All right, WTF

[firechiken]

Rodeo's running real rough at idle, like it's missing, up until about 3500 rpm, and then it seems to smooth out. I have good spark, but changed the plugs, wires, cap and rotor anyway, they were due. Have good fuel presure at the TB, but changed the fuel filter anyway, don't know when it was done last. Only code I had was for the O2 sensor, so I changed that. Checked distributor timing and it's right on, and almost no play in the dist. shaft. I'm getting dark smoke out of the exhaust, and thanks to the fresh blanket of snow we got today, I noticed a black goop coming out of the pipe, too. Any ideas on what could be causing this? Stuck or burnt valve? This came on suddenly, I've had no problems prior to this.

'92 Rodeo
3.1 iron head
TBI
no mods

[geoffinbc]

Sounds real rich. The coolant temp sensor may be out of wack.

Needs to read 3400 ohms @21*C(70*f)

[firechiken]

All right, I'll pull it off and check it in the morning. Thanks!

[firechiken]

OK. I checked the coolant temp sensor and thats alright. Finally got some good light to work with and I noticed one if the injectors was shooting a thin stream of fuel out of the center, so I'm sure that's the problem. Now, I have good injectors on my 4.3 TB that I was going to use for my swap. I don't have time to do that right now, and I'm wondering if I could use these without any adverse effects? It would be nice to figure this out before the snow comes this weekend.

[geoffinbc]

You could try them but they will run rich. When you get into closed loop however the ECM will compensate.

[firechiken]

I pulled the connector off of the injector that is bad, and it smoothed right out. I'm thinking I can limp it to the garage tomorrow and do the swap. Shouldn't take more that a couple hours, I hope!

[firechiken]

Well, the swap didn't happen today. The TB on the Isuzu has raised bosses and three holes on the throttle cable side for the throttle cable bracket to bolt to, so I have to drill three more holes in the TB from the 4.3. I did however replace my one bad injector with one of the 4.3's. Works fine, in fact it's running better now then ever, although that might be from the new O2 sensor.