Daytona Driveability Problem

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Darren C
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Location: Chichester UK

Re: Daytona Driveability Problem

Post by Darren C » Mon Oct 20, 2014 2:23 pm

Hmmm, Its always difficult to diagnose from an armchair, but if you've exhausted Carburettor adjustments and checks, then it could be ignition timing, advance/dwell, weak spark or compression.
That said I had a voltage relay once that dropped out the charge from the dynamo only below 1200rpm, car would die and fade on low voltage until it drove over 1200rpm. Took a while to find that one as there was no fitted amp gauge.
330GT 2+2 4HL 6727
Small things make perfection, but perfection is no small thing.

DWR46
Posts: 539
Joined: Tue Sep 22, 2009 8:23 pm

Re: Daytona Driveability Problem

Post by DWR46 » Mon Oct 20, 2014 6:01 pm

Thanks for all the thoughts. Ignition system is spot on as to timing, distributors set on the Sun machine, etc. Compression is excellent, no smoke. engine very smooth. I am tending to believe that at least SOME Daytona's have this problem to varying extents. Timo recalls having encountered at least one similar car, and Mike Pierce has dealt with three cars like this. In Mike's case, he found that adding fuel to the idle circuit helped the problem, but then the spark plugs turn coal black. This individual car is not that bad, and normal driving is not an issue, just when starting off on a hill. Daytona's tend to "come on the cam" about 1,500 rpm and this aggravates the situation somewhat.

Edward 96GTS
Posts: 55
Joined: Sun Nov 16, 2003 12:21 pm

Re: Daytona Driveability Problem

Post by Edward 96GTS » Thu Oct 23, 2014 3:30 pm

just came back from a drive in the daytona. went from stand still to speed on several different inclines. no stumble or hesitation at all, just smooth acceleration. my carbs were rebuilt by pierce manifolds approx 4 yrs ago.
mechanic did a great job at dialing in a perfect, bounce free idle of 900-950 rpm.

Timo
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Joined: Thu Apr 13, 2006 8:56 pm
Location: Riverside, California

Re: Daytona Driveability Problem

Post by Timo » Fri Oct 24, 2014 12:36 pm

Mr R.,

This has been occupying good part of my quite limited brain capacity for several days now without providing any real answers, but after re-reading your initial post wanted to clarify something.

Am I to understand correctly that this "problem" occurs ONLY when attempting "take off" (uphill) at or just barely off idle ("below 1000 rpm") ?
I have encountered some "barely" off idle slight hesitation "issues" on Daytonas where carbs have seemingly been previously removed and/or disassembled/re-assembled for cleaning/service. Some of the culprits I've discovered have included slightly misaligned throttle plates (removed during cleaning/service?) and/or slightly unevenly adjusted throttle rod links, which at the time I thought some "mechanics" may have not been able or willing to spend the necessary (some times long ?) time to get it right and if it have had slight effect on idle, they've "compensated" for it with air bleed and/or mixture adjustments.

Sorry, nothing better to offer at time, but I'll keep thinking (even though it often hurts more than it produces :lol: ).
I will also (attempt) to send you my direct email and phone number through PM, in case you wish to discuss this or other issues in person.
Timo

DWR46
Posts: 539
Joined: Tue Sep 22, 2009 8:23 pm

Re: Daytona Driveability Problem

Post by DWR46 » Fri Oct 24, 2014 12:56 pm

Timo: You are correct, only below 1,000 rpm under a load of starting uphill. I am sure it also does it on level ground, but the effect is negligible. Throttle shafts have never been out of the carbs, and synchronization is on the money. I have always been paranoid about clutch slippage, and try to always drive off using the least amount of revs in any car. I think I just need to give it some gas and forget about it.

Timo
Posts: 215
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Location: Riverside, California

Re: Daytona Driveability Problem

Post by Timo » Fri Oct 24, 2014 1:52 pm

DWR46 wrote:Timo: You are correct, only below 1,000 rpm under a load of starting uphill. I am sure it also does it on level ground, but the effect is negligible. Throttle shafts have never been out of the carbs, and synchronization is on the money. I have always been paranoid about clutch slippage, and try to always drive off using the least amount of revs in any car. I think I just need to give it some gas and forget about it.
I've always felt similar about clutch usage. If a specific vehicle has enough torque for taking off at or almost at idle I try to use it in this manner, unless there's a specific reason like testing some related performance aspect of specific car. I dislike sitting at signal lights with clutch/gear engaged to a point that even if I'm a passenger in a clients or some one else's car and driver does it, it bothers me :shock:
I'll keep racking my pea sized brain, but it seems you've exhausted just about all reasonably approachable avenues so far and might, in fact, just have to live with it.
Timo

