I know this is not a thirdgen camaro, but it is a TBI question. I have been a Lurker on your site for quite awhile and I am pretty sure you guys can help me with my problem. I have a '90 chev truck with a 454 and I have a big problem.
I need all of the help you guys have to offer. I replaced the cam and intake on my truck about two months ago. The truck runs okay a little sluggish, but okay. It does not run like it should and it runs worse than stock. I believe it is because it is so rich, I mean RICH.
Here is the deal:
Comp Cams 2030 cam(computer friendly)advanced 4 degrees at installation
edel. 3764 intake
timing at 8 degrees initial (stock is 4 degrees)
fuel at 12.25 psi (when stock pressure was 13 psi)
Truck has a brand new cat. 3 weeks ago.
I used Win ALDL to get the following info:
O2 volts at WOT .95 to 1.0
The rest of the time O2 bounces around and the BLMs and INTs are in the 115 to 120 range.
I am running the stock regulator again because the adj. Reg would only go as low as 13.25 psi. originally the stock reg. Was at 11 now it is at 12.25. I looked for a kink in the return line and everything appears good.
The computer says the temp. is running at 180 degrees the gauge agrees. It runs rock steady at this temp.
I do not know what to check from this point. I can not figure out what I should do from here and why the truck is so rich. Please help!!!

The truck is running a 15.5 secs. in the ¼ according to my Gtech.

 

update:
My IAC readings at WOT are 66 and at idle are 9 and idling in gear 28. ANy time I step on the gas on gear the IAC goes to 66.

The MAP at WOT is 4.4V and 1.0V at idle. It goes to 1.4V idling in gear.

The TPS is at .8V when idling and 4.3V at WOT.

The O2 readings are 1.008V at WOT.

The BLM was at 120 and the INT was at a max of 130 (slowing down with foot off gas) and a low of 113 at WOT it stayed below 120 most of the time.

If you could tell me if these numbers seem out of spec or anything I would appreciate it. I am going to try and re-lash the valves and see if that helps me at all.

 

Got the same problem man (mins 149 ci) I finally put my fuel pressure gague on and its reading 12.5 psi on stock injectors and my O2 readings are still high. Im gonna change the O2 sensor soon and clean the plugs off, I dont know what the heck is going on.

 

I am glad to see at least someone else is having similar problems. I have already installed a brand new AC O2 sensor and new plugs, wires, cap and rotor.

 

What do the 02 voltages look like when you get closer to 5k rpm and WOT? Cam changes typically cause the engine to run rich on the bottom end due to the volumetric efficiency has changed on the engine and your chip has not been adjusted.

 

It stays at 1.008V at any rpm, when I am at WOT. I thought this might be the problem as well, but it appears to be just as rich at 4900 as it does at 2200 rpm. Thanks for the idea.

I am going to try and re-adjust the valves and see if I got them a little too tight.

 

What is the correct way to set them? I went till they stopped chattering then 3/4ths of a turn more, maybe I sould have only gone 1/2?

 

That sounds like the correct way. I went 1/2 tur, but that was on a big block. I have a friend who swears that you have to adjust them running. You tighten them down until they stop clicking aand then another 1/32 of a turn. It is really messy, byt his vehicles are fast.

 

I would try more timing and see if it helps. It will also help alittle with the richness.(By firing sooner the air fuel mix gets to burn longer and more fuel is burned). I have actually seen this with WinALDL.

 

I had the timing as high as 16 degrees and it still ran like a dog. It seemed to be best around 8. I am pulling it apart right now to turn the cam back to straight up and check all the valves.

 

I am not an expert by any means with the TBIs but I was thinking that if i recall correctly that your TPS voltage was just a tad high. No biggy till I thought that by increasing the TPS voltage made the mix a tad richer!! What would happen if yall backed your TPS back off a little say to abaout .7 volts???

 

That is great. I was looking for someone to look at my sensor readings and see if they were in spec. When I get the truck back together tomorrow I will try that.

 

Someone needs to burn themselves a chip!!
How is your part throttle performance? Your BLMs indicate the VE tables are set higher than the engine wants (you want BLMs of ~125 in any of the 16 BLM cells throughout the operating range). Your WOT O2 voltages are also a little high, even though a switching sensor should never be used like a wideband.

Determine the PE (power enrichment) engagement point by looking at WinALDL while driving (look at TPS %). Then, drive around and don't exceed this throttle opening (keeping the ECM in learn mode). Try to get high rpm data, and try to do it while driving up a hill. Let the ECM "correct" the higher load VE with the BLMs. Then don't shut the truck off and try some WOT runs. If you are lucky, the O2 will be lower. If voltage is lower and performance improves, then that just proves you need a custom chip...