sageman's 'barn find' v6 sei s1

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Dean
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Re: sageman's 'barn find' v6 sei s1

Post by Dean » Fri May 17, 2019 2:48 pm

I have found much the same as Will states above but with my 12v V6, attaining the voltages stated in the manual is not possible as the throttle spindle is mechanically limited in its rotation in a way that does not allow the TPS to perform a rotation great enough to register .5v at idle and 4.5v at WOT, it should be noted (with my ECU version at least) trailing throttle fuel cut is triggered at anything below about .8v so it is possible to have throttle transition jerkiness at small throttle openings if not set correctly, in the end i gave up, drilled the TPS mounting holes to about 8mm and set idle to .1v below fuel cut threshold and gives 4.4v at WOT i think.

anyway, the reason for the reply is that i sort of remember your symptoms, if the car is running and the TPS is unplugged the engine idle will steadily increase untill it gets above 2500rpm, not sure how far above that it goes as i chickened out and plugged it back in, how or why it would do this i do not know, the only thing i can think is unplugging the TPS upsets the ECU which starts cranking open the ICV incrimentally for some reason. With the ICV unplugged the ECU selects mid throttle state and see's about a 2.5v signal from the open TPS circuit.

A lexia, although of limited use on older cars, can still be a valuable tool in terms of fault finding from live data readout, it should display the following live data:
Engine speed
inlet air temp
coolant temp
O2 signal voltage
O2 heating (on/off)
Drive state (neutral/Drive)
TPS voltage
Percieved throttle state (idle - Mid -WOT)
Ignition advance
ICV position (% open)
Mixture correction
Manifold pressure
Injection time (ms)
Battery voltage (at ECU)

See here for what it can do

D
92 Citroen XM Prestige 3.0i Auto R.P5678
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sageman
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Re: sageman's 'barn find' v6 sei s1

Post by sageman » Sat May 18, 2019 5:45 pm

spent several hours on the car today
TPS tested at
.46v at idle and 4.1v at WOT

however i then discovered that with it plugged in the rpms are uncontrollable as soon as you even start to open the throttle the rpms carry on increasing to about 3k i tried and failed to hold it at various rpms above idle it simply wasn't possible
i then unplugged it and it seems to me to rev how it should it also no longer comes back to idle in stages the TPS was the only thing unplugged at this point

ive also found that the throttle linkage/butterfly valve only come back fully shut sometimes explaining why i thought it did
and i think i do actually have a minor vacuum leak with my hand over the idle bypass the rpms decrease but not by much and with my hand over the main throttle intake and idle bypass it will only sometimes stall most of the time it will still run but at the point of stalling

given the throttle was entirly sized when i got it i think i might just get ahold of a new throttle body

i have also sourced the LHM leak on the drivers side
its coming from the high pressure line to the top of the strut and is leaking from the flexable tube to solid tube connection as it go into the engine bay and is coming from the smaller steel tube part the larger flexable part is dry
theres a clamp i removed but couldn't separate the two
are they meant to come apart
1976 Reliant kitten
1985 Reliant fox Tandy campervan
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1993 XM sei V6

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Dean
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Re: sageman's 'barn find' v6 sei s1

Post by Dean » Sat May 18, 2019 9:32 pm

They care a crimped joint, if you remove the pipeyou may be able to get it re-crimped atca hydraulics specialist or more likely a new flex section fitted.

D
92 Citroen XM Prestige 3.0i Auto R.P5678
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Re: sageman's 'barn find' v6 sei s1

Post by Dieselman » Sun May 19, 2019 10:23 am

Just keep lubing the throttle spindle and linkages. Mine were completely seized, but are no functioning properly.
Does yours have a working return spring?

Your TPS appears to be working, so the fault isn't that. A setting of 0.5v at idle and >4.5v at WOT would be prefereable to what you have.

You need to find the vacuum leak to be able to proceed. If you ahve a low volume of compressed air, you could use soapy water sprayed on the joints.
Don't forget to block the breather pipe from the throttle body.
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sageman
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Re: sageman's 'barn find' v6 sei s1

Post by sageman » Sun May 19, 2019 11:29 am

fair enough will try that first then
the bottom spring is fine this is how the top looked when i got it
the end closest the throttle body is now behind it so it act as a spring in the correct direction but how its supposed to be set up i dont know
the plastic gas ram seems to have no function either

Image

could this extra air be coming from the crank breather.... i best test this too
i do have an air compressor
i wonder how i could rig something up though i will think of something im sure

just to confirm this is the connection that is leaking
so this whole pipe needs to be removed from the car (somehow) and this joint fixed in someway by some hydraulics people

Image
1976 Reliant kitten
1985 Reliant fox Tandy campervan
1998 Peugeot 306 GTI-6
h̶o̶p̶e̶f̶u̶l̶l̶y̶ ̶a̶n̶ ̶X̶M̶ ̶o̶n̶e̶ ̶d̶a̶y̶
1993 XM sei V6

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