75ZT Community

Hi,

I have a problem and question with my 04 135 cdti ZTT auto 60,000ms. The question is, when I rev the engine I hear quite a loud whine in line with the revs. Is this normal and if so what is it?

The problem is that for some reason when I accelerate below 2000revs and the gear is still high (so the auto box hasn't changed down to account for the need to accelerate as I haven't done a kick down), the car struggles to accelerate smoothly and feels like it's pinking like in a petrol engine. Any ideas what this might be? I recently bought the car and fitted a Synergy 2 with Pierburgh maf, did the egr bypass (although with no gasket, fit a BMW pcv, and did the air intake mod. It seems fine when the car is cold, just seems to do it when warmed up and the gears change at lower revs.

I thought this was the Synergy, but I just switched the tuning bit off and it's still doing it. The maf switch is on. The Engine light has also come on, but again I thought this is to do with the Synergy as it came on a few days after I fit it and went off again when I changed the setting to 7 from 8. It has now come on again when running on 8 (more torque), hence why I tried turning off the tuning part today. The engine light hasn't gone out yet.

It also recently had a full service with filters etc. The idle is uneven and the engine rattles and is quite loud, although as I mainly know petrols, assume this is normal?

Pretty sure it was fine before I did the mods but it's always had uneven idle.

Hopefully someone can help me figure this out! Thanks!

Can't comment on the knock as I don't have a synergy.

The whine might be to do with the aircon. I ahve something similar, sounds like a hydraulic pump. I thought it was autobox or steering pump. But I got a lift in a friends car that was doing just the same and I said 'oh yours does that too'. He said yes it's the aircon, and switched to econ to prove it. I checked mine and it's the same. So I don't know if a regas is in order, or just a check of idler bearings. But worth a try switching to Econ first.

Duncan wrote:Can't comment on the knock as I don't have a synergy.

The whine might be to do with the aircon. I ahve something similar, sounds like a hydraulic pump. I thought it was autobox or steering pump. But I got a lift in a friends car that was doing just the same and I said 'oh yours does that too'. He said yes it's the aircon, and switched to econ to prove it. I checked mine and it's the same. So I don't know if a regas is in order, or just a check of idler bearings. But worth a try switching to Econ first.

Hi Duncan,

Thanks. Not sure it's that as had air con off while parked and revved engine. It recently had a regas. Was wondering if it might be the under bonnet fuel pump I can hear?

Whine and pinking would suggest to me that there is an issue with the HP Pump. A sweet M47 should be smooth and not rattle though!

JakeWilson wrote:Whine and pinking would suggest to me that there is an issue with the HP Pump. A sweet M47 should be smooth and not rattle though!

Hi Jake,

What is the HP pump? In tank or under bonnet?

Under bonnet at the front left hand side and is mechanically driven.

For clarity, HP is the High Pressure pump. Fixed to the engine itself. Left side of the car as you look into the engine bay, right side of the car itself.

Thanks again for the replies. Is it a pain / expensive to replace? I've ordered a diagnostic cable for the MIL that is still on. Maybe it will flag up on that or maybe it's worth just replacing to prevent anything else happening?

You will get a much better idea from a T4 (Testbook version 4.Computer Diagnostic System) session. It can tell you a lot more than the aftermarket cables and software. If it is the HP pump, the T4 would show if the common rail pressure was low. I believe it is expensive relatively, and is not the easiest of jobs especially as you need a special tool.

Duncan wrote:You will get a much better idea from a T4 session. It can tell you a lot more than the aftermarket cables and software. If it is the HP pump, the T4 would show if the common rail pressure was low. I believe it is expensive relatively, and is not the easiest of jobs especially as you need a special tool.

lol Typical. Currently have the car abroad and was planning on driving back over but not sure I want to risk it. Might be a ferry job!

Thought if I put all my issues down it might be easier to fully diagnose what might be going on. I can't get to a T4 as have the car abroad touring and no idea where to find one until I get back.

Been trying to narrow it down on the other forums, but as the HP pump seems a culprit, maybe all the info will either confirm or shed new light.


54 zt auto, 60,000ms 131 bought in Jan. Ran ok I thought although obv hasn't been looked after as well as I thought. Had a prang at the front end at some point.

Serviced with all filters, regas, new BMW pcv and front passenger wishbone.
Buckled rear passenger wheel but drove fine.
Fitted myself: EGR (Exhaust Gas Recirculation Valve) bypass, synergy 2 with PB maf, air intake mod.

Since realised: non-OEM intercooler pipes with 1 dodgy clip. No idea how old pipes are.
Slight whistle from engine when pulling away. Not sure if this is normal as don't know what turbo spooling up sounds like.

