87 TR rough idle and stalling/surging

Your use of the word "module" is maybe a better description (but it is essentially a big transistor that switches the coil primary current) so nothing different than what you been
dealing with already.

Understood, but it's still best to rule them all in, or out, for sure, when having a (new) problem IMO. If the system still has the same ignition system flaw, regardless of which coil and which module is where, then that can be a much more difficult thing to continue to track/investigate/resolve.

 

Not exactly. The first time I had taken the car out for about an hour's drive (instead of normal 10 - 20 minute jaunt), at the very end of the cruise the car ended up running on one bank would die if I didn't give it gas. When I gave it gas, it ran very roughly and really couldn't go more than 10 MPH. When the car cooled down it ran OK......until it heated up again. When my mechanic replaced the driver's side ignition coil/module/heatsink, the car still ended up running on one bank after a while, but would at least maintain idle of about 500 RPM without me having to gas it. When I replaced the passenger's side ignition coil/module/heatsink, the car still ended up running on one bank after a while, but I didn't need to blip the throttle when the car was idling in order for the alternator charging to kick in, and the battery light was no longer flashing very very dimly. So not exactly the same syptoms, because of these significant improvements I was referencing, but it still ended up running on one bank.

 

the power transistors are in the small black plastic what is mounted on the aluminum where there is also mounted the coil. just change both completly from one side to the other to test

 

you may connect your iginition timing light to the wire from the coil to the distributor cap. then you see if the problem comes from the coil to the cap or from the cap to the single wires for each cylinder. if first will be ok then have a look also at the rotor and at the cap

you may test also with a scope the signal from the rpm sensor ( even I think that this is not the problem )

 

no more responding?
gave up??

 

Ha-Ha, Herr Schwabel, you have no idea how bad my luck is! I went to change the ignition units (coil/control module/heatsink) several weeks ago. In doing so, I somehow lost the red plastic clamp that secures the wire connecting at the bottom of the ignition coil. I have spent over an hour of the last several weeks looking for this piece. My fear was that it would somehow end up in "the wrong place" and melt or somehow start an engine fire.

On top of everything, I've been in court more the last two weeks than I have been my entire life. Now that those issues are behind me, I finally finished the swapping of ignition units today. The problem still exists where one bank shuts down, and the engine hobbles along at low RPMs, really unable to rev. It seems like the engine does try to "recover" and run on both banks, but then goes back to one bank, then tries to "recover" again, and so on and so forth. While this is happening the oil pressure gauge pulses up and down.

(Still haven't found the little clamp, but I was watching (and smelling) the engine very closely until it was running at operating temperature for 5 minutes.)

 

so after swapping it is then the same cylinder bank not running right or the other bank?
the red plastic clamp on my car is already gone several years, so the ignition wire is holding only by the own pressure at tthe connector and have never problems

having been to court? you are a lawyer or have been at court because of speeding?

here in germany we often say: if something is going really wrong on one day then all is going wrong this day - your luck will come back

 

Shoot, I'll have to check that it is still losing the right (passenger side) bank. I was so excited to put the car back together and duplicate the problem, I forgot to verify which bank dropped. Hopefully I can get this done in the next week.

LOL, I'm not lawyer, and definitely not speeding -- the TR doesn't run long enough to speed.

I'm definitely hoping I've used all my bad luck and the scales will balance soon, thanks.

 

Finally got my car out this morning. Much cooler weather in LA than for the last several months. Took a while of me driving outside, then finally 5 - 10 minutes of me driving inside parking garage and car went down to one bank again. Same bank as before, even though I switch complete ignition coil units -- the passenger side was the one that failed.

 

so you checked with a strobe light if it is a problem of the igniton or not?
so strobe light on the ignition wire from the coil to the cap . I´m sure that you have there a spark. then also form the cap to the single cylinders. if no spark check the rotor and the cap. if spark then it is a fuel problem

 

Yeah I was going to ask whether you're positive its not a fuel system problem? I thought I read somewhere in this forum that the TR engine will only run on one side, not the other. I think Steve M mentioned it? I might be wrong but what have you done to rule out the fuel system?


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What a great post!!


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Yes. What happens when one bank drops off is that the spark goes from a real strobing, to like once a second, coinciding with the "breathing" of the engine. This is with the timing light connected to Cylinder #1.

What should I look for if I connect the timing light to the wire between the coil and the cap?

 

I believe these tests with the timing light and switching coil units were to determine if the problem was either with the spark OR the fuel. (so definitely haven't ruled out fuel system -- which was my first suspect)

 

If between the coil and cap, the light should appear to be on constantly... Basically the light would be flashing 900 times per minute, assuming that's your idle speed (RPM).

 

why 900 times a minute? you have idle speed from 1800 rpm?

if the strobe will nearly light/flash constantly ( so 450 times a minute ) if so then there is a problem of the distributor cap or the rotor. if not then there is still an ignition/electric problem

because of once a second strobing it is definitely not a fuel problem

 

Wait why wouldn't it be 900? The pistons share crank journals right? The crank is still moving at 900 rpm and aren't the six cylinders on each side igniting 900 times a minute?


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the ignition fires only all second RPM, so 900rpm divided by 2
it is a 4 stroke engine, not a 2 stroke what ignite every rpm

have a look at the crankshaft and the camshafts: 2rpm crankshaft and only 1rpm camshaft, and the rotor is on the camshaft

 

Lol yes I thought more about it last night too. I was wrong, Romano was right.


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Sorry, took me a while to test the car -- I live about a mile or two from the nearest fire here in LA and really didn't want to expose it to all the ash and soot that was flying around.

I connected timing light just underneath the coil, and strobe definitely *did not* flash nearly constantly once the passenger-side bank went bad - more like 6 - 10 times a second.

 

so you tested/changed already the power module with igniton coil ( 124273 ) as I remember?
then I would say it is an electric connection problem or the main igniton module ( 125828 )

 

Yes, I switched the new units to opposite sides.

I was afraid the problem might be something expensive like this.

 

Tommy, I would try contacting David Feinberg at Ferrari Service of Bedford. I believe he makes a replacement microplex unit of the Testarossa if that ends up being your problem. I believe he also has a fee for service option that might be worth while. Good luck and keep us posted with what y0u find.

 

Thanks Jeff! I actually had plans to call up a new Ferrari mechanic shop to have them make a diagnosis if they were familiar with the type of problem I'm having, but looks like they are closed today. I'll have another go at it tomorrow or next week. Your information could prove to be VERY useful, as I see the units go for about $2k USD a piece new. Wouldn't really want to take my chances on used eBay parts with something like that.