Cutlass Supreme engine problems

[unclehotte]

I have one more question. After installing new IAC, new fuel pressure regulator (with intake gasket I think) and installing a new vacuum modulator the car starts good and drives nice. BUT...... when I start it COLD and its COLD OUTSIDE (20-30 deg) the engine rpms still go up to 2500 till 3000, but come down within 10 till 15 seconds . Is this how its supposed to be or is there still something else I have to fix? (Before IAC and fuel pressure regulator this went on in the 2500-3000 rpms till engine was driven warm after 10-15 minutes) Another sensor I have to change still???

[hotrodolds]

That's not really cold, per se, but for a cold start, even at those temps, it is normal for a high idle to occur. However, that seems a little high to be idling. I've seen 2000-2200 for a few seconds, but that seems to be a little high, and a little long. I wonder if the coolant temp sender would be suspect? Hard to say on that, for me.

[ns87]

Mine does the cold high idle a lot. I agree with hotrodolds. The coolant temperature sensor for the ECM is the only damn sensor I haven't replaced yet lol

[19Cutlass94]

I know when I replaced my IAC I needed to do an idle re-learn. Not sure why though. But it fixed the problem. If it was the CTS, it wouldnt idle high, it would just run pig rich. If that sensor goes bad, the ECM thinks its -40* airtemp.

[unclehotte]

It smells pig rich when I start it cold. Since this might be the last sensor I guess I replace it, too. As I read in this forum there are 2 coolant temp sensors??? One for the gauge inside, the other for the engine/computer. Where is this one located??? Can I fix this myself like I did with the vacuum modulator or cant I reach it without a shop???

[19Cutlass94]

The one you need to replace is right above the thermostat/right below the TB.

[unclehotte]

What means TB???

[19Cutlass94]

throttle body

[unclehotte]

Thanks, I gonna check it out this weekend.

[Go4DaMo]

 

Was running great till some day after starting the engine idle run up to 3000 rpm. After parking the car for 2 days this high rpm stayed high for up to 20 min. If the car was driven every day it was just 4-5 min. After reading in this forum I changed the IAC. The change was, the idle still went to 3000, but only for about 20 seconds then it dropped to normal.I thought the problem was fixed. But NOW the car dont want to start anymore.

 

when it starts it shakes and spits white smoke and smells from unburned gas. After it gets driven it runs ok and when it is warm it drives normal. But the start problems are every time now( when the engine is cold).

 

I have a 1993 Z34, 59,000 miles, and am having these same problems. I nearly need 2 feet on the brake pedal as I pull out of the driveway.

 

On cool-starts (35-55 degrees Fahrenheit) this happened in the spring and now that temperatures are dropping, same problem. I fear damaging the engine block from it revving so high cold.

 

I haven't experienced low warm idles or rough starts. I would appreciate ANY input. Thanks in advance.

[Crazy K]

have you ever done the intake gaskets?

[Go4DaMo]

Thanks, Ken. I'll have to check the maintenance records. I just asked my mom ( the previous owner of 5 yrs) and she said no. Is that my problem? It hasn't done this all summer, just now that the weather's dropping below 50 again.

[Crazy K]

no guarantee... but the gaskets allegedly shrink when cold... and that would be when they are most prone to leak.

[Go4DaMo]

Genius, sir. That's a big help! What kind of labor is involved? With the snow flying, my Z may be parked for the winter, anyway, so the garage is all mine.

[Go4DaMo]

Today, I started it (outside temp: 50 degrees F) and it wouldn't drop below 3400 RPM at idle, making it undriveable. Do you think it's the gasket or could it possibly be a sensor?

[Crazy K]

want me to come down and look at it?

[Go4DaMo]

If you're in the area, throw me a text man. I wondered when you were coming around. I'm just going to dive into the gasket. Any recommendations on replacement gaskets? Brands, style, etc.

[bodeen2007]

i can also look at it and if you are scared by doing it let me know and i will come over and help u out i have done way to many lower intake gaskets on w-bodys . matter of fact i just did a z34 last week that one was a little more involved though cause i replaced all of the gaskets on the engine including the oil pan, head gaskets, intake and so on ............... but if u want help let me know

[Go4DaMo]

ok, thanks. Chris D's calmed me down pretty well, so I'm not afraid of it. I'll be aight.