MK3 ABF loss of power: Problem found & possibly solved

I beleive my MK3 ABF is down on power; I was in front of my mate in his Siemens AGG MK3 8V last week and could hardly get away from him in 1st and 2nd gear. Both cars are 3 door but he has a sunroof and I have air con. I have a lightened and balanced flywheel, tweaked TB and chipped which makes things seem worse. It seems I'm missing some power somewhere (or is the lighter MK3 8V with the smaller 020 flywheel and Siemens AGG engine a demon in disguise?) and I'm not sure whether it's my imagination but on hitting 4KRPM the car no longer feels like it 'comes on cam'

She runs like a dream and I get good mileage. Uses no oil and no blue smoke on overun etc.

Timed 2nd gear from an idle & 1000RPM to 7000RPM came out at 9.76s (videoed and imiage diting software used to set the timing marks so no reaction time error)

Swapped out the chip for the standard - no change

Discovered some holes in the centre silencer around the exit pipe but surely this isn't going to rob me of 30 odd horse?

Checked my cranking compressions (I guess they are ok? ) but TBH I'm not sure what the spec is:
Cylinder 1: 195 PSI
Cylinder 2: 197 PSI
Cylinder 3: 191 PSI
Cylinder 4: 188 PSI


Checked the state of the plugs and I'm a little suspicious as I replaced them about 2.5K miles ago but they look almost new - sooty around the base but the electrodes and centre are clean as a whistle; surely they should be a nice tan colour by now?

Are the plugs the right ones I wonder - BERU FGH-7DTURX?

I wonder if I'm just reeling from the fact that a MK3 8V is almost as fast as a MK3 16V through 1st and second. If not should I suspect the fuel pump now? I'm at a bit of a loss! [:^(]

 

Cant be sure on the answer without getting some further testing done. The only way to truely find out would be to get both cars on the dyno. Find out what power each is producing. Get the thing vag-com'd aswell. Your compression figures look very healthy though.

The 8v will probably pull away a little bit quicker, but once the ABF gets going you shouldnt have any trouble to be honest. I know my valver poops on 8v mk3's all day long unless there heavily modified.

 

Have you done all the usual checks especially on the vacuum lines. Check the colour of your spark. should be blue , not yellow/orange. may be running rich.. My compression where a little higher than yours but don't think there is enough difference between them to be a problem.

Would have thought a 16v would have the legs on a 8v unless driver skill is a factor.

 

checked the cam timing?

 

Timing is spot on; well the crank to exhaust cam is fine anyway. All vac hoses replaced with fancy hi-pressure PU stuff. No sticky callipers n all sensors look within spec on Vag-Com. It's really baking my noodle now as she runs super smooth! Gonna fire up ELSA tom n start systematically going thru the electrucs; check the relays, fuel pump voltage etc. I sold my inline fuel pressure gauge sometime back so may need to ask mt old man to knock me up a test tool for checkinh the fuel pump delivery. I'll check the quality of the spark 1st n the condition of the rotor arm/dizzy n leads too.

@Russ: Straight line runs only so no driver skill required;just an ill 16v!

^^All the info is a bit hotch-potch which is kinda like the norm for the inside of my head but I'll try n be a bit more organised when playing whodunnit tomorrow

 

don;t know whether it helps but my 5dr with sunroof and similar mods to you did 1000 rpm to 7000 rpm in just under 9 secs or there and there abouts when i came home last night ... my rev limiter kicks in at 6950 though so timed to that

 

Under 9 seconds... howl... frikkin gremlins...

Possibly a very silly Q: is the mark on the 02A flywheel a timing or TDC mark?

Gonna check the FPR next.

 

its the tdc mark. you can also go roughly on the crank pulley mark.

my lightened flywheel has no mark so used a few 3/8 extensions down cyl 1 to make sure it was right

 

Cheers Matt


Well at least I've confirmed the static timing is ok.

Can't be ar$ed going outside with a meter and the slaptop... Maybbe make a cup of tea first.

Next to check is the spark.

 

Bit of a wild guess but check the tps voltage as the wiring on mine had degraded and caused similar symptoms

 

I have to agree with Azure, I did 2nd gear idle to the rev limiter 4 times in each direction and got a mean of 8.8 seconds.

It's a 5dr with glass sunroof, NO mods of any kind, run (exclusively) on Sainsbury's Super unleaded (98RON)

Looks like your about .9 of a second down to me

Cheers

Simon

edit: Matt82, have you ever tried this test?

