[jonbill]

I've moved this thread to user projects.

[tristessa]

I've moved this thread to user projects.

Thank you. I could have just started a new thread, but this keeps everything in one place and gets the extraneous crap I've posted out of the Getting Started forum.

[apollard]

Disable fuel pump and check timing while cranking. No need to have it idling to make sure of trigger angle and timing

[tristessa]

Disable fuel pump and check timing while cranking. No need to have it idling to make sure of trigger angle and timing

Even with a dumb distributor controlling the timing with centrifugal & vacuum advance mechanisms? The only thing Speedy is doing right now is telling the ignition when to fire, the ignition tables and advance are all zeroed out.

Got it starting OK and idling in Park/Neutral decently; this engine has always liked to idle around 1000-1200RPM in P/N so that was my target for now. IAC needs more fine-tuning for warmup but I'll have to wait until the engine cools down again. The biggest problem at this point is that when I put it in gear, the idle drops way down to like 5-600RPM and the engine struggles to stay running, usually stalling out unless I stick it back in P and feather the pedal......and sometime even with that.

Realtime display also is showing some screwiness with the AFR. If I rev it a bit it gets rich in the 10-11:1 range, then when I let it drop back to idle it goes to 13.5-14.5:1 for a second or so, then creeps up towards 19-20:1 and sits around there.

Just infodumping while it's fresh in mind. Didn't remember to log anything because I'm a dumdum.

[apollard]

Yes, even with a distributor. You need to know base timing is correct, no different than any other time you remove a distributor.

However, seriously consider locking the mechanical advance and remove vacuum advance to use speedy. Electronic advance can really help these old engines. They benefit greatly from not being constrained by the old advance systems.

[tristessa]

Specs for this engine with distributor 0 231 170 137, per Mercedes:

Installation value of ignition distributor at starting speed without vacuum: 10° before TDC
Adjusting value of firing point with vacuum at idle: 10° before TDC
Test values ignition timing without vacuum, 1500RPM: 15-20°, 3000RPM 27-32°
Vacuum adjustment in direction of "advance" 4500RPM: 6-10°
Dwell angle at idle: 47-53°, change between idle and 3000/min: max ±3

Conventional tools: revolution counter, dwell angle measuring instrument, stroboscope

I don't see how I can set anything more than the installation value without the engine running, fuel pump connected or not. Setting the distributor to 0° at TDC, while not correct, is the best I can do with the factory mark on the harmonic balancer, and will let me get the engine started and idling well enough to put the tach/dwell meter and advance timing gun on it and properly set the timing to spec.

I'm not willing to hack up the only distributor I have for this car, but letting Speedy handle the advance timing is in the Maybe Down The Line plans. Either I'll find another Mercedes distributor to play with, or make an extended drive dog for one of the half-dozen VW distributors I have laying around, probably the late Vanagon unit since it's Hall-effect and has no advance mechanism because Digifant controlled the timing.

[PSIG]

If your distributor was adjusted properly before, then it still is. Speeduino does not change that. As your distributor is controlling timing, it should read

Installation value of ignition distributor at starting speed without vacuum: 10° before TDC

when cranking. So, kill your fuel pump (pull the relay or wire) and crank the engine to check timing at 10°. Reconnect fuel, start, and go from there. You cannot correctly check the other distributor spec's with such a high idle and poor vacuum (MAP). Your idle should be much lower when idle is tuned well. Search for how to tune warm idle and other steps after. Once idling well at normal rpm and timing, then do the other distributor timing checks.

[apollard]

Yes, setting the installation setting is what we are all saying. If I recall you removed the distributor so this must be verified. It is not possible to eyeball it to exactly 10* on installation. It must be verified. Do what David says above.

Even with timing set to zero everywhere in speedy, verify. Trigger angle could need adjustment. Just make sure it’s right or you don’t have a good foundation to build on.

[tristessa]

Got it, will do so when I have time to get back onto this. I'm at work the next couple days, then Wednesday I'm retrieving one of my other vehicles from the shop whether they're finished with it or not. It's been there over a month with no real progress and a complete lack of communication unless I show up at their door.

So maybe Wednesday afternoon but more likely Thursday.

[tristessa]

MAP sensor was connected to the wrong port on the TB, which could explain the poor vacuum signal. I read the donor vehicle's vacuum diagram backwards, and had the sensor connected to the port that's supposed to go to the charcoal canister. Shoulda known something was funky when I had to step the hose down that much, but even the correct nipple is larger than the MAP sensor and needed an in-line reducer on the hose.

Turns out I'd never noticed timing marks before because they were obscured by gunk...guess I didn't clean as well as I thought I did after fixing the leaky valve cover gasket 10 years ago. I'd seen the TDC mark and never needed to look any farther during tuneups because my timing gun has an advance knob. Got the balancer spotless and lo and behold, there's markings for ATDC 20° and 10° along with BTDC 10° 20° 30° & 40°.

I had a little time this afternoon and eked out a few starting attempts while logging, after fixing the hose connection and timing the engine to a confirmed 10° BTDC.