mfroniewski

I am at a complete loss here. I have no clue what could be going on, so hopefully one of you does. The car in question is a bone stock 1995 Civic DX, 2-door, D15B7, Manual tranny, 163k miles. I was doing a seafoam treatment when the car stalled while I was pouring it into the brake booster line. When it stalled, there was a bit of back-pressure that spurted liquid back out the line. I waited the 5 minutes and tried to start it. I cranked it for 5 seconds - nothing. Cranked some more, and it started, idled VERY rough for 5 seconds, and died. Cranked again - nothing. Cranked again, and rough idle again before it died. I haven't gotten anything out of it since. Here's what I've done over the past 2 days:

First thought was that it was flooded. I dried out the cylinders and intake manifold. Didn't work. Ok, so time to check for fuel, spark, and compression. Compression check was quick and easy, passed just fine. All cylinders were within 10 psi from 140psi after 3 needle jumps. Compression - check.

Every time I crank it with the injectors plugged in, the spark plugs are covered with fuel, and the top of the pistons are wet. The spark plug hole smells like fuel. This is true for all 4 cylinders. Checked fuel pressure, it's within spec. Fuel - check.

Popped out a spark plug, grounded it, got a spark. True for all 4 cylinders. Put in new NTK plugs anyways. The wires are good, ohmed the coil, and it's good, and put in a new OEM cap and rotor. Spark - check.

So shouldn't it be working? Well, I checked more stuff

It's not throwing any codes. I checked all vacuum connections, and they are connected and not clogged. Checked the TDC/Crank/Cyl sensors - good. Re-seated all electrical connectors under the hood. Maybe the timing belt jumped a tooth? Nope. With the crank pulley at the TDC mark, the lines on the camshaft pulley line up with the cylinder head. Also, with cylinder 1 at TDC in the compression stroke, the distributor rotor is pointing toward the cylinder 1 plug wire terminal. I even tried rotating the distributor while cranking to see if the timing was off anyways. It did nothing. Engine is grounded properly. All fuses are good.

I've tried starting fluid, and of the 10-15 times I tried, only 2 times did I see any glimmer of hope. It would ignite only about 3 times, and then return to normal fruitless cranking. I know the engine is sucking air in, because I can feel the vacuum on the hole for the idle air valve, and even more vacuum with the throttle body open.

Everything is fairly clean on this engine, so I wouldn't imagine anything is gunked up. My only guesses as to what caused this are coincidence, the seafoam it's self, the back pressure when it stalled, or the heavy vibrations while rough idling.

I know its a long read, but any ideas? I honestly have no idea why it isn't starting.

Former User

What color is spark at the plugs? It should be bright white.

mfroniewski

I would say it's white/blue. I checked the coil and wires, they both ohm'd good. New plugs (gapped to .040 in), cap and rotor, so I'm not sure what else could cause a weak spark.

Former User

Post clear pictures of the cam and crank at TDC1.

Are the wires in the proper firing order?

mfroniewski

The spark plug wires are in the correct order. It's dark out and my camera isn't the best, but I can try to snap some pics. If not, I can get some tomorrow.

Edit: If there was a problem with the valve timing or something else in the head, wouldn't I get a bad compression test reading? Would the gas/starting fluid ignite and come out the exhaust or intake? Because none of this is the case, I like to think that the problem doesn't lie there. Unless I'm wrong...

Former User

I'm not sure being a tooth off would cause those^ obvious problems. It's pretty easy to turn the crank pulley a few revolutions and shoot some clear pictures of the mechanical timing. You seem to have covered most of the common causes for a no-start problem, so it's important to allow us to see some of those test results, just to cover the bases.

mfroniewski

I'm not sure if you wanted any particular angles or shots of specific parts, so I just took pics of various spots.

Crank at tdc



Camshaft pulley

Former User

You are 180-degrees out of phase because the cam "up" mark is pointed down. Rotate the crank pulley until the cam "up" mark is up and the horizontal cam marks perfectly align with the top of the head. Shoot a picture of that. Then shoot a picture of how the pointer aligns with the white mark on the crank pulley. Never turn the crank pulley clockwise, only turn it counter-clockwise.

mfroniewski

I do go counter clockwise, and also use the starter to assist me

The camshaft rotated 180 degrees:



And where the crankshaft ended up:

Former User

Yep, the mechanical timing is fine.

I think we can safely assume that it's not a fuel problem because starting fluid did not fire up the engine.

This leaves spark and compression to review.

Did you do the compression tests? Did you repeat the test with the same results?

Is spark at the plugs bright white with only a faint hint of blue?

You are absolutely sure the plug wires are in the correct firing order, just like shown in the picture?

Do you have an OEM distributor?

