Diagnosing help - rev dropping

[Smithy]

On average, once every other journey this will happen. Revs, just for a moment, will drop ....almost like fuel starvation.

Obviously, been lots of threads similar to this, with a number of solutions, but this symptom doesn't really follow a trend. It'll randomly do it, and has not got any worse over the last 2 or 3 months it's been doing so.

Due to clean sensors and throttle bodyto see if this fixes prob. Thinking it's more a dizzy fault, but don't want to fall into the easy trap of replacing everything from dizzy caps to spark plugs etc


Has cut out 4 or 5 of those times when coming to a stop, and stalled, clutch dip. Stuttered while accelerating a couple of times. Stalled when first starting the car a couple of times, most of the times has happened during cruising, but an average journey is cruising mostly for me, so if random, ofcourse it'll be when it mostly happens. It is literally a momentary loss of power, did it yesterday while stationary, dropped to 500revs for a split second then back to normal. Odd. Hoping it'll just be a sticky butterfly from the heat drying things out a bit internally

 

[andyj]

1. Clean throttle body - free
2. New ECU control relay - £11 from VW

My bets are on the throttle body

 

[jatinder]

Crank speed sensor, or coil

 

[m0rk]

I agree with you there, sounds very similar to when mine suffered the same flaw

 

[Smithy]

Cheers guys.

Out of interest, will coil or crank speed sensor log a fault code?

 

[andyj]

crank speed sensor will I think, but I doubt the coil will.

you've just missed out on a spare coil I had, I've just sold it to a guy on here!!

Crank Speed sensors are about £50 ish from GSF etc

 

[Smithy]

well, a good clean out has definitely made the drive feel smoother, was quite a bit of gunk, but it was a long shot, and hasn't fixed the prob.

Gonna order a crank speed sensor and get it fitted, only 50 quid, if that doesn't work, I'll just sell it on for a little loss, better than letting a garage rape me.

Could I be really cheeky, and ask that some post up an engine bay pic with the location of the sensor marked out Going from what Haynes has said, it's one of 2 sensors I can see down the right hand side of the engine bay as you look at the car from the front. It's not very specific unfortunetly!

....pretty please

 

[Lukea6]

It's under the oil filter and to fit mine an engine mount had to be removed..

Before the speed sensor try the ecu control relay. Cheaper and takes less than 10 secs to fit!

 

[Smithy]

It's under the oil filter and to fit mine an engine mount had to be removed..

Before the speed sensor try the ecu control relay. Cheaper and takes less than 10 secs to fit!

Cheers dude, I finish work early on Monday so will go pick one up / order one afterwards. Read some similar probs on Club GTI and decided on the relay first, symptoms are all the same, bit of a lottery between 3 or 4 fixes.

 

[Smithy]

relay arrived yesterday, picked up from SEAT Cheshunt and fitted ...no stutters so far but more miles of testing are required before I'm convinced. Saying that, I have done approx 40 miles since fitting it, more than usual without a hint of stutter. We shall see....

 

[andyj]

how much did SEAT charge you ?!?

VW charged £10.80 I think for mine

You managed to change it ok yourself then......

 

[Smithy]

tart!

Yeah, tenner from the Stealer too. When you've never seen where or what the relay is, you kinda imagine it like other relays with wires hanging out everywhere lol Was surprised to find it just a small plug-in box.

Light in my dash has gone as soon as I fitted the new relay, doh!

Dunno if I've just imagined it, but 4th seemed to have more legs on it than previously. Surely a relay can't have effected this?

Still hasn't stuttered yet! If it hasn't after the weekend, I'll be 90% convinced it's fixed.

 

[Smithy]

Stuttered twice over this weekend, will try and get a VAG-COM done to see if anything flags up before trying coil next.

 

[jatinder]

coil or crank sensor mate

 

[GrayT]

May be worth checking for any fuel leaks. My Toledo suffered from hesitation for a while and wasn't diagnosed. Got gradually worse until I actually started smelling petrol and found I had a leaky fuel filter. Changing it tomorrow.

 

[Smithy]

Replaced both Ignition Coil & fuel relay, once every journey on average it'll stutter for a split second now. At least I have spares now

Want to get it VAG-COM'd before anymore money is spent. But already looking into the cost of Crank Speed Sensors/Senders. They're stupid money from dealerships, just wondering if the GSF part is the same.

92581 CRANKSH IMPULSE SENDER IBIZA 47.50 ? Seems too cheap to be true?



....and my passenger window has bloody broken now, and its HOT! grrr. Wire cable to bring it down has snapped grrr

 

[chillefc99GTI]

my GTI is the same going through the same changes tried air flow meter and dizzy cap so far none of them. possibly rotor arm but couldnt get hold of one till tomorrow so will try that then.

 

[Smithy]

Gona fit the new Engine Speed Sensor this week when I have a moment, and post back here whether it's done the trick. Rotar arm was my nx port of call after this.

If anyone's interested, I have 2 more of these sensors for sale, £45 which includes delivery. Will put them up in the for sale section officially at some point. They retail at £126 new, ridiculous!

 

[chillefc99GTI]

i seem to have sorted mine. simply removed the fuel pump relay and cranked it over for a few minutes. then put it back in. and since then had no probs what so ever back to its old self thank god

 

[Smithy]

i seem to have sorted mine. simply removed the fuel pump relay and cranked it over for a few minutes. then put it back in. and since then had no probs what so ever back to its old self thank god

hmmm, not heard of that before. What exactly are the cons of removing the fuel pump relay and having the car ticking over for a few mins, if any?

Worth a go I suppose.