Xantia TD '95, overheat, smoke, bad start

MikeT · Post by **MikeT** » 15 Sep 2007, 18:18

Yes, that's where it all began for me as my xantia seemed somewhat underpowered and I was unable to produce black smoke - a sure sign of excessive fuelling. I've since learnt and experimented and could create smoke screens the army would be proud of by adjusting the turbo boost cone. I've yet to play with the max fuel screw and other possible tweaks.

Thankfully, I have an efficient cooling system that coped with it most admirably and the temp gauge rarely passes the 85 mark unless idling or slow moving for extended periods in hot weather. I've been told I may have a "lazy" thermostat spring as the temp gauge will read about 75 when driving over 35/40mph.

I've now reduced the overfuelling (ergo power delivery) to a more environmentally friendly amount and, as I say, the engine now takes noticeably longer to warm up so I strongly believe excess fuel will increase engine (at least exhaust) temperatures markedly.

If you haven't already seen it, take a look here for most of the possible adjustments you can make to the BOSCH pump

http://dodgeram.org/tech/dsl/more_power/Power_ve.htm

Denis · Post by **Denis** » 15 Sep 2007, 23:27

Hello
I will now drive car with all new fixes, it seems much better, probably black soot had to clear up, now accelerating full 2nd gear in dark, car warm, other car driving behind me with lights illuminating smoke, it almost doesnt smoke.
Will check tomorrow with cold car.
Top speed 160 kmh doesnt seem fine, since 179 is factory speed, so will check and play with pump as per the link and eventually get leaky pump fixed.

In your first paragraph you probably ment underfuelling with underpower and no black smoke.
Did read about lazy thermostat and leaking pump problems and of course gaining knowledge in pump tweaking, which i also want to lurn so keep up the good work.
Denis

MikeT · Post by **MikeT** » 15 Sep 2007, 23:52

Yes, it does seem these diesels will accumulate soot in the exhaust with normal driving and when you accelerate hard, it all comes out in a big cloud and then nothing.

Sorry for the confusion; when I first drove this car I could not produce black smoke and thought it was undepowered, then I tweaked the fuelling and could produce plenty of smoke - too much in fact. Now I have reduced the fuelling again and have noticed how much longer it takes for the car to get up to normal operating temperature from cold. I was told that more fuel equates to higher exhaust temperatures, whether this transfers to the engine or not I don't know but it seems it does with my car.

I hope the improvements with yours continue. Good luck

Denis · Post by **Denis** » 16 Sep 2007, 11:56

Hello
What distance does it take yours for the temp to rise to 80, currently I get it in 4-5 kms, mild summer, no idling, just start cold car standing through night, and drive normally, with few traffic lights and no car jams.
Without thermostat it would need 15k's, if at all.

Did pump tweaking to more fuel also mean increased power in for example continuous uphill riding on highway with no speed loss.

Denis

MikeT · Post by **MikeT** » 16 Sep 2007, 12:31

Left overnight, starting from stone cold and driving off immediately, the temp would rise to 75-80 within a mile (when it was overfuelled). Now, with reduced fuelling, it can take 3 miles and still not reach 80 though the ambient air temperature is now lowering as our summer is over. This is with mild urban driving, 30-40mph, with three roundabouts and moderate traffic.

Yes, more fuel gave more power. I increased the on-boost fuelling which allowed the car to pick up strongly from under 3krpm and it continued past 4Krpm. I annoyed one BMW M3 driver who thought he could safely cut me up by out-accelerating me when I was at full power appx 40-45mph. He did manage to increase the distance but only just before I got to 70mph.

To increase off-boost power, you need to adjust the smoke screw under the small metal cap on top of the diahpragm housing. I've yet to fully experiement with this as I find off-boost power embarassingly slow, especially on inclines.

Denis · Post by **Denis** » 16 Sep 2007, 22:01

Hello
That heatup time seem fine comparing to mine with new thermostat.

I took car to highway today, to check speedo comparing to gps speed meter and it was very correct, actually car speedo showed a bit less speed.
On straight reached 174 kmh - 109 mph
till 160, temp was at 90, above that, rose to 95.
Lowering speed, started cooling off.
Will manage the pump someday since heating problem still persists.
Denis

Denis · Post by **Denis** » 26 Sep 2007, 18:07

Hello
Did few km's since.
Car behaving much nicer, doesnt heat over 80 even though thermostat is installed.
Corrections done:
the biggest water pump
flushed radiator
clean radiators from outside for airflow

speeds above 150-160 kph heating occurs, towing semiloaded trailor uphill for prolongued time, driving city mild accelerations and stops.
overheating stabilizes much quicker when road opens.

conclusion
problem not cured, many symptoms cured.
like car was given sedatives.

Smoking when cold is present and under load after some prolongued easy riding.
When say smoking, meaning black cloud all over the road.
Denis

MikeT · Post by **MikeT** » 26 Sep 2007, 21:43

Denis wrote:speeds above 150-160 kph heating occurs

To what degree?

