I have a 98 el falcon with the hybrid motor and auto in it, k&n filter, AUXR8 III snorkel, extractors and 2.5" mandrel bent redback exhaust with hiflow cat. Now the problem i have is that the motor has started to surge from around 25 - 2800 rpm to about 3500rpm and after that it revs just fine, not a problem. Ive replaced the leads, spark plugs and tried another coil and its still doing it, ive cleaned that isc thingy (shown in doco) and ive also reset the computer which seems to do little if anything at all, and the fuel filter has also been replaced. But something i have noticed is when i switch it from economy to power it dosent seem to be as bad so could there be something in regaurds to what controls the transmission and what controls the engine ?? Any help would be great,

Thanks

i had a prob with my EL lately...fuel pump died...shortly before i had that exact problem. New pump is in and im getting way better peformance and fuel ecconomy,....its been suggested to me that it wasnt puting out the right pressure and therefore the spray from the injectors wasnt as good as it could have been hence less peformance and fuel ecconomy at certain rpm's...round the 2000-3000 mark. Thats all gone now since i replaced the pump...

i also found that an EA single point injecvtion pump has too high pressure for an EL (doesnt work well), car goes like crap n wont accelerate well at all...i now more than ever realise how much a fuel pump effects the peformance of the car.

Its the fuel regulator that sets fuel presure

But if the pump isn't workng there'll be no pressure to regulate.

But it should b able to handle a higher pressure pump and be able to 'cut it down' to what is expected by the engine/ecu.

How easy is it to change the Fuel Pump and much do they usually cost

yep, not enough pressure it doesnt regulate it properly.


Pumps easy enough to change

6 screws in the boot u take out
then theres a adjustable bracket around this black lock thing...6mm (or was it 8mm) spanner you can eventually remove it,..tricky but its possible

then the lock thing on the tops plastic...really hard to get off but a hammer and screw driver you can turn it slowly

assuming you have already disconnected the fuel lines and electrical lines just lift the pump out and replace it with another one and do the above in the reverse order.

only prob you may find are the connectors on the top for the fuel lines may differ (as they made a few types)...soooo all you can do is take the actual pump off the bracket and reattach it to your old pumps bracket...

while doing this be careful not to hurt the float as you wont get a good reading on your fuel level in the future.


alosoooooo...mark the possition of the pump origionally n put the new 1 in the same possition, the further to the left its twisted the higher the level sits, the further to the right the lower...you need to make it reasonably accurate.

you know how people say 'i never let my car get below 1/4 a tank so the junk in the bottom dosnt get in the car'...well thats good...but a better reason for you not to let it go below 1/4 is so the pump always has petrol around it. The pump is 'cooled' by the surrounding petrol...if it gets to low and all it does is suck it up...it will overheat and shorten its life...so if you always let the car run low...think about that next time...its not just the particles its the temp of the pump.



Andrew

i didnt accutally think about it being the fuel pump only becuase it seems to run fine after 3500 ish rpm. I am a person because of the km's i do, i let my tank run low nearly every week, usually putting up to and plus 60ltrs in it, so maybe ive been the cause for this problem if it is the pump, is there a easy way to test if its the pump or not before i go out and buy another one ??

yep...disconnect the line at the fuel filter (under the rhs rear passenger door) and measure the flow when you turn the key (without turning over the engin). Im unsure what the volume should be but im sure somoene can tell you.

Also you might want to replace the filter...

i used to do the same thing, let it run really low...now i know it also cools it ill never be doing it again...pump was 250,000kms old...i owned the car for 6 months n it dies....maybe it was its age...or maybe it was the way i treated it...either way thats no reason to take risks.

I think my car might be doing the same thing. I sometime get a flat spot in my acceleration between 1500 and 3000 rpm, pulls like a 14 year boy beyond that. Doesn't happen all the time though. Is this what you mean by surge?

Yer it kinda feels at first like a flat spot but you can feel the car wanting to go and u see the tacho needle slowly struggle to go around but after it hits 3500ish it comes to life again.

my mates car was doing this and the problem was he was low on water in his raiator and it was blocked. this lead tofluctating levels of water passing through the bottom radiator hose and over the senser this made his cars idol surge. dont know if its the same sort of thing but that is what his problem was

that would be a very rare case...sounds odd lol...

most surging problems are related to tuning, and as its automaticly done it links back to air / fuel mixture probs and the car not being able to keep them stable...sooo normally points to leaking inlet gasket problems, or some kinda of fuel system issue such as dirty injectors or incorrect fuel pressure and therefore the injector spray isnt as good as it could be. It tends to go away at higher rpm because the revs are higher and therefore the inconsistancy'z in the air/fuel going in are not as noticable, but they still exist.