injectors?

[nuts4porsche]

if my injectors are not fireing,how do i fix this problem? relay or install new injectors? then what? rookie is lost guys! thanks

[MPDano]

I doubt all will go bad at the same time. Did you verify your relay? Do you have a Noid light? How did you verify they weren't firing?

[nuts4porsche]

this is my next step-just tryn to get 1 step ahead of the game. crappy weather here and thinking of the fastest and effective way to stay on top of it-thanks DANO! im killing batterys faster than i can check for more than one issue out!

[Phillyfunk]

I would check the relay 1st. All the injectors will not just go bad at once.. Just had this problem on my 83. cleaned all the contacts and installed a new relay.. fired right up.

[Landseer]

Jumper the relay. 3 way. Do you know how?

My experience is that if old, and cold, and a little wet, they'll fail on L jetronic.

[Danglerb]

Injectors are wired in parallel, so ONE short and they are all shorted.

[soltino]

Did you mean wired in series?

tino

[Danglerb]

Originally Posted by soltino

Did you mean wired in series?

tino

Nope, all of the grounds are tied together, and while two wires come out of the ignition box they are internally connected. All 8 in parallel, like the injectors were rungs on a ladder. A short on any of the wires to any of the injectors effects all of them.

Series connection would take a good amount more than 12 volts to open the injectors, more like 100 volts.

****** Injector failure modes.

Bad relay.
Fuse is blown or corroded.
Bad sensor input, green wire on early cars, crank position sensor on newer.
Bad wiring to the injectors, a short if none work, open if some.
Bad injector, dirty frozen, failed, and yes I have seen all 8 bad.

[lfausty]

blow fuse 22? - new relay sometimes wont work have to get yet another- fuel inj relay not fpump or and/or both

cepanel theres slot man slot auto relay xv? xv? make sure your relay in right slot on board?

u did the m28/14 16 engine swap,correct? not uncommon that fuse blows when reconnecting injectors to harness , and relay goes. and other fuses/ck all . blowermotor...
where you did engine swap recheck everything for good connection inj, grounds...
*make sure connecting relay prongs not bent,missed the boards connections spade or pushed it out the back of the panel. and/or anyother didnt get loose disconnected on the board while in there.
obv draining a big source for one and/or lot of smalls drains.

[bbsanchezi]

i agree it,all of the grounds are tied together, and while two wires come out of the ignition box they are internally connected.

[Landseer]

The two 12V feeds (each feeds 4 injectors) seem to be separately managed.
I think the diagrams are simplified.

Isn't that why the injector relay for LJetronic has two 87 leads?

[nuts4porsche]

thanks all! i will have alot of checking things when the weather breaks. i need to get it up and running-wife wants me to sell it!

[JK McDonald]

If the injector problem is on a 1980 model 928 wouldn't this be the older CIS mechanical style fuel system ? Perhaps Nuts4Porsche is having a fuel pump or warm up regulator related issue.

Michael

[nuts4porsche]

its a 1980 motor put in an 81' chassis. fuel pump is working fine. the wiring in the engine compartment hooked up fine. the 81' ran great untill it broke a cam bolt twice, nothing wrong with the car so i pulled the motor and put the 1980's in. turns over-wont start. put raw fuel in the intake-fires right up and runs great till fuel runs out. i jumpered the fuel pump because it wasnt pumping fuel-i have fuel to motor now and wont start. i do have the injectors from the 81's motor i will swap those out and see if that helps? any more thoughts would be great! thanks

[Danglerb]

A noid light is no more than $15, its generic to all bosch injectors which include most Fords, so its common and easy to find. Unplug an injector and hook up the noid instead, light flashes which injector would be getting power to open.

You can also listen to the injector click with a piece of rubber hose held to the injector and the other end at your ear.

No flash or click, check and/or replace the fuse and relay, then look at the green wire from the distributor.

*****
80 is Ljet in US, CIS in Euro til 83.
Two wires come out of the fuel injection brain, but they are connected together inside the brain.

[nuts4porsche]

hey all! i have new injectors but they are attached to the fuel rails-how do they come off? they are attached by the little rubber fuel lines and just spin,is there a secret to removing them from the hoses and fuel rail? thanks

[MPDano]

Mine had worm clamps on them from a hack job by the po. Most likely the stocks are held by a crimped on type that need to be cut off carefully. The same way you would cut of the clamp on doing the front fuel hoses located under the coolant reservoir area.