car is hesitant

[corradophil 3]

Here you go. Just taken photos of both sensors on mine.

 

You can't see the sensor in "Knock 2" very clearly because the rubber cap for the sender on top of the oil cooler is in the way, but I can assure you it is there and looks identical to the one in "knock 1"

[saysomestuff 0]

You are a star phil - thanks. I;ll give em a clean and see how we go. BTW, would a faulty one cause knocking when starting from cold that goes away after a few seconds.?

[corradophil 3]

Unfortunately not, they are basically microphones listening for pre-ignition, ie the spark plug fires too early causing the combustion to take place while the piston is still travelling up the cylinder, which can be very harmfull to the engine. This is known as knock, pinking or pinging, particularly noticable going up a hill in a high gear with at full or near full throttle, you can hear a quiet tinkling sort of noise, if you back off the throttle it will stop.

 

Is the oil light on, after start up when its knocking? If so first check your oil level, if ok you need to look at the oil pump strainer and the pump itself.

 

Does the knocking sound like a light rattly noise from the top of the engine (lifters) or more a kind of banging noise at the bottom of the engine (bearings).

[saysomestuff 0]

I'll have a proper listen under the bonnet in the morning,

 

thanks so much for your help so far Phil, I have a feeling that it;s a culmination of things making it run crap (fuel filter, timing etc) but i am mostly worried about this new knocking noise.

[Walesy 0]

the knocking when cold could be tappets couldnt it?.....

[corradophil 3]

I'll have a proper listen under the bonnet in the morning,

 

Can you record the noise and post it? It's not necessarily anything to worry about, but you need to identify what it is quickly just incase it is.

[saysomestuff 0]

I'll have a go Phil - It didn't actually make any noise this morning which is a bit worrying.

 

Having looked at the knock sensors, they look like crap and one has a split casing so I think they might explain the hesitancy, will replace this weekend (are they expensive?) along with fuel filter and I think it's time to lag all the wiring properly while i'm at it lol.

[corradophil 3]

I replaced the knock sensor on my Golf I used to have about 4 years ago, only 1 fitted to a 1990 8v GTI! It was about £50ish and took ages to get.

 

The knock sensor question came up because someone else asked if there are 1 or 2 on a 9A. I doubt they are causing the hesitancy in your case. The knock sensors are there to correct timing, if you had an earlier 1800 16v you would not have them at all.

 

Things I would check are.

 

1. Are all servicable items in reasonable condition, by these I mean, spark plugs, HT leads, rotor arm, distributor cap, fuel filter, air filter?

 

2. Are there any vaccum leaks on any of the hoses?

 

3. Is the fuel pump particularly noisy, if it is then it is struggling and probably not providing enough fuel pressure.

 

4. Are the ignition timing, valve timing and fueling set correctly?

[saysomestuff 0]

Yeah thats right, redcorrado asked, but he asked because that what showed an error on VAG COM when his car is showing similar symptoms. I would imagine it's possible that a faulty knock sensor would retard the timing when not required etc etc.

 

The power loss/flat spot is so predictable that it must be as a result of a failure of some sort (blocked something/broken something), it's just knowing which :lol:

 

Will do all the consumables this weekend and see what we come up with - and i'll keep my phone handy to record that knocking!

[corradophil 3]

Will do all the consumables this weekend and see what we come up with - and i'll keep my phone handy to record that knocking!

 

Cool, Ill keep an eye out for an update. Won't be on here on Sunday though because I'm going to watch touring cars at Snetterton. :mrgreen:

[veedub 0]

This is amazing, its almost as if u have been driving my car!!, i have the knocking 2, got a feeling its the big end...doh!!

gonna wip out those knock sensors and give them a good clean!!

will let u know if this sorts out my problem!!

im super glad i joined this forum...been trying to sort this prob for over 4 months!!

Cheers guys!!

[saysomestuff 0]

This is amazing, its almost as if u have been driving my car!!

 

LMAO that's what I thought when I started reading this thread!

 

i have the knocking 2, got a feeling its the big end.!

