Trouble shooting injectors Options

[Dave_Darling]

Do you have a "noid light"? Or some other light that can react to very short power pulses? If so, plug that into an injector plug to see if the electrical signal is getting there when the starter cranks.

The MPS is the hand-grenade thing with one hose and a four-wire plug going to it that sits below the battery. The trigger points are in the base of the distributor, with the three-wire plug down in front of it.

Again, check all of the wires, plugs, and hoses. Make sure nothing has come loose.

--DD

[Chris914n6]

Next step is to trigger the injectors manually under pressure, jumper wires to the battery. I like to use gator clips on the injectors and tap, just tap, the battery post repeatedly.

A volt meter will pick up on the pulses from the ecu, but just barely as they don't react fast enough. A test light would work better, specially if it's LED. I'll need to read up on trigger testing, it's old tech in my world.

Fresh gas is the best cleaner of old gas. They will clean themselves with use, but not like new clean like the ultrasonic cleaning does.
Considering one of the members blew a hole in his piston on a freshly rebuilt motor from the injector spraying a stream instead of a mist, might be worth it to get them cleaned anyways.

[LanceW3544]

I was able to manual test the injectors. Directly powering them from the battery they all spray great! where to dig next?
ECU?
Relays?
Tirggers?

Thank you everyone for your time and participation. Very grateful

[Chris914n6]

Most likely injector trigger.

https://members.rennlist.com/pbanders/DJetP...tm#troubleshoot

[Dave_Darling]

Again, check all of the wires and hoses to make sure they are plugged in.

--DD

[LanceW3544]

Again, check all of the wires and hoses to make sure they are plugged in.

--DD

Thanks for the reminder Dave. (IMG:style_emoticons/default/smile.gif) I believe that I do have them all plugged in but lets go step by step and make sure. Here I image one is the back of the Dizzy which should have a plug with three wires


Here are the grounds for the injectors. I was fearful of their connections So I have made them a new ground here.


Here is an image of the intake pipe which has a vacuum line that runs over the piece that connects to the Dizzy.


Then the last picture is to the hand grenade looking thing that attaches to the passenger rear fender wall.

What else should I be checking?

[mgphoto]

Pump keeps running after the 2 second interval means someone fiddled with the relays on the relay board.

[LanceW3544]

Pump keeps running after the 2 second interval means someone fiddled with the relays on the relay board.

All three relays are there. Are each of them interchangeable?

[mgphoto]

Pump keeps running after the 2 second interval means someone fiddled with the relays on the relay board.

All three relays are there. Are each of them interchangeable?

They are interchangeable but they must align correctly, the pins will fit and you may get some function.
The relays will fit in the socket several different ways but only one is correct.

[Dave_Darling]

What else should I be checking?

Make sure those are plugged in solidly.

Check the CHT connector. It's near the #3 spark plug; a single wire comes out of the engine tin and goes into a plastic box connector. Sometimes the connection gets broken but the wires still go into the box.

Do you know if the ECU is getting power? You can remove the ECU and check its connector for power on the correct pins. You could also turn the key on and then grab the throttle and open it. If you hear the injectors click (it will be about 10 times), then you know the ECU has power and can send it to the injectors. If you don't hear them click, it's not definite that the ECU isn't getting power, but it shows something isn't allowing the injectors to open at all...

--DD

[LanceW3544]

pulled all the relays which I have done before and firmly pushed them all down. For some reason this time something was different. I put about 20 miles on it thus far. Run but bucks a low RPM.

Thank you everyone for your help. You all have been great!

[Chris914n6]

Sounds like common corrosion. Give all the connectors a good cleaning.

[Bartlett 914]

pulled all the relays which I have done before and firmly pushed them all down. For some reason this time something was different. I put about 20 miles on it thus far. Run but bucks a low RPM.

Thank you everyone for your help. You all have been great!

Are you talking the round relays on the relay board? Move them around to different positions. This will help rule out bad relays. They can develop bad contacts internally. I have seen small particles of rust that can interfere with the relay coil / armature motion

[TheCabinetmaker]

One of those relays powers the injection system. The 4 pin connector on the rear drivers side of the board will leave the injection inop if it's not plugged in.