fuel injection issue, trigger points? Options

[luskesq]

Have a '70 1.7 that I picked up that hasn't been run in years. Gone through ignition, points, plugs, timing and it runs . . . badly. Discovered when running that I can pull the ignition wires to 1 & 2 and it runs the same. No injector clicking with key on and opening the throttle switch on 1 or 2. 3 & 4 click. Could the problem be the trigger points and do all stock 1070 1.7's have trigger points?

[swl]

I think that 1&2 failing is indeed half of the trigger points. Quick way to check is to reverse the plug on the dizzy. If the fault travels to 3 and 4 you have your culprit. Be very careful when you pull the plug. Very easy to break wires.

[brp986s]

All stock 1.7 have the trigger points in the distributor. The way to test them is have someone turn over the engine while you measure continuity between the center and either of the the outer pins of the distributor. The circuit should open and close once per rev of the distributor rotor. One side of the trigger will fire injectors 1 & 4, the other 2 & 3. As the triggers wear, the slider blocks wear out - the circuit fails to open, and the ecu doesn't receive the signal to fire the injectors.The function of the trigger points is unrelated to the tps. good luck.

[ejm]

Sounds more like a problem with the injector grounds. They are paired left and right. Check the three ground connections on the top of the engine case under the intake plenum.

[JeffBowlsby]

(IMG:style_emoticons/default/agree.gif)

[Cap'n Krusty]

I think that 1&2 failing is indeed half of the trigger points. Quick way to check is to reverse the plug on the dizzy. If the fault travels to 3 and 4 you have your culprit. Be very careful when you pull the plug. Very easy to break wires.

No way. The Cap'n

[luskesq]

All stock 1.7 have the trigger points in the distributor. The way to test them is have someone turn over the engine while you measure continuity between the center and either of the the outer pins of the distributor. The circuit should open and close once per rev of the distributor rotor. One side of the trigger will fire injectors 1 & 4, the other 2 & 3. As the triggers wear, the slider blocks wear out - the circuit fails to open, and the ecu doesn't receive the signal to fire the injectors.The function of the trigger points is unrelated to the tps. good luck.

Thank you all for the input. The ground connections are in place but I'll double check the quality of the connections. STUPID QUESTION??? Are the trigger points under the regular points, meaning I pull the reg. points & plate and the trigger is underneath and inside the distributor?

I wasn't certain if I even had trigger points (this is only my 3rd 914 but the last one I had was over 30 years ago. Thanks again all.

[brp986s]

2 phillips screws mount the triggers into the side of the distributor - no need to remove ign points/plate.

[luskesq]

All stock 1.7 have the trigger points in the distributor. The way to test them is have someone turn over the engine while you measure continuity between the center and either of the the outer pins of the distributor. The circuit should open and close once per rev of the distributor rotor. One side of the trigger will fire injectors 1 & 4, the other 2 & 3. As the triggers wear, the slider blocks wear out - the circuit fails to open, and the ecu doesn't receive the signal to fire the injectors.The function of the trigger points is unrelated to the tps. good luck.

Buried under the vacum hose to the advance is a 3 wire plug into a receptcle on the side of the dist. That piece goes into the dist but I don't see screws holding it in place. It is lower than the point plate so I don't see how I can either service it or replace it without pulling the plate (with points) off? Am I missing something (likely)? Thank you again for the help.

[ejm]

You need to pull the distributor to remove the trigger points.

No injector clicking with key on and opening the throttle switch on 1 or 2. 3 & 4 click.

Again...doesn't sound like your problem is the trigger points.

[luskesq]

Thank you for confirming what I suspected. I intend to confirm good ground connections as you suggested first before pulling the dist. Do easy part first & cross fingers.

[Tom]

An easy test is to hook up a meter to the injector plug to see if the ICU is sending a signal to the injectors. Plug has two contacts, one is ground. So check that the ground is good, then put the meter to the other connection and turn over the engine and see if the voltage gets to the injector. That way you are checking that the ground is good also from the injector to the rear junction for the inj. ground wires.
Tom

[rick 918-S]

I made a simple test light from a couple small wire connectors and a side marker socket from a 1980's GM car. The bulb was a 194 which is a small single filament bulb. I unplugged the injector and plugged the test light into the socket. Crank the car and watch the bulb. If the light flashes the wiring is good and the injector is dead. If no joy unplug the ground side of the test light from the injector socket and ground it. Re-test. If the light flashes the ground is dead. These old harnesses get brittle and can snap off. mid-stream causing a failure.

[realred914]

An easy test is to hook up a meter to the injector plug to see if the ICU is sending a signal to the injectors. Plug has two contacts, one is ground. So check that the ground is good, then put the meter to the other connection and turn over the engine and see if the voltage gets to the injector. That way you are checking that the ground is good also from the injector to the rear junction for the inj. ground wires.
Tom

yes but just do NOT accidently short the injector singal wire to ground when testing (cranking motor) if you short the singal wire from the brain to ground 9or short teh connector with your test leads) you stand a good chance of permantly destroying one of teh two power transisters that power the injectors, then it is end of the brain. i did this once. not fun, so be very carefull with the test leads when testing for power to the injectors.
one short at it is all over for the brain.