'94 SL500 - Gearbox? Ecu? Here we go again...

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Mine's a 320, no problem with the MAF wiring. When doing the TB/Upper/Lower harness I examined the rest of the engine bay harnesses, slitting open the outer cases, all good pliable insulation.

The only other dodgy harness I've heard about is the A/C fans.
 
I;ll keep my fingers crossed, then. The MAF wiring does seem quite flexible, and at least it would be very quick and easy to replace if necessary. Unlike the TB...
 
I suspect the rough running and stall is simply down to moisture in the dizzy caps if you haven't used the car over the winter.
 
On the subject of the MAF wiring, I don't know whether it was a problem on mine but I didn't want to take the chance so sent all the engine loom including the MAF wiring to SiLec.

I know it's a pain but if I would recommend that you send yours off. I doubt it would be too expensive as you have done the rest and it would cut down the chance of future problems
 
When you come to replacing the TB with a new gasket, I found it to be a right pain to keep the gasket in place and manoeuvre the TB onto it.

My 'top tip' to solve this was to zip tie the gasket to the TB using two of the 4 bolt holes (on the diagonal). Once in place, bolt up loosely using the other two holes which then centres the gasket. Then cut and remove the zip ties. Job jobbed.
 
I'll wait and see what it's like when the rewired throttle body is back on. I know that needs doing, and it should be with Sileck tomorrow.

I'm not keen on changing more than one thing at a time with a problem like this; if you change more than one thing, and the problem's still there, you don't know for sure which of the replacements is faulty.

That's a damn good tip on the gasket; thank you very much.
 
Rewired Throttle Body - No B****y Change

Fitted the rewired TB, but still the same.

Operating the TB manually before fitting it, it would move a fair way before the actual throttle butterfly moved, and the butterfly did not open more than about half-way. Is this some sort of limp mode, and can it be reset?

Fired up, the car still idles, with a fair few misfires, at around 1100-1200 rpm, and the throttle pedal has no effect for the first couple of inches of movement, though it then revs OK (in neutral and stationary). Once the coolant temp reaches just under 80 degrees, it cuts out and will not restart.

I've fitted new plugs, leads, and distributor caps and rotors. The engine harness and the TB have both been rewired. I've almost reached the point where I don't want to fix it, I just want to hurt the poxy thing. Badly.

Is it time to give up on the horrible heap? It's easily the least reliable car I've ever owned, and I wonder if I've now reached the point of throwing good money after bad.

Should I just throw it away and get something that actually works properly for more than two minutes? I'd like a decent R129, but preferably with the AMG bodykit; the ones without mostly look a bit blah to me. I don't want black or silver.

That said, though, there's a green one on Ebay (item no. 172298906020) that I rather like the look of, though I'd want a new MoT.

I don't want an R230, I don't want an Audi, I don't think I want a BMW (though a three-litre Z3 or Z4 - plenty about - might fit the bill). Would an SLK be a little small (I'm 6ft 1 in)? If not a Mercedes, what, then? A Saab 9-3? A Lexus SC430 (bit of a barge, though; again, plenty about)?
 
I'm not sure if your car has one or not but what about looking for the TPS (Throttle positioning sensor) it sound very much like this, usually located either on your throttle body, OR in the footwell of the car near the accelerator.. I've had this go twice on two different cars and its that, that gives you "Floppy Foot" symptom you describe and a max rev of 1500rpm..

Looks like this...

https://www.google.co.uk/search?q=1...MD8AKHWhbAOsQsAQIKA&biw=1536&bih=755&dpr=1.25
 
It sounds like the TB needed doing anyway so nothing lost.

Time for an indy with STAR.
 
The TB did indeed need doing, but it wasn't the cause of the problem, so nothing lost if I'm keeping the car. I'm about 60/40 in favour of getting rid of it at the moment, though...
 
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Have you check the gear box fluid level. When were the fluid and gearbox filter changed last?
 
Have you check the gear box fluid level. When were the fluid and gearbox filter changed last?

On that age of 129 the gearbox is hydraulic, so I'm not sure fluid level would produce the symptoms described.

Having been in one when the trans cooler pipe let go and eventually drive was lost due to fluid loss, it never caused the engine to go into limp mode.
 
If its a purely hydraulic box then lack of fluid would possibly explain a high idle =no T/C drag - lack of drive- failure to select 4th. Since it's such a simple thing to check thought I'd mention it? If there are electrical gremlins then already mentioned throttle pedal position sender sounds a good candidate but I am puzzled by the lack of warning lights??
 
On very low fluid the idle goes up very slightly but nowhere near the level stated. By this point the revs are flaring horrifically on drive, like trying to pull away with a totally knackered clutch. Even at that point 4th gear would still engage though.

This needs a STAR session to see what codes are held, no point engaging in further guesswork.
 
I'm not advocating guesswork just using the gearbox dipstick. ;)
 
Thank you, gentlemen. The gearbox fluid level is fine. Even if it were not, it would not cause the cutting-out, though.

Now here's a funny thing - or maybe not. If I disconnect the TB entirely, the engine starts and runs at the 1100 rpm idle OK - until it gets to about 70-75 degrees, when it cuts out.

Opening the throttle with the TB disconnected produces nothing until the mechanical opening takes place, then it hunts massively. Re-connnect the throttle body, and it revs OK on the throttle (apart from the floppy pedal) until it cuts out.

It looks as though the engine is running OK-ish, albeit with a high idle, until the cold start enrichment cuts out. Rewired or not, I'm beginning to think that the problem lies in the TB. Oh joy...

A few specific questions, if anybody can answer them.

Firstly, is it normal for a TB, off the car with no electrical connection, not to start mechanical opening until the arm has moved by twenty or thirty degrees?

Secondly, do I have a TPS, and if so, where is it located; it's not part of the TB, is it? If I do, and it's not part of the TB, how do I reset it? That's something I should be able to do myself.

It still looks as though if I decide to try to keep the car the only option will be a low loader; it's not driveable - well, not far - and the MoT has run out anyway.

:wallbash::wallbash::wallbash:
 
I tried the divining rods, but all I found was two oily hands...

Drew, to go back to your first post in this thread (seems a lifetime ago...), the ASR light is not coming on at all, even when I first switch on the ignition, nor at any other time. If it were the ASR, though, could it cause the stalling as well?
 
It's possible, in so far as the ETA is linked to the ASR system. I'm wondering if the insides of the ETA are failing/have failed, even though the wiring has been replaced.
 
ETA = TB, I take it?
 

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