I've got an 85 TR. It accelerates smoothly through the gears. Cruising in 4th or 5th shows a unique and frustrating problem. Cruising on a freeway in 5th gear for example, the car pulls strong to 2400 rpms, but at 2500 rpms, there is a hesitation....sort of a flat spot....in the acceleration. This hesitation disappears when I push through 2500 rpms to 2600 and beyond. I've rebuilt the fuel distributors, cleaned all ignition wiring and contacts..no change. I've had a good Jag/Ferrari mechanic of 30 years look at the problem. So far, he has come up empty. Anybody out there had a similar issue with a TR?.....any opinions as to what might be causing the problem. Regards, Dick Petrick
have a look at the micro switch at the trottle ( 121517 US or 131403for other ) is this only when driving or also when idling at about 2500 rpm? I once had such a problem and the TDC sensor ( 124241 )was not working right anymore
Ozziindaus - Yes, seems only in 4th and 5th. Most noticeable in 5th. Carguy - Yes, throttle application is constant.....cruising speed adjustment. Turbo-joe - Thank you. I will check out the micro switch. Shemmer - Thank you. I wlll check out the O2 sensor. Thank you all for your help with this problem. Regards, Dick Petrick
Throttle position at 2500 rpm is different depending on the load and therefore gear. Manifold pressure (MAP) is also different. So I would look at throttle switch and fuel distributors. I understand you've rebuilt the distributors but was the issue rebuilt back in? Just a thought.
As an elder 512TR driver I do have a guestion: Silly maybe but WHO HERE does cruise in 5th gear on the streets ? That is NOT F driving at all imo 5th gear is used to get her over 300 KM/h ! This Testarossa should be driven over 4000 rpm allways (imo ) So I don't think it to be strage when underrun - too low revs for this engine- this appears ... Please comment !
you are right mel going with under 2500 in 5th is a shame. I would say in the US with limit 55mph you only need 1st, 2nd and may be 3rd, no more. but nevertheless you may go also in 5th with 2000 rpm without problem if all is fine I think that the mixture is too lean and there for you have the problem Dick. and the longer it takes until the rpm going up the worse it is
I believe that the early Testarossa had a hesitation about the 70mph and in the UK they were adjusted by Maranellos to run a little richer that overcame the problem. HTH Phil
I have the same herky jerky on my BBI till about 3.5K rpm. The solution as above is you shouldnt be lugging the car. Its not a sbc low rev machine. If you go too rich on the mxture it will adversly affect thorttle response and power. I would guess that lugging a 512, will cause all types of stresses on the driveline for which it was not designed.
Agree on drive style. On rarely went into 5th unless ripping on the highway. Singing along at 2800 to 3500 all day. City driving I'm rarely out of 3rd gear. Possible mixture issue but would still be there in 1-3 gear. Stop *****footing in the b*tch. They don't like it. Adult or not. Feeling mature take your other car. Feeling frisky? Take the b*tch. R
^^^^^^THIS^^^^^ Fouling spark plugs can make her unhappy & hesitate. Find a real road and put your damn foot in it!!! Resume happy dance !
Can't think of any reason why not. They have a very wide powerband and very conservative valve timing. They should and are quite happy to spend all day at 2000 rpm. At low load there is zero reason not to. I used to show them to prospective buyers by climbing hills in 5th gear from 25 mph and accelerating all the way. If it doesn't pull seamlessly from 1000 to redline in any gear it has a problem. It is not an antique with carbs and 45 degrees of overlap.
