checked the thermostat...they can go bad and get stuck open..not letting your engine get up to heat..very cheap part...-

this is irrelevant on COLD start. If i read it correctly he has a problem with his engine in the morning...

[ST240]

OH NO! what is direct ignition? hahaha

timing from the ECU directly?

-Andre

[1991240xs]

and i had problems with my car when it was cold too...the open thermostat wouldn't let the car get up to heat...that's why the engine wouldn't preform-

[Nismo_Freak]

You are running the stock fuel pump?! Better get another one soon. The car may be running low on fuel pressure because the ECU is used to having a turbo fuel pump. When you turn off the car the ECU runs the fuel pump for about 3 seconds to leave the fuel system pressurized and filled. If you have a stock KA pump it possibly cant pressurize the system enough for start up. Clean the throttle body and MAS and see if that works. Also does your car go into a fast idle (about 1k Rpms) when you start it?

[hurddawg]

There is also a problem when I start the

car when its not warmed up. If I press on the gas pedal it seems

to want to stall out on me, and will continue to do this unless I let

the car idle for about 3-5 minutes.

it seems that the car warms up fine according to his post. With the last sentence I quoted from SRJesse, the problem is cured about 5 mins. He has no mention of other driveablity problems (hesitation, misfiring, gas mileage).

I've dealt with open thermostats before, not the SR in particular, but generally the car won't warm up at all with a thermostat stuck open.

What you saying are correct, 1991240xs, a bad thermostat will contribute to a ill-performing engine but from what i've read it doesn't seem to be the case. I was trying to point out in my last post that he is having trouble with his engine as soon as it starts in the morning (no time to warm-up). Since the engine is COLD from the get go and he is having problems, a faulty thermostat isn't the problem. I hope this helps you out...

[SpeedRacer1]

Mine has the same problem from cold start where if i push on the gas, the rpms will go down. This only lasts for like a minute or usually less. I just let my car get to normal operating temperature anyways so it will run fine when I start driving around.

[Rs4racer]

ive seen problems simialar to this.

it was the o2 sensor not being plugged in. make sure you have your o2 sensor plugged in.

also check for vacume leaks these will cause more problems then the feul pump and whatever.