MrNoisy

iTrader: (28)

So here's the scenario, I have a mystery fault which so far we've been unable to diagnose. I wanted to ask if anyone else has seen a similar problem.

The car is a 2005 Widetrack blob STI, main engine mods:
- SC42 billet with perrin hose
- 3 bar map sensor
- 3 port boost solenoid
- 650cc Lateral Injectors
- Japspeed FMIC
- HRC 290lph fuel pump
- RCM induction kit
...plus Alcatek ECU

Around the start of the year, the car made 440/390 on V-Power, standard engine internals.
I had a light accident toward the middle of the year, but apart from bumper damage the car was pretty much unscathed, yet now we're seeing a strange fault when mapping, and the car ran about 380 before it started to lean out as voltage dropped.
Initially a faulty alternator was suspected, which was replaced with a second hand unit, but the problem persisted.
We have also swapped the battery, and fuel controller from another 2005 widetrack but still nothing.
Today we also tried adding additional earthing straps, but the problem persists.

Basically, the car runs very rich most of the time, but as boost starts to climb to 1.6 bar, the voltage drops across the car and then it leans out.
Right now the boost is backed right off just to make it safer to drive. Thankfully it's not my daily driver, and the next thing to look at seems to be the fuel pump to check it and ensure it's not perished, but I wondered if anyone else had seen a similar issue as this is driving me mad and despite 3 visits to my local rollers we haven't managed to successfully cure it.

All advice appreciated, many thanks in advance

fawor

iTrader: (3)

4 years ago I had alternator changed -warranty claim, they did it 3 times as previus 2 were wrong(wrong part number), I had cell on with those 2 but charging was ok,a little weird.

XDevil666

Can a faulty alternator cause less power?

never realised it could, on mine i had the Cell lit on the alternator saying low voltage, but never caused me any issues so mapped it out, but i didn't realize it could have an effect on the car?

MrNoisy

iTrader: (28)

Part number of the replacement was identical and the same one made correct power.
It's charging correctly from what we can see with a multimeter; I've never had the car not start etc.
Basically it looks like there is a huge current draw from something at high engine load (boost) and we can't work out what.

wrxyz

iTrader: (2)

Is it a "huge current draw" or is it something like the higher frequency of vibration causing a broken wire to loose the connection?

MrNoisy

iTrader: (28)

Current drops from the 14's into the 11's

tjmatt

iTrader: (1)

The ECU should be able to compensate for change in battery voltage which could affect how fast the injector opens and closes.

How low is the battery voltage getting? Could the alternator have diodes broken which asctually discharge the battery at high engine speed? Could always run with the alternator belt disconnected and then the battery voltage should remain more constant if this is the case.

Fuel pump may be weak and lower battery voltage is not supplying enough fuel. Or it may be weak and unrelated to battery voltage, but can't supply enough fuel when the fuel pressure and demand increases with increased boost.

Perhaps there are two issues?

MrNoisy

iTrader: (28)

As above I've run the car with 2 different alternators and batteries (as well as a different fuel control unit), which I suspect rules out both those factors.

The fuel pump may be weak, although it's only 2.5 years old so I'd be surprised if I'd killed it so quick. The strange thing is that the volts drop and then the car leans out. If anything, if the pump was drawing more current I'd expect the fuelling to remain constant, that's why it's a head scratcher.

I'm starting to think an experienced automotive electrician may be required, as I can't keep affording to replace bits "in case"...
Was really hoping someone else might have seen this.
Only thing I don't have is an aftermarket FPR or fuel pressure gauge so can't check fuel pressure.

tjmatt

iTrader: (1)

Sorry I didn't re-read you post when thinking of what could be wrong.

Fuel pressure gauge would definitely be useful here to diagnose pump or FPR issue. An easy check is that the vacuum pipe to the FPR is not split as this would cause it to go lean on boost (and rich on idle).

As you say maybe a sparky or garage would be best bet now.

wrxyz

iTrader: (2)

Do you mean current or voltage, sometimes there is confusion.

Either way, those figures are still possible with my suggestion, also, where are you measuring that from?

wrxyz

iTrader: (2)

If the voltage is dropping - to the pump for example - the current through the pump will increase to try to balance the "power equation", so if you suspect the pump measure the voltage at the pump and if it drops i would do a quick calculation to see what the max wattage is, then compare that to the rated wattage of the pump.
See if the two still match up.

MrNoisy

iTrader: (28)

Thanks for the suggestions.
We were measuring voltage both at the battery with a multimeter and Simon was plugged into the ECU which apparently allows him to see the ECU and car voltage on his laptop as well (I may have described that badly or inaccurately sorry).

Darrell @ Scoobyworx took pity on me and sold me a 290 at his GB price so I will use that to replace the HRC unit and eliminate that as a possible symptom.
If the problem persists after that I guess the only thing likely to be remaining is a fuel reg issue, split hose somewhere or a broken or loose wiring problem.
Let's hope it's the simpler of those...

I admit I can do simple wiring, but I'm no master electrician
I have a multimeter, so how is best to measure the voltage at the pump - at the actual block going into the top of it outside the tank, or somewhere else, where the wiring comes in under the back seat perhaps?
And then how do I work out the wattage? Sorry for all the questions, appreciate the help.

MrNoisy

iTrader: (28)

Will check that as well ta

johned

Is this a smart type alternator on the car?.

MrNoisy

iTrader: (28)

Yes it is and yes I know they only charge when they need to; however, the problem is the voltage is dropping across the whole car not just at the alternator. We even tried running the car with lights on

Cocker

iTrader: (3)

what happens when its idling and some extra load kicks in - i.e the fan or something. Do the volts drop then?

