MFI no fuel to injectors

[dporsche74]

HI ,
I have a 1970 MFI ,
new fuel pump installs with lines,
I have fpressure to the fuel filter and to the MFI injector pump inlet port
but there is no gas getting to the injectors, lines are dry still
Any advise before i take it apart,

thanks!!

[RSTarga]

do you have the proper pump?

[dporsche74]

yup i do
stock bosch MFI fuel pump
everythingis brand new to the injection block inlet port
tank , lines, filter. clamps,

What would stop the flow ,
gunked up pistons in there,

[rsscotty]

You might start by making sure all fuel lines are done as per the diagram below. If you had the hard lines off from the mfi pump to the injectors , it takes a lot of engine cranking to get the air out and the engine to start. Is the cold start valve operational?
How long since the engine has run? Is the fuel pump and MFI pump new?

Hope this helps.

[dporsche74]

Still no start...

After cranking awhile i can get one VERY LOUD backfire with tons of smoke then nothing for another 20 sec of cranking then BANG Agian

This car has been sitting for yrs and yrs , E10 ate all the gas lines


All fuel lines are correct size and direction
fuel tank drained and cleaned new screen
MFI fuel pump is stock and flowing to the injector pump (alot of flow)
Control rod is moving freely
Fuel is getting to top of the injectors when cranking (few drips at a time)
Cleaned all injectors
Fe mark is lined up with the Pump marking
Ign rotor is lined up with Z1 mark,
New coil rotor, points , plugs ( getting large spark on all wire ends)
Compession test show +110 PSI all cylinders

This should fire

, She is baffling me but it is fun ,

Any ideas would be great

Thanks!!

[pszemia]

Hi, i had the same sympthom when i removed all the fuel lines from pump to injector, it was solved with grady advice to force the pump to full rich, and crank and crank and then fuel was coming again from fuel hard lines.

here is the post: MFI replaced throttle body gasket, now no start!

Byee

Ariel

[r lane]

fuel pressure to pump, fuel volume on the return line in 60 sec, is the rack free? If these 3 get passing grades, then the inj pump is getting the fuel but not delivering it. I guess if the inj pump has been sitting for a long period, delivery galleries to the pump pistons could be blocked. Take the lines off of the top of the pump and spin it over. Fuel should squirt out of the delivery ports. If not, ATF might help. Bob

[Porboynz]

The back fire is probably the cold start injected fuel lighting up in the exhaust system. The engine should try to start on the cold start injection only while cranking but it will flood fairly quickly so after 10 to 15 seconds cranking using the hand throttle positioned as normal you will need more open throttle using the pedal . I would check the ignition and make sure its not 180 out if the distributor has been out since the engine last ran. Check for compression on cylinder 1 as the Z1 mark comes around when turning over with a 19mm spanner on the crank. If you loosen the #1 spark plug you can hear the compression stroke. If thats all good the engine should run after a fashion with an aerosol of engine start aimed down the throttle bodies like a top fuel dragster, make sure you do not loose your eyebrows and have an extinguisher handy just in case. My 2.4 was layed up for 10 years and started fine, without that nasty ethonol stuff though.

[john walker's workshop]

could the ignition timing be 180 off? (the backfiring). is the pump timing at FE after #4? did you visually check for injector spray? are the plugs fouled black?

[dporsche74]

Thanks Guys,

so far....

made sure Z1 is number 1 cylinder, and dizzy lined up with the marking ,
(looks like it never has been moved)


the MFI control rack is moving freely back a forth,
and a hot wire engages the shut valve to the rear of the pump,

cold start is disconnected and mfi air cover is off,

compression is 110 on all cylinders,

Fuel out of bottom of filter is filling a 16oz bottle in @ 5 seconds,
( still need to test fuel presure tool coming)


Plugs are brand new and getting large sprak ,

only seen fuel drip fron the top of the injector line when cranked,
not the injector itself, at full pressure



Have not adjusted dwell., just the points,
but would dwell keep from TDC Z1 for starting??

Think next step is to prime the MFI pump by taking out the spark plugs to lower compression , unscrewing the tops of the injectors and
crank it fast for a few minutes to get the air out,
and then hook up the injectors,

the single backfire is so loud . it is like a 50mm cannon,
I thought blood was dripping from ears when it goes off ONLY after i turn the key to the off posotion, wierd...

[Porboynz]

From the top:

made sure Z1 is number 1 cylinder, and dizzy lined up with the marking ,
(looks like it never has been moved) :So you are sure #1 is on its compression stroke (only happens every 2nd revolution of the crank), and the rotor in the disty is aimed at the #1 plug wire. Follow the the HT lead to make sure it is the one going to #1)

the MFI control rack is moving freely back a forth,
and a hot wire engages the shut valve to the rear of the pump: Hot wire? If you have a permanent 12V to the rack shutoff then that will shut the fuel off as its designed to do on the over run to prevent backfiring right? Normal run mode is open circuit to this solenoid, 12V applied only when the engine is on over run above about 1500rpm and the throttle is closed making the microswitch. Maybe you should disconnect the wire to be sure

cold start is disconnected and mfi air cover is off: The engine will start eventually without the cold start, but reconnect it if you can.

compression is 110 on all cylinders, : Compression, spark, fuel. Now to get them happening at the right time.

Fuel out of bottom of filter is filling a 16oz bottle in @ 5 seconds,
( still need to test fuel presure tool coming): You checked for fuel returning from the MFI pump as well yes?
Plugs are brand new and getting large sprak , : Spark is good

only seen fuel drip fron the top of the injector line when cranked,
not the injector itself, at full pressure

Have not adjusted dwell., just the points,
but would dwell keep from TDC Z1 for starting?? In my experience a 15 thou gap at the points will enable most engines to run well enough to then use dwell meter for final adjustment.

Think next step is to prime the MFI pump by taking out the spark plugs to lower compression , unscrewing the tops of the injectors and
crank it fast for a few minutes to get the air out,
and then hook up the injectors, : Cranking without the plugs long enough to get good oil pressure is a good idea.

the single backfire is so loud . it is like a 50mm cannon,
I thought blood was dripping from ears when it goes off ONLY after i turn the key to the off posotion, wierd...: Maybe not so wierd, when you turn off the key you could cause a final spark (same as opening the points) and if the exhaust is full of fuel then kapow. I agree this is strange though

[john walker's workshop]

you mentioned a hot wire to the solenoid. if it's hot when cranking, the pump is basically shut off. it only gets hot on decel, until rpms get below about 1300, then it's released so the engine can idle. the micro-switch and a speed relay handle that.

[911skooter]

just overhauled my 70 E, I ran the elec fuel pump to prime the system with the key on..verified fuel to the MFI pump.. took out spark plugs to spin faster as engine new and tight. loosened inj lines at injectors..spun engine till fuel appearing at injectors (I had the ignition upluged so no spark)then tightened them up and put a cap of fuel down each velocity stack. reconnected ignition harness and it fired and ran on the 3rd revolution..ya hafta prime it and take the throttle off of the idle position as mentioned to turn the MFI fuel on..oh put the air cleaner top on before cranking so it doesnt backfire into the engine compartment and your face. injectors will need a push to get all the air out. apart from any unkown issues this should get fuel..they backfire when lean too..