93h22a4prelude

Maybe it is flooding... Try to start it briefly, then unplug the injectors and see if it starts for a second or two. If it doesn't try to start, hold open the throttle and see if it does, and if still no then try starting fluid.

Also throwing this out there: maybe the cat or exhaust is clogged.

mfroniewski

I did the compression test myself, only once. I had to borrow the test kit, but I do plan on testing it again tomorrow morning.

To my knowledge, the distributor is OEM. I bought the car a month ago, and it came with service records. Nothing indicated a new distributor. I am absolutely sure about the spark plug wires. I've checked that so many times, it's nauseating.

Checking the spark at night (just now) i was able to better see the color. It's blue, and looks to me almost a bit purple. I guess this points to a weak spark.

I have new plugs, cap, and rotor. Wires were all under 15k ohms, spec is under 25k. I also manipulated the wires to see if it would break continuity. No luck.

The coil measured .9 ohms at the primary winding and 15k at the secondary. I know the spec is .6-.8, but that's at 68 degrees, and it was much colder when I did the test.

Is there anything else that could cause a weak spark that I missed?

mfroniewski

I've been wary of it flooding, so I've been regularly taking breaks and letting it sit with the spark plugs out and throttle body open. Also, if I crank it and don't intent to make it fire (e.g. compression test) I unplug the injectors to keep it dry.

I don't think it's a clogged exhaust because after cranking for a while with injectors plugged in, I can smell fuel in the tailpipe.

Former User

Yes, spark is weak. That's the problem. Remove the coil and redo the Ohm tests at room temperature. For the primary winding measurement, be sure to subtract the internal resistance of the meter, which is determined by touching the two meter probes together. If the coil tests fine, have an auto parts store test the igniter unit. Also measure voltage on the Blk/Yel wire attached to the coil and igniter unit. It should have battery voltage with the key in ON(II).

mfroniewski

I'm sitting on the coil like a mother hen as I type this.

Is the igniter unit not something I can test myself?

And I'm getting battery voltage at the blk/yel wire.

Former User

There are tests, but they're complicated and many people won't try them.

http://www.tegger.com/hondafaq/ignit...r-testing.html

mfroniewski

I'm fairly competent with electronics, so I'll definitely give the tests a try. Thanks for the link!

mfroniewski

The primary coil measured 1.0 ohms - .3ohms internal resistance = .7 ohms. The secondary was 15.95k ohms, so the coil is good

Former User

Seems to be.

mfroniewski

There is a slight possibility that the igniter could be the issue. It is switching as it should, and there isn't a float issue, but the voltage going to the coil when the input (pin 4 in the link you gave me) is grounded is a tad low, 11.5v. Could this not be charging the coil as much, causing it to produce a weaker spark?

Former User

Did you do the test with the igniter unit removed from the distributor? What input voltage was used in the test? Did you also measure some voltage bleed when pin 4 is floating?

mfroniewski

I did the "off the car" test "in the car." With the coil out, I hooked up the multimeter to the wires that went to the coil. Unhooked the tach and signal wires, used the body ground. The igniter unit was getting 12.1v. I used the battery for the signal (ground/v+/floating). With the signal at ground, I was reading 11.5v at the coil. Floating and V+ were the same: zero volts, but it would slowly climb up at the rate of roughly 10mv/sec. switching between floating and v+ would not reset it to zero, but going to ground and back would.

So since the coil is getting the same 12.1v input as the igniter, then the igniter is grounding the coil, but it looks like there is some resistance there that is causing the voltage to drop a little. Would this .6v be enough to not start a car? I know it does get multiplied in the coil, but this seems like a bit of a long-shot. Is there anything else that could be the problem, before I drop a bunch of money on a new igniter? (broke college student here)

Former User

Here's how I look at it.

1) You clearly have weak spark that prevents the engine from starting.

2) Among several different tests that are typically done to reveal the cause of such a problem, only the igniter unit yielded the out of spec measurement, albeit by 0.5V. However, note that the example of a bad igniter given on the Tegger link for the same test yielded only a 1V out of spec measurement. My guess would be that the latter igniter unit completely prevented spark, whereas you have weak spark. If so, there would be a correlation between the magnitude of the out of spec measurement and severity of the spark problem.

I can't guarantee with 100% certainty that the igniter unit is bad, but if I were in your position, I would buy a new igniter unit. If you still have reservations about the diagnosis, you should next take the igniter unit to AutoZone for testing as this is a free service.

Do you possibly have a friend or classmate who has a Civic or Honda with a distributor? You could then try swapping in their igniter unit to see whether the engine starts.

mfroniewski

I swapped parts with a friends car, it turns out it was the coil.

Former User

Nice job. There are clearly some cases where the coil test misses a bad coil.