Intermittent Hesitations Throughout The Rev-Range

[jonny6 8]

Ive got this strange problem with my car that i noticed today , seems to have developed strange hesitation symptoms , its a strange because its not there all the time , somtimes it pulls through the rev range perfectly no issues at all , but other times it really feels like its struggling and holding back , im not sure whether its spark cutting out , or a fuel issue . its a 1.9 8v running twin weber 45's . i know it pretty hard for you guys to understand my crap diagnosis , but opinions on what route to investigate down first would be helpful . or similar experiences . fuel or spark hmmm...

[Paul_13 212 1 Cars]

Check your alternator voltage, see what that gives you.

 

Check/change fuel filter?

[jonny6 8]

what would alternator voltage determin paul ?

[bensonmi 4 2 Cars]

have the carbs been set up properly?

[welshpug 1,657]

what happens on the rev counter when it plays up?

 

nothing = fuel, merry dance/hiccup = ignition

[Paul_13 212 1 Cars]

If the alternator is faulty/dying it will cut out as it's not charging properly. Needs to be 14.4v.

Is it missing on idle? Or just under load?

[jonny6 8]

carbs have been balanced and fettled with , but not been on the dyno or had fueling checked , not ideal , but somtimes it doesnt hesitate and willl rev out hassle free , goes like the clappers .

i dont think the rev counter pics anything up to be honest , just slows down as its struggling to rev . Its fine on idle , no probs at all .

[TBC WEBER 45s 4 1 Cars]

Is it doing this when the engine is hot or cold

[Weser 30]

One thing that I would check as I had it on my and it cost me the price of the refurbishment of my dizzy trying to find it was that the low voltage connector plug on the dizzy has bad crimps and a loose connection. It gave the exact symptoms you are describing. Easy check when it does it wiggle the connector and see if it improves. I doubt this is the problem as it is quite unlikely but it is worth checking. Sounds to me like it is over-fuelling and flooding the engine a bit sometimes?

[welshpug 1,657]

If the rev counter behaves I don't think it will be anything on the LT side of the ignition system, given that the rev counter gets its signal from the coil, which in turn from the amp, and then the dizzy.

[Weser 30]

True, however mine seemed to weird not go nuts just showed the revs of the dying engine. If that makes sense? Thats why I thought I would add as it was a nightmare to find and I only did by luck.

[TBC WEBER 45s 4 1 Cars]

True, however mine seemed to weird not go nuts just showed the revs of the dying engine. If that makes sense? Thats why I thought I would add as it was a nightmare to find and I only did by luck.

I No what you mean had a mate how had the same prob his car was std it will sum times start sum times not when it started it was ok then just die so you are not going nuts but I think he is on about the car is ok but feels like the car has just put on 10th ton or as flat as a witch is tit

[jonny6 8]

only does it when throttle is pinned . engine is always warm . has no issues starting or idle . i think my next step is to get the fueling checked at wide open throttle . check if its flooding as it only seems to happen at full throttle .

[TBC WEBER 45s 4 1 Cars]

What fuel pump are you using

[jonny6 8]

standard fuel pump with 2 regulators.

[TBC WEBER 45s 4 1 Cars]

Is that the std pump for the injected system

[jonny6 8]

thats the one mate .

[TBC WEBER 45s 4 1 Cars]

The pump is the problem. I have run this system befor and had the same thing so I have put a facet pump on and sorted it out go for a silver top it is not so much feed back with the fuel as the red top when sat round in traffic

[jonny6 8]

you think thats the problem ? what issues is the standard injection pump causing then ? flooding it ?

[jonny6 8]

checked my jet sizes , idle jets are 55's, main jets are 150's . sounds about right doesnt it ?

[TBC WEBER 45s 4 1 Cars]

you think thats the problem ?yep!*** what issues is the standard injection pump causing then ? The std pump is a high pressure pump carbs like lots of fuel not pressure I no your got regs on ***flooding it ?no opposite you are emptying the float chamber befor it can fill up causing the dead feeling

[jonny6 8]

ahh i see , so my injection pump is providing high pressure (which is what injectors need) , but not high volume of fuel .

[TBC WEBER 45s 4 1 Cars]

ahh i see , so my injection pump is providing high pressure (which is what injectors need) , but not high volume of fuel .

that's the one

[jonny6 8]

thanks mate , much appreciated ..

[welshpug 1,657]

ahh i see , so my injection pump is providing high pressure (which is what injectors need) , but not high volume of fuel .

 

 

no, its providing both.