Hello all,

Long time lurker, Refreshed poster

I don't know whether I should post here or the Tipo section but I'll start here as this might be a generic query.

I had a STAGE II Cam fitted to my 1.6 Carb Tipo that also has a Mechanical Fuel Pump.

I now have a problem, sort of.

The car does not want to drive slowly and has a complex. It hasn't gotten much faster but it definitely does feel like it accelerates quicker... sometimes.

If I try to pull off from stand still after Tipo has warmed up and the coke is in, it jerks off (Jerks off? I didn't know cars could do that) until its over 2000-2500 revs. It's not a stall jerk but more a "I'm so fast I'm gonna drive into the back of that big red bus in front of us YAYYEE!" kind of jerk.

Its been taken for a tune up and once warm it idles perfectly.

When cold it behaves like an old car that wants to die unless the coke stays out and revving the engine at 2000rpms or more until warm and even then I can't drive it until the temp gauge moves a little bit. If I attempt to put the coke in even just a little the revs will eventually fall and the car will stall. If the car doesn't stall the revs rise back up to where they were and then will fall and raise at even intervals, like the engine is breathing or something.

I called Middlesex Tuning, some of you may have heard of them, and the guy over the phone, who sounds like an expert by the way, diagnosed my problem without even seeing the car based on the info I provided alone.

He said that

'The high lift cam is causing the fuel chambers to not fill up with fuel quick enough. so as I try to pull off there is not enough fuel. As the RPMs get higher there will be more fuel and the car will start behaving normally. There is no real cure for this unless one fits a fuel pump that pumps more fuel but then what will happen is that idle you'll have too much fuel and the car will run lumpy. The only work around is to blip the throttle before I pull off to fill the fuel chambers.'

I'll get used to it he says.

The advise he gave does work however it means driving around town is a nightmare as I sometimes have to do this blip thing even when I'm still rolling and in second gear which is quite difficult when you're slowing down whilst preparing to move if that makes sense? (Left foot on Clutch, Right foot on brake whilst using the same right foot to blip) It also means I cannot accelerate slowly unless I ride the clutch like a stripper rides the pole. Not only that it's drinking masses of petrol, although fuel efficiency on motorway journey's appear to have improved a lot so long as I don't have to slow down and then accelerate.

Now I guess its my fault as I should have bought a STAGE I cam but I confused STAGE I for Standard/Stock replacement.

I don't really want to have to put the original cam back in.

I would like to know if anyone knows what further modifications I would have to make to make my car drive sociably again.

List of current engine mods:

Apex-i Induction
Stage II High Lift Cam
Up rated Shim Lifter Springs
Straight through exhaust system
Head Skimmed

Now I don't think my car has an ECU that can be modified so that is sort of out of the question, unless I get a new one but if I do then it won't integrate with much as most of Tipo's engine is mechanical and not controlled by electronics.

Any ideas/advice/help/donations would be greatly appreciated

Thanks.

:wave: tech section might be better, i ask section mod

surely an electric fuel pump would be the answer to the problem?

A long time ago, in a Galaxy far, far away I had a Chevette 2300HS which had fast road cams, or in other words, high lift cams. Through the mists of time I seem to remember that on their own they made the car difficult to drive. However, and this may not be what you wanted to hear, along with the cams came a pair of Webers (40DCOEs?), a big valve head, free flow exhaust manifold, fabricated inlet manifold and a higher capacity fuel pump.

The high lift cam is to allow the valves to open further and for longer (I think) which is mainly pertinent at high revs, but will still have an effect at the lower end of things.

It sounds as if you need either a higher capacity fuel pump or maybe a twin choke carb. On the other hand, maybe you could invest in a big valve head, free flow exhaust manifold, fabricated.........................

Actually, that wasn't much help was it?