Tried to create a new thread - wouldn't work - so I'm going to try it via a replay to a thread close in content...

I'm having a heck of a time trying to pin down a problem and wondered if anyone might have an idea I haven't tried.

Car: '86 Accord LXI, FI engine (20A4), 5-speed manual

Symptom: Car won't fire-up (start) using starter. Car will start with a short 10 foot push and a pop of the clutch. Runs fine for mileage once started ('flat spot in 3K RPM range only anomoly)

Replaced or verified working:

• Temp sensor to ECU replaced (it was bad)
• New distributor (complete, all components)
• New coil
• New fuel injectors
• New fuel filter
• New plugs
• Wires checked
• Ignition switch bypassed (12V applied directly to condensor high side - verified dash engine lights lit, even tried to start it this way in case problem with ignition switch in "start" position)
• Main fuel relay pulled and verified on bench. Backup fuel relay tried. Loosened nut on fuel filter, turned engine on, fuel squirted out, retightened nut).

Original problem was traditional non-start on a hot day after sitting in the sun, would start after cooling off. That led to the fuel relay and fuel filter items above.

One day on the way home, turned a corner and engine died. Wouldn't re-start. That led to the coil and distributor replacement. No change after coil replacement, originally started after distributor replacement. Drove over weekend, let sit in sun, all seemed fine again.

Next day, went to leave work - no start. First time tried push start - started and drove fine.

Next up was verifying the ignition switch in the "start" position was supplying power to the coil. Also tried the direct connection batter to coil via the hot side condensor lead. No change.

Next up was the fuel injectors. No change.

I'm out of ideas... Starts easily with a push (I can push it 10 feet, jump in, pop clutch, and go). Today leaving church I parked with rear wheels on a foot high mound of dirt. Just rolling off the mound was enough to start it with the clutch.

Anyone have any thoughts on what could cause the symptoms - fix this?????

 

Made a new thread for you.

When you turn the key to start the car, does the starter spin the engine, or does nothing happen?

 

Thanks for the thread


Knew I forgot a "checked this" piece of information Yes, starter spins. Checked via the oil fill on the valve cover that the starter is engaging and the engine is turning over as well (camshaft turns, valves open/close).

 

Since the engine runs after popping the clutch, you can rule out timing and compression. Also the starter is likely off the list, since it spins the engine at the normal rate.

You need to determine if you are missing spark or fuel when the car will not start.

If you spray starting fluid into the intake hose, can you get the engine to fire up and run? Do you hear the fuel pump prime when you turn the key to the II position, but do not try to start the vehicle?

Plug one of the spark plug wire into a spark tester (or old spark plug with the threads grounded) and see if you get spark when the engine is cranked normally.

 

If I turn the key on and off multiple times in a row (triggering the 2 second main fuel relay activation), I can also smell gas (btw no leaks - all connections, injectors, fuel filter, etc. dry externally). Don't have any canned starter fluid. Tried with some carb cleaner, 1/2 second shot via the PVC port into the throttle body.

Yes, you can hear the main relay click on, then after approximately 2 seconds turn off. Can also hear the pump. Question for future reference - in reviewing the electrical system diagrams, can't see anything that would cause fuel to not flow when starting via the key, but would lead to fuel flow as a result of pushing the car for a few feet.

Ok, tried 2 different old plugs (always keep last set during tune-ups for emergency use). Verified electrode grounded via resistance check, tried both #2 and #4 wire. Turned to start position for 2 seconds in a pitch black garage - no spark.

Would have never thought based on all the other testing and that it runs with a push... Just goes to serve as a reminder - regardless of other indicators, always do the simple tests regardless.

Now the question becomes - what can cause a lack of spark while attempting to crank with the starter, yet full spark and immediate engine start from a couple of feet rolling start? Keep in mind two things... 1) dash engine light stays illuminated while cranking and 2) a direct connection from the positive terminal of the battery to the positive lead of the condensor doesn't result in starting when cranking via the starter. (also note that correct lead of the condensor verified by engine light and oil pressure light turned on entire time connection was made and fuel relay turning on upon initial connection.)

Oh - and thanks...

 

I'd recommend not to jump directly from the battery for future testing. You can possibly do some damage to the wiring or electrical components if you jump to the wrong connection.

Your problem is not spark when turning the key to the start position. Need to do some testing to identify the problem.

I think your next step is to test for voltage on the blk/yel to the coil while the coil is plugged in. You will have to back-probe the connector. See what happens when the key is in the II position (like when you pop the clutch) and also when you turn the key to the start position.

