308 QV Basket case Engine miss

Not much....LOL!

The failure mode is cracking and arcing to the head, if you don't see cracks or tracking then the real test is watching the arc at the spark plug.

Colortune to the rescue!!!

Gosh, Rocko ...they can't ALL be cream puffs!

 

Thanks, John...

 

You rock.....welcome to the website man....

 

Bravo post.

 

8 cylinders...they DID lie in the ad, about the 6 speed transmission.

There's your legal grounds....

 

Little to none, I hope!

 

Hi, Rob. They're the P.O.'s wires, but I'll check the records. No faults from them so far, but I do want to pull the dist. caps and have a look at the rotors. The BP7ES is what's in there now and runs great in this car. The existing plugs show healthy wear and are nicely-rounded at the tip. I want to get some fresh ones in there as a baseline and...to quote Bobby "Boris" Pickett: "...to get a jolt from my electrodes.."

 

In fact there should be some resistance in the extenders, as well in either the wires or the plugs. Hence the choice of BP7ES vs BPR7ES. I am using the Iridium plugs and I have to tell you they are really great. Steve M posted the ohms in the extenders (red vs black) here but am having trouble finding the post. I will get back to you.
Here is one refrence but not the one I was thinking of:

http://ferrarichat.com/forum/showthread.php?t=273126&highlight=ohms+extenders

 

Extender color does not correlate with extender resistance:

http://ferrarichat.com/forum/showthread.php?t=212698

 

Ok put the new wires and plug in now the entire rear bank is dead. No power to the coil. Worked fire before. I noticed a green wire off so I put it back where it belonged no luck. A lot of corrosion in the terminal ends so I replaced them all, Still no luck. The tach used to go crazy when it ran rough thats why I replaced the crank sensors. After a few restarts tonight it would go dead then come back on line. PLEASE dont tell me I fried a digiplex. Seriously all I did was change the wires and maybe knock the green one off the rear coil then put it back on when I noticed it. You dont think I got a hold of some bad crank sensors do you? Is there a feed fuse going to each coil?

 

Oh yea 2 extenders were arched and 2 wires were dead open 1 each on each bank. The 6 cylinder thing was a joke.

 

Tostapchuk; You know, every one of these things needs something... These cars have distinct personalities, and your car is telling you something.

How true mine is saying PLEASE HELP ME IVE BEEN NEGLECTED AND ABUSED FOR YEARS.
Well she has a good home now

 

All I know is that I freaked out when I took it to the mechanic and was given an estimate for $18636 to fix the mechanicals which were supposed to be perfect and $9500 from the body shop to fix the minor paint imperfections. It had 1/8 inch cracks in the deck lid and everything else was checked. So far have re-painted it and fixed about half of the stuff on the mechanical estimate. So far im in about $2500 so I still feel Im ahead and getting somewhere. Thank god I know body work and am a reasonably good mechanic just never touched a Ferrari before. Thats why I joined this group. To get an education from the pros.

 

No, they are unfused, but they do take a path thru the fuseblocks between the top of fuse #2 and the top of fuse #1.

What version 1985 308QV? Euro or US?

Do you mean that there is no +12V present on the G (yellow) wire connected to terminal 15 of the dead coil when the key is "on"? The terminal 15s on each coil are daisy-chained together so it would be unlikely to have one OK and the other not OK (unless it's a local wiring/swaging problem).

 

Steve
It is a 308 QV US version. I have no power to the coil when the key is on or the engine is running front bank only. As far as the rest no 12volt present on the yellow wire. Should I make my own jumper? I dont know who did what on her in the past but from the rear its Yellow Yellow Green Green front bank Is Yellow Yellow, Yellow Black Yellow Black. Would this affect the sensor input to the tach also? When I cut the old end off green corrosion came out of the spade end and the wire when striped was off colored showing where decay was evident.
I am wondering if I should back track the wire and replace them entirely. I had intermittent spark from this bank when I did a plugs out test also using a timing light. I wonder if it was weak on the other end and since putting in good plugs and wires it put a heavier load on it and fried the other weak spot.

 

Yes -- but just repair the existing wiring.

That all seems correct (if the yellow wires are on terminal 15 of each coil, and the green and yellow-black wires are on terminal 1 of their respective coils).

All of the yellow wires should be electrically connected together (locally) so I'd guess that you've got some corrosion in the swaging in the female connectors -- clean, reswage and maybe solder (to not just rely on the mechanical squeezing for a good electrical connection).

The fact that one of the yellow wires is at +12V with the key "on" confirms that everything upstream is OK.

You can download a copy of the 307/84 '84-'85 US 308 QV OM here:

www.ferraridatabase.com

and the wiring schematic is in Section 5.

 

Steve
I am looking at the schematic and it kind of makes since. If the yellow jumper is broken it will kill the rear bank and the tach. As I see it the yellow wire jumpers from the front bank to the rear bank goes thru the coil bridge then to the Tach. Please correct me because I am reading a Euro manual but it cant be that different.

 

Don't follow you here because the tach signal (on both the euro and US version) is the MN (brown-black) wire from pin 10 on one of the DigiPlex ECUs. However, if one of your coil's behavior was "erratic", this could cause the signal on the MN wire to also be erratic.

For some things, they are close enough, but your US version uses a K-Jetronic with Lambda injection system; whereas, the euro version uses a K-Jetronic without Lambda injection system -- the electrical differences here are very significant so you should really get/be using the US version schematic and OM.

Have you confirmed that your Frequency Valve is "buzzing" (as it should) whenever the engine is running?

 

But the Green negative input wire goes to the tach which measures the coil firing thru the digiplex. If the coil doesn't fire then no input signal. Or am I grasping at straws

 

As far as the frequency valve buzzing I am not sure of that. Where is it located. I manually pushed on the Bosh swash Plate to force fuel into the system just to get it started again. I heard a lot of buzzing from everywhere

 

Not on the 248/82 (euro 308QV) OM schematic -- the green wire only goes to one of the DigiPlex and the Diagnostic Socket. Do you have the print number XXX/YY on the OM you are referencing.

This is where having a copy of the 307/84 OM would help you, but if you do a search on "frequency valve" here you should get many prior threads with pictures.

The "buzzing" you hear when you deflect the airflow metering plate is a different buzzing from the injectors. Best to "feel" the frequency valve, by touching it, to confirm/deny if it is vibrating.

 

The green wire feeds into the Digiplex then the digiplex feeds into the tack. Green wire is socket 11 Tach outfeeds to socket 10 of the digiplex. Page 73of the European 308 Owners PDF Cat 248/82 n2500

 

Digiplex sends the signal to the tach

 

Steve from our conversation.
Right now I should concentrate on getting power to the coil and see if that helps work the problem out. I think but do not know that the green wire is the ground leg of the system and that the digiplex measures the current drag and sends that information to the tach. If there is no 12V applied to the 15 pole on the coil then there is no current draw and the Tach would get no information from the digiplex. Am I correct in assuming that the positive wire on the coil is always hot when the key is on but the digiplex engages the ground for coil firing?

 

Kevin, your spirit is inspirational.

I'm left wondering what month this will be named as "Thread of the Month" in the Fchat newsletter... I'm picking Sept/October. Since I'm creating the betting pool, I can pick two.