[Mk2] [Turbo] Walbro pump + Aeormotive FRP = rough idling! But why?

[misterT]

I've fitted an Aeromotive FRP 13101 and a Walbrbo fuel pump.

When setting the pressure on the fpr i have paperclipped +B and FP to get the pump going without starting the engine, also vacum line disconnected.

Is this right? Or should i have the engine running when setting the pressure? Vacum line connected or not?

Now, when i start the engine it runs like crap, unless i disconnect the vacum line to the FRP. ??

Have i done something wrong?

Please help me!

Thanks
Dean.

By running crap i mean revs going up and down, 750rpms then sudden drop to 300 ish, then back up, ect, etc. And if i rev the engine, when it drops naturally it will stall or just about keep running.

[karammander]

u need to set it with the engine off and with the vacuum line installed.

think its something like 38psi base with engine off..

cheers karam

[misterT]

Thanks Karam,

I've set it up properly now, but its still idling a bit "lumpy". I'm not sure this is even related now.

The engine was running fine after a lot of work recently, except one of the spacers on the fuel rail was broken so wasn't sealing against the head properly.

I've changed all the spacers and the injector seals - problem solved - but now it wont idle properly.

Could this just be due to the Unichip needing a re-map, or should i be looking somewhere else?

The only things that have iv'e changed since the problems started are a Walbro Fuel pump, and the FRP. It was running fine before this.

Explanation of rough idling is on the first post, this is when the engine is warm too.

I've checked the Throttle control valve, and set it as per BGB, but its still the same.

Plugs are new, leads look ok, dizzy and rotar all fine.

Any ideas?

Thanks,
Dean.

[misterT]

Update - i've just checked all the fuses - all ok

I've also checked the ecu for errors - normal

Starts up fine, seems to ruk ok at times, but other times the revs are still dropping, going up and down like a yoyo!

Idles at around 700 - 750, then drops anywhere from 250 - 400 ish, then back up, back down, every couple of seconds.

I'm baffled.

Any ideas?

[misterT]

Quick question...

Does the Walbro pump use more power than the standard fuel pump?

If so, i think this may be battery related.

I've had a few dying battery problems lately, i'm pretty sure something, somewhere is draining it, but maybe the Walbro is draining more power and making the car run lumpy?

Is this a possiblilty? Could a weak battery make the car idle badly?

I checked the voltage from the battery today, and it measured 10.4V

When the car is running its showing 14.5V At least the alternator is good.

Knackered battery?

[SFLee]

battery does play wier part

u can always try turn light on as soon as u started the car see it cut out or not

[Slarty]

I wouldn't have thought it was the battery Dean, once the engine is running, the alternator provides all the electricity the car/engine needs.

Sorry I can't help with the problem matey sounds like it's getting you down!! We'll have to meet up soon so I can see your shiny new engine I've been adding a few bits too

[misterT]

I wouldn't have thought it was the battery Dean, once the engine is running, the alternator provides all the electricity the car/engine needs.

Sorry I can't help with the problem matey sounds like it's getting you down!! We'll have to meet up soon so I can see your shiny new engine I've been adding a few bits too

Yea whenever you like mate.

And yes, this is getting on my t1ts to say the least!!

I just want to get her running nice, have the ecu re-mapped, and leave her alone..... for a while.

I had her booked in a couple of weeks back for a re-map, but before i even left home i had problems which resuted in me spending all day outside the tuners taking my engine to bits, and putting it back together. Then i went home!

Now i've sorted the previous problem and have another one.

Who was it who said " if it aint broke dont fix it"

Damn me for fiddling all the time.

[misterT]

Quick update for anyone whos interested.....

I started her up tonight, when cold she runs fine, seems to warm up a bit quicker than normal but idling stable just over 1000rmps.

As it warms up, drop down to 750 ish, as normal, and seems to tick over nicely if left to idle.

However, now the engine is up to temperature, if i increase the revs and let them drop naturally, it will drop below 750, sometimes as low as say 300 and either pick itself back up again, or stall completely.

It has a unichip fitted which does need a re-map because the injectors, fuel pump, turbo have all been upgraded recently. Personnaly i cant see this being the problem as it ran fine untill i fitted the pump and fpr.

WTF is going on??

I can only see 2 choices left.

1. remove one thing at a time untill it runs ok again, then leave it
2. Let my sladge hammer try and "fix" it

If i had enough hair to grab, i'd have pulled it all out by now.

[Slarty]

It "might" be a combination of the injectors (540 jobbies?) and the FPR mate. The flow from the injectors will be a bit higher than the 440's and if the pressure is a little out too, it might all add up to a bad idle?

Just a thought!

[Chumbaside]

Have you changed your coolant recently at all? i experienced fallings revs when car was warm, and it turned out the new coolant level was low, causing the temp sensor to give a wrong / no reading so the ECU was mucking up the fueling!

If not, it sounds like it could be a leak in the vacuum side of the pipework. Check al your connections, particularly ones around the boost sensor and the loop across the plenum. I replaced mine with silicone hose and found that it was collapsing, again causing rough running/dodgy idle.

