Gas Flood on TBI

[letsrollusaf]

Basically the problem is this....Every once in awhile i'll be driving and it will bog down real bad and want to die but it doesn't as long as i give it gas, a couple of times when I've come to a stop at a stop sign it dies instantly. Well I open the hood and it reeks of pure gas....i give it a minute to air out and I go to start it and nothing it cranks but no pushover.....i give it about 5 more minutes and then it starts up fine...when all of this happens the Check Engine light comes on and its spits out the code 15 for low coolant temp (not sure what that would have to do with anything like this, but it always kicks out when the truck dies or won't start with this problem) A little history on the truck, this only started happening when I put new headers on it from the stock manifold, i've been running it with open headers for a little bit. I've got the O2 sensor in on a collector but not sure its doing any good. Basically its just throwing too much fuel in....any advice or help?

 

[Chaddy]

sounds electrical to me

 

[BoondocK5]

first thing first, check for proper fuel pressure.

 

[87350blaz]

it maybe could be your o2 sensor. with open pipes and no back pressure might not get a good reading.

or your throttle postion sensor. The fuel mixture leans out because the computer does not receive the right signal telling it to add fuel as the throttle opens. Eventually, the oxygen sensor senses the problem and adjusts the mixture, but not before the engine stumbles.

 

[dyeager535]

I say look up the code 15 and see what triggers it.

Low engine temp (whether real or indicated) is going to flood the engine, it's equivalent to choking a carbureted engine when it's at operating temp.

 

[kwissman]

If your O2 sensor is mounted at the collector, you will need to upgrade to a 3 wire heated sensor. The sensor is too far from the combustion event and it does not get hot enough to operate correctly. I got my 3 wire NTK off ebay new for about 20 dollars I believe it was PN 293000 or something like that. All you have to do is run switched power to it and it will work.

 

[84zz4ss]

I say look up the code 15 and see what triggers it.

Low engine temp (whether real or indicated) is going to flood the engine, it's equivalent to choking a carbureted engine when it's at operating temp.

Verify coolant temp sensor operation. False ect data will cause a rich condition.

 

[87350blaz]

do you have just one o2 sensor runing with open headers?

 

[letsrollusaf]

Yea i just have the stock O2 sensor which looks extremely black, and the wire is pulled very taught at the collector.

 

[Russell]

Replace your temp sending unit.

As mentioned, if the ECM thinks it is -40F out (which a failed temp sensor will cause the ECM to think) it will choke the your engine big time and run super rich.

Your 02 sensor is black becuase of the coolant temp sensor issue. The sensor is located at the front of the intake beside the thermostat housing, and has a 2 pin connector with a black wire and a yellow wire hooked up into it.

The Temp sending unit has as much, if not more to do with your fuel calibrations than the 02 sensor does.

As far as the 02 sensor goes, if you're running long tube headers, you'll probally need to get yourself a heated 02 sensor. Running open headers simply doesn't work at all, as the 02 sensor will be picking up atmosphere 02, and will big time make your truck rich as well. You can extend the purple wire on the 02 sensor if needed be, just don't touch the black wire that comes right off the 02 sensor itself, its a calibrated length.

 

[letsrollusaf]

Well I believe I had made a rookie mistake by buying one of these "Speed" chips that have two wires on them and you hook it up to that temp sensor, well I only had it on for about a day or two when it really started running like ****, in any event the lines that I spliced into off that sensor (blak and yellow lines) were still open. Basically there was open wires on that temp sensors and black and yelllow wires, so i electrical taped over it.

 

[Russell]

Them things are a crock, go ahead and hook the TPS back up and you'll be fine again

 

[letsrollusaf]

As far as the temp sensor, does the connection side need replacing or the sensor itself embedded in the intake manifold? Also what does the heated sensor do that the regular O2 sensor does not and also are those lines usually long enough to reach collector? How hard is that one sensor anyways to change......