Whos Got Problems??

[jeremiahkellam]

I've got problems!!
I know just enough about engines to get me in trouble, and I'm not sure if that is the issue here:
Swapped HO intake for Cobra/GT40
BBK shorties
and an E303

When I changed the cam, everything else stayed, no new timing chain, no valve springs.

I'll throw this in the mix as well... before changing out cam, set crank to TDC, when I pulled the timing chain cover, I could swear the dots were not lined up. I pulled the sprockets off, and the key on the crank and the pin on the cam were alligned, I scratched my head, slid the sprokets back on and everything lined up... again maybe I just didn't see it right...but...

It starts and idles. It idles high, around 1000, any lower and it just surges.

I have not had a chance to drive it yet, only idle it and roll the throttle by hand. It seems like it is real rich, at idle anyway...

So...went to dyno this morning, first pull, it ran up to 3800 and fell on its face, and we aborted. 2nd pull, same thing. 3rd pull, it did the same thing, but we stayed in it, it pulled all the way to the limiter. The graph showed when it started to stumble, the hp curve just remained steady, at a whooping 205 +/-. The a/f was right at 13:1, jumped to 14:1 at 3700, then shot up to 18:1 around 4200(side note, the operator didn't seem to sure his O2 sensor was working right)

So... air leak?? (tried spraying carb cleaner around base of intake, no sudden change in rpm)
timing??? (bad timing chain, bad damper...)
or... valve float???

I did find a small vacuum hose that was loose, the small one that goes from the intake to the canisters on the passenger side.

[jeremiahkellam]

MAF is stock, i've cleaned it, again. When I got back home from dyno, I found that when I last removed and cleaned the MAF, I had taken the back plate off of it, and didn't put it back on. I found it and put it back on. The computer is stock, A9L I believe. It is not the one that came with the car. The car originally had an auto, when we swapped it, I had a problem, got a rebuilt comp from Autozone, and it worked fine after that. The injectors are the original 19lb. I cleaned them and replaced caps and orings while swapping the intakes.

Don't ask me how many miles are on the engine, I bought the car in Jan of 08 with a stuck odometer at 152000 (hell, could have 200000 by now??...)

[Chuck]

Is this in your sn-95? The A9L is a fox computer, and had a diiferent connector unless the harness has been swapped.

You mentioned having an auto at one point...on the fox cars if you use an auto O2 harness with an A9L, it will zap a ground trace in the computer. Been there, did that. The good news is the trace is easy to solder a repair in.

Check fuel pressure, timing, and TPS voltage. The stock style balancers can start slipping on the outer ring.

Chuck
CMC #14

[jeremiahkellam]

My mistake, it is the correct computer, what ever # it is. Again, it ran fine after swapping computers, this problem is just since cam / intake swap. I thought maybe the balancer had slipped. When I had put the timing chain back on, I turned crank a touch to make sure dots were perfectly lined up. When I put the damper back on, it was pointing at 5 ATDC (+/-)

I've played with the timing from about 5 to 15 BTDC. But I still haven't got to drive it after these little adjustments (cant get over speed bumps is subdivision) and I only got 4 pulls on dyno and no chance to tune, they pushed me out the door (thanks Village Automotive...)

I guess I'm more worried that it might be valve float given the age of the engine (that and the fact it is the hardest to fix on short notice...)