350 TBI issues

[crash2]

True and that didn't solve a thing. Well if I leave the Temp Sensor unplugged it runs perfect besides raising its idle about 100 rpms by unplugging it. So I'm wondering it there is an issue with the wire from it to the ecm or if it is an ecm issue.

When you unplug the temp sensor--it goes EXTREEMLY rich. damn I forget the specs on it when disc..

 

[Binder]

Well if I leave the Temp Sensor unplugged it runs perfect besides raising its idle about 100 rpms by unplugging it. So I'm wondering it there is an issue with the wire from it to the ecm or if it is an ecm issue.

Not necessarily but possible...Unplugging it IIRC makes the PCM think the engine is really cold and IIRC forces open loop which effects other things. I think on your PCM that wire goes to pin B8 if you want to do a continuity check on it.
Mike the amount it goes rich is a variable from temp to temp and is also different for each BCC.

 

[Binder]

Didn't you say you replaced the CTS? Here are nthe specs on it.
You'll never guess where I stole this from.:;

Coolant sensor approximate resistance specifications:
177 ohms @ 212 deg. F. or 100 deg. C.
241 ohms @ 194 deg. F. or 90 deg. C.
332 ohms @ 176 deg. F. or 80 deg. C.
467 ohms @ 158 deg. F. or 70 deg. C.
667 ohms @ 140 deg. F. or 60 deg. C.
973 ohms @ 122 deg. F. or 50 deg. C.
1188 ohms @ 113 deg. F. or45 deg. C.
1459 ohms @ 104 deg. F. or 40 deg. C.
1802 ohms @ 95 deg. F. or 35 deg. C.
2238 ohms @ 86 deg. F. or 30 deg. C.
2796 ohms @ 77 deg. F. or 25 deg. C.
3520 ohms @ 68 deg. F. or 20 deg. C.
4450 ohms @ 59 deg. F. or 15 deg. C.
5670 ohms @ 50 deg. F. or 10 deg. C.
7280 ohms @ 41 deg. F. or 5 deg. C.
9420 ohms @ 32 deg. F. or 0 deg. C.
12300 ohms @ 23 deg. F. or -5 deg. C.
16180 ohms @ 14 deg. F. or -10 deg. C.
21450 ohms @ 5 deg. F. or -15 deg. C.
28680 ohms @ -4 deg. F. or -20 deg. C.
52700 ohms @ -22 deg. F. or -30 deg. C.
100700 ohms @ -40 deg. F. or - 40 deg. C.

 

[TreeClimber]

I have a spare computer for a 92 TBI GM 350.
Came out of a cash for clunker rig (just in case)
Located in Bremerton / Port Orchard area

 

[KAZU]

Check plugs and cap. If they are fine spend the $40 on TPS and ignition control mod.

Since your tranny is affected I'm pretty sure it's your TPS.

 

[Binder]

If they are fine spend the $40 on TPS and ignition control mod.

Since your tranny is affected I'm pretty sure it's your TPS.

I'm prety sure the TPS is new and I posted how to test it in post #7.
You can also test the control mod without throwing more parts at it.

 

[KAZU]

You are right, but they are $20 and it's always good to have a spare one.

Some new TPSs can fail. All you have to do is run the motor and unplug the TPS and watch the spray as you rev it. However, if it is as he is describing, it's hard to tell by that method.

 

[ManiacMagoo]

The tps tested out fine. The ignition module tested fine. Temp sensor volts are right along with everything else. At this point besides taking it in which I can't afford or just giving up on it. It is no longer throwing codes. Just damn near dies when you lift off the throttle slowing down or barely touching it in a parking lot. Almost like it loads up. Im half tempted to pull my intake and see if there is a crack in the egr port like I have seen before. All I know is it is going through a lot of gas now. For an idea like a lot a 3 mile trip across town cost me an 1/8th tank of gas and it has the 40 gal tank in it :booo:. Im also wondering if it might be an injector issue dumping to much fuel when I let off causing it to almost die then when it gets it burned catches back up. I've seen egr issues and this isnt like any I have seen anyone run into.

 

[Binder]

The tps tested out fine.

