Hey i got a 91 ef with a mild built ls(built bottom end).
Wen i go to start it up cold it starts up but dies. i have to hold the rev at 3,000 rpm for about 2-5 min depending on how cold it is,
i have never experienced this problem before and have no clue what it could be.
no cels
runs top notch after its on its own.
one theory i have is that it mite be running wierd cause the previous owners put a b16 intake manifold on it and only 4-6 bolts match up, rest are missing, maybe a bad seal????
it does need a tune up bad but never experienced this problem because of a tune up.

does anyone have an idea on wats going on?
thanks!

 

I think a bad intake seal would shoot your RPM higher since you would have a vacuum leak.
Sounds to me your problem might be IAC FITV related... or maybe the IAT.
Does your ECU throw any codes?

 

it throws a code one in a while wen i floor it, its a solid blink then 7 short ones with out a pause so idk if its iat and tps or my speed sensor.
i just put in a newer iat sensor i found lying around and took that code off.

its not reving high, im stepping on gas pedal to hold it at 3,000 to warm it up or else it wont run on its own, get wat im saying???

 

can anyone help me out with this?

 

last time that happen to me the head broke some valves...another time dizzy wasn't working correctly...

 

wats the best way to figure that out?

 

Bad cold starting could be coolant temp sensor,ecu is not getting told that it is cold so it does not apply"choke"so to speak

 

how would u check if the coolant temp sensor is bad? i know where its located

 

Find a manual somewhere on here that will give you the values for testing the wiring and the sensor I dont know for sure off the top of my head.
I will try to check back later and let you know but you will need an ohm meter or a DMM with ohms setting on it.

 

i tested the left coolant temp sensor, not the sending one and had 1.0 ohms while cold, and like .2 wen hot, and after i did that, cel came on for number 6! im guessing that temp sensor needs to be replaced then huh?

 

look up the cel (chech engine light) codes for obd0 and it will tell you what code 17 is i long blink is a tenths and the short flashes are ones so one long flash followed by 7 short would be a code 17

 

i have a aic code 14 its not idleing to high or roaming i just replaced it but the cel light is still on before i replaced it there was a bouncing idle now it idles higher when motor is hot but not terribly high no higher than 2k my biggest problem is if i get on the gas slowley the car will rev like it is supposed to in other words if i tach it all the way up but dont stomp on it just slowley push it to 7 it will make it to 7 but if i stomp on it it will instantly die down or or if i downshift onto the power band and get on it it just boggs so pretty much my ls swap into my ef is not getting the power the motor is in the car for

 

i am throwing a code of 17 since i got the car, vehicle speed sensor whichi dont care to fix at the moment, i am trying to figure out why i have to warm my car up in the morning like a carburator!

cel just came on, i checked my ecu and it blinked a 6, i know how to read these. it came on after i checked the resistance in the plug.

if its showing a 1.0 when cold then a .2 wen hot, does that mean i need a new coolant temp sensor???

 

Can anyone help me with this, now its throwing a code for number 6, coolant temp sensor. It threw the code after testing it. My car barely stays running untill warm now! it used be able to be on its own after 3 minutes of me reving up 3k, then letting it warm up on its own, anybody help me out?