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Spurious Substandard Replacement Parts - Warning

It a heat thing, i don't know enough about the DME to say if it would shut down at a certain temp, and I am not even sure where it would get that info from,

the blue sensor is just measuring the cold end, for startups, you have changed this anyway, the only other sensor would be the oil temp sensor,
does the S have one of these?

I have looked through PET and cant see one of those or Knock sensors, but I can see two temp sensors, the other thing would be the TPS, but they are £404 from Porsche,

Can you swap one off the other car?





 
Way lander, correct only the 2 temperature sensors-the Bosch blue socket DME engine sensor & the Lucar blade single wire Gauge temperature sensor but no oil temperature sensor ,just the usual oil pressure gauge in central console.
So 1st things 1st- changed Bosch plugs back to the NGK plugs it came with which were virtually brand new ,checked gaps & reset to 0.7/0.8 mm where necessary.Also checked resistances of my spare coil which are within spec so will fit tomorrow after I have driven at correct temperature ,this evening used it but only down to the village so not even warm.I did notice it was slower to start with the single terminal conventional plugs but that might be because I earlier let it warm up at idle after fitting the NGK plugs.

So after changing coil,maybe onto removing AFM ,it's top & checking Spring & tracks.

Fortunately,it helps me fall asleep working through the various procedures.????
 
[:)]

I am still struggling with what would be giving the dme the info to shut the revs off

there does not seem to be enough info being given to the dme, from the shortage of sensors, the only other thing would be if it had the ref/rpm sensor gap getting to big with the engine heat, but that seems a bridge a bit far
 
Join the club-I've been racking my brains for months! Sorry to be so ignorant but what's a TPS.?
I have checked my Bosch manual & the DME connection drawing doesn't include an oil temperature one.
As to the engine sensors,I admit to fitting these myself using an old sensor with a suitable thick washer glued on to adjust the "new" secondhand die cast socket bracket but also admit I have never checked the sensors since - perhaps the clamp bolts have loosened but all these theories stumble at the precise rpm cut off figure I experience.Also the same temperature point.
 
Have you tried changing the DME relay, or using a jumper temporarily?

Another thing worth checking is the fuel pump fuse and connections, bad contacts or fuse can produce funny symptoms.
 
Stan,I have changed the relay to my new spare ,at the time because the engine just died on me at some traffic lights just as it was my turn to move off but have to admit not trying my jumper kit specifically to see if it makes a difference.
I have checked fuses & overall both our 924S's have been very reliable with that regard but there's no harm in having another look( when this useless rain stops).
Trouble is as with many reflections about this,it's difficult to relate everything to the precise rpm and/ or temperature cut off??
Colin.
 
vitesse said:
Join the club-I've been racking my brains for months! Sorry to be so ignorant but what's a TPS.?
I have checked my Bosch manual & the DME connection drawing doesn't include an oil temperature one.
As to the engine sensors,I admit to fitting these myself using an old sensor with a suitable thick washer glued on to adjust the "new" secondhand die cast socket bracket but also admit I have never checked the sensors since - perhaps the clamp bolts have loosened but all these theories stumble at the precise rpm cut off figure I experience.Also the same temperature point.
Click to expand...
TPS throttle position switch, i believe its a bit on/off in the 944, but not the turbo that's different, and even more money


 
Silly me-of course-one of the 1st things I did was to check I was getting full throttle allied to checking the TPS & resetting it according to Haynesmanual/Clarkes Garage instructions.
The actual changeover point from idle position to full throttle is fairly low down below 4500rpm -I triple checked it as I had been warned previously not to fiddle with it.
Since the problem existed before & it hasn't got worse,I presume it's not the TPS.
 
does the car have the KLR system like the turbo?

I have read a couple of USA posts sayong the KLR has caused rev issues when the car gets hot


 
As far as I am aware,the 924S's don't have the KLR system -reading my Bosch manual again on Friday ,I think it's used where a catalyser & lambda probe are used
 
Had a bit of time to research, so from what I read the Rev limit is fuel cut off, the reason I would say that is because if it was ignition the fuel would be pumping in the cylinders and when the sparks came back you will have swapped your porker for a Scooby

I think I would be looking for a known good Motronic to test with
 
Thanks Waylander-I understand the reasoning -I just can't fathom out what is producing a temperature related signal at precisely the speed cut off rpm ,as as soon as it happens,if you back off to lower revs,the engine carries on responding as normal until you hit the same speed limit-if you change up ,it carries on accelerating so it's got to be a signal to the DME,because the DME casing can't get particularly hot under the dash
Having refitted the NGK plugs it has made no significant difference and why would the cut off point be 4500rpm hot.
Unfortunately ,my wife doesn't understand when I said I wanted to swap out the DME from her 924S to try that out-I don't know why she's so suspicious.
Also I don't believe in nor wish to keep replacing components willy nilly to solve the problem to be left spare everything.I would still be left ignorant of the actual cause.
I can't believe that possibly a cable joint is expanding losing contact at precisely those revs either.
 
well that kinda just leaves the ref and speed sensors,
I think I might try re-gaping those to the flywheel,

think the only way your going to prove if its fuel or sparks is to have a fuel pressure gauge connected when it happens, dont need to worry about the sparks bit unless the fuel pressure remains constant,


 
I'm just working out how to hang on to the bonnet with the pressure gauge in my free hand whilst my wife drives down the Formby bypass with the bonnet open at the suitable speed[8|]:ROFLMAO:
 
Think a longer pipe will help, but as blade suggests it must turn off the injectors,

need to find a way of monitoring the pulse to he injectors
 
When I changed back to the NGK plugs last week,the Bosch ones were very sooty,although I have recently been using the car for short local journeys.
Anyway decided to check the mixture yesterday using Albert Walsh's Hawk analyser & adjusted to 2.8/2.9 CO which is slightly weaker than it was running at.
Next week I intend to take out a plug after running it hot & check the appearance.
Must admit when I checked the fuel pressure before Xmas, I dont think I had the engine that hot so can't say what happened with the gauge if revved to 4500rpm as I was more concerned to check a) the pump output b) the FPR .
So I'll fit the gauge again ,get the engine hot enough & see what happens around 4500 rpm.Previous check showed correct pressures with a warm but not hot engine for both the standard & turbo FPR which I left fitted-even correct pressure increase when vacuum pipe clamped.
Without an oscilloscope,it's difficult to check the injectors although my Bosch manual gives details.
I might also try James at Only 9 to see if he'll lend me a spare Motronic to try as you suggest,Waylander.
 
Been up in Northumberland until this pm so got to try & find some time later this week-you might have sensed from the general tone of my posts that I run the car as far as I can at minimal cost until have pinpointed a problem when I am then prepared to shell out to resolve it.
My feeling is that a rolling road session would only demonstrate the problem but still need to discover what to change to resolve the problem.
I have used a guy in Widnes on various occasions to remap other cars so your hint will prompt me to give him a ring to see if Mike has anything to contribute-he does go back to my Rover Vitesse SD1 days!
 
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