E21 will turn over but not run

[epmedia]

Some of today's observations,

1. I tried cranking the motor this morning just to see if it magically fixed it self. It did not. I turned it over 6 to 10 times and gave up, what is interesting is i forgot to reconnect the hose to the nipple side of the accumulator when i installed it yesterday. Should i have seen some gas under the car from when i cranked it earlier??????? Does this give any clues to a bad pump?

2. I also removed the fuel distributor and metering housing, I turned the key on for the pump to prime some gas while i watched the main inlet fuel line. I heard the pump hum but saw little gas come out. What should i have seen?

3. I also inspected the dipstick and mine does not have a place for a vacuum line, it looks like someone bypassed it?


I am cleaning all the parts this weekend and will reassemble. Just wondering if these are symptoms of bad fuels pumps.

The small hose on the accumulator connects between the in-tank pump (if equipped) and the suction side of the external pump. If you had a full tank of gas it would definitely siphon out the detached small accumulator hose. Hard to say if the in-tank pump could pump gas out the hose while the external pump is running. The engine definitely will not run with that hose disconnected because the fuel supply system would be full of air (air is also what happens if these hoses have never been replaced).

With a proper fuel system (including good hoses/connections!), lots of fuel at very high pressure will spray out!

The bottom of the dipstick tube on most 2.0L engines uses a 'coupling' (big rubber hose) to connect the tube to the engine block. Double check to see if yours has one.

Just fyi: a good external fuel pump is capable of 'holding it's own' during typical driving conditions without assistance from the in-tank pump. However, not recommended to run with a bad in-tank pump for long term, because the external pump would have to work harder. Originally, the pre-80 e21 did not have in-tank pump, there was a recall to have the in-tank pump installed, both my '78s never had the in-tank pump installed.

Be safe with the fuel!

[epmedia]

Doesn't the accumulator have a check valve? I remember on my 82 it went bad, and had starting trouble, specially when hot

The check valve is on the outlet of the external fuel pump. Fuel flows from check valve to the accumulator, then to the fuel distributor. When the accumulator goes bad, fuel will leak out the small hose and into the suction side of the external fuel pump, thus loosing fuel 'rest' pressure and sometimes (a really bad leak) a decrease of fuel 'system' pressure.

[mossyoaks]

If the engine is getting flooded with fuel, then the fuel mix needs to be leaned (assuming all is good with the fuel distributor and air-flow/volume meter).

* use a long 3mm allen tool to adjust the idle fuel mix screw. The screw is very sensitive, even just the weight of the tool will change the fuel mix! Small 1/16 turn increments and keep track of the adjustments! CCW= less fuel. CW= more fuel.

My 78 will not start <now> after I adjusted the idle fuel mix screw. Can't retrace my steps and get it back to the original point.

Is there a 'starting point' once the mix screw is completely turned CCW? (like 1.5 turns CW on a standard carburetor).

When adjusting the 3mm screw from the beginning setting at 1/16th or 1/8th turns CW, I'm not getting to the sweet spot -where it will fire off- And I know how easily the plugs become saturated when running rich.

[epmedia]

My 78 will not start <now> after I adjusted the idle fuel mix screw. Can't retrace my steps and get it back to the original point.

Is there a 'starting point' once the mix screw is completely turned CCW? (like 1.5 turns CW on a standard carburetor).

When adjusting the 3mm screw from the beginning setting at 1/16th or 1/8th turns CW, I'm not getting to the sweet spot -where it will fire off- And I know how easily the plugs become saturated when running rich.

What prompted you adjust the idle fuel mix screw?

The mix screw will fall out if it's turned too far in either direction (many many turns). There really is no starting point, except for attempting to set the 'base setting' (diy/faq thread) - have to be careful not to flood the engine with fuel.

Yes, it's very easy to flood the engine with fuel when 'tinkering' with the fuel mix.

[mossyoaks]

This car had not been operated/run in years.

I had to replace the fuel tanks and all associated pumps/filter/lines.
The oil was diluted w/fuel from previous attempted starts.

After an oil change and new plugs finally got it to run.

I wanted to fine tune it so decided to adjust the fuel mix screw.
Once I did, couldn't get it to start again and so put it on the back burner.

Just getting back to it now and thought I'd find a starting point to set the screw.
I'll just work my way up from lean to rich I guess.