I may be getting closer to an answer, but I want to see what you all think. Today, I checked spark to the plugs with different testers on the wire and plug ends. Cannot get my inductive timing light to work off an auxiliary 12v battery on the floor, and the leads cannot reach the front battery. BUT, the new dial settings seem to be much smoother than before. Originally, we were trying to dial in 38* of total timing by setting the knobs at 12,28,-2. Doing 13,17,8 seemed to make a positive difference. I may be imagining things, but the eye-stinging richness seems to have gone away. I can actually work over the engine while it's running now. Then, I brought out the carb synchrometers, and things got interesting. In reading Birdman's tutorial, and watching the 17min youtube video on this process, it seems the stacks all should be flowing about 3.5 at idle, and about double that under load. At first, the problematic right front carb was reading about 5, the left front carb was reading around 7, and both rear carbs were reading 10. While I had the motor running, I sprayed a ton of Gumout down all the throats, and the problematic carb seemed to flow much better. BUT, I think something still is off. After spray cleaning the throats, my final readings were: FR 8/7 8/8 10/10 10/10 REAR Aside from not being totally synched, aren't those readings WAAAY too high for idle operation? Would that indicate a float issue or an idle jetting issue? Or no issue at all, and I'm back to the drawing board? Image Unavailable, Please Login Image Unavailable, Please Login
Yes. If the warm idle speed was ~1000 RPM and the idle timing on both banks is ~7 deg BTDC = it means at least 1/2 of the cylinders aren't actually contributing at idle. If you remove the spark plug wires one at a time at idle, the idle speed should drop by the same amount (and the engine "note" should change equally) when each wire is removed; if you remove a wire and no change in RPM/note = that cylinder really isn't running at idle. (Although, you have to be careful not to shock yourself -- so do at your own risk.) PS Not sure an easy way to confirm/deny this, but, with a multi-coil, waste spark system, getting the firing order right (and checking it) isn't as easy as with rotor-type distributors. Since you also run out of steam on the high end, that indicates that whatever cylinders aren't contributing at idle, they also aren't ever contributing (and that, usually, is not the signature of carb trouble which tends to work at the high end even if idle is mucked up).
Steve - I apologize if I miscommunicated the readings; the CARB FLOW METERS read in the 7-10 range. That was what I wondered about, as every video I've seen synchronizing them at idle has read much lower air flow numbers. The IGNITION is set to 13* initial advance, which I haven't been able to verify by timing light, but seems to be working better.
The exhaust being different between the two sides is not unusual. The muffler is not divided by sides. The exhaust is usually stronger out of the left side.
You seem to be making some progress. The carbs seem to be responding. However, you will probably have to really rebuild the carbs if you want things to be smooth and function as they should. There are so many parts and adjustments when you rebuild a carb, that is is almost necessary given their age and infrequent use prior to your purchase. If you rebuild them, then you will know exactly what is going on with the filters, floats, jets, throttle plates etc. For example, just with the float, you check the pivot hinge, the float weight, solder joints for leakage and then measure and adjust the 2 float levels. Now you have all the other parts of the carb and then do it three more times! Imagine all the things that are dirty, mis-aligned or not all the same, like jet sizes. Spark Plug Wires-You mentioned earlier that you are not using the extenders with your spark plugs. I have the same set up but use the extenders because the spark plugs are so far down the hole. As I look at your picture, I notice the red plug end and the black rubber plug. What are you using to connect the end of the red plug to the spark plug? If it is a flexible wire, are you sure that is is firmly snapped onto the top of the spark plug electrode? I would double check to make sure it "clicks" onto the electrode, otherwise, you may be getting a spark from an indirect connection.
Much too high (for a ~1000 RPM idle with reasonable timing) -- you have some cylinders that aren't contributing at idle. (In fact, at 13 deg BTDC at idle, you should be closer to 3.0 Kg/hr/barrel).
GREAT! Now we've found something! Where should one start looking for a source on this one? Cam timing? Floats?
I already gave my initial diagnostic recommendations -- determine which cylinders are not operating at idle (the pattern of inoperation can be a clue), and determine if the firing order on the new ignition system is correct or not.
Steve - I'm sorry if I sound like a broken record, but I don't have your level of technical proficiency. - My plug wire tester showed that all wires were getting spark. - My plug tester got a spark out of each plug. - I've visually confirmed that each DFU coil is firing. - I've verified that every wire is connected to the proper coil terminal and cylinder. - The DFU lead wires are pinned into all the proper connectors as per the instruction manual. - Ignition timing should be more-or-less reliable at this point. - The XDi dip switches are set correctly for an 8cyl/4cyl tach system. - The XDi is drawing proper 12v power from the starter B+ terminal. - The DFUs, motor and battery are properly grounded. I'm ready to believe half the engine isn't firing (I guess that's what a ton of people suggested at the outset, based on the symptoms), but HOW - in a technical sense - does one diagnose which cylinders aren't firing if the ignition is properly timed and working?
