Spurious Substandard Replacement Parts - Warning

[VanhireBoys]

Hi All
I'm trying to get an 84 Lux back up and running after a long layoff. The car is in Co.Mayo and has been stood for about 14 years or so. A workmates father bought it years ago with a view to fixing it up.

The car is in relatively good shape given that it was dry stored. I advised that the belts and pump should be changed before attempting to start but that was duly ignored ...!

Car has no spark and the coil is not being triggered so this says to me that the crank/rpm sensors are not reading. A few checks and it was conformed that the crank sensor was gone.I told my workmate Shane that the car could be doing with both sensors.

In my absence he got 2 substandard sensors from some cowboy outfit and fitted these himself. Turned the key and she went to fire but then promptly ate the rpm sensor. I took a look and the sensors he got are too thin to go in the bellhousing bracket, and slightly longer than the originals.

Ive said it before on many an occasion that at this stage in the game its better to get the genuine part. In most cases they will be only marginally more expensive than a crappy unbranded piece of sh**e

Im not going to start naming the brands that should be avoided but have yous come across substandard stuff that should be avoided ?

 

[Waylander]

did he throw the metal cover away?

i have used all sorts of cheapo brands for all sorts of cars over the years, and had faulty main stream brands too,

I tend to avoid Chinese cheapies if i can when it comes to electronic parts, as far as the ref and rpm sensor goes, just use the BMW ones half the price the lead is just a few inches longer,

and that's a Bosch one, you can pay massively over the odds for a P part

 

[vitesse]

I've fitted replacement sensors in both our 924S's purchased from GSF Motor Factors locally for around £73 the set of 2-they looked identical ,weren't Bosch but European brand -I think they were for Saabs,etc .had no problems with either set.
We need a list compiled of similar such "spurious " parts where savings to be made with part no cross reference-eg Volkswagen wishbones ,handles ,sensors etc as when I've asked at VW parts counters they always need their part references even though they know what you're asking for.

 

[Waylander]

Have a look at

www.pdlibrary.co.uk

 

[vitesse]

Brilliant,Waylander-wish I'd known about that ages ago-many thanks.

Perhaps I can pick your brains on a problem I have with the red 1987 924S I use as a track car although very road legal.
I've read everything I can find through & through & haven't come across any real mention of it.
Car starts fine from cold & hot at the 2nd attempt.When cold & before the temp gauge passes beyond the centre red block on the gauge ,the engine will rev right round the clock in all gears-but once really hot ,say 3/4 way round the temp gauge ,there is a rev cut off point at 4500rpm in any gear .
Checked fuel pump pressure-correct(turbo FPR fitted anyway),fitted new engine temp sensor (ie the DME feed),no difference,checked signal from coil -OK-I understand the idle stabilisation valve is independant of the DME,as is the thermotime valve but this latter item seems to be the only sensor which is temperature sensitive apart from the engine temperature sensor.
Any ideas where to look as I can't find any detailed info about the Rev limiter function being relative to temperature & after all it's ok when cold.
Regards
Colin.

 

[Waylander]

Sounds like I need to do some research as I don’t know that much about 924’s

any other details that you might feel relevant, like when this started to happen and if there was any other work carried out at around the time the issue started

 

[vitesse]

Started several years ago although I can't pinpoint when I noticed it as generally I don't race up through the gears on the road.
It became more obvious at a Curborough sprint with R13 possibly 4 yrs ago when we started using the figure of 8 circuit using 2gear as I usually had to change up to 3rd gear as it cut out at the wrong place just before the crossover then had immediately had to change down again at that "unbalanced" point.
I was too busy then to realise ( or look at the rev counter) -I just thought it was the normal DME rev limiter but realised afterwards driving home it happened in all gears at 4500rpm.
In normal road /motorway use it doesn't matter much because of the torque & 5th gear allows comfortable cruising at my usual speed of 79mph??.
I can't think of anything I altered/done that could cause this apart from fitting a Dansk SS rear pipe & box & it's always run on Bosch supafour plugs.
It's always had very low co2/HC emissions every MOT,idles correctly & does 30-32mpg on long runs.
It came with a large cone filter to which I fitted a support bracket because it came with it just resting in the engine bay-it's had new Valeo plug leads & a circular throttle cam but no DME meddling .
Colin
Puzzled of Formby??

 

[Waylander]

So I guess the trick now is to try and determine what could control the revs

computer is one, the S is the same as a normal 944 So has the blue DME temp sensor, the ref sensors and does it have knock sensors?

need to discover if the engine is getting retarded massively on the ignition side

or if the fuel is getting cut off

not easy with no place to plug a computer in to

 

[vitesse]

I have a strobe timing light with inductive pick up & rev counter so could highlight the timing marks & see what happens around 4500rpm & beyond- both cold & then hot.
Fuel delivery is more tricky as presume need an oscilloscope to check injectors -will check tomorrow but am sure there is an analyser socket-my wife's 924S has one for a large round plug forward from the bulkhead on the battery side & mine has a small socket on a flexible lead near the rear of the fuel rail.

