rorf
Active Member
Keep it up, holding thumbs for you
SL280 to SL55 conversion
- Thread starter fast28
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- conversion sl280 sl55
I took the plunge and bought a Chinese Star diagnostics C3 system. After configuring it and getting it to run on a used Dell laptop I plugged into the cars diagnostic port and read the coding for the existing engine ECU. Plugged in the "as new" SL500 ECU (both Bosch Motronic ME2.0 ECUs) and Star recocognised a different ECU module asked me if I wanted to proceed with transferring the identification number (VIN) - yes and then stated start car. Started the ignition (noted "start error" message had now gone) and the engine fired into life!
no missing cylinders and no leaks! I left the engine to run up to temperature and topped up the coolant and noticed the electric fans come on, all good.
Today I filled the transmission with new fluid and checked and filled the level at 80 degrees. Went for a short test drive to monitor any noises and everything so far looks to be in order, went to the local village train station carpark which was virtually empty and did a few laps with varying throttle levels and WOW! great acceleration and great V8 noise! There's a bit of resonance coming into the cabin just over 1200 rpm and I've an exhaust leak where the welded brackets have partially come off the pipes. I've yet to get the car past 40mph to test all gears are engaging and the transmission isn't going into limp mode but looking good so far.
Today I filled the transmission with new fluid and checked and filled the level at 80 degrees. Went for a short test drive to monitor any noises and everything so far looks to be in order, went to the local village train station carpark which was virtually empty and did a few laps with varying throttle levels and WOW! great acceleration and great V8 noise! There's a bit of resonance coming into the cabin just over 1200 rpm and I've an exhaust leak where the welded brackets have partially come off the pipes. I've yet to get the car past 40mph to test all gears are engaging and the transmission isn't going into limp mode but looking good so far.
John Jones Jr
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Fab thread, great to hear it's all coming together.
rorf
Active Member
Wow progress is good, well done.
Took the car out for a longer test drive yesterday evening, enjoying the torque very much! but 2.5 miles into the test drive and disaster struck, the car lost total electrical power. Driving about 50mph on a straight secion of road I managed to coast into a layby. I had no electrical power at all, the gauge cluster needles all stopped in their last positions and not even any voltage to power an interior bulb, nothing, completely dead. Called out the RAC who arrived fairly promptly and discussed the situation. Measuring the voltage at the battery as close to nothing and warm to the touch we concluded that there must have been a substancial short-circuit. No fuses were blown. I can only presume at the moment that part of the alternator/starter to battery cable has shorted to the car chassis, either caused by friction or heat exposing the live cable. Tonight I hope to get crawl under the car and take a look at the loom under the engine.
If anything good came out of this test drive it was that the car was shifting through all gears, meaning that the rear diff is working with the E430 EGS controller (1:2.82 ratio rear diff), no limp mode being engaged. Unfortunately with the loss of all electrical power I've lost all the adaptions and will have to start again.
One thing that is killing the enjoyment of this car is the extremely loose steering play that I'm trying to fathom out. So far the car has new control arm bushes, shocks, springs, steering arms (all three), ARB bushes and steering damper.
but 2.5 miles into the test drive and disaster struck, the car lost total electrical power. Driving about 50mph on a straight secion of road I managed to coast into a layby. I had no electrical power at all, the gauge cluster needles all stopped in their last positions and not even any voltage to power an interior bulb, nothing, completely dead. Called out the RAC who arrived fairly promptly and discussed the situation. Measuring the voltage at the battery as close to nothing and warm to the touch we concluded that there must have been a substancial short-circuit. No fuses were blown. I can only presume at the moment that part of the alternator/starter to battery cable has shorted to the car chassis, either caused by friction or heat exposing the live cable. Tonight I hope to get crawl under the car and take a look at the loom under the engine.If anything good came out of this test drive it was that the car was shifting through all gears, meaning that the rear diff is working with the E430 EGS controller (1:2.82 ratio rear diff), no limp mode being engaged. Unfortunately with the loss of all electrical power I've lost all the adaptions and will have to start again.
One thing that is killing the enjoyment of this car is the extremely loose steering play that I'm trying to fathom out. So far the car has new control arm bushes, shocks, springs, steering arms (all three), ARB bushes and steering damper.
Doodle
MB Enthusiast
Perhaps in need of a steering box refurb.
IanA2
MB Enthusiast
Afaiaa MB steering boxes rarely go phut.
V12
MB Enthusiast
No, they just wear more and more until you feel like you're captain of the titanic...
Doodle
MB Enthusiast
John Jones Jr
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Is there not an adjustment screw on your cars St.box? If so, from what I recall it's turned anti clockwise to remove play. The steering idler bush is worth looking at anyway and the damper too. Consider a wheel alignment also, especially since you've got a different lump up front.
Doodle
MB Enthusiast
IIRC the 129 doesn't have adjustment.
If it's proper slop as described, alignment won't make any difference.
The 129 is no different...Olly had mine refurbished by his contact for a much more reasonable fee. I expect it'll be much easier to remove on a G!
If it's proper slop as described, alignment won't make any difference.
The 129 is no different...Olly had mine refurbished by his contact for a much more reasonable fee. I expect it'll be much easier to remove on a G!
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John Jones Jr
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No adjustment, bummer! That's the end of that so. Yep, if there's slop an alignment won't make sod all difference but I reckon the OP should get an alignment done once the slop is cured.
Doodle
MB Enthusiast
Ironically it would have been easier to do while the engine was still out. With a V8 up front it's a bit of a pig to remove.
Congrats on getting it done! Never thought it would get done... so many unfinished projects on this forum..
Total electrical loss? Hmm got to be something silly like you say..
Total electrical loss? Hmm got to be something silly like you say..
Electrical short turned out to be the power supply on the starter motor solenoid 
, the connector was touching the the engine block and over a short time had rubbed through the heat shrink insulation and shorted out. All repaired and repositioned and electrics back! needed to recharge the battery so no engine start yet.
Steering seems to have no play in any of the joints but definitely hell of a loose feeling while driving. I've seen seal repair kits for the R129 but unless there is someway to get the gears to interact more closely like on the earlier boxes with the adjustment screw then the only hope is a new or reconditioned box.
, the connector was touching the the engine block and over a short time had rubbed through the heat shrink insulation and shorted out. All repaired and repositioned and electrics back! needed to recharge the battery so no engine start yet.Steering seems to have no play in any of the joints but definitely hell of a loose feeling while driving. I've seen seal repair kits for the R129 but unless there is someway to get the gears to interact more closely like on the earlier boxes with the adjustment screw then the only hope is a new or reconditioned box.
Doodle
MB Enthusiast
Vague and sloppy around centre, or when starting to change direction on the wheel?
If it's really bad, you'll feel a slight bump at the point where you've taken up all the slack and the steering starts to stiffen under load.
If it's really bad, you'll feel a slight bump at the point where you've taken up all the slack and the steering starts to stiffen under load.
The sensation is like the car is being drawn left and right and when you try and compensate on the steering wheel it takes a fair degree of movement before any input is transferred to the wheels - quite unnerving!
I do see on a picture of a SL320 (96) that the Pitman arm has the adjustment bolt, I will have to check my car to see if they continued this feature.
I do see on a picture of a SL320 (96) that the Pitman arm has the adjustment bolt, I will have to check my car to see if they continued this feature.