What Steve said was to unplug each wire and listen for a change in RPM. Each one should cause a similar decrease in revs/sound. Or you could get the distributor(s) working and eliminate the new system entirely ;-)
Does this mean: 1. that you've studied the schematic, and verified the actual wiring (both going to and leaving the coils), or 2. just that someone placed some numeric labels on the coils for only the spark plug wires leaving the coils that go to the corresponding number cylinder?
If half the engine isn't firing, then the exhaust header from that cylinder will be cool. Use a laser thermometer and measure the temperature of the header as it comes out of the cylinder.
Steve - Have studied the schematic, but only verified that the correct plug wires go from A1,A2,B1,B2 to the proper respective cylinders. I have NOT verified that the wiring between the XDi "brain box" and DFUs is correct. Will be a b***h to get at the way he mounted the box in a custom bracket, but I will go through the pinouts tomorrow. Joe - I don't have an infrared thermometer, but will grab one on the way home from work tomorrow. Did you notice my post from yesterday that one side of the muffler seems to be emitting heat but no forceful air?
The XDI has a status light. If all is OK, I believe it will be steady green. From what you posted and checked, I think the unit is working. Plus, as I've said before, it does work and fire your engine and if it goes to 5500, ignition wise, it should go to 7500. I still think the ignition is generally OK. Regarding the pin-outs-Make sure the wire and pin is fully locked into the sockets. You can usually see the metal edge of the pin right to the edge of the plastic socket. If you have to re-set a pin, the manual has a section on how to release the locking mechanism of the main socket. I think its at the end of the manual. When I setup mine I had a misplaced pin, and my car would not start. Your's starts and runs, so I would be very surprised if the pins are not correct. Regarding the mufflers, you should be able to feel some force to the air with your hand. Heat, but little air, could indicate an obstruction in the muffler. Can you loosen an exhaust joint before the muffler? (Sometimes the exhaust seal, "donut" does get stuck and it becomes a production.) Also, if this is a USA car, are the air injectors and one way valves intact? The air injector tubes are prone to rust and cracks. Although they may cause an exhaust leak, there still should be good flow through the headers and exhaust pipes.
Air injector rails left with the smog pump (previous owner). I do not know what sort of bungs they used to plug up the holes. Need to check that, I guess (I have a set of Verrel's sitting around). The green light on the XDi is steady on. Tomorrow's tests hopefully will be: 1) Verifying the trigger wheel is set to 11th tooth trailing edge at TDC 2) Try to get timing light to work and verify advance settings 3) Individually pull plug wires to observe effects
I am begrudgenly typing this because I am afraid it is a silly guess, but what the heck, I would hate for this to be it and not said anything. After I rebuilt my engine it would not start and I was pulling out my hair. I logically thought that the coil in the front was for the front bank, and the coil in the back was for the back bank. After looking at photos from before the rebuild, I saw that they really were just the opposite, so I just swapped the high tension leads, and she fired right up. Now you have a waste spark setup, so what if the second firing is just enough to make it go, but not at the right time? Long story short, make sure the high tension leads on the coils did not get swapped.
Just going through scenarios in my head, and I'm wondering what the symptoms would be of a partially-seizing or badly torqued exhaust cam. Would one header would show little forced air coming out, and waste gases back up through the carbs. Either way, if the ignition all checks out, the heavy-breathing carbs would seem to point to a cam issue, not a fueling issue, no?.
E-Dino - I'm still trying to wrap my head around how this would work for the XDi, but it's a new possibility to check. Let me go back through the wiring diagrams in the manual and see if I can track these down. With the electromotive system, it's somewhat dummy-proof because there are color-coded wires that run directly from each DFU to the control unit. I keep looking for this alleged "jumper" the connects the DFU's, and it doesn't exist in the diagram. These aren't wired according to "front" or "rear" bank; just DFU 1 (with coils A1 and B1) and DFU 2 (with coils A2 and B2). Everything is clearly marked, so it's hard to see how that could be reversed.
E-Dino has me thinking.... Is there a safe or practical way to check actual firing order without electrocuting oneself? It would happen too fast to observe with a naked eye, but is there any device or specialty shop equipment where we could just connect my 8 wires and see if the firing order matches a 308's?
I've already sought professional help. My ignition shop says they can't get me in until June for a diagnostic; ditto for both independent Ferrari shops here. Just killing time hoping I figure it out before I start racking up diagnostic hours (especially if this is a problem with multiple systems).
But the first thing that you are going to do is pull the plug wires one at a time tonight right? And yes the engine has to be running. And you can loosen the plug wires before you start and you don't have to pull them out of the hole, just off the plug. Ground them on the side wall of the hole to keep from getting shocked. And if you get shocked… hmm… WHEN you get shocked you will regain use of your bladder in four to six weeks. Or not. Sorry, I couldn't resist, just pull the plug wires with a pair of insulated pliers and ground on the side wall of the hole. No shocking involved.
Yes, Saabguy. Until someone who does this for a living can make room for me in their shop, I will be running every test I can to get to the bottom of it. TODAY, that will be pulling the wires one by one.