Denis wrote:conclusion
problem not cured
Smoking when cold is present and under load after some prolongued easy riding.
When say smoking, meaning black cloud all over the road.
Denis

Sounds like the pump is overfuelling. Maybe you could try reducing the "smoke screw" as shown in the pump tuning guide previously linked?

Denis · Post by **Denis** » 26 Sep 2007, 22:38

Hello
Yes, ill dig into pump, link is known as said before.

Temp rises to approx 89, but its not a definite value, could go higher if for ex. i release throtthle and fully press it and keep it so.
Having it pressed with no abrupt changes is keeping heat in acceptable range.
Denis

MikeT · Post by **MikeT** » 26 Sep 2007, 23:16

Denis wrote:could go higher if for ex. i release throtthle and fully press it and keep it so.
Having it pressed with no abrupt changes is keeping heat in acceptable range.
Denis

Having re-read all the posts I'm uncertain about a few things. It was claimed the '95 model may not have an ECU and the photograph you posted of the "air sensor" is inside an ECU housing but the ECU is clearly not there and yet your fusebox shows the ECU diagnostic socket.

Maybe someone else knows about the year/model differences, I'm afraid I don't. Additionally, I don't know if the fuel leak at the pump lever has any bearing on your problem(s).

Before you change any fuelling settings (and when you do always note them so you can revert back if need be) did you reconnect the atmospheric pressure switch? I believe it has a direct influence on emissions.

However, the smoke screw (as far as I can tell) only affects off-boost fuelling but may help reduce the excessive smoke on cold starts and acceleration below turbo boost.

If you're creating excess heat at high speeds that may be related to on-boost overfuelling which can be also be adjusted by rotating the boost plunger (below the smoke screw).

Denis · Post by **Denis** » 27 Sep 2007, 09:35

Hi

MikeT wrote: Having re-read all the posts I'm uncertain about a few things. It was claimed the '95 model may not have an ECU and the photograph you posted of the "air sensor" is inside an ECU housing but the ECU is clearly not there and yet your fusebox shows the ECU diagnostic socket.

Thats what I'm screaming about all the time now.
What kind of mixed car is this.
No ECU, diagnostic switch, and ECU housing having sensor in it.

Maybe someone else knows about the year/model differences, I'm afraid I don't. Additionally, I don't know if the fuel leak at the pump lever has any bearing on your problem(s).

This could affect the fuel returning to the tank when car stays undriven for few days. so more cranking is needed to start the car.
If pump the primer, it starts instantly.

Before you change any fuelling settings (and when you do always note them so you can revert back if need be) did you reconnect the atmospheric pressure switch? I believe it has a direct influence on emissions.

Reconnecting it doesnt affect anything, could be little less power in low rpm, but that is just a slight feeling.

However, the smoke screw (as far as I can tell) only affects off-boost fuelling but may help reduce the excessive smoke on cold starts and acceleration below turbo boost.

If you're creating excess heat at high speeds that may be related to on-boost overfuelling which can be also be adjusted by rotating the boost plunger (below the smoke screw).

Ill then have to temper with both since when cold, I get smoking in pretty much off idle rpm, and when warm, ride it close to turbo boost, then fully press throtthle, and here goes black smoke screen.
Denis

MikeT · Post by **MikeT** » 27 Sep 2007, 12:31

I'm afraid I don't know enough about the various sensor configurations and ECU management, hopefully someone else can help but working with what we do know...

Yes, the fuel pump leak may well be causing the fuel to draw air back into the fuel feed. If your fuel feed line is see through you can see any air bubbles as you pump the primer.

If the atmospheric sensor has little effect, personally I would leave it connected while you sort out what you can.

I created the same smoke effect you describe by over adjusting the boost plunger so you may want to try rotating it in 20-30 degree increments (counter-clockwise) until the smoke (and power) lessens to your satisfaction. Hopefully, it may also reduce the excess heat problem you're experiencing.

Post by **philhoward** » 27 Sep 2007, 21:00

Just because there is a diagnostic socket in the fuse box doesn't mean the engine has an ECU - it could be for all manner of other ECUs as they all talk along the same bus system (ISO) i.e. ABS, Alarm...

Denis · Post by **Denis** » 29 Sep 2007, 10:05

Hi
Socket could really be for ABS.

Feed line is black, but can see realy tiny amounts of fuel gushing past seal on a previousely clothed pump, when press the primer.
Ill connect sensor and check with prolongued use.
Car is now mostly on apprx 77°C, only certain occurances rise it to 82-83, wich Is ok for normal use.
Still would like to fix smoking with pump play, Ill make another small movie for visual info.
Denis

Post by **CitroJim** » 29 Sep 2007, 21:40

Denis,

Your leaks: If you are seeing them on the pump throttle spindle when you squeeze the primer bulb this may indicate a blocked or partially blocked fuel return line back to the tank. This is the fuel line that connects to the front of the pump in the same place as the injector leak-off pipes.

If the return line is blocked, this causes excess pressure to build in the pump and can blow seals. It could also account for your smoke as the internal pump pressure is wrong and this could result in over-fuelling.

Put your mouth over the return line and you should be able to blow down it.