1G 4g63 n/t issue

[Stevens Talon]

Ok so my 1992 6 bolt non turbo 4g63 decided today that when at the end of my road when I went to pull out it stalled, and would not start back at first. It cranked normal but wasn't hitting at all, after about 3 min or so it roughly started back and cleared up and was fine to get back home.

The only 2 codes (which have been there for months) is 11 for O2 sensor and 21 for coolant sensor. I just don't have the funds to replace this min.

Where would be a good place to start diag as I'm at a loss where to start.

 

[pauleyman]

Ok so my 1992 6 bolt non turbo 4g63 decided to day that when at the end of my road when i went to pull out it stalled, and would not start back at first, it cranked normal but wasnt hitting at all, after about 3 min or so it roughly started back and cleared up amd was fine to get back home, the only 2 codes (which have been there for months) is 11 for o2 sensor and 21 for coolant sensor jist dont have the funds to replace this min. Where would be a good plave tonstart diag as im at a loss where tonstart

Start with coolant temp as its cheap. O2 shouldn't keep a car from starting but a coolant temp will.

 

[Stevens Talon]

Thanks for the reply im going to replace it, just trying to wrap my brain around it so i have to ask why would the coolant temp sensor cause it to stall then not start. I can see if it too rich being hard start due to being rich but it was literally not hitting at all, even thought maybe it was either flooded or not getting air so open the throttle full and partial and still wouldnt even hit or sputter then after sitting enough to read codes and alot more cranking it finally sputtered to life and ran and idled perfect

 

[pauleyman]

Thanks for the reply im going to replace it, just trying to wrap my brain around it so i have to ask why would the coolant temp sensor cause it to stall then not start. I can see if it too rich being hard start due to being rich but it was literally not hitting at all, even thought maybe it was either flooded or not getting air so open the throttle full and partial and still wouldnt even hit or sputter then after sitting enough to read codes and alot more cranking it finally sputtered to life and ran and idled perfect

Check for spark and fuel. Ignition power transistor can fail intermittently and suddenly. At least a visual check of connection would be a good idea also.

 

[Stevens Talon]

Thanks for the reply i am goimg to go thru and check and clean all the connectors ect but why im at a loss is a few min after it quit i got it started back and has been fine since so diag wise every thing is checking good at the moment

 

[steve]

trying to wrap my brain around it so i have to ask why would the coolant temp sensor cause it to stall then not start.

Many threads here with the answer but the bottom line is when the CTS fails it can act like it's disconnected and tell the ECU the coolant is about -74F and the ECU will dump a lot of fuel in an attempt to get something to vaporize. But when is actually normal temp this cause the plugs to get fuel fouled and you have to clean or replace them after fixing the CTS to get it to start.

 

[Stevens Talon]

thanks for the explination

 

[Stevens Talon]

Can some one give me the o2 sensor readings for a nt 4g63 mine seem off at .074 volt hot at idle .073 volt at 2000 rpm and .186volt at 4000 rpm

 

[steve]

The only tuning you can do with a stock narrowband O2 sensor is adjusting the fuel trims that are generated in closed loop. That's all about how quickly the O2 sensor switches when the ECU dithers the AFR on either side of 14.7:1 at idle and cruise. At idle and at a 2000 RPM steady state the O2 sensor should be switching back and forth high and low. I'd say also as a steady 4000 rpm but I forget what the high cutoff is for closed loop.

 

[Stevens Talon]

Not trying to tune trying to diag a o2 sensor code and trying to determime if it the sensor or something else

 

[Stevens Talon]

Just an update, I found several broken connectors (will get replaced when funds allow) but found the coolant temp sensor plug and prongs severely corroded inside the connector to the point it was creating resistance. Cleaned pins and replaced connector with spade connectors (TEMPORARY TILL I CAN GET NEW CONNECTOR) and ran tests on O2 sensor and seems to be reading off. Will replace that and update as I can.