 

been meaning to, but out of the 700+ miles it did this weekend, i didnt get a chance for silly burgers like that

i may give it a go tonight, it is packed to the roof with tools so im not expecting miracles

 

It's not a bad "quick an dirty" test, you'd need to brim the tank and watch the test conditions for it to be really meaningful but even so, it gives you an idea.

Mine was empty, well apart from 100kg's of me and 20 worth of fuel... (I was meaning to try some simple mods (and take the back seats out) but pulled it off the road and put the engine in a Corrado instead )

 

Well cheers guys; not had a chance to check anything else over yet- Fuel pump voltage is good (not that it means much) but that all I've had a chance to look at.

Edit:
I'm thinking along the lines of:
Worn cams (Can't check at the mo as can't afford new gaskets)
Not seeing WOT (easy to check with vag-com)
Dodgy knock sensors (How do I go check these other than re-torquing them)
Seized ancillaries (Power steering pump, water pump, AC compressor, alternator, cam tensioner etc)
Sticky/faulty FPR or failing fuel pump perhaps?

Gonna change the fuel filter (was swapped out last year!) as at 6 cant really complain.

I'll try a few more timed runs in 2nd and post up my results.

 

I'd be more inclined to look at the "normal" service items first: plugs, leads, cap, rotor, fuel filter, air filter.

Double check you have the right "heat" range in there, too "cold" won't really hurt but too "warm" could promote some light det (which could retard the timing)

Personally I use regular copper NGK's, I'm not a fan of those 3 prong long life things you can't gap em properly

What fuel do you use? Any chance you have had a bad batch?

I guess check the various senders/sensors, if the temp sensor is a bit off the ECU could be running a little rich and it could have melted the cat (can't remember if you have one or not) but I'd have thought you'd notice on the fuel consumption unless it was really subtle.

 

today i put bosch platinum plugs in mine. ill let you know how those go

 

All the service items are relatively new:

Plugs have around 2.5k on them (replaced Jan 09- triple electrode Beru numbers (Z90)from VWSpares. But I never gapped them.
Leads - seem okay but I'll do the old'mist water over them in the dark trick' I have a spare set that I'll swap in tomorrow.

Airfilter - an ancient K&N but and was cleaned and re-oiled maybe 12 months ago (I'll check this tom)

Fuel filter - replaced April last year.

Okay I've just looked through the receipts and I've never replaced the dizzy cap or rotor - How do I know if they are fekked? What should a good spark look like on the plugs as I checked the other day and they are bright blue/almost white?

Fuel is not an issue as this has been over the last few hundred miles and I've been swapping out BP/Shell/Tesco with no effect.

She runs very smooth - no hesitation/stuttering in short like a dream and I get very good mileage.

Scratches head!

 

what sort of mpg are you getting mate? usually its one of the best indicators as too the condition of an engine. next time your engine is warmed up and your doing some A road cruising reset the MFA by holding it on 0 for a bit and let us know what mpg your getting.

I noticed my mpg had gone down a bit and shoved a batch of injector cleaner in the tank, and ran a load of carb cleaner through it. You can notice the difference and mpg improved.

Mine had the full monty of a service 6 months / 4K ago so its nice to know that everything that could be replaced was replaced.

a faulty dizzy would cause noticible running probs so i doubt its that. mine is still original at 120K + but even if i brought a new one i doubt you would be able to notice the difference.

You will probably find its an accumulation of little things like dirty fuel lines/injectors/FPR..filthy manifolds, worn/tired harness connectors/sensors/wiring, mechanical wear of tappets/cams etc etc.

How many miles has yours done? has the coil been replaced as they are a very common fault. Mine ran poorly before it failed.

 

She's just hit 140K.

Excellent mileage (35mpg+) on cruise; over 40+ on long journeys. Pretty much the same as my last MK3 16v

Harness connectors and earths are all pristine and all sensors appear in spec as per Vag-Com/ELSA. You could eat your dinner off the engine but that doesn't mean much (RIP-MK3 will be along to take the wizz shortly )

I have a few known good items that I'm going to swap out in order shortly:

FPR
ECU and fuel pump relays
Coil
Leads
IAT
CTS
TPS

I am then gonna start systematically checking the loom and earth points. PITA

Hey at least I've learned something today; I didn't realise it was possible to dissasemble plug leads

EDIT: and BEFORE I do ANY of the above I will be gapping my plugs

 

i put peasant fuel (95ron) in on sunday. i only got 345 miles on this tank. last one did 380 and that was with the gf thrashing it a lot.