Code help for 89K5 TBI

[bigcat44]

I just installed a new dual exhaust (FM40 series) along with Hooker headers and an Edelbrock performer intake manifold. I had a difficult time starting the rig back up as I blew my ECMB fuse. Before I determined that I pulled the distributor thinking it was off 180 so I flipped it and re-wired. After finding the fuse the truck fired but it was obvious the timing was way off! I then pulled the distributor again and flipped it back to the correct position and re-wired and then set the timing. Now the truck idles pretty rough and the Check Engine Light stays on. I am getting codes 33 and 44. I am pretty sure the O2 sensor is shot as this got clipped during the header install but what could that cause both codes? My vacuum lines are connected good except just behind the throttle bodies there is a valve mounted to the manifold kind of short and it has a hose that runs up to a T fitting on the firewall??? That is the only hose I could find and I haven't been able to find pics of an engine bay that would show this. My next concern is on the Throttle Body there is a metal bracket/line that connects to a vacuum type valve mounted on the firewall, this is for cruise control correct? My eyelet broke off the diaphram of the valve so I cannot connect the bracket but my cruise has never worked so I was thinking I didn't need it. Sorry for such a long post I am just lost right now!!

 

[Bubba Ray Boudreaux]

CODE 33
MAP Sensor Check the vacuum hoses from the MAP sensor. Check the wiring at the ECM. Replace the MAP sensor.

CODE 44
O2 - Lean Exhaust Check the ECM wiring connections, particularly terminals 8 & 15. Check for vacuum leakage at the TB base gasket, vacuum hoses, or the intake manifold gasket. Replace the O2 Sensor.

 

[justinf]

I would start off with the O2 sensor. You are pretty sure it is junk, so go get a new one and put it in. then start up the truck and see how it runs and what codes if any come up.

 

[mikeash]

My 1990 with throttle body was throwing the same codes and was running very rich and would sometimes idle rough and die. My problem was the MAP sensor vacuum hose that went to the back of the throttle body was not connected. Plugged it in and the engine light hasn't come back on and mileage went from 8 to 13 miles per gallon. My map sensor was by the left rear of the tb and the fitting was in the back of the tb. The map sensor will cause the O2 sensor to throw a code because it resorts to running so rich.

 

[mikayak390]

I assume you tried this already but when you set the timming did you disconnect the green or brown wire to the computer. When I put my motor in last year I forgot about that little detail. The light said I was exactly where I wanted the timming, but I was actually 20 something degrees out. I was getting all sorts of check engine lights and it ran very poor. Two days later someone told me to pull the wire before setting the timming. Amazing how much better it ran when I did it the right way. It did not help my ego that he pointed out that the instructions to pull the wire were written on the front of the engine bay.

 

[bigcat44]

Well I just picked up a new O2 sensor and will put that in along with checking all the MAP sensor connections when I get out of work today. I didn't disconnect any wires when I set my timing but I guess I'll be doing that today! By any chance could someone post a pic of their engine compartment specifically the TB hose set-up and intake manifold set? That would give me a really good peace of mind

 

[bigcat44]

Alright I just finished up on the rig. My timing was slightly off but the main culprit was the maf sensor hose became disconnected where it mounts to the TB. That probably occured when putting the air filter back on as the hose fitting was loose on the hose. The Maf sensor problem caused the O2 problem, no more CEL. Thanks for all the help!!