starnes28

1990 camaro rs with 305 tbi stalls right after starting one time after it is warm. I don't know why can anyone help me

ex-x-fire

Iac might be dirty.

cfs2chvy96sub

ok question is being iv replaced my ignition module due to the stalling when warmed up ,iv seen my bro replace the whole distributer after that didnt work on his cougar ,but iv never dealt with a tbi car before ,it was carb or tpi ,tbi iv heard is not that great do deal with

goliath88

fuel pressure, start there. check for clogged filter. dont start changing parts unless you wanna have a bunch a new sensors for no real reason.

waylor

I just came across this old thread. Been searching for someone that has same problem as I do. This is it! Has anyone found the correct answer to this problem??? Thank you in advance!!

Sweatlock

iTrader: (1)

On my ‘92 305 TBI, when I start it in the morning to go to work it starts after a second or two, runs fine except for an occasional ‘stumble’ at idle in closed loop and only at idle. Once warmed up, if I turn it off to, say, get gas, and it’s only off for a few minutes, it will start at the first touch of the key.

HOWEVER, if it’s warmed up and sits for about an hour and then I go to start it, it will stall and die. If I goose it just a little it will run fine. I’ve not been able to figure out why it does this and whether or not it’s tied-in with the stumble.

The car drives great under all other conditions.

robertfrank

iTrader: (27)

My 91 does this as well. If I start it first in the morning, I can crank it and it will act like it wants to die unless I blip the pedal. If I stop and let it sit for a bit, if I don't almost put the pedal to the floor to start it, it will immediately die and it will just sit and crank. Its a pain in the ***

CadeAtkinson

My 89 formula does this as well. I've been trying to fix it forever and I've heard everything from IAC to MAP sensor to 02 sensors and Fuel filters. I've read threads where people have replaced these parts and some have gotten lucky others have not. My suspicion for my car is the MAP sensor but I haven't had the chance to replace it yet so I don't know for sure.

Schurkey

There's a dozen reasons for these problems. Any of them could be the "correct" answer.

Verify fuel pressure.

Connect a scan tool, look for "codes", but more important, look at the data stream for issues with sensors or outputs. I'd pay special attention to the IAC response, coolant temp sensor, and TPS.

How long has it been since these vehicles had a proper tune-up? Spark plugs, test coil and plug wires, distributor cap and rotor, ignition base timing, fuel filter, heated air intake, PCV system, vacuum leaks, cranking compression test, clean the throttle plates, verify the fuel tank venting/charcoal canister.

Sweatlock

iTrader: (1)

in my case, I have driven around with a scan tool connected to the ALDL and with it on the passenger seat - no codes.

I have replaced the following:

TBI removed and cleaned
TBI gaskets including base gasket
Both fuel injectors
Fuel filter
Fuel pressure diaphragm and spring
Intake manifold and gaskets
PCV valve & filter
EGR, gasket, solenoid and vacuum lines
CTS
IAC
TPS
MAP
Oxygen sensor
Catalytic converter
Spark plugs
Spark plug wires
Distributor cap
Distributor rotor
Distributor ICM
Ignition coil
Engine timed to 0 deg
ECM w/ AXKT EPROM
Air filter
Oil filter
Mobil 1 5w30 oil, 5 qts. every 3K miles
Fuel evaporative system (charcoal canister, valve by the gas tank)
All vacuum lines

All parts either new AC Delco or NOS, all work done by myself.

The car had sat for quite a while when I bought it, it had a new GM Goodwrench 305 engine installed, which was verified through receipts and the barcode on the oil pan.

Since it had sat, I consider these parts to be maintenance items.

Schurkey

What is the data stream saying about the sensors and outputs?

What is the fuel pressure?

Sweatlock

iTrader: (1)

I haven’t verified fuel pressure due to the challenges in doing so on a TBI car. I was told the car was sitting because the fuel pump went out and was then replaced. Yeah, I know...

I can’t remember what brand of scan tool I have - I can confirm this evening. I bought it off eBay; it’s ‘vintage’ and uses modules for different car brands and years. May use an RS232 if it’s even capable of downloading data and I’d need an older pc to do so, which I don’t currently have.

Just to clarify, not all of the parts were replaced as the result of this issue - the intake manifold & gaskets were replaced because the engine leaked from the lifter valley down the back of the engine. I don’t like leaks, so I took off the intake and replaced the intake gaskets along with applying the ‘Right Stuff’ front & back on the China wall, no more leaks.

Also, my specific issues are these: after the car is at operating temperature and then parked for approximately 1 hour it is difficult to start and I have to goose the accelerator. Under all other conditions (cold start, <1 hour, >1hour) it will start & run just fine. The other issue is a stumble at idle which is very intermittent - it only seems to occur at idle and it could be a week or more before it does it.

The car runs great under all other driving conditions: no hesitation, plenty of torque/power for a TBI, no flat spots, good throttle response. It’s very fun to drive. So these two issues are just weird. It did both a lot more when I first bought it and prior to replacing a lot of parts, but it hasn’t been eliminated. This is my daily driver car that I drive to work Monday through Friday/Saturday.

Some other things replaced, again, not necessarily for this issue:

Alternator
Distributor pickup
Thermostat 195 deg. F
Radiator, heater & all hoses
Fuel tank cap

There are two things that have to happen when I own a car: everything must work and there can be no leaks.