207 GTI - THP Engine Issues

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DHallworth
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207 GTI - THP Engine Issues

Post by DHallworth »

My brother has had a 207 GTi for over a year now and has had silly little problems with it. The high pressure fuel pump on the end of the camshaft packed in causing it to barely run, then the other day it started to choke at higher RPM which turned out to be the cat blocking up and choking the car.

It's always felt a little flat and has never felt like a GTi should do.

Anyway, in a moment of madness this morning we took it to a place in Glasgow called Ecotune who have a fantastic reputation locally for remapping. They put the car on the rolling road and it only made circa 140bhp, not the 175 like it was supposed to.

They played with the turbo blow off valve and have said that it's working ok which apparently is quite unusual on these cars.

They remapped it and it's now running 175bhp but with the map on it should be running in the region of 210bhp.

This afternoon I've removed some of the sensors from it, MAP sensor, Boost pressure sensor, and whilst we were there I cleaned the camshaft position sensors as well. The guy at Ecotune reckons that it's being strangled somewhere, hence not running as it should.

I've had Peugeot Planet on it but cannot find any faults stored anywhere, unfortunately I didn't have time to go through all of the real time parameters as Andrew was in a rush as time had slipped past.

The guy has said that once we've had a fiddle with it he can rolling road it again to see what the power output is, but at £100 per dyno run I want to be fairly sure we've sorted the problem before spending the money.

Has anyone got any ideas what could be upsetting it?

Thanks in advance!

David.

Deanxm
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Re: 207 GTI - THP Engine Issues

Post by Deanxm »

Got to be a metering issue if its running fine but lacking power, lack of fuel air or exhaust flow or the ecu not seeing all the incoming air.

Not your fuel pump again starting to suffer is it?

Or the ECU is detecting knock and is backing things off a bit at the top end....................

D

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DHallworth
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Re: 207 GTI - THP Engine Issues

Post by DHallworth »

My initial thoughts were the MAP sensor tbh, Dean. That's what made my Xantia feel really flat and powerless when it packed in.

Hopefully tomorrow I'll get it on Planet and get a proper look at it. The MAP sensor looks identical to the Xantia V6 one but has a different part number so I'm reluctant to change it incase the internals are different and it blows my good one.

David.

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DHallworth
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Re: 207 GTI - THP Engine Issues

Post by DHallworth »

Had Peugeot Planet on it again tonight looking at the real time values... There's no fault codes stored anywhere on the Engine ECU but the downstream lambda isn't getting any voltage...

Engine ECU

Intermittent Fault
Inlet air temperature sensor signal. Short circuit to positive or circuit open.

Downstream Sensor Status - Weak
Downstream Oxygen Sensor Voltage - 0.00mv

Proportional upstream sensor voltage - 1469.67mv (switching)
Upstream sensor regulation status - closed loop

Upstream sensor heating OCR - 43.4%
Downstream sensor heating OCR - 12.0%

Upstream mix correction factor -1.5% - 1.5%
downstream mix correction factor - 0.0%

Measured throttle angle - 5 degrees

inlet camshaft dephaser position - 36 degrees
inlet camshaft dephaser position reference value - 36 degrees
(both vary when revved)

petrol rail pressure - 49 bars
petrol rail pressure reference value - 49 bars

downstream oxygen sensor value should be between 100 and 900mV.

Ho Hum... Will need to keep digging.

David.

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Re: 207 GTI - THP Engine Issues

Post by Deanxm »

Did you plot the values to a graph? I've found to track down these issues you need them in graph form, usually get throttle position for reference and then dump in lambda, maf and boost or map depending on setup then put lambda in fuel pressure and injection duration and ign ADV then take it for a good drive while it records the data.
You can then sit down and see what's happening.

Are you sure the injectors and coil are good, I know its a very common late gen TU engine issue but I've seen this low power and sleeping DS oxy sensor before on 206's and c3 and its always been injectors or coil even though it's running fine.

D

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DickieG
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Re: 207 GTI - THP Engine Issues

Post by DickieG »

The THP engine is very prone to getting a build up of carbon on the inlet valves to the extent that the valve is prevented from closing so it suffers a loss of compression. Due to it being a direct injection engine the inlet valves are not getting cleaned by petrol, the solution is to do a decoke (I remember doing those 30 years ago) or a much cheaper solution is to get someone to blast crushed walnut shells into the inlet chamber to remove the carbon. The long term preventative method appears to be one of disconnecting the crankcase breathers to stop oily deposits collecting on the inlet valves. Last week I diagnosed a neighbours Pug with the engine and the above fault, the car has done just 44k :shock:

So long story short, back to basics and do a compression test to eliminate the above as a possible cause.

