View Full Version : Miss on track
My Track Nova 1.4 carb started missing yesterday on the same bit of the track each lap, then recovered each lap after the corner.
I assume this will be lack of fuel as it is at the same place each lap?
The only thing I can think of is....there were some passengers and the fuel line was slightly squashed under the harness where it attaches to the seat.
The car drove home (120 miles) perferctly well and obviously I can't test it the same way until the next track day.
If the pipe was squashed, despite the carb having a resuviour, would this cause the missing and then recover again as I slow down for the hairpin bend?
its unlikely that the fuel line is the problem. you use, on average, a teaspoon of fuel to cover about 30metres on a track in a small engined car.
it could be a wiring fault, some muck in a fuel line, air getting in the fuel line or even oil sloshing about.
what particular part of the track was it on ??
mk1nova_rich
19-11-12, 04:58 PM
How much fuel was in the tank on track?
thegingerwhinger
19-11-12, 05:23 PM
it was at knockhill yesterday i presume, as i was there aswell.
Probably happend on one of the tightest right handers i presume? So its possible to be fuel starvation as its swishes over to the passenger side of the tank and away momentarily from the pick up, plus the fact you had passengers so more lean????? Just in idea.
its a carb engine & the float bowl should more than cope with that..
its a carb engine & the float bowl should more than cope with that..
Not really... even the fecking huge float bowl in T40's cant cope properly and the pump runs like a bastid to keep up after a hard blat/corner etc.
the pierberg has that stupid plastic swirl pot too doesn't it? as i very roughly worked out the fuel usage at 20ish mpg in my previous post, the fuel line alone holds enough fuel for a good 1/4 mile, i just think there is another problem, possibly the fuel pump is on the way out or is full of crud
It was at Knockhill and it is the straight just before the hairpin.
It was perfectly fine the rest of each lap.
The fuel tank was half full and I have run it before round the track with far less fuel in it.
I did spill a little oil topping up on the leads but didn't think that oil on the leads would short out, if it is w wiring/ignition issue, why only at the same point each lap on the track?
The electric fuel pump is only about 6 months old, would it just be that with the extra weight of another person, the pump wasn't pushing enough through? The car didn't feel much slower with another person.
Ginger whinger's car looks fantastic and goes very well.......slightly jealous.
[QUOTE=marc69;2092865]It was at Knockhill and it is the straight just before the hairpin.QUOTE]
So at one of the fastest bits on the track coming up to the hairpin?
[QUOTE=marc69;2092865]It was at Knockhill and it is the straight just before the hairpin.QUOTE]
So at one of the fastest bits on the track coming up to the hairpin?
Yes, i think I reach 90 (slow for most other cars)
Hmm strange, so is it at your max on that straight when it misses then or in the run up to it after leaving Clarks/Carlube Corner(right hander, off camber, on an incline)?
I don't know the names of the bits but it is half way through the straight before the tight hairpin, I think it is after clarks (the stand). The hairpin is where they do the drag racing from. It had been fine all day but just at the end of the day started doing it.
It is really wierd because it drove home normally and I don't know how to test it without owning my own track!
Fuel evaporation possibly then as the engine would be pretty hot after a days racing, would progressively build up heat throughout the day that it wouldnt have in the morning when the air is a hell of a lot cooler, especially up there. Driving home there wouldnt be any extreme loads on the engine so its pointing to something that happens at its peak and when hotter in my guess. Kinda has to be something you work on/test at Knockhill if theres nothing obvious or someone in the know can point you towards.
Can you state your setup please?
It all points to fuel starvation to me under hard cornering,especially now you are mentioning electric fuel pumps
Thanks Kev and I see what your saying but I often overheat the car so much that the oil thins and then the tappets are noisey each time I come off the track. This time I changed gear mostly at 6k rather than 7k so as not to push it too hard and I didn't get noisey tappets once so I assume from that i didn't heat the engine as much as before?
I assume we agreed that it is definately fuel?
It looks like I'll have to start from the fuel pump and go through all the pipes checking there is enough pressure and also giving the carb a clean but what you said about it only happening at the peak is spot on. The only other thing as the temperature was so cold, the carb wouldn't freeze at all would it?
Can you state your setup please?
It all points to fuel starvation to me under hard cornering,especially now you are mentioning electric fuel pumps
The set up is a 1.4 OHC with a 1.6 head. Pierberg 2e3 carb. I can't recall the make of the pump at the moment but I bought it new 6 months ago and was told it has good enough psi for up 2.0. The car has done Knockhill tracks days one each month since April with no issues, this just happened all of a sudden towards the end of the day yesterday.
Thanks Kev and I see what your saying but I often overheat the car so much that the oil thins and then the tappets are noisey each time I come off the track. This time I changed gear mostly at 6k rather than 7k so as not to push it too hard and I didn't get noisey tappets once so I assume from that i didn't heat the engine as much as before?
I assume we agreed that it is definately fuel?
It looks like I'll have to start from the fuel pump and go through all the pipes checking there is enough pressure and also giving the carb a clean but what you said about it only happening at the peak is spot on. The only other thing as the temperature was so cold, the carb wouldn't freeze at all would it?
Not sure but Sunday was a bloody cold day down here so up there in them there hills it must have been freezing. I only live 15 mins away and it could be a gloriously warm day, drive up there, still sunny but blooming cold like a 10 degree difference :wtf:
Ahh bite the bullet & get yourself a bigger lump under the bonnet lollollol
thegingerwhinger
19-11-12, 10:17 PM
i was trying to tell him to move to 16se, but for a 14nv with a twin choke peirburg carb it goes pretty well for have 14" road going tyres on. hope your feet have thawed out now Marc lol
i was trying to tell him to move to 16se, but for a 14nv with a twin choke peirburg carb it goes pretty well for have 14" road going tyres on. hope your feet have thawed out now Marc lol
Aye by all acounts hes doing pretty well in it, the 14nv's providing a good learning curve before the want for more speed/power sets in :d
Thanks, yes I'm still with the 14nv for the moment, it's cheap and was reliable!
If I go a lot faster I'll probably have to upgrade suspension etc more again and for a novice like me, the handling is great and relatively safe/predictable.
Although being one of the slowest cars on the track is pain, and yesterday becoming the slowest.
Yes, my feet have thawed out thanks, I think a heater and dash has to go back in.
monks69
20-11-12, 05:04 PM
Pretty mad but my nova had a bit of a misfire at the last knockhill, not mannaged to ahve a look at it yet but i was assuming it was a fuel filter
I managed to get it too play up here last weekend when really pushing it hard. As soon as it started missing, switched off fuel pump and pulled in, still fuel in the carb so it's not that.
Today i opened the distributor, the weights under the rotor arm seem a bit loose, the one lowest to gravity hangs down a few millimeters although the springs still pull a little. Is this the wear of the springs that is causing my problems? Would it be causing the ignition timing to advance too much at high revs?
I will put in my spare distributor but when the ice clears and I can test it........
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