I'm looking at a shop manual wiring diagram and the radio condenser appears to control the spark timing? Do you know how this operates? I am more familiar with 90+ accords that had the ECU controlling spark timing.

 

I had a fuse in line when I did the connection to the battery - and had verified the proper connection with an ohm meter between the coil and the chosen condensor lead before doing so

The blk/yel wire is in parallel with the condensor (the black/yel wire from the ignition switch splits coming out of the wiring harness at the coil feeding both).

The condensor is just a capacitor for eliminating RFI (that annoying static one hears on the radio when if it isn't connected). The spark timing is all controlled in the distributor in 86's. Both the ignitor and cam position sensor are in the distributor (they moved the ignitor external to the top of the fender well on VTEC engines I think). The ECU on an 86 only controls the fuel side of the equation (throttle body FI).

Here's the ignition side from my shop manual:


The ignition switch being bad would make sense giving that it'll start with a push (alternator then supplies power to the coil, even though the ignition switch doesn't) - but that's why I did the direct connection to the battery. Based on that test, I'm at a loss... Note also that the alternator light (charge warning light on the diagram) also comes on while attempting to crank (bright when in the on position, dims when turning starter as it pulls juice), which is another indicator of voltage reaching the IG terminal of the switch. A real puzzler...

Tomorrow after work I'll see about carefully piercing the insulation of the wire going into the coil connector with a straight pin to see if I can monitor the voltage while trying to crank.

 

You could check whether the ignition switch opens the IG circuit when the key is turned to START. I remember 1 or 2 threads where that was the culprit (although they were newer Accords).

Couple ways to test:
- Disconnect the switch & use a continuity tester.
- Unplug the little wire (S on the starter) so the starter doesn't actually run. Then measure voltage at the bk/y wire at the distributor in both positions. Wiggle the key around to see if the connection is flaky while in the START position.

It's curious why the charge warning light would light up, but maybe there's a way to backfeed that lamp through the voltage regulator while the alternator is spinning? So I wouldn't trust that lamp to prove the IG circuit is live while cranking.

 

Jim - your comments are the reason why I originally jumpered straight over from the battery to the condensor lead - to insure there was voltage at the coil in the start position. There is a 'feedback' (or back feed if you prefer) path for the alternator to supply the voltage, which is why I tried the switch bypass I mentioned in post 1. Here's the path highlighted:



Here's a pic of the connection when I did the jumper - basically bypassing the ignition switch while trying to start:


-----------------------------------------------------------

PAHonda - took a number of measurements. Pic below shows the test points I used, with TP1 being the condensor lead and TP2 being the connector at the distributor (it unplugged, meter into connector contact for the coil):


With the engine running, I disconnected the condensor and measured the voltage at the condensor lead (TP1) with the engine running - was 12.1 volts.

With the engine off and the key in the "On" position, measured the same spot (TP1) and got the same 12.1 volts.

With the engine off and the key in the "Start" position and starter spinning, measured the same spot (TP1) and got 10.1 volts.

Disconnected the plug on the coil and inserted my meter probe into the connector end for the Bl/Yel wire (TP2) and repeated the measurements for the "On" position and "Start" position (with starter spinning) - exact same measurements I had at the condensor lead.

The measurements basically give the same "test results" as when I jumpered across from the battery to the condensor lead - voltage at the coil, no fire.

Still baffled... (me, not the car).

Seems like there has to be something else (another connection - maybe to the ignitor in the distributor) that is there when doing a rolling start and that isn't there when doing a starter crank... but I'll be darned if I can find any hint of it in my shop manual.

There are 4 connections to the ignitor in the distributor. Three of them are shown in the ignition wiring diagram I've been using. The 4th connection isn't shown - is a green wire - and I suspect that it's the feedback to the ECU unit, but I can't find it shown anywhere.

Wouldn't think the 10.1V when cranking would be the issue, especially in light of the attempted start with the jump from the battery to the condensor lead (using 16 AWG wire with a 10A fuse inline btw).



*bangs head on engine header*

 

What is the voltage across your battery terminals when you try to start the engine? You may be jumping the 10.1 volts to the igniter.

You may want to charge the battery and see if your voltage measurement changes.

You can also try charging the battery to see if it gets above 12.4 volts. Turn on the headlights and see if it drops voltage slowly.

Here is a good video on doing some electrical diagnostics.