I'm transplanting an '87 2.5 Turbo engine into an '86 300E on behalf of a friend. I have done a very similar swap into a 190E in the past, so the project isn't totally unfamiliar to me.

However, when I did the 190, I transplanted the whole wiring harness from a diesel car to a gasser. I don't have that luxury/curse with the 300E.

In this case, I want to get by with the bare minimum in order to get the car functional and driving under its own power. To that end, I'm trying to figure out the minimum number of electrical and vacuum connections that I can use in order to still result in a running car. Here's what I have come up with so far.

1. Starter motor electrical connections
2. Oil pressure and water temp sensors
3. Alternator wiring
4. Vacuum source to brake booster
5. AlDA vacuum source
6. "Flying Saucer" vacuum amplifier for transmission vacuum source
7. Vacuum shutoff to IP

Can anyone else list items which would be necessary for engine operation? (apart from fuel supply and return lines)?

Thanks,

SteveM.

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'93 190E/D 2.5 Turbodiesel 5-speed (daily driver)
'87 190D 2.5 Turbo rustbucket - parts car
'84 Dodge Rampage diesel - Land Speed Record Holder
'13 Ram 2500 Diesel
'05 Toyota 4Runner

You need vacuum to shut off the engine which can be accommodated with an electric solenoid or a Diesel key switch.

You need a glow relay which takes +12V when the key is in run, +12V when the key is in start (tap off the neutral start switch) and ground and sends +12V to the dash glow indicator. Later style afterglow relays have a connection to a coolant temp sensor either in the head or beside the thermostat.

The 602 engine has a vacuum pump for the brake booster, engine shutoff and ACC.

ALDA takes a pressure signal from the intake manifold with an overboost protection solenoid that requires +12V when the engine's running.

Flying saucer can be bypassed. Route the forward port of the VCV through a damper to the tranmission modulator. You might have to back off the modulator a notch or two to soften the shifts.

There's a computer for idle control but IIRC you can bump up base idle to where it'll stay running on its own.

You might have to bypass the Klima relay so the gasser ACC will engage the AC compressor.

Sixto
87 300D

Good points sixto.

I have the GP relay setup from the W201 car. I need to play around with it a bit to see if it can be wired directly to the fuse box, but the neutral safety switch is a good idea for a source of 12V.

I'm curious about bypassing the flying saucer. What kind of "damper" can be used for that purpose?

Idle control will be done mechanically, and the A/C won't be functional.

Also, I've always wondered what the electrical connection is on the front of the air filter box. What does this connection do?

__________________
'93 190E/D 2.5 Turbodiesel 5-speed (daily driver)
'87 190D 2.5 Turbo rustbucket - parts car
'84 Dodge Rampage diesel - Land Speed Record Holder
'13 Ram 2500 Diesel
'05 Toyota 4Runner

If the glow relay has 4 small pins, pin 1 gets +12V to start glowing. Pin 2 gets +12V while the starter is engaged but the relevant event, as I understand it, is pin 2 stops seeing +12V when the starter motor disengages. That's the signal to stop glowing. Pin 3 goes to the glow light in the dash and pin 4 is ground. If there's a fifth pin, it's an afterglow relay. To complicate things, there are replacement afterglow relays that have 4 pins. Good luck.

There should be 2 cylindrical green dampers in a BFS system. One between the VCV and BFS and one between the BFS and the transmission. Reuse one of them.

Not familiar with electrical connections in front of the air cleaner but I'll guess it's a MAF sensor for EGR and ARV which are emission control devices. You don't need them if you're not keeping the electronics.

Sixto
87 300D

I believe that all 602 turbos have afterglow if that helps you, including the '87 190D turbo.

__________________

Gone to the dark side

- Jeff

MAF? Methinks you mean AFM.

__________________

Gone to the dark side

- Jeff

All right!!!

There's some excellent information - especially about the pins on the GP relay. If I have to go from scratch - I'll know which wires to use.

Also, thanks sixto on the green "damper" information. I just have one more question that I hope you can help with - What's a BFS. I know that the VCV is the vacuum control valve on the side of the injection pump. Are you saying to draw vacuum for the transmission modulator from the front port on the top of the VCV? (I think there's a blue colored vacuum manifold with 2 ports)? Then route the vacuum through one of the green dampers, and on to the tranny modulator? If so, that will be simple and straightforward.

SteveM.

__________________
'93 190E/D 2.5 Turbodiesel 5-speed (daily driver)
'87 190D 2.5 Turbo rustbucket - parts car
'84 Dodge Rampage diesel - Land Speed Record Holder
'13 Ram 2500 Diesel
'05 Toyota 4Runner

BFS = blue flying saucer.

