[DeTomaso] Unhappy motor - looking for suggestions

Charles McCall charlesmccall at gmail.com
Sun Feb 22 09:38:15 EST 2015


Hi all

 

Last fall, I commented that my engine wasn’t running well. Symptoms may be found in the e-mail below, and consensus was that they sounded carb related, or perhaps timing related, and a number of people offered suggestions. But the symptoms were sort of strange and didn’t seem to perfectly fit any of the theories as to the problem. 

 

On a whim, over the winter I changed the MSD 6-AL electronic ignition, since I had a spare and since the last time it failed, it gave some really weird symptoms; erratic and sporadic problems. I sent the box to MSD over Christmas for analysis and they confirmed that it failed their test and had some issues. OK, sounds promising but was that the cause of my problems?

 

It’s been a harsh and snowy winter, but it has rained all week, which cleaned most of the salt from the roads. So I took the car out today. I’ll feel better after a longer trip, but the first impression is very positive. The hesitation and stumbling is gone, no starting problems, and the car ran very very well. I’m cautiously saying that the problem has been fixed. 

 

I wanted to leave for posterity the fact that when the MSD box fails, it isn’t always catastrophic. It would actually almost be preferable if it would, since I have a spare it and it would make the problem a little more obvious. When they start to fail they get flaky – symptoms that come and go. Both times they have failed I have started by inspecting from top to bottom my carb, since the symptoms pointed in that direction. Have an engine problem that you can’t eliminate? Try looking at your electronic ignition if you have it – it can cause all kinds of weird running issues. 

 

Thanks to all who answered

 

 

>
>   Anyway, my engine is not happy. This morning in the hotel parking lot I
>   really thought that we'd have to skip today's event because it wouldn't
>   start and didn't sound like it was even thinking about starting. Took
>   probably 5 minutes of crank-wait-crank-wait before it fired. Yesterday
>   at the gas station it took 2-3 minutes to start, something that has
>   never, ever happened before. It is really hard to describe the problem
>   so much of it is "feel", but I'll do my best.
>
>
>   A few weeks ago I noticed that the engine would tend to stumble if I
>   would floor the throttle, then clear its throat and pull. For example,
>   I like to heel-and-toe, just because, and when blipping the throttle it
>   would stumble instead of rev. The engine also felt a little rougher, as
>   though it vibrated more than I remembered it. I don't remember if this
>   was before or after I did a short tune-up, by adjusting the valve lash
>   (I have mechanical lifters), and cleaning the K&N air filter by
>   applying K&N filter oil, etc. or if it is irrelevant. So I was messing
>   around in the engine bay recently...
>
>
>   This weekend the engine felt considerably worse. It felt like it would
>   stumble under partial throttle as well. It would stumble a little bit
>   under trailing throttle going downhill as well, so I don't think it is
>   a clogged fuel filter.
>
>
>   Oil temp is perfect. Oil pressure is perfect. Water temp is perfect.
>   The engine idles perfectly. But if you floor the gas from idle, it'll
>   stall. The engine doesn't feel crisp, it feels bloated and soft, if
>   that makes sense. It feels rough, and it feels like it occasionally
>   stumbles under constant throttle at highway speed. It pulls hard when
>   accelerating, but I don't think as hard as it used to, or as high (I
>   have a 6500 rpm limiting chip in the MSD that it used to pull very
>   easily to).
>
>
>   Suggestions for where to begin looking? And other info that would help
>   in troubleshooting?
>
>
> !DSPAM:54568258260291209923907!
> _______________________________________________
>
> Detomaso Forum Managed by POCA
>
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-------------- next part --------------
   Hi all


   Last fall, I commented that my engine wasn't running well. Symptoms may
   be found in the e-mail below, and consensus was that they sounded carb
   related, or perhaps timing related, and a number of people offered
   suggestions. But the symptoms were sort of strange and didn't seem to
   perfectly fit any of the theories as to the problem.


