A week ago I swaped my 350 for my 305, the 305 was running good and the 350 came out of my old camaro and nothing changed, just a minor rebuild and some head work.

Engine started first crank which was awesome.

Drove engine 300ish miles like a little old lady while I did some tuneing to get rid of my richness... decided to start seeing how it acted at WOT, but I could not get to WOT... the engine massively bogged down before it got even close. It accelerated great, as long as you did not open throttle to fast. I was getting some knock so I tuned it out, I even unhooked the knock sensor for a few to make sure the ECM was not retarding the timing too far.

Did some calculations and figured my BPC should be at 128, I had it at 122. (the chip I have from "350 caprice tbi" was at 135 bpc)

Got out the timing gun and found out I was running way advanced (had it where it pulled the best vaccume at idle), so I droped it back to around 6* now and had to reset idle, idles steady and still cruises great... just can't get to WOT. I checked for vaccume leaks and have none. I even tried my old chip in the car from when the same engine ran in my old camaro, only thing different now is this time I have an IAC... and still no change.

So what would cause all this dislike my car has for WOT?

 

i had a similar problem with my car a while back, the TPS had taken a dump. it worked fine below half throttle but anything more & it was like i turned the key off.
also check your fuel pressure & ignition system.

 

Watch your fuel pressure at WOT (tape your gage to the windsheild), you may need a better fuel pump.

 

For a TBI the pressure guage goes in where the filter is, and the hose is really short, but WOT in park (you can still feel the lack of power/rev in park) FP is putting out 15 psi-ish, just like it does at idle. So since it still studders and my FP aint changeing im guessing it aint my pump.

I am starting to think it is a spark issue, but I am not finding/hearing any knock, I have had my distributer timeing from 0 - higher than 8 and it wants to do it anywhere.

According to ALDL my TPS seems to be working fine. ( not sure that means it is )

any other ideas?

 

Do the WOT in Park again, and look into the TB (from a distance). Watch the injections to see if they suddenly quit or do something else funky.

 

Lack of fuel! Still 305 injectors in the TBI I assume? If so you need a BPW of more like high 160s. My 305 was running with 161 BPWC, 305 injectors and 17 psi of fuel pressure to make it happy. I then went to 350 injectors at the 15 lbs fuel pressure and was able to reduce the BPWC down to like 140ish. It flat rips through the gears. My suggestion is grab some 350 injectors, go back to 135 BPWC, stock fuel tables, use winaldl to record BLM data, and tweak the VE tables, the go to the timing and tweak on them. I like to use 10* initial to 1,200 RPM where it starts to advance evenly to 2,400 where I have a full 30* advance in the timing tables. I then add 10* of vacuum advance in by 10 in/hg of vacuum starting at 5 in/hg. Sounds like a street performance curve for a standard distributer, well it is. I then tweak the timing from there listening and datalogging to make sure it isn't pinging. Just one word of warning these advance settings will give you explosive torque and throttle response that is hard on transmissions. My 305 is making my built 700r4 slip going into 3rd @ part throttle. Problem arises from lack of line pressure due to low throttle position and a very aggressive engine tune. Finally I have my PE spark set around 4*. That gives me 34* total timing @ 2,400 and above. It creeps slowly roughly 1* per 1,000 rpm after the max 3,200 table to a total of 38* @ 5,800.

 

redn, yeah maybe my injectors are being goofy, maybe my module is bad.

fast, if it was a lack of fuel i would not be running rich ( I may not have mentioned that ) and as it says in my sig, I am running 65# injectors, not stock TBI car injectors which are 45#.

I am gonna swap my distributor and coil tomorrow since i got another one laying around.

Any other ideas?

 

I doubt that it is the module or the injectors acting goofy. Something is wrong with the fuel or timing. I originally had the same problem. I had it so rich at one point that I could not get the engine to rev over 3,500 RPM in drive. 9C1/Van injectors you say. The stock cop car bin should not have been 135 on the BPWC. That is what a regular 350 with the 61 lb/hr injectors runs. The 9C1 should have been in the low 120 around 124 IIRC. My 1992 G20 350 van .bin that I started with on the old 355 used 124 and it had the 9C1/Van injectors too and that is with the stock 12 psi fuel pressure. By increasing the pressure to 15 you lowered the requirement on the BPWC alot. Try about 118 and see where that gets you. Another possibility is that you have the Part throttle nailed but you are dumping TOO much fuel into the engine at WOT. Do you have any datalogging from the higher MAP, mid-higher RPM areas? In my G20 it was easy to get those but probably not so easy in a F-body.

 

Another possibility is the IAC. I had one crap out on me while the ALDL data said it was changing (it wasn't). the ALDL data only shows what the ECM told it to do, not feedback/results of the ECM's "orders". I would also imagine the TPS is the same way, so it could also be either of these.....

 

swaped my whole distributor and coil, no change.

I checked my FP a little closer, put the guage under the hood... it reads a constant 13 psi at idle and it dont change much at WOT doing 40 while it's bogging, lowest it droped was right above 12 psi.

I used to run with no IAC at all, and I tried the chip that was in the other car with this same motor, still did not like it... so I don't think it can be my spark or fuel tables tables. I mean this engine use to run exactly the way it is now just with no IAC... same exact set up, and it wont even run well with the chip it use to run with before.

As for my TPS sensor, what ALDL says it is reading is all based on the same input that the ECM is reading from it. ALDL can't make up voltage that it thinks it is reading from the sensor, so it can't be bad.

 

did you solve this problem? I am having almost the same issue. Mine just boggs down down at a lower RPM.

Would definately like some of your input.

 

My spark tables were jacked up, took a while to figure it out because nothing changed on the motor, just swaped it from one car to another... different rear end though, I dont know if that changes load much, I guess it could. Any ways I pretty much doubled my spark tables at first and got some major responce and went from there.

Hope this helps

Shaun