Cheers

Mark

[misterT]

It "might" be a combination of the injectors (540 jobbies?) and the FPR mate. The flow from the injectors will be a bit higher than the 440's and if the pressure is a little out too, it might all add up to a bad idle?

Just a thought!

Yep 540 jobbies mate. So this "could" be something the tuners can sort out when they remap the chip? Possible i suppose. It does seem to drive ok, just not idle well.

Chumbaside - Coolant has been changed but it was running fine untill i fitted the pump and fpr.

As for the vacum leak, i've checked/replaced most of the hoses and it was still the same. I havn't changed the ones going to the boost sensor though so i'll try that next.

Thanks fellas. [/quote]

[misterT]

i've now replaced all the hoses that go to the boost sensor and i've completely removed the fpr and its still the same! I doubt this could be a problem wiv the pump as i'm presuming it either works or it doesn't? It seems to be working fine. Only thing i can think now is i've damaged one of the sensors on the tb while constantly removing and re-fitting it. Here we go again.... Any other ideas? Thanks, Dean.

[greeny]

Dean,

so uve changed the injectors before this problem and it was fine?

I had a problem where i changed my injectors, i set the link up with my laptop and couldnt get it to idle smooth at all,

I found it was a vaccum leak from one of the injector seals that id nicked when installing them (very easy to do, i find a little bit of silicone grease on the seals makes them pop in much easier), was causing a vaccum leak sucking extra air in but not enough to leak fluid.

Im surprised that youve changed to 550's from 440's and its been running fine on the same map tho.

Definately sounds like a vaccum leak to me tho aslong as uve set your

[misterT]

Dean,

so uve changed the injectors before this problem and it was fine?

I had a problem where i changed my injectors, i set the link up with my laptop and couldnt get it to idle smooth at all,

I found it was a vaccum leak from one of the injector seals that id nicked when installing them (very easy to do, i find a little bit of silicone grease on the seals makes them pop in much easier), was causing a vaccum leak sucking extra air in but not enough to leak fluid.

Im surprised that youve changed to 550's from 440's and its been running fine on the same map tho.

Definately sounds like a vaccum leak to me tho aslong as uve set your

Hi Greeny,

Yep, it was running fine mate, obviously needs a remap to get it running perfect but was idling and driving fine, no probs at all.

i had the same problem with the injector seals, was giving a loud sucking noise, but i've sorted that with some new seals and some new spacers under the rail.

that last sentance you wrote mate,

"Definately sounds like a vaccum leak to me tho aslong as uve set your"

Your what?

Dean.

[tubby_mr2]

YOUR WHAT god dam it lol

sorry to hear your havin grief mate...

[misterT]

YOUR WHAT god dam it lol

sorry to hear your havin grief mate...

LOL! Yea, this has been going on far too long mate.

It's got to be something silly, i just don't know what.
I've just ordered a new oxygen sensor as i keep reading stuff about them affecting the idle when the engine is warm, and if i unplug it when the engines running, it makes no difference at all!! Surely thats not right?

[greeny]

Dean,

so uve changed the injectors before this problem and it was fine?

I had a problem where i changed my injectors, i set the link up with my laptop and couldnt get it to idle smooth at all,

I found it was a vaccum leak from one of the injector seals that id nicked when installing them (very easy to do, i find a little bit of silicone grease on the seals makes them pop in much easier), was causing a vaccum leak sucking extra air in but not enough to leak fluid.

Im surprised that youve changed to 550's from 440's and its been running fine on the same map tho.

Definately sounds like a vaccum leak to me tho aslong as uve set your

Hi Greeny,

Yep, it was running fine mate, obviously needs a remap to get it running perfect but was idling and driving fine, no probs at all.

i had the same problem with the injector seals, was giving a loud sucking noise, but i've sorted that with some new seals and some new spacers under the rail.

that last sentance you wrote mate,

"Definately sounds like a vaccum leak to me tho aslong as uve set your"

Your what?

Dean.

lol dont know where the rest went, i think i meant aslong as uve set your...fuel pressure correctly, with the idle hunting it does point to a vaccum leak to me, u sure u didnt nick a seal when installing the injectors?

[nuttasie]

perhaps the walbro can supply the fuel at full pressure all the time(low revs)were as the std one might not,hence theres 2 much fuel being chucked in at low revs combined with the 540's.

try it at a lower pressure just for idling test then chang it back . and if it changes get it remapped.

just chucking thoughts around in my head,sorry can't help much.

[misterT]

Here we go again....

Right, after reading hundreds of posts and searching my ass off, i've tried:

ECU Errors - none, Every god damn fuse, New Oxygen Sensor, New Battery, Replaced Throttle body + ISC Valve, + TPS, Bled the coolant, new injector seals, new fuel rail spacers, replaced vacum hoses, checked/cleaned the plugs, checked/cleaned dizzy cap + rotar.

I've tried re-fitting the standard FRP, and with new adjustable FRP.



ITS STILL THE FOOKING SAME!!

AAAAAAAAAAAARRRRRRRRRRRGGGGGGGGGGGGHHHHHHHHHH!!