Random bogging down/engine cut.

[Brigsy]

Ive had a problem with the van since rtoc frog of pod.

To cut a long story short i had the van running really well with the 'dd autosports' cam. In the goal for more power i fitted a piper 285 dialled in at 116deg.

At rtoc day i managed two clean runs then every time i hit 6200+rpm in 2nd gear the engine would just stop revving, afr's off the scale lean but no mis-fire or nothing. By simply letting off the accelerator & stamping it back down the engine came back on song & was fine.

On the road i very rarely have this problem at all, only appears with the drag radials on/drag strip runs from standing start, i assume its down to more load with no wheelspin. I have an occasional 'pop' when pulling away in first gear on the roads but no big deal.

I initially thought the fuel pump was on its last legs so have changed pump, fpr, dizzy cap & rotor arm. Also have changed the fuel pump sender.

Took the van to usc & ran it yesterday, first/second gear no probs, flat shift into third & no power at all, engine wouldnt even rev picks up about 3-4 seconds later after releasing throttle.

Could this be fuel surge or possibly be ignition related? The needle on rev counter was staying rock solid yesterday so i assume the tdc sensor is working ok. Also my fuel tank is baffled as per the stock gtt tank.

[Matt Cole]

Clutching at straws here briggsy, could be an intermittant air leak somewhere (afr's going quick lean). Or fuel cutting as you say. Float bowl might be replenishing from second to third gear then emptying when powering on.

[Brigsy]

Possibly mate. All the wiring is in good nick to the pump, i need to bypass or change the pump relay to rule that out. The ph1 pump might not be up to the job?

Im going to make the dizzy adjustable again, could be right on the edge of the contacts thus poor spark under hard load?

[Mart]

Float chamber emptying.

[Brigsy]

Fuel pump not up to the job or swirl pot needed?

Im tempted to slot a 2ltr swirl pot in using the ph1 pump for lift & fit a cossie 044 to fill the carb.

[Mart]

Neither mate. It's just an unfortunate characteristic of the 32dis when running big boost/high rpm. It can be rectified though - I posted on a thread a couple of months back about supplying the float chamber with more fuel.

If you think it's a pump issue, simply 'T' a boost gauge, or pressure gauge in general, and see what the fuel pressure does when it hits that 6.2k rpm.

Adding more pressure to the needle valve is a bad move - It'll just force the valve open & flood the chamber/carb in the process.

BTW, why is the cam timed that far retarded?

[Adey aka Ewok]

I've got a 12v solenoid that was going to be used as a second feed to the float on my old car as over 22psi I was getting float chamber empty on high rev gear changes, drop me a pm if you want to try it, similar setup to ave had on his car, plan was to boost activate it and feed fuel in at the main jet cover bolt

[Matt Cole]

Briggsy, get rid of that dog **** ph1 pump as well, (does anyone believe they flow more and provide 3 bar presure?). As suggested, float chamber emptying sounds like a good start. Other option to swirl pot would be some injectors additional to the carb. Could be mounted discretely and controlled as cheaply as you want.

[IANMM]

didnt scoff have something like that a few years back plumbed into his carb?

[Slim]

this happens to me too

[IANMM]

wouldn't it be lovely to have a see through carb

[Brigsy]

Neither mate. It's just an unfortunate characteristic of the 32dis when running big boost/high rpm. It can be rectified though - I posted on a thread a couple of months back about supplying the float chamber with more fuel.

If you think it's a pump issue, simply 'T' a boost gauge, or pressure gauge in general, and see what the fuel pressure does when it hits that 6.2k rpm.

Adding more pressure to the needle valve is a bad move - It'll just force the valve open & flood the chamber/carb in the process.

BTW, why is the cam timed that far retarded?

Cam is retarded for more top end power

I think this is a pump issue myself, as i can rev it to 7.5k in 4th & 5th gears without emptying the float/leaning off. Ive got all the bits to supply more fuel to the bowl but as it has never leaned off in high gears ive never seen a reason to mess about with it too much.

I will whack a gauge on & see whats happening with the fuel pressure, its hard to get it to replicate on the road though, as wheels are normally spinning like feck in 1/2/3 gears on road tyres. No load no problem really

It seems to be worst when fuel is under half a tank thats what made me think about a swirl pot.

