Rich on Start up - Hesitates when cold - Suggestions

[rmjsupra]

Whats up guys, ok did some digging, but found nothing.

Have a 86.5 N/A, since I bought the car it has hesitated to start when cold, takes a couple of seconds.

I let it warm up for a sec and drive it, care will not accel good until it gets above 2500 rpms, while its cold. Once it gets to operating temp, it hestitates less but still does not pull hard until it's above 2500 rpms.

This lead me to believe it is running rich, car passed smog no probs here in Cali. This is what I have changed

- Distributor
- Dist. Cap and Rotor
- NGK Plugs (yes gapped correct)
- New Spark plug wires
- Tested coil and ignitor, great!
- All new vacuum hoses
- Timing set to 10 degrees befor TDC, per FSM
- New radiator hoses, thremo, and heater core hoses, and bypass coolant hose

Any ideas, car runs godd, just bugging me that if I wanna floor it I have to weight till about 2800 rpms till I feel a real pull, almost feel like Vtech, lol.

Does not heat up, only leak I had was my blown PS rack, just changed it.

I thinking it might be the coolant temp sensor to the ECU.

Thanks in advance for the help.

 

[dumbo]

Mine never pulled before 3500RPM:naughty::biglaugh:

More seriousy though, check your codes.http://cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=23

 

[jetjock]

This lead me to believe it is running rich, car passed smog no probs here in Cali.

Does that make sense? Do as dumbo said and check codes. And yeah, I'd be looking towards the coolant sensor too but not because of richness...

 

[rmjsupra]

I'll check the codes today, ran the codes once already when my distributor died and only code up was the ignition stuff.

If the coolant temp sensor is not reading correctly the ecu will not know when it is warmed up or not.

 

[jetjock]

If the coolant sensor is shifted that statement is true. That's unlikely though. Plus it'd have to be shifted in the right direction. However if the coolant signal is shorted or open/disconnected (typically what happens) the ECU will default to hot and run the engine lean. Easy enough to check with a meter. It's even easier to see whether the mixture is lean or rich. Beats guessing....