Random engine hesitations/shakes

[smiles11]

Hello everyone. I have a 1970 911E. Car runs great & I’ve already put thousands of miles on the car since buying it. However, I’ve noticed lately there are a few concerns that I’d like to troubleshoot with the gear heads here.

1. On cold start, at beginning of idle; the throttle lever no longer holds the rpm’s in place like normal. It takes the car about 15-20 seconds of manually using the gas pedal to hold rpm’s before the throttle lever will actually lock the rpm’s in without dropping.

2. Also during the beginning of a cold start idle, the car will hesitate several times in short bursts. Creating a subtle shaking effect. I’m wondering if it’s a bad fuel filter or if I need to clean the spark plugs. I’ve read that moisture build up can create hesitation & misfire? Also, at random times while accelerating in 2nd & 3rd gear, the car will start to show the same symptoms. Slight hesitations in the throttle.

Once the car is up to temp though, the symptoms disappear & all is right as rain. So other than the start up idle weakness & the odd hesitations. What do the pros think?

TIA

[RobFrost]

Not a pro but what carburation does it have?

First steps I'd suggest, in this order are;

a) check ht leads are on properly
b) clean points & set gap
c) a good run
d) check plug colours, clean plugs and set gaps. New plugs if necessary.
e) fresh fuel

From plug colour you are likely to get some insight into any carburation issues which may exist.



Sent from my SM-G988B using Tapatalk

[Hi_Fi_Guy]

You may want to pose this question on the early911s website forums where there is much knowledge and experience with these early cars.

I can’t speak for a fuel injected 911E but my own carbureted 1971 911T can be quite cold blooded. I typically let it warm up for 5-10 mins or until the oil temp gauge registers before driving in cooler weather.

[smiles11]

I normally let my car warm up as well. I checked the HT leads & connections all look good. I went on a good run today, seems to still have hesitations under acceleration in 2nd & 3rd gear. Drove 80 miles & after about 10 miles the hesitations got less & less noticeable. I’m afraid I am going to cause more harm than good if something is wrong. Any other suggestions?

[timmy2]

As asked before, carbs of MFI?

[smiles11]

Originally Posted by timmy2

As asked before, carbs of MFI?

Didn’t know there were 70E cars with carbs.

Mine is MFI

[smiles11]

Bump

[RSTarga]

Is your hot air hose to the MFI pump hooked up? Normally when you start using the hand throttle idle speed goes up as car warms up. Sounds like it your warmup regulator may not be working properly.

[proporsche]

is your hand throttle holding the linkage at all or did it slipped?
when was the last time you checked your distributor points-clean them also see after the distributor timing...
good point on the hose being in place to the fuel inj pump

Ivan