Hesitation.....RR (3B)

[steverrquattro]

Another thread on hesitation..............

I've read through the other posts and tried just about everything to resolve this issue so before I go any further, just thought I'd check with you guys to see what the next step should be.

The car is a UR Quattro with an RR (3B) engine which has been ugraded to RS2 spec. by Dialynx and it should be running circa 360BHP. Initially it was showing no faults in the motronic memory but it ran like a dog. After pressure testing the MAF to turbo hose with Andy P, I replaced several components as listed below:

1. Air filter changed
2. Spark plugs changed and gap checked
3. MAF to Turbo hose changed due to split
4. WGF valve changed - small leak
5. Wastegate diaphragm OK
6. Air circulation valve OK
7. Vacuum lines on Inlet manifold changed
8. Dizzy cap and rotor arm replaced due to oil in cap and worn contacts.
9. Engine coolant temperature sender
10. ISV solenoid checked using auto test mode
11. Injectors checked using auto test mode

The car goes relatively well in 1st and 2nd with a hint of hesitation at the top end of 3rd, but it is really noticeable in 4th as the car does not want to go much over 4000rpm on WOT and the same again in 5th.

I checked the codes again today and it is not picking up anything.

So I'm running out of ideas, although I did think about doing the following:

1. New injector seals + general service as I noticed one of the end caps is cracked
2. Change the fuel pump as the pump is the original UR one
3. HT leads

Any othe rideas?

[Tonks4x4]

What voltage is the alternator kicking out?

Try a new coil on it.

[Mikes2]

No sign of HT leads or knock sensors on the list.

I take it RS2 spec didn't involve switching to a coil per cylinder setup

[steverrquattro]

No sign of HT leads or knock sensors on the list.

I take it RS2 spec didn't involve switching to a coil per cylinder setup

I meant to add HT leads - will add to list. Thinking about it, I'd also read about knock sensors, but need to look up how these can be tested.

It is still using a dizzy setup.

[rj scotty]

What a coincidence, I'm having a problem with deviation and repetition

[UrS4boy]

Knock Sensor Info

... Thinking about it, I'd also read about knock sensors, but need to look up how these can be tested. It is still using a dizzy setup.

Knock sensor info:

http://forums.quattroworld.com/s4s6/msgs/21047.phtml

[twoqu]

Do the fuel pump. A K Jet pump is high pressure/low volume whilst a std Motronic pump is lower pressure/higher volume. Or just go straight to the best and use an 044!

[AndyP]

I have a 3B coil we can try, it came off mine when I was swapping parts trying to find a cure for my mis-fire.

[steverrquattro]

Do the fuel pump. A K Jet pump is high pressure/low volume whilst a std Motronic pump is lower pressure/higher volume. Or just go straight to the best and use an 044!

Where is the best place to get an 044 pump from?

[twoqu]

Of course it could also be something to do with the tank itself if its a fuel supply problem. Not sure if they had the infamous coating on them inside but I do remember the late Phil Payne gutting one open to attend to the collector area in the bottom of the tank where there is I beleieve some sort of filter. I worked on an UR once that also has a factory fitted restriction due to the fact that the feed tube had a large blob of weld covering the top which reduced the effective bore of the supply. Had to find an unrestricted one to replace it as didn't fancy mucking about with a tank! It was not a problem on standard power levels.

[AndyP]

Where is the best place to get an 044 pump from?

I got mine from Andrew Page, about £150 I seem to remember

[Tony Stark]

My chipped 3B had this same hesitation, the last few times i drove it before pulling the motor would be useless in 3rd or higher. I replaced loads of tired parts with no success.

I always knew my knock sensor cables were breaking up, wasnt till i removed the inlet i could see the sensors themselves are well past it, and one had corrosion getting into it on closer inspection.

Do you have a boost gauge?

[twoqu]

http://forums.quattroworld.com/4000/threads/5193.phtml

If you scroll down to fuel tank repair you can see the problem. Thats not the UR one I have seen but the construction is similar with that sock filter!

[twoqu]

Might be an idea to incorporate one of those clear in line filters between the tank and the pump even if only temporarily to see if any muck is coming out. We fitted one and that gave us the first clue that all was not well as we could see it being emptied by the pump!

[steverrquattro]

My chipped 3B had this same hesitation, the last few times i drove it before pulling the motor would be useless in 3rd or higher. I replaced loads of tired parts with no success.

I always knew my knock sensor cables were breaking up, wasnt till i removed the inlet i could see the sensors themselves are well past it, and one had corrosion getting into it on closer inspection.

Do you have a boost gauge?

I had a look at the knock sensors when the IM was off yesterday. The nearest one to the bulkhead has the outer casing broken and the other one has no casing on it at all!

TBH, neither of them look in good condition. AndyP has posted me some useful links:

http://www.ebay.co.uk/itm/PULSE-SENS...item58993b7b45
http://www.ebay.co.uk/itm/PULSE-SENS...item5d366571eb