I already researched but didn't find much so here goes. Saturday my car started running horrible...almost like it was missing. Had no power. I scanned it and there were no codes. I checked the spark at all of the cylinders and tested my injectors. Everything was fine. I decided to scan it again and this time it came up with a code either 13 or 18 I forget which one but is said crank signal low or no signal. Its a '94z and I thought only the '96 and newer had crank sensors? It had no SES light on the whole time. Anyway, with the code up it seems to run alot smoother except it only idles between 5-600rpms when its warm and in gear -A4-. This causes the oil pressure to drop to the red zone and the check gauges light comes on. I have to put it in nuetral quick and the pressure goes up to a safer number and the light goes off it then idles about 700rpms. When the motor is cold the oil pressure is good -about half-way. I wont have a chance to mess with it again until tomorrow (tuesday). What would cause this low idle condition and would the low idle cause the drop in oil pressure? If the low idle isn't effecting the oil pressure could my sending unit be bad? The Z just turned 130k but ran great before Saturday. Obviously my oil is full but i figured i'd better establish that anyway. Any help would be great.

Nathan

 

TTT

 

when was the last time you removed the tb and cleaned all of the oil residule? Clean the IAC and all of the passages? You might have to replace the IAC because it might be sicking.

 

check your oil pressure manually, thats exactly how my car acted when the 02s were messed up , try un plugging them see if it runs better, also try your Iat sensor

 

I dont want to scare you but are you hearing any strange knocks or ticks. The motor could be on its way out. Whenever I hear low oil pressure I think about my 94 z28 which has very low oil pressure and has some ticks and knocks coming from the bottom end. This may not be what is wrong with your car but it is something to consider.

 

Thanks for the replies...TB was just recently cleaned...IAC was not I will check that out today. My O2 sensors appeared to be working correctly when I had the scanner on. I will also have to check my oil pressure manually today. As for the ticks - besides the shi++y paper gasket blowing out 2 weeks after my header install it doesn;t sound like I have any noise. I will have to fix the leak so I will be able to tell better. Also today I noticed a slight stumble at around 50-55mph when the torque converter is locked up in O.D. If I press gas down just hard enough that it doesn;t unlock or downshift it will stumble but as soon as the R's reach about 2000 it stops. As for the Iat it reads about 120 deg. F which is around where it should be givin the conditions outside when I checked it. If my motor is on its way out im in the market. Thanks again

Nathan

 

update...Had the z out today and when it warmed all the way up the oil pressure gauge dropped to zero at a stop in gear. As soon as I put it in nuetral it rose to about 10-15. Happens everytime the rpms get low enough. I finally sat thier one time in gear with the pressure all the way down to see if I would hear any valves or anything. I figured if the oil pressures really that low the motors done for anyway so I might as well try it. I have my income tax check in the bank so I was prepared. Actually it would just be inspiration for a 383 build-up . I left the pressure at zero for about 2 minutes and heard nothing unusual. I cant believe I doubted the trusty LT1 in the first place...better not speak to soon though.