Surely if i fit a decent pump with a better flow rate, the regulator will return the fuel that isnt needed to the tank & as the reg sets the pressure it shouldnt alter at the needle? 044 is prob overkill i admit id probably pick a cheaper alternative.

[Ashy]

sounds like you need a new inlet manifold with a couple of injectors in the back

[dave j gtt]

Cam is retarded for more top end power

I think this is a pump issue myself, as i can rev it to 7.5k in 4th & 5th gears without emptying the float/leaning off. Ive got all the bits to supply more fuel to the bowl but as it has never leaned off in high gears ive never seen a reason to mess about with it too much.

I will whack a gauge on & see whats happening with the fuel pressure, its hard to get it to replicate on the road though, as wheels are normally spinning like feck in 1/2/3 gears on road tyres. No load no problem really

It seems to be worst when fuel is under half a tank thats what made me think about a swirl pot.

Surely if i fit a decent pump with a better flow rate, the regulator will return the fuel that isnt needed to the tank & as the reg sets the pressure it shouldnt alter at the needle? 044 is prob overkill i admit id probably pick a cheaper alternative.

As mart say sounds like no fuel for a second Or

are the breathers on petrol tank breathing enough ??? just a fort

[The new Bill J]

.....just a fort

No it's not. This is a fort:

[Mart]

Cam is retarded for more top end power

I think this is a pump issue myself, as i can rev it to 7.5k in 4th & 5th gears without emptying the float/leaning off. Ive got all the bits to supply more fuel to the bowl but as it has never leaned off in high gears ive never seen a reason to mess about with it too much.

I will whack a gauge on & see whats happening with the fuel pressure, its hard to get it to replicate on the road though, as wheels are normally spinning like feck in 1/2/3 gears on road tyres. No load no problem really

It seems to be worst when fuel is under half a tank thats what made me think about a swirl pot.

Surely if i fit a decent pump with a better flow rate, the regulator will return the fuel that isnt needed to the tank & as the reg sets the pressure it shouldnt alter at the needle? 044 is prob overkill i admit id probably pick a cheaper alternative.

Dude, I know why cams are retarded thus so 116 just seems a bit extreme for a 'T28' power band. It was a rhetorical question

Aii, the fpr does regulate the fuel pressure to the carb, but it'll only retain base pressure so much! I found when fitting a Walbro high o/p job that the o.e regulator wasn't upto the job, hence I had to fit a Malpassi fpr. I'd guess the 044 output is somewhat higher than the Walbro...

Fit the pressure gauge & go from there.

[GTphil]

Interesting read this thread

I have a similar issue at the moment although my cam is currently at 110 degrees retard (soon to be 116) on the road it's fine will fuel for 24psi for the odd burst but leans off at 6.7k rpm at 22psi it's fine but not from a standing start it gets worse the lower the fuel level is.

With slicks it will lean off at 20psi high up in the revs/gears due to the increased load.

A few things I will be trying to solve the issue even so I can run 22psi with slicks

tee the frp vac pipe into the comp housing on the turbo

running a large/fat live wire to the fuel pump so it carries the amps better to try and zing the pump up a bit at high revs. ( I run a sytec fuel injection pump)

opening the second stage to 1.4mm (currently 1.3mm)

It would seem with anything over 22psi and a heavily retarded cam there isn't much you can do other than a secondary injection of fuel at high boost.

How many times over the years have people come across this issue and not been able to solve it compleately?

Does anybody know how stu clarck solved the issue? He used to run mega silly boost from what I remember.

[Mart]

There is a solution - I've posted about it several times in the past.

The other alternative (which I've also mentioned before) is to fit a rising rate fpr as opposed to the o.e 'static' fpr.

[Brigsy]

Can you remember the part number for the rising rate reg mart?

[GTphil]

There is a solution - I've posted about it several times in the past.

The other alternative (which I've also mentioned before) is to fit a rising rate fpr as opposed to the o.e 'static' fpr.

I'm pressuming that a rising reg will be able to keep "pace" so to speak with the boost pressure?

[Mart]

It will, and even if it wasn't instantaneous as such, there'll be enough fuel reserve in the float chamber anyway.

[dave j gtt]

No it's not. This is a fort:

.................................................. ........

[dave j gtt]

No it's not. This is a fort:

which thought or thorght is this ??? you get my drift people knew what i ment.

you only wrote as you dont have pennys to go play in ya evo coz der dat bad on petty

On a serious note were is that? and what is it called ? is it in france by any chance ?