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DHallworth
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Re: 207 GTI - THP Engine Issues

Post by DHallworth »

Thanks DickieG.

I'll try and get another look at it sometime this week and will do a compression test to see what's going on.

When the timing slips on them they usually put the EML on with the depollution system faulty message being shown on the screen. This time there's nothing showing. It's just running like crap so carbon'd up valves does make sense.

I might see if I can get the borescope down the plug hole whilst they're out and have a look inside it and see if I can see anything.

David.

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Re: 207 GTI - THP Engine Issues

Post by Deanxm »

Pop the inlet pipe off the throttle body and perform a leakdown test while having a listen, that will show up a bad valve seat and confirm which valves.
Its a good call Richard although maybe not the easiest thing to rectify unfortunatly if your correct.

D

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DHallworth
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Re: 207 GTI - THP Engine Issues

Post by DHallworth »

Apologies for the lack of responses on this... It's my brothers car so I don't see it very often.

It's spent the last 2 days in Peugeot for them to investigate a lack of power. They're said there's no fault codes stored which I'd already told them when we dropped it off, apparently all of the sensors are giving readings that are within scope, and they reckon it's driving fine even although it feels flat.

They offered to do the timing chain but at a little over a grand it's a stab in the dark! So, I've now got 2 choices. I either buy all of the parts and do the timing chain myself or I take it to a specialist who can check the timing for £125. If it is out, they can set it for another £50 on top of the £125 to check it, or if they find the chain is stretched they can replace the whole lot for just over £500.

These engines have a habit of snapping the chains at around 70k miles apparently anyway so I'm tempted just to buy the stuff and crack on with it to be honest.

David.

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CitroJim
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Re: 207 GTI - THP Engine Issues

Post by CitroJim »

How much work is involved in swapping the chain David?

Shocked they can stretch and break at 70K.. They seem a retrograde step compared to the timing belt.

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Re: 207 GTI - THP Engine Issues

Post by Deanxm »

Did you get a chance to do a compression test on it David?

D

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DHallworth
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Re: 207 GTI - THP Engine Issues

Post by DHallworth »

I started doing a compression test Dean. Stripped all of the coils and plugs out of it and then realised that the thread on the plugs is different from any of the adapters that I've got for our compression tester.

I drove it home from the dealer this morning, it's not slow but it just feels flat. I'd expect a 207 with 175bhp to be quicker then the Activa, The Activa would run rings around this one though.

I've been looking for some seafoam type stuff to put through it to clean the back of the valves but can't find anything. There's Subaru's upper engine cleaner that you can get which I might try.

I've got the workshop manual print out for changing the timing chains, it doesn't look that bad a job.

Jim, if you google Peugeot 207 GTi timing chain, the net is littered with stories of these chains stretching and snapping. It's a BMW engine that's in the DS3 & DS3 Racing, RCZ , 208 GTi, 207 GTi, Mini Cooper S, etc.

All of these cars have issues with the timing chains. I remember seeing a 6 month old DS3 racing in Citroen Glasgow in pieces. When I asked what was wrong with it they said the timing had slipped causing a misfire :shock:

There's superseded cam sprockets, cam chain and tensioners available.

What's really annoying is that this is such a common problem and this car has only covered 60k miles. It's got full main dealer history as well and there hasn't even been sight nor sound of a goodwill gesture from PSA.

Hey ho, if we don't do the chain we're going to be trading it in to get rid of it. After all of these problems, and given the fact that all of the high performance PSA cars use the same engine, I don't think it'll be replaced by anything Peugeot or Citroen.

David.

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DHallworth
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Re: 207 GTI - THP Engine Issues

Post by DHallworth »

Well I've chickened out of doing the chain myself. The job has been given to BL Auto's and is being done at the end of October. Everything timing chain related on the engine is being replaced. I described the symptoms to Robert on the phone and he said that it certainly does sound like timing issues so hopefully this'll be the end of the problems, once and for all.

David.

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CitroJim
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Re: 207 GTI - THP Engine Issues

Post by CitroJim »

Do call in and see me on your way down and back David, will be good to see you...

Fingers crossed this'll be the solution to the issues....

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DHallworth
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Re: 207 GTI - THP Engine Issues

Post by DHallworth »

Will see what I can do, Jim. It probably won't be on the way down as we'll be leaving Glasgow at about 6pm and travelling down during the evening. Will see what time we get finished on the Saturday.

David.