Everything is fine when cold.
With synergy off and maf on: Engine is "tappety", idle is uneven although not badly, torque below 2000 revs before turbo kicks in is poor. Gets worse as it gets warm - sometimes can't pull away without hesitation or "pinking" feeling unless I use kickdown to change up.

With synergy on, feel more torque, no more boost than usual I don't think even on high setting. Again, great when cold, but when warm, same as above.

Thought the rough running might be the synergy. Ran through checks with Roverron. Maf seems fine, although when unplugging Maf and turning both switches on, he said the car shouldn't start. It started first time every time, so not sure why, although he doesn't think it's the Synergy.

Ever since I made the mods, it hasn't run as well and MIL has been going on and off. Now on permanently. Waiting for a diagnostics cable to see what the fault codes are.

Yesterday the fuel went below quarter of a tank. Was fine, but when warmed up lost torque below 2000 revs and car hardly pulled until turbo / 2000 revs. At one point, I stopped at a car park. Turned the engine on and heard a sudden loud whine. Not sure where it came from but it only happened once and it was loud. Guessing it must be the HP pump as you suggested?

A few things I'm trying to narrow down from reading and suggestions:

- HP pump as suggested.
- Need to clean map sensor / inlet manifold?
- Leak from intercooler pipes? If so, replace clips or just replace DIY setup with OEM? If so, would prefer silicone but can't find them online.
- Faulty intercooler?
- Roverron suggested that the EGR might not be liked by the intercooler pipe sensor, and consequently it's making adjustments wrongly?
- Also read that sometimes the air intake mod can cause problems by causing fuel starvation?
- plug on injector rail suggested? Also plugs in backwards.

Either way, the Synergy enhances the issue/s already there. Confused as to what it could be and short of doing everything.....ideas? Eternally grateful!

I can't see the intercooler O rings on your list. If you have a bad leak from these you would get a whistle and power problems as it would be losing air. Have these been checked?

Duncan wrote:I can't see the intercooler O rings on your list. If you have a bad leak from these you would get a whistle and power problems as it would be losing air. Have these been checked?

When I had it serviced at the MGOC Ian pointed out the non OEM hose setup and said there were no orings as they aren't needed in the current setup.

spuggied wrote:

Duncan wrote:I can't see the intercooler O rings on your list. If you have a bad leak from these you would get a whistle and power problems as it would be losing air. Have these been checked?

When I had it serviced at the MGOC Ian pointed out the non OEM hose setup and said there were no orings as they aren't needed in the current setup.

Oh, that different from OE. I guess that means a non-OE intercooler too, so maybe this has cracked as already suggested. The whistle you mention isn't normal for sure.

Duncan wrote:

spuggied wrote:

Duncan wrote:I can't see the intercooler O rings on your list. If you have a bad leak from these you would get a whistle and power problems as it would be losing air. Have these been checked?

When I had it serviced at the MGOC Ian pointed out the non OEM hose setup and said there were no orings as they aren't needed in the current setup.

Oh, that different from OE. I guess that means a non-OE intercooler too, so maybe this has cracked as already suggested. The whistle you mention isn't normal for sure.

Below are some pictures although really hard to get good ones. I can see the original intercooler from the front (I think! Assuming it's not the radiator?) but can't see anything attached to it. The pipes are attached to a smaller unit (1/3rd size) behind the radiator. You can just see it in the pics. Can't see oil on pipes although there is dried gunk but hard to know if this is from the pipes or just general. The only point of weakness seems to be the spring clip on the top hose. There are also spring clips attached to the hose that goes I to whatever that long bar is running along the bottom of the car behind the radiator.

Also, quick question on the fuel pumps - just went to look for under bonnet and don't have one. Can hear in tank pump priming. And think I can see the high pressure pump (Bosch) below left of inlet manifold?. Can also hear it doing something on ignition (small hissing sound?) checked the voltage to the low pressure sensor (connected to fuel filter?). Voltage is supposed to be 3.9 with ignition on. Getting 5.6. Any relevance?

Whine / whistle is also coming from what I think is the HP pump (or at least the same area) when stationary revving and accelerating. The pitch goes up and down in line with the revs.

Had Synergy off now for 2 days. Engine ticking over like a bag of bolts.... . How common is it for the HP pump to fail? If the in tank pump was on it's way out, would this cause any of this and put more pressure on the HP pump?

Forget the whine - obviously it's a common problem and there's no solution yet it seems.

http://forums.mg-rover.org/showthread.php?t=137491

So the only problem is the performance issue. When at low revs, warmed up in a high gear, the car will not accelerate much if I open the throttle more, say at 1500 revs. I have to kickdown to get the revs up so I can accelerate smoothly. If the whine is being caused by fuel pressure increase in the lines, and the in-tank pump sounds fine, isn't it less likely to be an issue with the HP pump or intercooler pipes? It feels more like when I used to have an MGBGT and the mixture was wrong so it was sucking in too much air and there was less power.