will not stay running after every cold start......

[Valdez3584]

I'm new to the forum world, but this is my last option. Nobody has been able to help me with my 98 240. Every morning I go to start my car it will not idle unless you force it to. After that it is fine. Shut it off it starts and idles like it should. When I get to work and work a full day without starting it. It will do the same thing, so my car won't run from a cold start; however, it will start fine when its at normal operating tempature. Oh, and it also blows black smoke out the tailpipe until you get it to run right; which tells me it dumping fuel from the time I shut it off to the time I start it. Anybody have any ideas?

[kouki munster]

Could possibly be a bad coolant temp sensor, do a quick search on nico for the fsm for your car and look up the test procedures for it.

[mechanicalmoron]

It wouldn't be my first guess, but if you think it's dumping gas, you could have a leaky injector, or the seal around one could be bad. Then when you turn it off, it will bleed out the excess pressure into the manifold/head.

Also, check that it idles at the right level and if not adjust the iacv, and check your ecu for codes.

[Valdez3584]

I have the fuel pressure gauge hooked up and fuel rail out of the intake so I can watch the injectors. pressure has dropped from 38 psi to 29 psi in about 20 minutes. Does anybody know what the spec is for dropping fuel pressure?

[Valdez3584]

I just realized something that I did awhile back. My car started to run funny and my MAF took a crap, so I priced one out. Turns out that is a $460.00 part. That is ridiculos, so I went to the junk yard and pulled one from a Nissan sentra 1.8L. My car is a 2.4L. I looked up part number and says it will not work. I still put it on it ran fine, but could that be my problem?

[mechanicalmoron]

I just realized something that I did awhile back. My car started to run funny and my MAF took a crap, so I priced one out. Turns out that is a $460.00 part. That is ridiculos, so I went to the junk yard and pulled one from a Nissan sentra 1.8L. My car is a 2.4L. I looked up part number and says it will not work. I still put it on it ran fine, but could that be my problem?

I don't know about the mafs being the wrong one, is that when the problem started?

What happened to your other mafs? Still got it?

I was getting a mafs code took it out, sprayed with carb cleaner, it's fine now. Although I never had an actual problem with the running, just the code.

Use B12 chemtool or something on the wires, and be careful to keep crap out of it. Then try it again.

[OutToWinPAHC]

Carb cleaner leaves a film, they do sell MAF cleaner, as for buying one I am sure you can get a used unit for about 50 bucks, people swap out the 300zx with a tune when running 300-500hp a lot.

[OutToWinPAHC]

Oh and your OBD2 check your codes if you have any. Also do maintenance, plugs wires, car rotor, check your ignition timing, clean the IAC, maybe even do the injector orings

[mechanicalmoron]

Carb cleaner leaves a film, they do sell MAF cleaner, as for buying one I am sure you can get a used unit for about 50 bucks, people swap out the 300zx with a tune when running 300-500hp a lot.

oops.

Well, b12 SAYS it doesn't leave anything.... and it made my code go away.

[Valdez3584]

I do have the original MAF when I plug it in I have to force it to stay running at idle. I have cleaned it with MAF cleaner but it didn't help, so I went to junkyard and found one for a 1.8L and I'm sure that's when my idling issue in the morning happened. I just ignored it BC the idiling issue while driving went away. I have a new OEM MAF for $90 instead of $460. I'm going to put that on and recheck. Just want to say thank you to everyonewho has posted. You guys helped me a lot.will keep everyone posted.

[mechanicalmoron]

I do have the original MAF when I plug it in I have to force it to stay running at idle. I have cleaned it with MAF cleaner but it didn't help, so I went to junkyard and found one for a 1.8L and I'm sure that's when my idling issue in the morning happened. I just ignored it BC the idiling issue while driving went away. I have a new OEM MAF for $90 instead of $460. I'm going to put that on and recheck. Just want to say thank you to everyonewho has posted. You guys helped me a lot.will keep everyone posted.

Idle issue when driving?

You mean throwing it in neutral and/or braking made it dip and/or die?

If this was the case, your MAFS was probably fine, and there was an IACV issue, either plugged up or adjusted wrong. Either use carb cleaner on it, or just re-adjust it, that's what I did and it worked fine, although I guess I should have cleaned it. Maybe putting in the new MAFS that's a little wrong just made the ecu keep revs a bit higher, so you don't notice.

If it still happens with the new correct MAFS, look up how to mess with the IACV. And because it took me forever to figure this out from bad online pictures, it's the screw that you can turn with your screwdriver PARALLEL to the firewall, it's not a squeeze/hard to reach.