Loss of power and grinding noise

[Supafly270]

Hello,

I had a long journey in my 996 c4s 2003 tiptronic planned and started it as usually with filling up some petrol.

Once filled, the car felt a bit difficult to start, it didn't want to start and actually failed the first time round. The second time it did start but after applying some gas.

Started my journey down the motorway and the car felt fine, I put on the cruise control and settled in.

After about 15-20 miles, the car did what I could only describe as a "hiccup"(possibly a misfire..?)

Anyways the cruise was still on and I carried on and the car seemed to be running fine.

I then proceeded to try and overtake and I had barely any power, the car actually changed down to 4th to get some power.

I also noticed that the petrol gauge was going down quick!

Something was clearly wrong, I came back to the first lane and carried on going, not asking for any additional power, to try not to tax the engine

I soon came to an exit after say 5 miles or so and as I slowed down on the exit which was a slight hill, I pressed the gas and the car made like a grinding noise upon the pressing the gas pedal. I can only describe the sound like a stuck a starter motor that isn't pulling back.

I pulled onto the hard shoulder, stuck on the hazards and turned the car off. Being miles off from my destination, I started the car again which it did with no issues. Tried to pull away and it felt totally normal. Went down a dual carriageway for the next 100miles and it behaved as though, nothing had happened.

Picks up speed fine, slows down normal, and the fuel was going down at a normal rate.

So please can I ask if anybody has had any of these symptoms?

I have driven the car 200 miles since the incident and it hasn't missed a beat!

The night before my journey, a friend did tell me that they could smell fuel ever so slightly, could the fuel pump be failing? Have I sprung a leak?

The car accelerates with no holdback, no strange noises, engine bay has no leaks or any fuel being sprayed anywhere, where I park the car its been dry too.

This could be totally unrelated but a couple of nights ago the car did complain about coolant level being low, I topped up with about 3 litres of distilled water as I have no idea what's currently in there and I have it booked for a complete coolant service.

The other issue I am aware of is that, I have to sometimes start the car in Neutral, not always but sometimes I do if that is of any help.

The car has had within the last 6 months, brand new coil packs, spark plugs, engine mounts and suspension related bits and bobs.

oh and I also dont have a check engine light and it didn't come on when it had the issue on the motorway.

Any help would be much appreciated

Thank you

 

[deMort]

A difficult one to answer as there seems to be several unrelated issues here ..

You filled up with petrol and these issues seemed to have started from there ..

From that the usual .. was it diesel or was it contaminated fuel .. i kinda doubt both as it would have died if it was diesel and contaminated fuel would tend to be a more permanent issue ... check your receipt anyways .

Petrol gauge going down quick .. rather strange .. even a car running rich won't be that noticeable on the fuel consumption but the fuel pump / sensor will need checking .

Noise and im kinda stumped .. fuel starvation perhaps ..

Coolant low .. 3 ltrs is a significant amount .. there is a leak somewhere which i would get a garage to concentrate on .. they need to find an external leak other wise it could be internal ... that might be a cause .. i kinda doubt it but to be honest this is a weird set of faults .

Car starting only in neutral .. the gear linkage on the box is partially seized .. it needs freeing off .

Fault code read out is needed ..

I'm also wondering about the CPS .. not really the usual issues for this but its still suspect .

Fuel pressure .. CPS and the coolant issue basically needed checking along with a fault code readout to move on .

 

[steve1]

Had a similar problem about a year ago 2002 tip just drove out of garage after alignment and it seemed to go onto 2 cylinders, drove about 50 mtrs and stopped no additional symptoms, waited about a minute and re started and all was ok no problem since, no fault code no engine light.
The alignment was at quickfit though :?:

 

[RobFrost]

I also noticed that the petrol gauge was going down quick!
...

Everything as per normal in that regard then! :lol:

 

[RobFrost]

possible causes

Causes of lack power accompanied by high fuel consumption:

Excessively rich fuel mix
- faulty sensor? Check for error codes.

