92 k2500 idle problem

[chevyman98]

Picked up a decent looking 92 k2500 for fairly cheap fir a new dd sold my new one so the wife could have a nicer car since she hauls the kids more than I do plus I hated the 2012 compared to the gmt400s, figured it'd be simple but looking like it's not. I posted on another site my computers down other wise I'd copy and paste everything. I'm going to redo my grounds next other than that I'm stumped at the moment

 

[chevyman98]

I have a 92 k2500 with a 350 it starts up idles high but runs rough then dies. You can start it back up a couple times then on the 3 or 4th time it will be hard to start but when it does it black smokes like it's over fueling. Then clears out after giving it gas to keep it running. PO put on new cap rotor wires and plugs. Im sure its a sensor but plan on pulling the plugs seeing if there are gapped right maybe put ac delco plugs or ngk. I need to see if there are any codes. Any suggestions on what it could be, IAC, map or EGR maybe.


Not sure if this helps but it has gibson shorty headers with o2 in driver side header tbi spacer snorkel to inner fender for cooler air and suppose to have a custom burn chip. Is there a way to tell if the chip is bad.

Well the scanner doesn't do odb1. Ive unpluged everything one at a time. O2 sensor, ect, map, IAC, TPS, and nothing changed the way it was running. I went to the garage to get a can of brake clean to check fir vacuum leaks I came back truck was idling high and had a much louder air suction noise coming from the TB. I cut the truck off started it back up and the noise want there.

Unpluged egr and capped off vacuum port on tbi nothing. Pulled IAC and found this filthy and a damaged spring. Guess this could be my problem. Local parts stores only had borg warner and house brand. All aroun$50. I can get a acdelco for cost threw work for $32 but have to wait till Tuesday if I go that route. I may just get the part store one see if it fixes it if not I'll return it and get the delco and continue to troubleshoot


Had some time to mess with the truck. Egr drops 2inhg in 20 seconds, also found what seems to be a loose ground wire coming from battery terminal to fender ground. Also cleaned my grounds to thermostat housing. I only have two grounds.
1 from battery to head
1 from frame to body that's small braided one. I thought there was suppose to be at least one more.

 

[chevyman98]

Can I run a ground from block to frame and get the same results? Would you say the egr is bad?
Last question when the trucks running and I was looking for vacuum leaks with the air cleaner off You hear the normal sucking noise then the truck idles a little lower then the sucking noise gets way louder starts running rough and dies. Possible bad injectors? Im going to pull the throttle body and rebuild clean it up see if work can clean the injectors if not bake them.
Thursday I had the scanner hooked up giving it slight throttle around 1200rpm run decent then I let off to see if it would idle it did then brought the rpms back up to around 1500rpm it would show esc counter and knock slowly going up if it was above 1500rpm.
Iac is showing 140 KOEO.
Running under its own no throttle inout by me it goes from 800-1300 rpm and iac ranges from 85-140

I've sprayed everything with brake cleaner and doesn't seem to change. I think when I rebuild the tbi I'll change all other gaskets besides intake if no change then I guess it'll be time to do intake gaskets.

Pulled the tb found some loose screws I guess it could affect the way it runs, also looks like fuel has being leaking from diaphragm area for a while.


Ran the truck about 15 secs to get the tps voltage of .54. Seems like one injector isn't atomizating fuel like it should

 

[98_k1500]

Sounds like the MAP hose may be cracked. Good place to start anyway.

 

[chevyman98]

I looked but I'll check again.

 

[chevyman98]

Finally got some time. Line to map looks good, pulled plugs on driver side look fouled. I bought some ac delco rapid fires hopefully get them in tomorrow

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Passanger side look similar.

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I'll try to get pics tomorrow. I'm going to try and run a compression check tomorrow.

Also found this just checking the cap and rotor.

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[chevyman98]

Anyone?

 

[chevyman98]

Compression was good. 180-175 on all cylinders

 

[michael hurd]

I don't like the look of the wire on the pickup, as well the base of the distributor is corroded, even the screw holding the ignition module is corroded. If there is high mileage on the motor, you might better off to drop in a new distributor than remove to change the pickup, and remove the module to clean, and apply new heat sink grease.

A complete new unit on Rockauto is about $ 70.

 

[chevyman98]

I didnt like it either. I thought the under side looked like it may been acring from the tanish color. Put new rapid fire ac delcos in seem to do better but then started acting up.
What's the map reading and voltage suppose to be at idle and with key on engine off