 

[Waylander]

Does the car have knock sensors?

the round plug is readable by durametric not sure about the square one,

when it hit the 4500 limit, is it a clean cut off or is it what I would describe as a messy one, with surging and miss firing

 

[vitesse]

I don't think the 924S 2500cc engine has a knock sensor(s)-just has the 2 reference sensors in the bell housing (both replaced 3/4 yrs ago)
The effect depends how you are driving -on a full throttle sprint the engine just stops revving fairly abruptly-on a gentle acceleration its starts to pop & bang as one approaches the 4500rpm sector just like fuel shortage -back off & it picks up until the same thing happens,so then change up & it carries to 4500 in that gear say third & then repeats.
Before the temp gauge reaches the middle sector ,it just carries on soaring upwards to 6-6500 rpm-i would normally change up just before then -even on track.
I haven't had the time yet today to look at it -or check your query about knock sensors technically-I know my Bosch fuel injection manual shows DME terminals for the built in rev limiter.

 

[944Turbo]

I think - its a long time ago - but when the coil was breaking down on my turbo it would only rev to a certain point and it was worse when hot - the workshop manuals had some figures in ohms for checking the coil. Easy check if you can find the correct section and have a multi-meter handy.
Tony

 

[russmw]

Does it rev over 4.5k stationary when warm or suffer the same problem? Many years ago a friend had a mk2 golf gti 16v with the same problem, simply stopped reving beyond a limit and after swapping coil, fuel pump & various sensors it turned out to be the spark plugs were breaking down. New set and all good again.

Thanks

 

[vitesse]

Checked the engine & yes it does have the large round OBD socket -never used in either of our cars-plus the small round 3pin socket near the fuel rail,again never used.
I must admit to not really questioning the efficacy of the Bosch Supafour plugs for several reasons:-a)they have not done much mileage
b)I've never had problems in 34yrs of using them in various cars c) I'd considered that they would be hardly likely to break down precisely at exactly the same revs in each gear.
Probably sensible to check them out-if they are ok,then I'll have a spare set for either car.

 

[vitesse]

Yes ,I have checked the coil & it gave all the right readings but having a spare perhaps worth swapping just to check-again I had considered it but couldn't see why a faulty coil would break down so precisely at the same revs in each gear.

I am getting increasingly willing to be proved wrong.

 

[944Turbo]

Yes ,I have checked the coil & it gave all the right readings but having a spare perhaps worth swapping just to check-again I had considered it but couldn't see why a faulty coil would break down so precisely at the same revs in each gear.

I am getting increasingly willing to be proved wrong.

Yes would be a little strange but maybe the point where more spark is needed - thinking about it though is it the point at which the AFM barn door is fully open? Could the end of the track be damaged? I am not sure why that would be worse when warm though.

Tony

 

[vitesse]

When I had a Rover Vitesse SD1 in the '80s ,I tweaked it as much as I could for road use ,fitted Janspeed exhaust system ,fast road cam,Jaguar air intake system,Petrol filter engine breather and adjusted the spring position in the AFM-it had the Rover version of Bosch Motronic so barn door type.
Having discovered that dodge,I did that to my wife's 924S -in both cases it was easy to remove the black plastic top to the Spring /tracks.
So in my investigations of this problem on my 924S,I had suspicions about the AFM tracks but haven't managed to remove the black cover yet whatever I've tried unless I damage it badly.Of course It was also my intention to weaken the spring setting to get a quicker throttle response to compliment the circular throttle cam .
Methinks it is probably a better idea to remove the AFM to do this -also less chance of taking a finger off with the necessary sharp Stanley blade??

 

[944Turbo]

I think the top can be eased up with a flat blade screwdriver, but again long time since I had a play! I increased spring tension on my turbos and a friends I worked on to remove a mid range rich spot, I think with time the spring had become weaker and the door was fully open earlier than it should have been. there is a good write up here http://www.clarks-garage.com/shop-manual/elect-22.htm
Tony

 

[John Sims]

...Methinks it is probably a better idea to remove the AFM to do this -also less chance of taking a finger off with the necessary sharp Stanley blade??

Another situation of working on Porsches where a trained mechanic mouse would be such a help.

 

[vitesse]

Ha-ha,John-Tony,I've always found they are glued on rather well & have needed the glue line cut through with a Stanley blade-subsequent replacement using silicone sealant which left protruding slightly makes for easier later removal.

Big shortage of trained mechanic mice up here -I blame it on the failed apprenticeship scheme & my use of bait in the garage-I dont want the little swines eating through my stored MGB GT at the end of the garage[]