87 Testarossa - Has No ignition to spark plugs - *Both Banks* Need assistance please?

[QUOTE="Tom LI-NY, post: 147776241, member: 248895"]...Is this a Bad Crankshaft TDC Sensor 'or' Bad RPM sensor or BOTH?... (rear engine clutch/bell housing)[/QUOTE]

Yes, if either of the flywheel sensors fails = both banks will have no spark. Have you tried unplugging/inspecting/replugging the 4-pin round connector under the coolant expansion tank?

Measuring the AC voltage between the two pins of each flywheel sensor during starter motor cranking should be:

RPM sensor = ~ 2V AC

TDC Sensor = ~0.2V AC

if they are working, but, without the special 25-pin test breakout box, you'll need to do something special to make the measurement yet keep the sensor plugged in -- the "jumpers" I use to make the measurement at the 2-pin connector of the sensor:
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and in use:

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Stylized waveforms that you would see during starter motor cranking using an oscilloscope if they are working:

RPM Flywheel Sensor
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TDC Flywheel Sensor:

 

INCREASE THE GD TIME ALLOWED FOR EDITING! -- it took me a while to find all the pictures, and I was still trying to get them in the right places (PS image editing mixed in with text sucks!). Here's what the post above should be:

[QUOTE="Tom LI-NY, post: 147776241, member: 248895"]...Is this a Bad Crankshaft TDC Sensor 'or' Bad RPM sensor or BOTH?... (rear engine clutch/bell housing)[/QUOTE]

Yes, if either of the flywheel sensors fails = both banks will have no spark. Have you tried unplugging/inspecting/replugging the 4-pin round connector under the coolant expansion tank?

Measuring the AC voltage between the two pins of each flywheel sensor during starter motor cranking should be:

RPM sensor = ~2V AC

TDC Sensor = ~0.2V AC

if they are working, but, without the special 25-pin test breakout box, you'll need to do something special to make the measurement yet keep the sensor plugged in -- the "jumpers" I use at the 2-pin connector of the sensor that keeps it connected, but gives me a place to connect my multimeter probes:

and in use:



Stylized waveforms that you would see during starter motor cranking using an oscilloscope if they are working:

RPM Flywheel Sensor:
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TDC Flywheel Sensor:
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Don't forget to also unplug/replug the round 4-pin connector under the coolant expansion tank.

 

Steve...

Still waiting for your Testarossa Maintenance and diagnosis book. If you were to compile and organize the information you post it would be a hugely valuable resource. Print it in a spiral binding and sell it for a couple of hundred US. Sell a hundred or more copies here and make 20k! It need not be fancy, the content presents the value.

If you add a few chapters of fluff (style, history etc) you could likely sell it through a publisher.

Put me in line for book No.1.

PS: I am sure that other folks here on FChat would happily let you use their posted photos etc (with permission) for additional help in your efforts.

 

somtimes there is little corrosion and when unplug und plug again it gets a little cleaner, may be use also WD40, and check if a wire is broken

 

Yes, to rewipe the electrical contacts -- it can even fall out. It's in a near horizontal orientation, and has no locking feature to retain the two halves together other than a friction rubber sleeve (IIRC) and a plastic clip holding its wire bundle to the wire bundle next door. Consequently, the vibration of the wire bundle can cause small relative motions between the contacts (resulting in fretting wear) which is terrible for connection reliability. Truly a bizarre choice/implementation by the Designers IMO.

 

I did not know Steve was doing this. He should charge a lot for it.

 

I'm not -- but I do accept $s

I might do something fairly soon describing how to modify a 308 so that the headlight lever positions are inverted (and submit it to the FML and post it here), but "fairly soon" might be several years with my present Honey-do list...

