Xantia HDi power gremlins

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Rhothgar
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Re: Xantia HDi power gremlins

Post by Rhothgar »

wheeler wrote: 07 Apr 2024, 18:10 The pipe100% just pulls off the butterfly.
You could just remove the vacuum ‘supply’ from the solenoid & block it there.
Again you can run the engine with this butterfly pipe disconnected & blocked and the car will never throw up a fault or warning lamp about it.
Oh OK. I gave it a good tug but it didn't seem to want to come off. It's not like a normal pipe end as you see at the solenoid side. It seems to have a shroud around it.

I'll use a bit of duct tape instead on both pipe end and solenoid connection and give it another spin.

If it runs better, I may well order a new solenoid valve from Autodoc as they've sent me a free shipping email today.
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Re: Xantia HDi power gremlins

Post by Rhothgar »

wheeler wrote: 07 Apr 2024, 18:10 The pipe100% just pulls off the butterfly.
You could just remove the vacuum ‘supply’ from the solenoid & block it there.
Alternatively you could just clamp the pipe with a brake pipe clamp etc.
Again you can run the engine with this butterfly pipe disconnected & blocked and the car will never throw up a fault or warning lamp about it.
So here is the latest!

I just dare not tug at the pipe at the butterfly valve anymore. It doesn't appear to be a slide on pipe like what you see at the solenoid valve.

I failed miserably to try and seal off the pipe at the solenoid valve that controls the butterfly so I've given up on that for now until I can see better how it is connected.

I have tested all three solenoid valves and they each give 13 Ohms so I now know that they are all within specification.

One thought that crossed my mind is whether the vacuum pump is failing when provide enough vacuum when the car is revving at higher revs or high load and then failing to actuate whatever it needs to.

I thought I had the correct wiring diagrams for my RHZ engine but there are some anomalies between the diagrams which leads me to think the earlier RHZ engines (ie the year before my car) had a different method of control. There is no butterfly solenoid shown in the diagrams I have and surely that would form part of the power unit diagrams? I'll have to dig my manuals out again as, a few years, ago I printed what I thought were the correct diagrams for my engine and laminated them.
wheeler
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Re: Xantia HDi power gremlins

Post by wheeler »

Worst case if it broke you can run it no problem with the butterfly disconnected, thats the way i have deliberately run every old HDI I’ve owned.
As for the solenoids, that only really shows the coils are ok, it doesn’t mean they are sound mechanically, the valve could still be stuck/blocked.
RHY engines only have the 2 electro valves. RHZ has the extra solenoid for the wastegate.
There are 2 main different types, early ones with the single plug ECU or the later ones with the 3 plug ECU.
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Re: Xantia HDi power gremlins

Post by Rhothgar »

wheeler wrote: 09 Apr 2024, 19:00 Worst case if it broke you can run it no problem with the butterfly disconnected, thats the way i have deliberately run every old HDI I’ve owned.
As for the solenoids, that only really shows the coils are ok, it doesn’t mean they are sound mechanically, the valve could still be stuck/blocked.
RHY engines only have the 2 electro valves. RHZ has the extra solenoid for the wastegate.
There are 2 main different types, early ones with the single plug ECU or the later ones with the 3 plug ECU.
Well mine is definitely the one plug EDC15C2 and has the 3 electrovalves.

And that's very good point you make about it not proving that they are sound mechanically.

The next thing I really need to do is load test the wiring. I thought I'd done that previously and then maybe take some plumbed-in pressure measurements. Just reading up on the Mityvac 8500 and wondering whether to splash out on a decent tool. I was thinking with a really long tube I could have the gauge in the car and go for a run with the other half reading out the figures. Have the bonnet unlatched so it doesn't squeeze the pipe and perhaps get a fuller picture of whether full vacuum is being produced.

Having said that, would you expect to see full vacuum in the system? I cannot recall seeing any figures quoted for the level of vacuum in.

The other issue I've just thought of is unless you have three gauges you can only test one line at a time unless the vacuum is common to all of them? Which I suppose it is at the vacuum pump as there is only one take-off from memory.