You're not changing much, just cutting the BFS out of the loop. The VCV aft port connects to the engine vacuum pump. The VCV forward port, the one with the slot, connects to the transmission modulator through a damper you should already have. Everything else should be capped.

MAF, AFM, whatever it is that measures airflow that's gonna sit in a box in the garage

Sixto
87 300D

+1 on the AFM

I've removed them with no ill effects. I wanted to be sure after 30 years the thing still works and wasn't getting sticky half open or closed. or the spring adding too much restriction trying to close it against the sucking of air into the engine.

With the intake to the ALDA, the engine runs like it wants freedom and Autobahn.

I'm liking the clean look more and more. I'm considering going to electric pump for power steering with a speed sensitive switch/relay on the pump to only activate it at 1) after a tap from the brake light switch and condition 2) less than 10 mph from a tap of one of the ABS sensors. May have to add a dedicated speed sensor in order to not throw the ABS into any issues. I wonder if the speed speed could be measured with a low enough impedance to still throw a triggering circuit and at the same time have enough juice for the speedometer? Any electrical guys know?

This may be a simpler way on the electric power steering: Buy a cheap off the shelf with a relay harness with a 10 second ON activation timer built in. Have it trigger on when one of the micro switches in the clock spring are triggered which cut off the blinkers by some angle on the wheel. Then if you were doing any steering or paralell parking you would have power steering pressure on, but never on with cruising or highway driving. That should be pretty easy to tap into that signal in several places in the easier to access wiring under the foot kick panel.

I would also like to use electric vacuum pump with hysteresis, then use a Vacuum pump gasket as a template to cut some sheet metal for a Vacuum pump blocking plate.

I also think that the belt tensioner could be eleminated. It would make installing and removing the belt more of a hassle, but the belt could route in a simple circle crankshaft, A/C comp, water pump, alternator, back to crank. If you have proper working electric fans and don't sit stuck in traffic every day then you really never need the mechanical fan and clutch either. I've been running fine with just the temperature sensitive and a/c sensitive electric fans on my 87, 89, and 99 for years now thru summers in the deep south.

This would eliminate the parasitic drain of the vacuum pump, reduce stress/vibration/thumping/wear metal on the timing chain, timing advance device, and injector pump.


Summary of parts eliminated: EGR valve, EGR pipe, EGR micro switches, EGR module, EGR switch-over valves, EGR vacuum lines, AFM and/or MAF (diode/resistor mod on the 98/00), solenoids, cut off switches, vacuum amplifier, intake choke, intake choke vacuum lines, intake choke actuation rod, intake choke vacuum solenoid, vacuum pump (blocking plate and gasket installed), power steering pump/pulley (electric used), mechanical fan, mechanical fan clutch, belt tensioner, belt tensioner shock, belt tentioner spring, belt tensioner pulley.

Mods: electric vacuum with hysteresis, electric power steering with brake light switch and low speed relay activation, shorter serpentine belt.

Parasitic engine load reduction: mechanical vacuum pumping action for vacuum, mechanical losses in reciprocating mass and friction on IP timing device cam, belt tensioner, power steering pump

Benefits: Clean front of engine, clean rear of engine, clean sides of engine, easier vacuum diagnostics, no grenading vacuum pump bearings, less engine wear, extremely quiet micro fuel sipping idle, fewer vacuum leak sources, $50 Dorman vacuum pump from any local autoparts store.

Parts list: DORMAN 904214 (904-214), self made sheet metal blocking plate from vacuum pump gasket template, 1992 Toyota MR2 electric power steering pump, misc wiring, fuses, relays, hose fittings, shorter serpentine belt


Summary: more reliable, more MPG, cheaper in the long run, much cleaner engine bay, saves the environment from clean/green diesel with fewer CO/CO2/hydrocarbon emissions.

This thread is seriously lacking pictures

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Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

Check if that Dorman Electric VP is Continuous Duty Rated or not !
FOMOCO and Fiat's Gringo big brother are using that VP for HVAC , Etc
AND NOT BRAKING!

Alternator upgrade!

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'84 300SD sold
124.128

You need the tensioner idler for sufficient belt contact with the crank pulley. If you go from alternator to crank to AC compressor, you'd be left with less than 15* of belt contact on the crank pulley. Maybe if you run an electric water pump and move the alternator to the water pump's position...

I'd rather run a vane type mechanical pump from a late 97-99 606.





Sixto
87 300D