 

:cry:

[veedub 0]

Had my Knock sensors off 2day, they are looking in kinda sorry state i.e all the plastic has cracked and broken off.

However, gave them a rub down with a bit of wet and dry paper and the car did perk up a bit!!

Now trying to find someone who will sell me a set on new ones!!

Bought a set of kr cams 2day! Gonna fit the inlet cam next weekend and watch it fly!! Woohoo!

[redcorrado 0]

just out of interest ,did the knock sensors look the same ? or where they different .

[veedub 0]

both the same!! are they supposed 2 be different?

[redcorrado 0]

Well thats what i was never sure of ,see the vw garages i contacted told me the 9a engine only had 1 sensor ,when others said they had 2.So i could only order 1 just incase the other was different i didnt want to waste £50.

But i m having the first 1 fitted monday,i shall see what happens and if i need to get another after that.

[dubweiser 0]

Vag com was mentioned in this thread but i wasnt aware that the vag com could be used with this engine??Any ways i had the same type of problems with my 2l 16v and it went on for ages and after replacing everything i thought possible it turned out to be the lambda that was knackered.Hope this helps mate.

[Supercharged 2]

Vag com was mentioned in this thread but i wasnt aware that the vag com could be used with this engine??

 

Yep, Late 16v Corrado's fitted with the 9a and ABF engines use the digifant system that includes the self diagnoses feature...

[corradophil 3]

The 9a has ke-motronic, and does have on board diagnostics, but I'm unsure what vag-com software if any is compatible with it.

 

ABF was the "tall block" fitted to Mk3 Golfs, Seat Ibizas etc, but not factory fitted to Corrados.

 

If anyone has any info about using vag-com on a 9a I would be very interested.

[Supercharged 2]

Ah, cheers Phil, I thought some C's got the ABF...??

[corradophil 3]

Ah, cheers Phil, I thought some C's got the ABF...??

 

Only the ones that people have done themselves.

[RW1 0]

The 9a has ke-motronic, and does have on board diagnostics, but I'm unsure what vag-com software if any is compatible with it.

 

 

If anyone has any info about using vag-com on a 9a I would be very interested.

 

Yes, it is but you need to use v409.0 or later with the baud rate set to 4,800 for the engine ECU. If you leave it set to free run or enter at any other speed it will choke the ECU which means switching the ignition off and then on again and then try again. Use the otpions and set "start baud rate" to 4800 and save it. I run two separate directories on the laptop, one for all cars set to 9600 and 16v 9A directory with 4800 set. The two copies of VAG-COM see the authorisation OK. The 9A's ECU is odd ball and very picky on the communications even if you do above, the laptop port may still hinder you.

 

Did two 16v 9A's on VWCCGB NatDay, Sunday at Castle Howard. Just need now to crack the '92 G60 that defeated me yesterday. My optp-isolator is away in Italy this month to sort out some new software on beta testing for PDAs so I don't know if it may be the reverse of the 9A, ie it doesn't like the electronic interface.

 

9A Engine ECU won't work with v311, v208, the early versions that are commonly knocking around and you must have an electrionically isolated interface, opto types won't work.

 

ABS is as usual as per other C's if fitted with the ECU controller.

 

I thought some C's got the ABF...??

 

As said, if so, it's a transplant.

 

 

.

[corradophil 3]

RW1, thanks for the info, I have been trying to find out a little more about this for a while. I have vag-com on my lap top, not sure what version though. I use it for my Seat Leon 20vt with OBD2, but have made an adaptor to change from the serial connection to the 4 plug on the Corrado.

 

I have an opto isolated interface so it looks like I won't get very far with what I have. Can you offer any suggestions of where I can get an electronically isolated interface?

[redcorrado 0]

well i replaced the knock sensor ,and the car is the same .but the colour of the knock sensor i bought was green and the one which came off was blue.

seems strange ,maybe i need to look a

[veedub 0]

Green? Mine are black with a blue plug!

How many did u replace?

No improvements at all? Starting to think it might be the lambda sensor!