And having said that, I've just read that the vacuum value should be 1 bar at idle speed.

I was hoping one day to get a mate to knock me up a 4185-T connecting sleeve for checking the turbocharger pressure on the induction pipe.
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Re: Xantia HDi power gremlins

Post by Rhothgar »

@Wheeler

Here you go. Does this connection look anything like yours did? Left hand yellow 'circle'.
IMG_0198.jpg
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Re: Xantia HDi power gremlins

Post by wheeler »

Yep, exactly the same. Now i have seen the picture it reminded me how i remove them. A pick in the slot you can see to kind of grab the pipe & pull it out. There is deffo nothing else holding it on, just push on like they do on the solenoids. They can be tightly stuck if they have not been disturbed for a long time.
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Re: Xantia HDi power gremlins

Post by Rhothgar »

wheeler wrote: 10 Apr 2024, 14:50 Yep, exactly the same. Now i have seen the picture it reminded me how i remove them. A pick in the slot you can see to kind of grab the pipe & pull it out. There is deffo nothing else holding it on, just push on like they do on the solenoids. They can be tightly stuck if they have not been disturbed for a long time.

Well now you’ve said that I’ve realised that I was pulling on the wrong pipe!

You mean the one with the Clic-R clip.

I’ve also just noticed the word ‘Out’ on the solenoid valve. ‘

So In is obviously the opposite and is I suppose on the vacuum pump side of the solenoid valve.

Testing on the in side is always going to show a vacuum.

On the butterfly valve, there is a connection for the ‘in’ and the ‘out’. Again, I will happily stand corrected and perhaps need guidance on this but I suppose they are on the pressure side and the suction side?
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Re: Xantia HDi power gremlins

Post by wheeler »

No, pulls of from here.
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Re: Xantia HDi power gremlins

Post by Rhothgar »

wheeler wrote: 10 Apr 2024, 20:07 No, pulls of from here.
Image
Cheers buddy. That's what I thought but when you mentioned a clip, my eye was drawn to the clic-R clip on the pipe behind.

Was just about to order some vacuum piping then realised that I think I've already replaced it. Obviously not all of it as I was unable to remove those pipe but I think I've done others. Looks like I'll have to do it all over again.
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Re: Xantia HDi power gremlins

Post by Rhothgar »

Managed to get the HDi running at full boost last weekend but still getting horribly high air flow at idle.

Biggest issue I have at the moment is that I still cannot get the Lexia to read.

So I took a look at the OBD today and two of the pins were pushed back. This is because I took them all out last August to 'nip' the pins up. It actually seems I ended up damaging the terminals in the ODB.

It's a little strange as my ELM327 reads but the Lexia does not.

If I don't get any joy soon I am going to butcher one of the the Lexia leads and wire directly back to the ECU from Pins 7 and 8 on the OBD socket. Previously I ended up going to my mate's garage and using his Bosch KTS520 with breakout leads directly to ECU.

What a faff. I have tried to use a pick to try and get the two terminals back to some semblance of order but still no reading.

I just wonder if the drivers are installed correctly. I can see two devices:- Actia USB and Other Unknown device. My memory is pretty foggy when it comes to Lexia but am I right in saying that just the one device should appear in Device Manager?

I cannot find a PSA interface checker and maybe this is another issue as a neighbour gave me his old Lexia but maybe the drivers are not the correct ones? I really don't understand the software / interface side of things.

Any advice much appreciated from a regular Lexia user.
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CitroJim
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Re: Xantia HDi power gremlins

Post by CitroJim »

Have you tried your Lexia on your 3000008 Roger? Just to confirm it's more or less functional. It may not do much but it should act as a go/no-go test.

I once wired the diagnostic signals from the Auto Gearbox ECU on an XM directly into the back of an ELIT as the ECU was from a late Xantia and the wiring was not present in the XM 30 pin diagnostic socket to allow it to be correctly read...
Jim

Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
Rhothgar
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Re: Xantia HDi power gremlins

Post by Rhothgar »

No I ha en’t as yet Jim. I think software won’t read the 3008. Too early I believe.