MrNoisy

iTrader: (28)

The car behaves as you'd expect, the voltage dips momentarily into the 13's but then goes back up into the 14's again and tends to settle around 14.4-14.5.
Even with the headlights, aircon and rad fans on it was still low 14's at idle.

MrNoisy

iTrader: (28)

Bump, any more ideas?

jura11

iTrader: (7)

Hi there

Not sure,but we run Syvecs with small Odyssey battery and on the start up we are seen as low 9-10V,but usually when car has run we are always seen around 13.5-14V

What battery is yours?

Are you running Wideband ?

And lastly is possible check if yours Lambda sensor is OK?

Fuel pump wiring I would suspect too,but this shouldn't cause something like this,but faulty fuel pump itself can cause car will run lean,but still I would suspect like Lambda or Fuel pump,possibly battery and wiring

Are you running aftermarket FPR? If yes please check FP when you will see voltage drop


Thanks,Jura

MrNoisy

iTrader: (28)

Hey Jura,

Battery is an Exide, probably less than 6 months old, and we eliminated that already (see above).
I'm not running wide band.
Lambda sensor yes I did wonder about that myself as well as the car has had a new set of RCM headers and it would have had to be transferred BUT I wouldn't expect that to cause the car to lean out as if it's knackered apparently the ECU should compensate and also throw a CEL.
I'll check it anyway today.

Fuel pump is being replaced today; we'll take some base readings with a multimeter on the current draw to the pump and then I'll haul it out. Scoobyworx 290 is going in in its place (old one is an HRC unit but I believe the Scoobyworx is a modified HRC unit anyway).

And I use the OEM regulator - Simon says I don't need an aftermarket one at the power I'm running.

jura11

iTrader: (7)

Hi there

Thanks for reply

Yes Exide we run on our wagon too when we run 2.35L

If you are not running wideband and still using on yours narrowband(OE Lambda O2 sensor),then faulty Lambda can cause those issues,but voltage drop if can cause hard to say

I'm pretty sure we run on both 2.1 or 2.35L same HRC 340LPH without the issue,we run this pump with meth or on T99/V-Power,in yours case I would have look on the connections on the pump or even check fuel sock which is on the bottom of the fuel pump if its not dirty plus I would check fuel pipes inside the tank if they're attached to pump etc.

What I know fuel pump can cause those issue when car running lean due the faulty fuel pump or not attached fuel pipes(or simply they can pop off when car is on the boost etc.,I know few guys have issues with the HRC fuel pumps due this)

Assume you are still running OE Fuel pressure,then you should be OK without the aftermarket FPR

Thanks,Jura

MrNoisy

iTrader: (28)

Yes OE pressure.
We've just replaced the fuel pump, and the car idle has changed, cycling revs between about 900 and 1100rpm every 10 seconds, which may well indicate a problem with the previous pump I suppose.
Still to check the O2 sensor, will do it later, but the regulator and all hosing is fine, no obvious issues

jura11

iTrader: (7)

Hi there

I would check again fuel pump and mainly if all hoses are attached and if there is no loose connection on wires or hoses

Hopefully you will get this sorted there


Thanks,Jura

wrxyz

iTrader: (2)

Morning Mr Noisy, I hadnt forgotten about you....
Kids birthdays and the like !

Just read through the posts a few times; the initial problem - correct me if im wrong - is that the voltage is dropping as the engine load increases. There is also a problem with the fuel ratio leaning out on boost.

Someone suggested fitting a fuel pressure gauge, I agree, a £16 ebay one should be good enough to see if the pressure is dropping off or not.
Looking at this again I am not entirely convinced that there is a pump issue; if the voltage to the pump is dropping off then eventually the pressure will drop; that would be normal, not a pump fault. It's just getting less 'power' to run the pump.
Although the system can accommodate - adjust - the fueling to allow for variations in many areas, there are limits. I dont know enough detail about the parameters to say if the volt drop you are seeing can be accommodated or not.
As far as I am aware the o2 and lambda sensors do not operate on boost, or at idle; the system runs purely on the map(on boost). Maybe this isnt the case with Alcatek, I'm lacking in experience there. But its worth checking, before you go looking at them.

Hope I havent added to the confusion.

MrNoisy

iTrader: (28)

Nothing loose, all hoses attached and clipped, all wiring blocks attached and clipped.
The pump was a tight fit as it was bigger than the old HRC unit it replaced but no other issue I could see. I replaced the sock on it with the new item as well - I'd re-used the old Subaru one previously but this time I'm replacing that too to eliminate it just in case it was clogged or dirty.

wrxyz

iTrader: (2)

Is there any chance that you have a nipped fuel pipe or could there be a pinhole in the pipe that is allowing air into the system

jura11

iTrader: (7)

Hi there

Did you tried the car after you fit the new fuel pump ?
Do you have still voltage drop at full boost ?

Only thing which I would now think if you have voltage drop,are injectors which I would at least check,if they're not clogged etc

Here is our old datalog,as you can see there is small dip in the voltage,this has occurred on all logs which I've and which I've logged



In yours case I would say can be fuel pump which has been faulty and if you will now put yours car on RR everything should be OK

Did you spoke with Simon about this ?

Thanks,Jura

MrNoisy

iTrader: (28)

Okay so another development...the siren on my Clifford packed up on Sunday.
Having spoken with the fitter he told me where to check and I found the multiplug for the siren had been pulled out, presumably when the ECU had been accessed. So now of course it's a question of - was this plug the cause. It's either going to be that or the fuel pump, but we'll know if it's fixed tomorrow. Wish me luck

MrNoisy

iTrader: (28)

Shouldn't have my friend, all the lines run under panels so it should be fine, I haven't been changing em. Will let you know how tomorrow goes

wrxyz

iTrader: (2)

that would certainly cause the pump to cut out, and the increased vibration and movement at higher revs and boost would be shaking it about a bit more.....