hesitation on acceleration

[john123]

Hello all. My 1966 230sl is at the end of a six year long total restoration. Rebuilt engine, new fuel tank, rebuilt fuel pump, rebuilt fuel injection pump, new injectors, new cold start relay, ,new spark plugs,  Pertronix ignition and coil, and just about everything else.
The problem that my mechanic is experiencing now is that the car starts immediately cold or hot, but when attempting to accelerate it hesitates severely and will stall.
Given the above, what do you think are the most likely reasons for this behavior?

[lpeterssen]

One can be a Distributor that is not doing its thing.

At IDDLE timing should be something like 6 degrees BTC.

At 3000 RPM timing should be 30 degrees BTC.

Fuel delivery problems are also a cause for failure like the one described, but as you mention all those new components, it’s less probably that comes from there the failure.

It is better on this old cars to have a NEW DISTRIBUTOR from 123ignition.com.  Worn components on old distributor even having installed a Pertronics electronic ignition conversion may cause problems.


Nevertheless the best person to ask things like this is Joe Alexander on the forum.

Best regards
L.Peterssen

[dirkbalter]

I would go for fuel delivery first and check that sufficient flow and pressure is present. Make sure the pump is connected correct and +/- is not switched.

[lpeterssen]

Also was thinking last night over the pillow on this matter….  Have you completed the LINKAGE TOUR. that is described on this forum? Maybe a wrong proportion of fuel to air may be causing this hesitation  to accelerate.

[Pinder]

sounds like it goes lean or rich during accel. check the linkages as suggested by Peterssen.

[rwmastel]

Yeah, I third the motion, if that's a thing.  With so many new (changed) components, you really need to set something as a good known baseline.  Linkage is probably the best place to start, then troubleshoot logically from there.

[roymil]

Given you said it had a long restoration, it wouldn't be a shock to find the air filter clogged up with dust, paint, and who knows what.   That might still allow a smooth idle but not allow enough air at higher revs.  We have no mass air flow sensors with computers constantly adjusting mixture, so the whole system really counts on consistent air.

[Benz Dr.]

Set ignition timing to about 8 - 9 degrees BTDC on early style ignition systems. Later USA style systems with aluminum distributors should be somewhere around 3 degrees BTDC to 1 or 2 degrees ATDC running at idle. Total advance should be around 36 - 40 degrees BTDC, at, or slightly before,  3,000 RPM. Max advance of 38 degrees BTDC is where you make power.