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tbi 350 running rich and dies

ok, so no ses light period, so couldn't pull codes. where should the light be? on the fuel level side by the parking brake light? or under the speedo by the 4wd light? i guess i need to pull the gauges and see whats up, which is fine to get the wiring for the temp sensor.

also, there are 2 coolant temp locations? the one on top of the motor where the coolant comes out and to the radiator? there's a wire connector there but all looks good? could the sender be bad?

IMG_3792.jpg


and a second on the drivers side between the 1 and 3 cylinders? not sure what that broken wire goes to, connected the two but didn't do anything.

IMG_3794.jpg


and anybody know what this wire connector goes to? passenger side valve cover.

IMG_3793.jpg
 
Every time you turn the ignition on the SES light should come on (to indicate the bulb works). It is located in the cluster with your speedometer. If it does not work, your bulb probably needs to be replaced. I would do that first.

The coolant sensor on top of the intake manifold is the one the TBI uses. The one on the block ... I honestly don't know. But I believe that dangling wire should be connected to that sensor. Mine appears to be green and black and is connected to that sensor, just like yours look like it should do. Does your coolant gauge work?

The knock sensor is located on the passenger side of the block somewhere.

The loose connector, are your IAC and MAP sensors connected? I looked at that and there isn't much else over there to connect to... just the coolant sensor, IAC, MAP, EGR controller TPS and the ESC. Maybe your TPS is not connected, it's on the side of the throttle body.

Wait, that connector looks like it is wrapped around the other harness a few times. Can you unwrap it and see what it would reach? Maybe that is your coolant sensor? Can you identify the colors on the wires for that loose harness and the ones to your coolant sensor? If I have this right ... Yellow is coolant sensor with a black return, Dark Blue, Gray, Black is TPS, Gray is 5v sensor reference (?)
 
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That loose connector laying on the valve cover is for a smog pump control valve that he might not have. I had that same connector loose on my truck as well. The temp sender for the gauge is in the head and the EFI system uses the one in the manifold. Really need that light fixed first!
 
no coolant gauge is not working. i'll get the dash apart and check/change that bulb for the ses light. anybody know what # bulb it is? 194?
 
Ok, you have to get that working first. You should be able to test the coolant sender with a multimeter. Maybe someone knows how?
 
redbird00 said:
no coolant gauge is not working. i'll get the dash apart and check/change that bulb for the ses light. anybody know what # bulb it is? 194?
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i forgot the number of that bulb, but don't ask me how i found out about that it twist turns from the back, spacship K5........no more pull/push bulbs in the dash, printed circut....mebe PC194 or 168.
 
the black wire in the second pic is definately to the gauge, drove it around and got it warm, and hooked it up and sure enough, temp gauge went up! so now the gauge works. haven't gotten a chance to pull the dash yet. maybe sometime this week.

it was real hard to get started from being cold. think its all related?
 
Yes, the coolant temp sensor tells the engine how cold it is. With no signal, I think it sends a -40 degree Fahrenheit signal, so basically it's flooding your engine because it thinks hell has frozen over.
 
ok for reference, it is a 194 bulb.

the bulb looked fine, but when replaced with a new one it worked and was able to pull codes finally!!!

got 3 of them

15 - coolant temp/low temp
33 - MAP sensor(low vacuum)/MAF sensor/MAP sensor(high voltage)
45 - 02 sensor(exhaust rich)

got this info from the site provided earlier in this thread.

not sure what to do about the code 15 or 33? i have a new 02 sensor, should i go ahead and install it now or wait until i work on the code 33 first?
 
Replace the coolant temp sensor and it'll get rid of at least two codes. It's running rich because the CTS is telling the ECM it's very cold out. The richness is giving the O2 sensor fits...

Rene
 
I'm a "one at a time" guy. I'd try just the CTS first and go from there. My 90 had a bad CTS when I bought it, it was why I got it so cheap. It'd load up so bad it would smoke black, stall and not restart until it cooled down all the way again. I never changed my O2 sensor...

Rene
 
I agree with changing just the CTS to start. Remember, the O2 sensor is probably reading the flood of gas as a problem. Fix the CTS and then I bet it clears up. If not, then change it.

The map sensor is easy, too, but I would also wait until the CTS has been replaced. Just get a little screwdriver and jam it down the 4 slots on the side of the sensor and it pops off the holder. Or you can remove the single bolt that holds the whole thing to the bracket.
 
Mine just unscrewed like a big old plug...3/4" socket I think? Literally a 3 minute job and it's right behind the T-stat with one plug on it.

Rene
 
redbird00 said:
because its been running rich for a while, should the 02 sensor be changed?
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Not neceserely. You can remove it and use a specilty cleaner for O2 sensors. But I never have tried it. O2 sensors can be had for $25. ish. I've read some stories on Bouch being no good but I have used them and had 0 issues...
 
Finally checked codes....

Okay, so today it was almost 90 degrees and I was off work so I actually got to work on the truck a bit. I checked the codes and it is not throwing any. It is still running so rich that it makes you sick to be outside of the truck when it is running. Since its been a while, I will refresh the memory. Same problem as redbird only I have already replaced the CTS and O2 sensors. Since I am not getting any codes....someone suggested that I may have an injector that is stuck open. How can I check for this or do you even think that this is possibly the problem. I keep telling myself I just need to drive her up 95 a ways and let Jessie James look at her! We were actually thinking of coming to DC this weekend to see the Cherry Blossoms....maybe if I get two days off again we can try to head that way!

Any help or suggestions would be great!! You all are great!
 
Here are a few things to check:

Ignition on, motor not running, examine the fuel injectors in the throttle body. They should not be expelling any fuel.

If they are spraying, power off, disconnect the injector wire harnesses (clip off) and re-test. If they are still spraying, you either have bad injectors (leaking) or bad o-rings around the injectors.

If they are leaking, disassemble and check for cracked o-rings (two - one top and one bottom per injector.) If they are okay, replace the injectors (and o-rings, they should come in the kit). They are about $75/ea.

Be SURE to get the EXACT injector for your engine. (Other injectors will fit in but may have the wrong flow levels. NOTE: This could also be your problem, check the part number of the injectors you have.)

You may also have a Fuel Pressure Regulator over-pressure problem. The FPR is pretty easy and cheap to replace if you need to do that. Be sure to take it apart slowly and note the location of the spring (which will fly out if you are not careful!) for re-assembly. It is at the top rear of the injector housing and comes off pretty easily. Replace the gasket while you are in there.

Finally, your fuel return line could be blocked, I am not exactly sure where it is, but I am sure you will have to remove the FPR and then it should be one of the two lines in/out of the outside of the FRP. When too much fuel is present, it is returned back to the fuel tank via this line. (NOTE: I am not 100% sure the Chevys do this, but most FI vehicles do, so I would imagine the Chevy TBI does).
 
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