Another 4.3 TBI Qestion

PUO-BANNED · Oct 30, 2009

1990 s-blazer hard to start when hot, cranks slowly then starts but sometimes have to hold pedal to floor to get it to start. Put in on a scanner today, coolant temp reads OK (195) TPS is reading .66 at idle, MAP reads 1.09 at idle. I replaced th ESC and CTS with a known good unit off my 89 that runs fine. What else should I look for? I want to get it ready for winter so the wife doesn't have to drive her car in the snow.

JOOP · Oct 30, 2009

fuel pressure??

Binder · Oct 30, 2009

Holding it to the floor puts it in clear flood mode which means it cuts the fuel. So is it just flooding?

PUO-BANNED · Oct 30, 2009

Binder said:
Holding it to the floor puts it in clear flood mode which means it cuts the fuel. So is it just flooding?

Thats what it's doing. white smoke when it finally fires. Is it possible the injectors are leaking down after I shut it off?

PUO-BANNED · Oct 30, 2009

JOOP said:
fuel pressure??

Checked It's fine. I'm just picking brains before I tear into it any further.

Binder · Oct 30, 2009

PUO said:
Thats what it's doing. white smoke when it finally fires. Is it possible the injectors are leaking down after I shut it off?

Could be but that shouldn't leak much fuel. After you turn it off it shouldn't hold fuel pressure so if it leaks it's just at atmospheric pressure.....I guess if the fuel lines were routed up high or the car parked nose low it could leak a bit....I think it's more likely that the fuel is going in when you crank it like if the temp sensor was bad and the choke stayed on. You say the CTS checks OK so it must not be that......

theAuthority · Oct 30, 2009

PUO said:
1990 s-blazer hard to start when hot, cranks slowly then starts but sometimes have to hold pedal to floor to get it to start. Put in on a scanner today, coolant temp reads OK (195) TPS is reading .66 at idle, MAP reads 1.09 at idle. I replaced th ESC and CTS with a known good unit off my 89 that runs fine. What else should I look for? I want to get it ready for winter so the wife doesn't have to drive her car in the snow.

Same pre-runner blazer you used to smuggle cocaine in the spare tire ? :fawkdancesmiley:

PUO-BANNED · Oct 30, 2009

Binder said:
Could be but that shouldn't leak much fuel. After you turn it off it shouldn't hold fuel pressure so if it leaks it's just at atmospheric pressure.....I guess if the fuel lines were routed up high or the car parked nose low it could leak a bit....I think it's more likely that the fuel is going in when you crank it like if the temp sensor was bad and the choke stayed on. You say the CTS checks OK so it must not be that......

Air switch, air diverter, IAC? I let it sit for a while and it fired right up. the scanner I used was a autoxray 6000 and it said the temp reading was right on.

theAuthority said:
Same pre-runner blazer you used to smuggle cocaine in the spare tire ? :fawkdancesmiley:

Burned that one.

Bill USN-1 · Oct 30, 2009

Verify the map reading with the local baro.
I have a scale listed in the parts required FAQ on binderplanet.
also verify the tps is reading right thru the whole scale.

You say the fuel pressure is good...what is it?
A kink in the return line will increase the pressure on the feed side.
You can disconnect the return and run it into a can then start it and see if it helps.
Pressure on the return side should be near 0psi and the inlet is 9-13psi