Another IP repair question

[ewenke]

First, a big thank you to all the knowledgable people who answer questions for the naive people like me.  I routinely use the search function for help and usully find it.

  Joe's answer to the fuel pump installation issue leaves unanswered for me, the amount of time required to get fuel from a rebuilt pump to the fuel injectors.

My repair manual has a different method to prime the lines.  I disconnected the IP linkage lever.  Energised the choke selonid on the intake manifold.  Started the car and manually opened the FI pump to full throttle.  I ran the car like this for about 2 to 3 minutes and did not have fuel to the injectors.

My question is,  how long should I have to run the car before I get fuel to the injectors?

Thanks for the help, Everett
 

[glennard]

In first one second the engine turns 5 or 6 revs on Start.  This means each cylinder has fired 2 1/2 or 3 times-- 6 revs take about 1/5 of a second.  The check valve in each injector should have residual pressure.  Each rev injects 3 shots of gas-153624 orderwise.  Well tuned engine catches by the 3rd rev.

[ja17]

Hello Everett,

You may be surprised how long it may take, especially if your chasing air bubles around in the lines. You will need to be sure that fuel is being delivered to the IP first of all.  If you crack the lines at the injectors you will know when the fuel reaches the injectors. After tightening the lines you will still have to crank the engine a bit.  That is why I like to remove the spark plugs, it allows the engine to spin much faster and save wear and tear on the starter.

Your repair manual method will work also, howver you may foul some spark plugs by the time you get it up and running.

If you had the fittings off the top of the injection pump, make sure they have been torqued to 18 ft. lb. during re-assembly or you will never get fuel out of the injectors.

[Fano]

Hi everett,

i've recently had to prime my IP after doing some work on the plungers. It take a surprisingly long time to prime the pump. At some stage my 652 battery even went flat. If you are certain that there is fuel flow from the fuel pump (Under the gas tank) through the gas filter and into the IP inlet pipe, then what I can suggest is that you use 24v instead of 12, so that it cranks the engine faster, and this will also not drain your battery either. here's how:

Make sure you have a strong battery for tghe car. You'll also need a second, idling car available. Connect a set of jumper cables from the idling car to the battery on your SL. Start the cranking. You'll hear the fuel pump under the tanks make a higher pithed 'buzz' than it normally does; and the starter motor will crank must faster too. Keep at it till you see fuel emergiing from fittings.

If there's anyone out there who disputes this method for safety reasons, please advise; but it's worked quite nicely for me.

Let us know how you fare.

Fano

[ewenke]

Thanks for the help, but I must admit the problem was novice stupidity on my part.  I didn't have the geared sleeve that hooks the fuel pump to the engine installed.   Believe me, nothing happensd when that is missing.

Everett

[jacovdw]

quote:Originally posted by Fano


...then what I can suggest is that you use 24v instead of 12, so that it cranks the engine faster, and this will also not drain your battery either. here's how:

Make sure you have a strong battery for the car. You'll also need a second, idling car available. Connect a set of jumper cables from the idling car to the battery on your SL. Start the cranking. You'll hear the fuel pump under the tanks make a higher pithed 'buzz' than it normally does; and the starter motor will crank must faster too...

Not to be a stick in the mud, but I beg to differ with this one.

If you connect 2 batteries in parallel, for example when you jumpstart another car, you don't get 24V, but only 12V.

With parallel connected batteries, the total current supplied is more than what one battery can supply (voltage remains the same).

With 2 series connected automotive batteries, the voltage would be 24V and the total current would be equal to what one battery can supply.

[glennard]

Sorry, Forgot to add- 'Install coupling sleeve'.  While at it- Did you sync the IP to the crank?