WHAT'S LIMITING MY POWER?!?!

The PPI never mentioned a power loss, and it was done by a nationally respected Ferrari master mechanic. Mind you, it was mid-March with bad roads, so who knows how much actual driving he did. He noted that the distributors were full of oil and the carbs were out of sync, causing a misfire and backfire.

My goal was to set the car up to run as reliably and optimally as possible. My years of f-chat reading indicated getting rid of the airbox restriction and upjetting the carbs off the bat, and even my PPI mechanic said to get rid of the crappy points, so I upgraded to electromotive. I actually thought my big projects would be tackling a suspension and fuel hose redo. I wouldn't have tweaked the carbs or messed with anything if I thought I'd be chasing down this issue, but i thought I was doing some solid pre-delivery optimizing. I guess I still have the old jets to pop back in if necessary.

 

Scott- didn't take any offense; just trying to fill in the background gaps on what motivated all this. Made TWO interesting discoveries, for what it's worth. First, I found my baggie of salvaged jets in case I wanted to go back to stock. The previous owner was running 200, 125, 55. Is that not richer than my setup?

ALSO...........When I manually checked the throttle for range of motion the other night, it was my friend who pulled the airbox. He would have been the one to notice any irregularities, except that he's not a Ferrari guy. When the ignition shop buttoned up the car, the airbox was gently placed over the carb studs for shock protection, but not fully screwed down, because I had mentioned wanting to pull it again and replace the fuel hoses. I totally forgot that, and, Bottom line, I discovered the four velocity stacks tonight in my box of parts to re-install. Apparently my two runs last weekend were done without them. After all this, could THAT cause these problems?

Lastly, all the top techs and electromotive folks are saying to dial in 8-12 degrees of initial advance. Just noticed that the plate in the engine bay says 3 degrees. I trust you guys more, but thought it interesting.

 

It's not the shop's fault; they wanted to put the airbox back on for shock protection, and asked if I wanted everything fully reassembled. I actually told them no because I wanted to send the box out for fresh powder coating and redo those carb fuel lines. It just sat so long waiting for driving weather to come around, I'd forgotten.

 

BigTex -

The BOX always was on; it was just stuck on over the 16 carb studs, and not fastened down. Won't happen again

 

I was re-reading the Birdman carb synch tutorial, and - based on some of the symptoms they mention relating to idle jet issues, I think that could be a contender.

 

I also want to check all the chassis grounds. Will report on that.

 

Brand new battery

 

Today I put the airbox back on, along with the velocity stacks, to try a short trial run. Adding the trumpets didn't help at all. I DID notice, curiously, that the right-most front bowl was spitting so badly, at one point I literally saw enough fuel spit out to audibly slosh against the bottom of the deck lid. I cut the power at that point. Interesting that people observed my Cyl 8 plug to seem a bit lean-running.

Sooo, I purchased enough carb rebuild kits to do all the carbs, plus upgrade to sealed bearings. That will be the next technical challenge, but thankfully there is a GREAT Youtube video (maybe by one of our own) going step-by-step. We really should photograph that for a Birdman tutorial. Will also check/service the floats.

Between all new fuel and vapor lines, filters, and carbs, that should cover rebuilding the fuel system. (I guess I need to figure out how to clean out the gas tanks and service the check valves, too).

In the meantime, I'll proceed with restoring the airbox and maybe opening a formal restoration thread on the car. No reason a bogging issue should detract from an otherwise-positive sprucing up. The former owner let her mechanically waste, so it's time to get her ready for prime time again

Thanks to everyone who's given their advice and input along the way. Will circle back once I get going on things.

 

I literally watched a carb spit like a burst from a drinking fountain, high enough to hit the bottom of the engine lid and make a big wet splotch. ARGGGGHHHHH!!!!

Okay, so a carb rebuild kit is on the way, BUT let's review a couple things in the meantime before I pull them apart.

So far, I've checked:
1) coils are firing
2) plugs on both banks are firing
3) timing is set correctly at the ECU
4) plugs are connected to the proper terminals and cylinders
5) engine ground is connected
6) DFU grounds are connected
7) DFU pins are properly connected at each DFU
8) free opening of butterfly valves at WOT
9) exhaust obstructions

I have NOT verified:
1) Alternator health
2) 12V B+ wiring from alternator to ignition, rather than powering off of stock loom
3) Trigger wheel "starts" on 11th tooth, per manual
4) Apparently there is a SECONDARY rev limiter that can be tripped, per the manual, and I'm not sure I understand how.
5) Manual mentions something about certain older vehicles needing a tachometer amplifier, as the XDi is designed to read off as 12v source, and older cars use a 120v output. Anyone?
6) cam timing
7) valve health
8) fuel tank filters
9) fuel lines
10) Apparently there is a jumper between the DFUs that synchronizes them, and - if connected backwards - can seriously mess with timing. Can't see it or find in manual diagrams.
11) carb obstructions or float issues (will rebuild)

 

I will get the car on the lift this weekend and do the engine turning test. I did not think about that as a possible diagnostic, but I definitely can handle that. Do you actually pump the gas pedal to get fuel to the bowls, or just turn the key to the second position? How would you disconnect the ignition? Just pull the leads on the DFUs, or is there a good fuse to just disconnect?

Also, the PPI did a full compression test, and all cylinders were 150-155. Compression should be okay.

 

I just got off the phone with my ignition mechanic, who verified that he checked everything with a timing light against the dial settings, and that everything matched up. As a professional engine tuner, he said my problem sounds like fuel starvation at higher revs, and maybe (also) jetting issue.

Also found out he DID use a tachometer adapter. He mentioned that my carbs did NOT look so bad when he put the new jets in, synchronized them, and checked the throats/butterfly valves.

Anyone have any thoughts on the safest way to check fuel pump flow/pressure? I'm concerned I'm going to wind up setting my car on fire trying to be a shadetree mechanic.