Steve Meltzer
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Re: Daytona Driveability Problem

Post by Steve Meltzer » Fri Oct 24, 2014 2:59 pm

This is definitely tangential to Dyke's annoying problem, but relevant to taking off from idle....I'm a big fan of "Click and Clack, the Tappet Brothers". They have always advocated teaching a student to drive a stick shift by learning the " friction" point with the right foot completely off the throttle until the car begins to move. Only then does the car get more fuel. I employed that method when I taught both my wife and my son to drive a manual transmission; both of them still talk to me and the clutch they learned on 22 years ago, is still in great shape.

Like Timo, they also espouse sitting at a light out of gear, in neutral.

Reporting for NPR. steve
steve
meltzer, "“With a Ferrari, whatever it is, it’s a $1000. If that’s what it is.”"
'66 330 GTC, '72 Daytona-red, did they make any other colors?

afwrench
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Location: upstate new york

Re: Daytona Driveability Problem

Post by afwrench » Fri Oct 24, 2014 5:11 pm

Hi Dyke, is it possible that one or more of the carbs is off just a bit or needs a modification on the float setting? Thinking that this happens just on a hill,could one or more of the carbs fuel level be low in the bowl such that it is ever so slightly starved while pointed uphill? Mike
72,365gtc4,14681,2007 599 GTB

DWR46
Posts: 539
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Re: Daytona Driveability Problem

Post by DWR46 » Fri Oct 24, 2014 7:52 pm

Mike: Another good thought. I am running the Euro float settings, which are higher than the US specs. They were also rechecked a short while ago. No fuel spilling over through the auxiliary venturis, so not too high.

SLM
Posts: 110
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Location: PA

Re: Daytona Driveability Problem

Post by SLM » Mon Oct 27, 2014 2:28 pm

Dyke,
I was just out for a weekend cars and coffee drive with a freind who has a Daytona. He has the exact problems you describe. I almost passed him going up a hill in my MGA. :)
This car never had this problem before. It's at the shop know and I will report back what they find.
Steve
62 250GTE S/N 3733

DWR46
Posts: 539
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Re: Daytona Driveability Problem

Post by DWR46 » Mon Oct 27, 2014 2:32 pm

SLM: Thank you.There is speculation that this issue is fuel related. Mike Pierce believes that if you run race gas, the problem will disappear.

Edward 96GTS
Posts: 55
Joined: Sun Nov 16, 2003 12:21 pm

Re: Daytona Driveability Problem

Post by Edward 96GTS » Mon Oct 27, 2014 3:33 pm

i doubt this is fuel related as im running the same crappy gas here in the peoples republic of california. and old gas at that.
ed

DWR46
Posts: 539
Joined: Tue Sep 22, 2009 8:23 pm

Re: Daytona Driveability Problem

Post by DWR46 » Mon Oct 27, 2014 4:00 pm

Ed: our wonderful federal government has mandated over 100 different fuel mixtures throughout the US. Fuel in my part of the country can be very different from what you have, plus it all changes with the seasons also.

Timo
Posts: 215
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Location: Riverside, California

Re: Daytona Driveability Problem

Post by Timo » Mon Oct 27, 2014 4:08 pm

Edward 96GTS wrote:i doubt this is fuel related as im running the same crappy gas here in the peoples republic of california. and old gas at that.
ed
+ 1,
although I have experienced "bad" gasoline related issues (only) once or twice in past 30+ years, but nothing consistent. Once even on across country drive soon after filling up almost empty tank at some point and after using it all during subsequent hours/miles, re-filling the tank with fresh batch, vehicle ran fine again.
As I mentioned earlier, I've been able to remedy all running related "inconsistencies" I've come across in Daytonas by "tuning".

Mr R.,
probably not a cause, especially since they would present other problems, but have you eliminated all possible vacuum leaks sources ?
Obviously U.S. spec vehicle has many more such potentials.
Is yours running with all emissions control system intact and operational ?
Timo

Edward 96GTS
Posts: 55
Joined: Sun Nov 16, 2003 12:21 pm

Re: Daytona Driveability Problem

Post by Edward 96GTS » Mon Oct 27, 2014 4:19 pm

i think the key to solving this is the fact that it only happens on an incline.
since it happens only when under extra acceleration load(as opposed to level acceleration), double check the components that come into play under the extra load.
can you duplicate the stumble on a level road when starting out in 2nd gear?
ed

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