RXSpeed16

iTrader: (41)

Need some help on another cold start issue. I know there are many cause I read as many as I could find. Have a '87 TII with 12K miles. Has all emissions except split air pipe port blocked off for RB RevII exhaust.
When it is warm outside:
Car starts, idles and runs strong.
Engine does normal 3000, 1500, slow drop to 750. (Probably rules out thermowax pellet?)

With cold air temps:
Car starts, it will rev to 3000 rpm and cut out within 3-5 seconds. No combination of throttle/gear/brake will keep it running. I can increase the revs with throttle in the first few seconds, but it will not stay running. Also, I hear a click from somewhere behind the guage cluster and then it will die.
Have double and triple checked vacuum lines and connections.
Would water thermo sensor cause this?

Any ideas you guys have would be greatly appreciated. Thanks.

RXSpeed16

iTrader: (41)

So I tried it at lunch and it started up first try. No weird behavior whatsoever. So I am pretty sure it's a system that only activates when the ambient air temp is lower (60ish or below). Had a constant 200mm/hg vaccuum on startup at lunch as well as during the few seconds that the car is running when it is cold. (Measured on aftermarket gauge)
Anyone have any ideas what it could be?

RXSpeed16

iTrader: (41)

Car won't start again today. I re-adjusted the TPS and made sure all sensors were plugged in. Have a track day this weekend and need to get this fixed. Any ideas welcome!!! Thanks.

hanman

Sounds exactly like the water thermo sensor. Pull the plug and make sure all the pins in the connector are good.
When mine went bad, the car would start, although it took longer, and the only way I could keep it running was to "feather" the gas pedal. Once it warmed up it was fine.

RXSpeed16

iTrader: (41)

Thanks. I'll take a look at the sensor at lunch. PO may not have installed an oem one. Any way to tell other than looking to see if it has a green clip? Also, I cannot keep the car running no matter how much gas I give it. I can get it to rev in the first couple seconds, but it will die no matter what. I'm thinking AFM, but it only happens when it's cold. Did this happen to anyone with AFM problems?

puhpaper

iTrader: (6)

I had a similar problem. My issue was my fuel injectors were gross from over x amount of years of usage. I bought some of that fuel injector cleaner you put in your gas tank from pep boys, and she fired right up. Give that a try?

eff_three_see_es

iTrader: (11)

water thermo sensor def. i broke mine putting on an alternator that i blew at like 3 in the morning with no light. car ran like hell when it was cold and would not get better till it was fixed.

RXSpeed16

iTrader: (41)

Tried the injector cleaner. I'll see if it works. Gonna check the thermo sensor. According to the FSM, there should be continuity below 90 degrees C. In case I can't find a thermo sensor tomorrow, I can just jump the connection on the harness until the car warms up, and then plug it back in once it's warm? Probably not gonna sleep much tonight. Thanks for the input everyone.

Go48

iTrader: (7)

Check for air leaks in the intake system between the AFM and the TB. Also, make sure that AFM connector is plugged in and that the contacts are clean.

RXSpeed16

iTrader: (41)

Well the car started right up this morning. No problems whatsoever. So, with the rtek 1.5 and the injector cleaner, the car runs much smoother and does not have the starting issue. It may have been warm enough this morning and these changes may not have fixed it. Gonna pick up a new temp sensor anyway. I may try different ECU/temp sensor combinations and see if I can find a definite solution for future reference. Thanks again for all the help.

RXSpeed16

iTrader: (41)

Hey Everyone,
The cold start is back and the threshold for starting/not starting is about 65~70 degrees. Tested ECU connections for:

AFM: Pin 2J, 4.5 Volts when closed. Sweeps to .5 V at full throttle. (Same readings if car wouldn't start and after warming engine)

Water Thermo Sensor: 2.2 V @ 65 deg. (Wouldn't start) / 1.5 V @ 80 deg. (Started) / .4 V @ operating temp engine
- Smoothly lowered from 1.5 to .4 as engine warmed up.

Engine pulls 20 inches of vac and is solid when running. Could I still have an intake leak if it's normally that high?

Noticed that the coolant opening has been welded over on the TB so I'll open it up today to see what was done. Is there a possible cause I should look for while I'm in there? Thanks.