95 running rich and more

[Fishtrap]

My tahoe is burning very rich, to the point of burning so much gas that I can't drive it. It surges and with shut off at idle and driving when stopping at a light. When it shuts off I have to jump it 50% of the time. Battery is 6 mos old and tests good, alternator is good. Replace starter cable and alt wire, O2 sensor, plugs and Dist cap and rotor. Brake light flicker also. Been checking grounds wires. No luck so far.

 

[aznpersuasion]

how do you know its running rich? check for codes. a faulty sensor may not also trigger a CEL. first things i would look at are plugs (gap), wires, air filter, MAF sensor, MAP sensor, IAT sensor, TPS sensor if you have any of those. probably even crank angle sensor and distributor sensor if you have one. since you have to jump it when it dies makes me think your charging system is suspect. how do you check your alternator?

 

[Fishtrap]

It's running rich because of the thick black shoot coming out of the exhaust and can smell it.

 

[aznpersuasion]

ok, well check those things. ohm out the sensors. could also have stuck injectors. i still dont see how any of that would require you to jump it though when it dies.

 

[Fishtrap]

Plugs are new last weekend and I did check the gaps. New wires,cap and rotor. It's not the charging system, my mechanic confirmed that. He has way to busy to get my tahoe in the shop and Im working out of town. Trust me, I know charging systems on vehicles, outboards and marine diesels. This is something else, maybe a sensor that I have no idea on how to check. Charging system wouldn't make the brake light do what they do, I keep thinking that Im overlooking something simple. It took me a month to find one little thing on my daughters Gen 1 Honda Insight.

 

[aznpersuasion]

i think the brake light is something separate. my brake light goes of randomly too, but its just the ABS module freaking out. well easiest first, air filter. but ill assume you checked that. have you checked compression?

 

[Fishtrap]

Air filter is good, have not checked compression. It has a throttle body and those injectors appear to be doing what they should. I just don't want to spend a grand on this thing and not get anywhere. I just checked and cleaned the grounds, and the surge is still there and it cut off. While running it at 2k rpms I noticed the speedometer moving with the surge whle just sitting still and not moving.

 

[aznpersuasion]

thats weird. is it 4wd? my 99' has the vehicle speed sensor is in the trasnfercase. i understand. i just rebuilt my motor and couldnt get it running the other day :/.

 

[Fishtrap]

Yes 4wd. Very Wierd and frustrating

 

[aznpersuasion]

well hopefully someone else can chime in. it sounds to me like either a separate short in the harness and some sensor that is faulty.

 

[Fishtrap]

Unfortunately it has the OBD1 connection to get the codes, very few have that in my area now.

 

[lesterl]

Check the CTS near the thermostat housing, it is a 2 pin plug, unplug it and ohm it out.

 

[lesterl]

Codes can be pulled with a paperclip across the upper 2 right pins on the diagnostic connector under the steering column..... turn ign on (dont start) and the codes will flash out.

 

[Fishtrap]

Ok, have done that on the Insight. Where can I find what the code mean? I replaced the battery just to try and make sure that I was getting full power, now it doesn't want to start.

 

[lesterl]

http://www.s10forum.com/forum/attac...052466-little-help-needed-gm-sensor-chart.gif

 

[lesterl]

Does the truck try to start? Pull the fuse for the injectors, or unhook the wiring harness from the injectors. Does the truck crank and start of some carb cleaner then?

 

[Fishtrap]

It didn't start after 4trys, then it did then cut off and hasn't started since.

 

[lesterl]

Well, disable fuel. Crank some to clear flood. Supply a fuel source such as carb cleaner and if it fires on that I would suspect either a stuck injector or more likely a bad/ open Coolant Temp Sensor (CTS), if the sensor has gained a lot of resistance or opened up then it will think it is near 40 below and just dump gas down the intake.

Now if you are having electrical issues, that could cause the ECM to act up.

If you pull the codes I can tell you what they are and probably what they mean.

 

[Fishtrap]

Ok, will do that after work tomorrow. Thank you

 

[lesterl]

NP.... Have had the bad CTS do the whole no start/ eating gas at a rate you couldnt drive it before...... easy to test and cheap to replace.....