Need Help Diagnosing an Issue
#1
Pro
Thread Starter
Need Help Diagnosing an Issue
First off, the car is a '73 2.0 with dual delorto carbs. I only include as I think the issue may be carb related. Also, I recently changed the oil in the car, although I don't believe this has any bearing on the issue.
New years eve, I was driving to my parents' house- approximately 50 minutes away. I had no issues with the car until about half an hour into the drive. I was going a steady 70 (just over 3k in 5th gear) on the freeway, and felt the car stumble a bit. The sensation was almost like the car had lost power momentarily; I would equate it to when my 951 burned thru the speed/reference sensor wire. I did not think anything of it at the time. A couple of miles later, it happened again but more pronounced. I noticed the tach suddenly dropped at the same time. As soon as I put my foot down, it all came right back. I nursed the car to my destination without any further issue.
On the return trip, the car seemed to do the same thing more frequently, and in 2nd, 3rd, and 5th gear- I am not saying that it did not happen in all gears, but those were the ones I noticed. Often the issue would happen right as I was about to shift, so around 3k to 4.5k rpm. The car never stalled, and I did not see any loss of lighting in the gauges.
Has anyone had anything similar or have any ideas of where to start troubleshooting? I plan to pull the carbs and clean them this weekend, if I find time, and go from there.
New years eve, I was driving to my parents' house- approximately 50 minutes away. I had no issues with the car until about half an hour into the drive. I was going a steady 70 (just over 3k in 5th gear) on the freeway, and felt the car stumble a bit. The sensation was almost like the car had lost power momentarily; I would equate it to when my 951 burned thru the speed/reference sensor wire. I did not think anything of it at the time. A couple of miles later, it happened again but more pronounced. I noticed the tach suddenly dropped at the same time. As soon as I put my foot down, it all came right back. I nursed the car to my destination without any further issue.
On the return trip, the car seemed to do the same thing more frequently, and in 2nd, 3rd, and 5th gear- I am not saying that it did not happen in all gears, but those were the ones I noticed. Often the issue would happen right as I was about to shift, so around 3k to 4.5k rpm. The car never stalled, and I did not see any loss of lighting in the gauges.
Has anyone had anything similar or have any ideas of where to start troubleshooting? I plan to pull the carbs and clean them this weekend, if I find time, and go from there.
#2
Official Wednesday AM Red Bull F1 test driver
Rennlist Member
Rennlist Member
I'd bet a carb issue as well- some dirt in the jets somewhere?? Reminds of a trip with my dad in the '80's driving a new to me 356 cab from CA to IA. We were maybe 10 miles into a 1500 mile trip when the car stumbled on a busy CA freeway- started to panic, but luckily never did it again on the whole trip. Only other issue was 6 volt headlights at night!!!! And the fact we drove within a mile of a tornado in Kansas...
#3
RL Community Team
Rennlist Member
Rennlist Member
Could be:
Fuel pump starting to go
Fouled plug
Cap or rotor
Fuel pump starting to go
Fouled plug
Cap or rotor
#4
I would think it an ignition problem, like you are losing power to the coil. If it was a fuel problem, it would not abruptly die, but rather seem like it was running out of fuel. What zeros in on it being an ignition problem is the tach movement. Means that the car missed a spark. Coils do not go bad, but maybe bad points or condenser, points plate ground lead, bad ignition switch, etc. Crack in the cap would cause one cylinder to misfire, bad rotor would strand the car, spark plug or wire problem would cause a steady miss and reduce the power but not make the tach jump
since we are listing cars we own:
1960 silver 356 cabriolet
1960 blue 356 roadster
1961 red 356 roadster
1962 white 356 super 90 cabriolet
1964 buick riviera Dad purchased new
1965 red 356 sc
1966 Chevrolet Corvette
1967 MGB gt special
1967 MGB gt special (yes two a glutton for punishment)
1970 green 914-6 5100 miles
1970 yellow 914-6 restoration project
1971 white 914 motor trend car of the year
1971 orange 914-6 sportomatic
1971 blue m-471 914-6 gt
1971 green 914-6 5400 miles
1971 Jaguar OTS six cylinder
1972 red 914-6
1972 orange 914-6
1972 silver 916
1973 green 914 2.0
1973 red 914 2.0
1974 white 914 1.8 10,000 miles
1974 black 914 limited edition
1974 black 914 limited edition from matsuda collection
1974 white 914 limited edition
1975 yellow 914 six conversion
1976 orange 914
1976 black 914
1976 red 914
1976 red 914 11,000 miles
1976 blue 914
1976 silver 912e
1977 MGB original paint 42,000 original miles
1985.2 white 944 automatic
1986 white 944 automatic
1998 silver boxster
1999 Mercedes 320 fourmatic
2001 silver boxster
2004 silver boxster
2004 VW Beetle ultima edition one of the last air cooled off the line
2005 Mercedes c230 compresor
2006 Ford GT late July build
2006 black cayenne
2016 Mercedes e convertible
also
1995 BMW k1100rs
2009 BMW k1300s
listing these reminds me of "I have a button bigger than yours and mine works"
Please everyone, I have listed these (even though I do own them all) as a joke and to show everyone how car SICK I am.