   On a whim, over the winter I changed the MSD 6-AL electronic ignition,
   since I had a spare and since the last time it failed, it gave some
   really weird symptoms; erratic and sporadic problems. I sent the box to
   MSD over Christmas for analysis and they confirmed that it failed their
   test and had some issues. OK, sounds promising but was that the cause
   of my problems?


   It's been a harsh and snowy winter, but it has rained all week, which
   cleaned most of the salt from the roads. So I took the car out today.
   I'll feel better after a longer trip, but the first impression is very
   positive. The hesitation and stumbling is gone, no starting problems,
   and the car ran very very well. I'm cautiously saying that the problem
   has been fixed.


   I wanted to leave for posterity the fact that when the MSD box fails,
   it isn't always catastrophic. It would actually almost be preferable if
   it would, since I have a spare it and it would make the problem a
   little more obvious. When they start to fail they get flaky - symptoms
   that come and go. Both times they have failed I have started by
   inspecting from top to bottom my carb, since the symptoms pointed in
   that direction. Have an engine problem that you can't eliminate? Try
   looking at your electronic ignition if you have it - it can cause all
   kinds of weird running issues.


   Thanks to all who answered



   >
   >   Anyway, my engine is not happy. This morning in the hotel parking
   lot I
   >   really thought that we'd have to skip today's event because it
   wouldn't
   >   start and didn't sound like it was even thinking about starting.
   Took
   >   probably 5 minutes of crank-wait-crank-wait before it fired.
   Yesterday
   >   at the gas station it took 2-3 minutes to start, something that has
   >   never, ever happened before. It is really hard to describe the
   problem
   >   so much of it is "feel", but I'll do my best.
   >
   >
   >   A few weeks ago I noticed that the engine would tend to stumble if
   I
   >   would floor the throttle, then clear its throat and pull. For
   example,
   >   I like to heel-and-toe, just because, and when blipping the
   throttle it
   >   would stumble instead of rev. The engine also felt a little
   rougher, as
   >   though it vibrated more than I remembered it. I don't remember if
   this
   >   was before or after I did a short tune-up, by adjusting the valve
   lash
   >   (I have mechanical lifters), and cleaning the K&N air filter by
   >   applying K&N filter oil, etc. or if it is irrelevant. So I was
   messing
   >   around in the engine bay recently...
   >
   >
   >   This weekend the engine felt considerably worse. It felt like it
   would
   >   stumble under partial throttle as well. It would stumble a little
   bit
   >   under trailing throttle going downhill as well, so I don't think it
   is
   >   a clogged fuel filter.
   >
   >
   >   Oil temp is perfect. Oil pressure is perfect. Water temp is
   perfect.
   >   The engine idles perfectly. But if you floor the gas from idle,
   it'll
   >   stall. The engine doesn't feel crisp, it feels bloated and soft, if
   >   that makes sense. It feels rough, and it feels like it occasionally
   >   stumbles under constant throttle at highway speed. It pulls hard
   when
   >   accelerating, but I don't think as hard as it used to, or as high
   (I
   >   have a 6500 rpm limiting chip in the MSD that it used to pull very
   >   easily to).
   >
   >
   >   Suggestions for where to begin looking? And other info that would
   help
   >   in troubleshooting?
   >
   >
   > !DSPAM:54568258260291209923907!
   > _______________________________________________
   >
   > Detomaso Forum Managed by POCA
   >
   > DeTomaso mailing list
   > [1]DeTomaso at poca.com
   > [2]http://poca.com/mailman/listinfo/detomaso_poca.com
   >
   >
   > !DSPAM:54568258260291209923907!
   _______________________________________________
   Detomaso Forum Managed by POCA
   DeTomaso mailing list
   [3]DeTomaso at poca.com
   [4]http://poca.com/mailman/listinfo/detomaso_poca.com

References

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   3. mailto:DeTomaso at poca.com
   4. http://poca.com/mailman/listinfo/detomaso_poca.com


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