 

Hi Tom ,Shane hear ,nu to this chat page ,I have a 87 Testarossa are having a similar starting problem to yours ,could you tell me or post a photo of the part numbers of that TDC an RPM sensors you fitted to your Testa ,cheers

 

Thanks for that Tom , Cheers

 

I am in the process of replacing the broken connectors on both sides of this harness (C9), and wiring on the side that is closer to the engine is very brittle and the insulation is cracking and falling apart. I decided to replace the wires with the proper color wire, but as I pulled the wires out of the sleeve, I noted that both the black and blue wires are not insulated with the exception of 6 inches on each end, and the bare copper is wrapped around the yellow and green wires, respectively (black/yellow shown):

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is there a reason for this setup rather than just using two fully insulated wires? I am going to bypass the round connector on C9 and use a weatherproof deutsch connector along with C11 which I already replaced with a weatherproof deutsch connector.

 

Yes -- the "bare" wire strands act as a shield to prevent/reduce electro-magnetic noise on the center insulated wire (this construction is also known as "coaxial" cable) -- see Fig 2 in any of the TR wiring diagram books (it shows the construction you describe). It's important because these are low level signals, and the "pulses" on the spark plug wires and in the dist cap/dist rotor generate a lot of electro-magnetic noise.

 

Interesting, I thought it might be related to that. Would it be better to use some external EFI shielding sleeves, or just attempt to create this with new wires?

Todd

 

You'll need to do something that is functionally similar on the physics level -- the center conductor being completely surrounded by the other conductor. Having those copper strands just helically-wrapped around that center insulated wire seems a little "handmade/homemade" to me -- but would work, and does make it easy to connect to the "shield" to the short wire pieces needed at each end to go to the connector terminals (if by EFI shielding sleeve you mean more of a thin metal foil wrapping, connecting a wire to that can be tricky). The shield on a coaxial cable is more of a woven/braided thing (but then the center conductor is usually a solid wire so that's not so flexible).

 

may be you can use antenna coaxial cable ? and put black shrink tubing around

 

I agree. It seems very homemade, which is why I reached out. I wasn't sure if this was a factory wiring setup. Also, with the insulation cracking with heat and age, it seems this could be at risk of a short. That was my biggest concern when I inspected the wiring. I contacted this company: Zippertubing https://www.zippertubing.com/products/shrink-n-shield-2- as this seems like an appropriate product. They confirmed it should work, so I will give it a try unless anyone sees an issue with it here.

They told me to order it here- https://www.mcmaster.com/products/heat-shrink-tubing/performance~interference-shielding/?utm_medium=chat&utm_campaign=link-shared-in-chat&utm_source=livechat.com&utm_content=www.zippertubing.com. 1/4 inch before shrinking seems to be the appropriate size for 2 wires. The site recommends a grounding braid - what do you think about that?

Todd

 

Something like this?

https://www.amazon.com/wlaniot-RG174-Coaxial-Rg-174-Meters/dp/B07L67M9YT/ref=sr_1_5?crid=21VTL33BA5JW&dib=eyJ2IjoiMSJ9.-hTLpXLLayeC05ET_BbofQYBO1mNziDQkLpGE226jxZsAor7Jju1nXMyEYwlCJrzmSPkYAvqCtxZswR1NKCDqmtuKLk5PPZZIzZVoiJukwjfIaML4OkpUWRqx6fdarhFTVgKmenM-S6LH4VFxbWXIYifzXsnEWXI9usCk3vMwVAPpZwIkOciL9raMFwFrGN_ntBBOqb1moB2F7wEHgZDcAOCuxoogdwqBgUJhD48ppAZjLCjMfgaWFL9TziaVnff3Fziw5wLViJ5Rcr3mZccMMsi4cAc7RXS7Um-vb4C0NrgnLCmZHdd9rJbDzGkmFysA-rJNcj98oiiXFd-0S0RldLPGCqNp2qmCcajSvHBy68.GMwLQIzvVV8foy4oy9G3x9esuyIuHdq2T3bSUu48qlE&dib_tag=se&keywords=radio%2Bantenna%2Bcable%2Bshielded%2Bhigh%2Btemp&qid=1739285331&s=electronics&sprefix=radio%2Bantenna%2Bcable%2Bshielded%2Bhigh%2Btemp%2Celectronics%2C128&sr=1-5&th=1

Do they make it for high heat applications?