WHAT'S LIMITING MY POWER?!?!

Saabguy - the only minor correction is that each bank has its own coil pack, but they're both controlled by ONE computer.

 

That's an easy enough thing to try tonight, although I checked both DFUs for spark at the outset by pulling off the wires, and the coil terminals were sparking. I also verified that the plug wires from DFU #2 were hot using a spark plug wire tester, so we know that the coils are firing and the plugs are getting fire. We also know that the front bank has (or had at PPI) good compression, so that bank SHOULD be getting fired just fine. I can't speak to the accuracy of the actual timing yet, but the unit is dialed in correctly. So either the unit is not firing with correct timing, I've got a set of bad plugs, or there's something wrong with the front head. But I doubt it's a bad DFU. Nonetheless, will report back tonight after I swap them.

 

Starting tonight's session now. Switched the plug wires tit-for-tat on the coils, BUT there's not enough give in the harness to switch the DFU feeds. I'm working on it...
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Okay, I successfully re-wired DFU2 as DFU1 and vice versa, including swapping the ground wires, pinout leads, and plug wires. The result was SOMETHING, but inconclusive at best (to me, anyway). Unfortunately, even after warming up, the engine was running so roughly - and the searing rich stench returned - that it was both hard to stand over the motor OR get a good read on the change in engine behavior at the rear bank. It was idling around 700rpm in this configuration, and sputtering awfully, so it was hard to tell for sure. A couple plugs were "inconclusive," even after several tries.

5-OK 6-OK? 7-MAYBE 8-OK
1-OK 2-OK 3-BAD 4-BAD

6, however, gave different results four separate times.

As far as I can thus tell, the coils/wires firing a dead bank yesterday fired at least half the opposite bank today.

This doesn't outwardly suggest anything to me about the plugs themselves, or the banks. Not sure how to analyze the coils, except to say that something clearly is wrong at the ignition level (at least its maybe not cam timing?), and certainly sticks a fork in my theory about a fuel obstruction to the front bank.

First thing tomorrow, I'm going to make an appointment with the ignition shop for as soon as he can get me in. In the meantime, I just today received the last item I needed to start restoring the fuel system, so there's something I can work on in the meantime...

Sincerely,
Frustrated in Ferrariworld

 

Really, Saabguy? I can't even replace my fuel filter or do an oil change this weekend? It just seems - the more I think about it - like the timing is off on the ignition, OR it's firing out of sequence.

According to my plug/coil configuration, I'm running 1-5-3-7-4-8-2-6 firing order.

I think what remains is actually doing a diagnostic on the ecu and coils, which is beyond me. Heaven knows, as do the dozen or so of you patient contributors, that I tried my hardest to chase this down. Alas, I think I'm foiled.

 

Tires are new; should be fine I'm scheduled to take the car back to the ignition shop next Wednesday. Honestly I'm a bit relieved. Will give my guy the list of things Ive checked, and let him do his worst.

HOWEVER, he still believes its a fueling issue and says there's no way the green solid light should be "on" on the control unit if any part of the system is out of whack.

 

Unfortunately, electromotive doesn't have another expert in Chicago, and neither of the independent Ferrari master mechanics here are seasoned at electromotive (I asked, and they tend to use Petronix in 308s). So, for the time being, he's got better diagnostic equipment and mechanical experience/dexterity than I do. I think I've been bothering the f-chat community at large long enough for input, and this clearly is beyond my competency.

 

DavidB -

You are completely correct. It was cyl 1&2 bad. I was jotting down quickly while fighting bad gas fumes

 

Car went back to the ignition shop yesterday morning. They could not have been more accommodating or thorough. They verified that the laser reader was correctly positioned, and that it was on the trailing edge of the 11th tooth at TDC. They verified timing with a light and also electronically with a meter. They used a crank simulator and various voltage meters, etc and confirmed that the coils, wires, and plugs are doing what they should be doing. And they went step-by-step to check the wiring at the control box, DFUs, etc. EVERYTHING CHECKED OUT FINE, and they took pictures of every step in their diagnostic process for me.

Then he went for a spin.

Called me and said - as a performance tuner who's driven more cars than he can count - he's pretty certain my "bogging" issue is a slipping clutch. He says the fact that you can watch the revs spike when you hit the throttle, but the car lags behind while accelerating (linearly, but very sluggishly), indicates the engine power not being transmitted to the gears.

PPI originally indicated that the clutch was taking up at the top of the range and needed "adjustment, possible replacement," but I've been okay with the shifting so far, and it was nothing like the symptoms when the clutch on my old 928 failed. Clutch is a few items down on my list of things to do, so I'll just move it up the list and tackle it now.

HOWEVER, still doesn't explain the carbs sucking 10kg/hr at idle, or no apparent change in engine performance pulling the front bank wires. He agrees on that front, but confirms that - at any rate - it's apparently not the ignition.

My thoughts are now to change the clutch, then send it back to my PPI mechanic for a follow-up inspection to ferret out any remaining issues.

 

The main reason I "upgraded" to an electronic ignition was that my original supposedly was way out of whack and in need of refurbishing, per the PPI in March 2014. Unclear if it works properly.

PPI noted backfiring and misfiring, but also that there was oil weeping from the cam seals into the distributors. May have been related, but I didn't want the Seller's mechanic (who agreed to cure the PPI issues) messing with the cams, and my own guy suggested I get rid of the points and go with something electronic. Seemed like a good workaround until my next cam reseal.

 

Saabguy -

Yes, took an inductive timing light to the wires, and wires are getting spark. Interestingly, it seems to have no problems starting off the line in 1st, but I swear it's like the hand of G-d holding onto the rear bumper as you try to accelerate. I mentioned in the first post that you basically have to take it to fourth gear just to get it to ramble along at 25mph.

Going back to my original thesis - that there may actually be several "problem" items happening at once - I spoke with David Feinberg this morning to get a list of clutch parts I should procure, and he suggested it could be a combination of clutch, PLUS someone in the past mis-calibrating the idle setup on the carbs (either jets/screws or linkage), which results in the heavy breathing and loss of power. He said the ignition timing and idle can be set correctly, but at the wrong degree of compensation for idle mixture, which can show correct idle speed on the tach and correct ignition timing with a light, but cause the carbs to breathe wrong.

I DID verify last weekend that the flywheel TDC mark corresponded to the cam shaft TDC marks, so - coupled with the strong compression numbers - I think it's fair to say the cams are reasonably correctly timed. Leaves either a fuel starvation issue or a carb air intake issue.

So again, since we now KNOW there's a bad clutch, I'll address that, maybe rebuild carbs anyway, then have a local master mechanic do the proper synch. I'm comfortable with that.

Prepare for a separate restoration thread...