Fuel going unburnt
- lack of ignition? Check for error codes
- lack of compression? Check for error codes

Mechanical drag (engine)
- internal coolant leak? Check if oil is milky
- mechanical failure e.g. water pump? Monitor temperature, check oil/filter for swarf, listen for noises, monitor coolant & oil levels

Mechanical drag (transmission)
- Check transmission oil for swarf
- Listen to transmission
- Check front diff / drive to front wheels (not sure how)

Mechanical drag (other)
- Handbrake binding / not fully off (usually burning smell)
- Check shafts for foreign material wound around

 

[Supafly270]

Hello all,

Thank you all for the suggestions. Apologies I havent had a chance to update the post.

I have been driving the car regularly and it has been running perfectly. Really unsure as to what happened on that particular day that it threw the mini fit.

I'm going to put it down to possibly the fuel that I used from the services on the M1, It was 95 unleaded and I do tend to always fill up from Shell and use the 99 Unleaded plus. I dont think that should cause any issues but I really am unsure as to what else I could put it down to as the car has been running really well.

Thank you all for your quick help and the invaluable knowledge

 

[Supafly270]

Hello again

So yesterday went for a spin

I filled the car up and it was slow to start, I have noticed this in the past where if the car is hot it struggles to start and usually after fueling

I started driving and noticed the car wouldn't get past 4500 revs

It's a tiptronic so I did ensure I had it in the 'manual" mode to try and push it past

From what I've read. It could be the fuel cap not creating enough pressure due to age?

The cps is on its way out

The MAF is having issues...? I am going to test this by running it without the MAF connected briefly

I fill up at the same shell fuel station with super unleaded every time

Any suggestions would be greatly appreciated

Thank you

 

[infrasilver]

I had a dodgy CPS that would act as a rev limiter around 4000 revs, an intermittent fault that took me a long time to diagnose, almost worth just changing to eliminate and save the pain of investigating?

Fuel pressure could be a cause but I feel it's coincidence that you are fueling up and it is just the hot start that's the problem?

I don't know if you saw thread, my engine to chassis earth is (possibly) causing my hot start issue, all the strands are corroded under the sheathing? I also had a corroded battery to chassis cable go on me a few years ago, ran like a pig until the lead actually gave up, fitted a new lead and it was fine.

 

[Supafly270]

Hi

Yes I did see the thread with regards to the battery cable going bad.

I'm unsure as to if I'd be able to do the cable change myself but I'd certainly like to attempt it

I would change the cps and although I've seen the instructions on replacing I'm unsure as to exactly how messy the top bolt will become to get the cable off.

Will attempt it one of these days and probably purchase a new fuel cap just to be on the safe side

Thank you

 

[infrasilver]

Both jobs are really easy if you have the car on axle stands, you can do the earth cable with just the wheel off, it's a 13mm nut and 13mm bolt the other end.

The only issue may be is the allen head bolt for the CPS may be corroded and may not come out easily, although plenty of penetrating fluid in advance may help some? The other end of the CPS is just a connector that unclips easily.

 

[Supafly270]

I'd like to attempt both these jobs. I have this issue where I replace parts even when they seem to be running fine.

I went for a spin again tonight. It warmed over a short period of time and then I floored it in 2nd and held it all the way through to 6000 revs so there were no limits at all and felt sweet

Actually it felt amazing!

Getting a new fuel filler cap this week.

Would you recommend the cps from Porsche or can I get an oem one from say euro car parts

Thanks again

 

[infrasilver]

Either Porsche or a genuine Bosch, Bosch will usually be cheaper.
I think 0 261 210 248 is the Bosch number for the 3.6 cars.

Also I note your car is a Tip so may not be as easy as I made out, it is easy for a manual car but I'm unsure what space there is with the Tip box?

 

[Supafly270]

Hello

Finally got a chance to get the car jacked up. It's been turning off on the dot when it gets to temperature and is struggling to start

Got it jacked up, and im struggling with the arch cover inside

The Allen key screws are all rusted and feel like they're glued on. The plastic screws are very difficult to take off but have come off

I am truly stuck with the metal Allen key screws and was wondering if anybody has tackled this?

Im currently thinking to drill them out.

Pics attached

 

[petero]

If you are trying to undo the wheel arch screws with an Allen key you will struggle as they are Torx head screws (T-30 IIRC) and a Torx driver of the correct size will be far more effective.

I managed to get all my plastic fasteners apart using a car trim removal tool without too much trouble.

Good luck!

 

[Supafly270]

Pics attached