since we are listing cars we own:
1960 silver 356 cabriolet
1960 blue 356 roadster
1961 red 356 roadster
1962 white 356 super 90 cabriolet
1964 buick riviera Dad purchased new
1965 red 356 sc
1966 Chevrolet Corvette
1967 MGB gt special
1967 MGB gt special (yes two a glutton for punishment)
1970 green 914-6 5100 miles
1970 yellow 914-6 restoration project
1971 white 914 motor trend car of the year
1971 orange 914-6 sportomatic
1971 blue m-471 914-6 gt
1971 green 914-6 5400 miles
1971 Jaguar OTS six cylinder
1972 red 914-6
1972 orange 914-6
1972 silver 916
1973 green 914 2.0
1973 red 914 2.0
1974 white 914 1.8 10,000 miles
1974 black 914 limited edition
1974 black 914 limited edition from matsuda collection
1974 white 914 limited edition
1975 yellow 914 six conversion
1976 orange 914
1976 black 914
1976 red 914
1976 red 914 11,000 miles
1976 blue 914
1976 silver 912e
1977 MGB original paint 42,000 original miles
1985.2 white 944 automatic
1986 white 944 automatic
1998 silver boxster
1999 Mercedes 320 fourmatic
2001 silver boxster
2004 silver boxster
2004 VW Beetle ultima edition one of the last air cooled off the line
2005 Mercedes c230 compresor
2006 Ford GT late July build
2006 black cayenne
2016 Mercedes e convertible
also
1995 BMW k1100rs
2009 BMW k1300s
listing these reminds me of "I have a button bigger than yours and mine works"
Please everyone, I have listed these (even though I do own them all) as a joke and to show everyone how car SICK I am.
#5
Rennlist Member
since we are listing cars we own:
1960 silver 356 cabriolet
1960 blue 356 roadster
1961 red 356 roadster
1962 white 356 super 90 cabriolet
1964 buick riviera Dad purchased new
1965 red 356 sc
1966 Chevrolet Corvette
1967 MGB gt special
1967 MGB gt special (yes two a glutton for punishment)
1970 green 914-6 5100 miles
1970 yellow 914-6 restoration project
1971 white 914 motor trend car of the year
1971 orange 914-6 sportomatic
1971 blue m-471 914-6 gt
1971 green 914-6 5400 miles
1971 Jaguar OTS six cylinder
1972 red 914-6
1972 orange 914-6
1972 silver 916
1973 green 914 2.0
1973 red 914 2.0
1974 white 914 1.8 10,000 miles
1974 black 914 limited edition
1974 black 914 limited edition from matsuda collection
1974 white 914 limited edition
1975 yellow 914 six conversion
1976 orange 914
1976 black 914
1976 red 914
1976 red 914 11,000 miles
1976 blue 914
1976 silver 912e
1977 MGB original paint 42,000 original miles
1985.2 white 944 automatic
1986 white 944 automatic
1998 silver boxster
1999 Mercedes 320 fourmatic
2001 silver boxster
2004 silver boxster
2004 VW Beetle ultima edition one of the last air cooled off the line
2005 Mercedes c230 compresor
2006 Ford GT late July build
2006 black cayenne
2016 Mercedes e convertible
also
1995 BMW k1100rs
2009 BMW k1300s
listing these reminds me of "I have a button bigger than yours and mine works"
Please everyone, I have listed these (even though I do own them all) as a joke and to show everyone how car SICK I am.