I’ll probably end up directly soldering respective
Pins 7 and 8 of OBD to ECU
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Re: Xantia HDi power gremlins

Post by wheeler »

Rhothgar wrote: 20 Apr 2024, 15:35 Managed to get the HDi running at full boost last weekend but still getting horribly high air flow at idle.
Is it running fine now but you just have high air flow at idle? If its not over 500 mg/cp leave it alone.
Every RHZ engine i have owned always had an air flow at idle of 500 mg/cp 8-)
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Re: Xantia HDi power gremlins

Post by Rhothgar »

wheeler wrote: 20 Apr 2024, 22:11
Rhothgar wrote: 20 Apr 2024, 15:35 Managed to get the HDi running at full boost last weekend but still getting horribly high air flow at idle.
Is it running fine now but you just have high air flow at idle? If its not over 500 mg/cp leave it alone.
Every RHZ engine i have owned always had an air flow at idle of 500 mg/cp 8-)
You see! I’m having sleepless nights thinking about the car

I cannot measure it due to OBD issue but it was around 470 last time I was able to measure.

My focus on this has now turned to fuel economy and what I believe are abnormally high throttle position percentages under conditions where the throttle is being ‘tickled’.

Wish you’d have seen my other post as I ended up buying a new Lucas air mass meter on Wednesday. Fitted it Friday so cannot return. It made no difference to the reading when compared to the famous £8.08 Intermotor one I bought in August. Never mind.

Because of communications issue with Lexia, I’m now thinking of taking the dash out to repair the damage to the 2-3 OBD terminals that has occurred back in August. The ELM327 module I have works or did, at least, yesterday morning. Some of the tangs with the terminals have folded back. When I had issue last year, I stripped each wire out and prised them closer. That and the insertion of a cheapo ELM module with male terminals that probably aren’t the best tolerance has probably done more damage when all that was wrong was my Lexia was dying.

I wish there was someone near to me that had a Lexia so I could check whether theirs reads before I create myself a mammoth job!

Mind you. It needn’t be too near as I could brim the tank and check MPG over a longer distance but that sort of defeats the object of reducing fuel usage.

Basically plugged Lexia in again yesterday to actually test if anything changes reading wise when vacuum is manually applied to the EGR. Apparently the air flow should drop by about a third as it adjusts.

One thing I should really check is the intercooler for leaks. I checked all the pipes from the turbo to and from it last weekend. Had a thought that the whistling I hear, ie the turbo spinning, could be either that or a leaking inlet manifold gasket. I did buy a new gasket last year as I wanted to remove the manifold and check if it is badly restricted as if the wrong amount of air is actually getting in then that could result in the poor mpg. Also, the ECU might be overfuelling because of the high airflow at idle. Pretty sure the air flow is probably high across all the range? Stands to reason, surely?

The signal voltage of pin 5 of the air mass meter is too high at 2.42 bolts at idle. It should be 2V I believe.

Also did a leak-off test on Friday. They were all roughly equal but 45-50 once the diesel from the pipe had drained into the bottles. Excessive leakage doesn’t lead to high fuel consumption but neither does it rule out poor spray pattern.
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Re: Xantia HDi power gremlins

Post by wheeler »

Rhothgar wrote: 21 Apr 2024, 03:41
Basically plugged Lexia in again yesterday to actually test if anything changes reading wise when vacuum is manually applied to the EGR. Apparently the air flow should drop by about a third as it adjusts.
If the EGR is opening when you apply vacuum to it then yes the airflow reading should reduce by roughly a 3rd when its fully open. Is this happening?
Rhothgar wrote: 21 Apr 2024, 03:41
The signal voltage of pin 5 of the air mass meter is too high at 2.42 bolts at idle. It should be 2V I believe.
Cant really remember what the correlation between AF & voltage is.

I should add that my 500 mg/cp airflow on every RHZ i have had is completely intentional.