What do you mean by "tested fine"? Did you adjust it? If you don't adjust the TPS you're wasting your time.....

Temp sensor volts are right along with everything else.

What do you mean by "right along with everything else"? Did you check it per the table I posted?
After all of this I bet you have a bad EGR.

 

[zukkev]

The tps tested out fine. The ignition module tested fine. Temp sensor volts are right along with everything else. At this point besides taking it in which I can't afford or just giving up on it. It is no longer throwing codes. Just damn near dies when you lift off the throttle slowing down or barely touching it in a parking lot. Almost like it loads up. Im half tempted to pull my intake and see if there is a crack in the egr port like I have seen before. All I know is it is going through a lot of gas now. For an idea like a lot a 3 mile trip across town cost me an 1/8th tank of gas and it has the 40 gal tank in it :booo:. Im also wondering if it might be an injector issue dumping to much fuel when I let off causing it to almost die then when it gets it burned catches back up. I've seen egr issues and this isnt like any I have seen anyone run into.

Damn, you still haven't figured this out????:eeek:----> Quick test---disconnect the damn vacuum line at the EGR and plug it....take it for a test drive, and report back with the results....:awesomework:

 

[ManiacMagoo]

The TPS is right at .54v and opens smoothly to around 4.6v's. As for the temp gauge yes I tested it off your table.

 

[zukkev]

Did you try unhooking the vacuum line at the EGR yet???:corn:

 

[Bill USN-1]

Unhooking the EGR hose may not prove anything.
Carbon can hold the valve open with the hose off.
May be better to manually move the valve diaphram and see if it affects the idle.
It needs to be pulled.
I have also seen plates used without a solid gasket to keep it from porting gasses.

When Checking the IAC you my=ust jump A and B of the aldl and turn the key on.
IAC should buzz. Then disconnect.
Turn key off.
remove jumper.
start motor and check for the vacuum in the port above the IAC.
should be none.

Set min idle to about 600.

I have not seen fuel pressure readings for the inlet and return yet either.

Bad wiring or sensors normally set a code.
vacuum and fuel problems normally won't.
They are not system problems.

 

[zukkev]

Unhooking the EGR hose may not prove anything.
Carbon can hold the valve open with the hose off.
May be better to manually move the valve diaphram and see if it affects the idle.
It needs to be pulled.
I have also seen plates used without a solid gasket to keep it from porting gasses.

When Checking the IAC you my=ust jump A and B of the aldl and turn the key on.
IAC should buzz. Then disconnect.
Turn key off.
remove jumper.
start motor and check for the vacuum in the port above the IAC.
should be none.

Set min idle to about 600.

I have not seen fuel pressure readings for the inlet and return yet either.

Bad wiring or sensors normally set a code.
vacuum and fuel problems normally won't.
They are not system problems.

Although your suggestions are valid---he stated in the beginning that the rig idles fine, which would negate the carbon thing...if you unplug the EGR, and the stumble goes away...well, there's your fix...The EGR is opening too much too quickly, squelching the air/fuel mix when it needs it, with inert gas...And no, it will not set an egr code...maaaaybe a lean code, but doubtful. Seen many of this exact symptom with the result being a bad EGR....

 

[Bill USN-1]

Idleing fine may be different to you and me compared to him.
I have found very few problems that were actually the EFI's fault and were actually mecanical issues.
But most don't understand electronic fuel control so it's the first thing to get blamed when and engine doesn't run right.

 

[zukkev]

Idleing fine may be different to you and me compared to him.

Yup, couldn't agree more---it's just sooooo fun trying to diagnose a rig over the intardnet!!!!
To ManiacMagoo, any updates???:corn:

 

[ManiacMagoo]

Sorry been lazy lately. Well with all the great help you guys have beenI ended up looking at an issue no one has said. I tore the intake off to find a small crack in it in the egr passage. Put on a different intake from junk yard runs great now. :redneck: Only reason I thought of it was one of my dads friends back when I was in high school had a similar issue and put a new motor in. He replaced everything like me. it was a small pain in the ass to see but it was there and this is the 3rd time personally I have seen it. Sad thing is he didnt need a new motor to fix his issue he just had to much money in his pocket.