Twalker

1997 Honda Civic Del Sol

​Engine B16A2, Manual Transmission

1.6L DOHC 16 Valve VTEC

TL;DR: my car will crank but not turn over. the fuel pump is priming when I turn the key to the ON position, I'm pretty sure the fuel injectors are getting a signal from the ECU, the spark plugs are in specification, and the ignition wire resistance is within specification. I am getting no spark at my ignition coil. is it common for ignition coils to fail? can you think of another possible cause for a no-start condition on this model?


About a month ago my engine misfired on startup and threw a CEL with these codes: P0300, P0303, P0304. I brought it to a shop, and they said the spark plugs were quite dirty and could be burning coolant. They tried to pressurize the coolant system for almost 24 hours to see if a leak would sprout and affect start-up. They were unable to reproduce the misfire.

About a week ago, I hopped in the car one hot morning, and the engine would crank but not start. I'm trying to diagnose the problem myself because I paid way too much just to have the shop say the car is fine. Using the "fuel, compression, spark" mantra, I firstly looked at the fuel system.

For the fuel pump, the Haynes manual states the pump will prime when the key is turned to the ON position. The priming is audible and sounds like a whir that lasts for 2-3 seconds. I am able to hear this sound, which I believe indicates the fuel pump is getting a signal and pressurizing the fuel system. I do not have a fuel pressure gauge, so as a secondary check, I broke open the banjo bolt on the fuel filter; some fuel spurted out of the filter. This makes me assume the fuel system is pressurized. I also believe this means there is no problem with the main fuel pump relay, since I'm assuming that relay is responsible for sending the initial signal to the fuel pump when the key is turned to the ON position. Please correct me if I'm wrong here.

For the fuel injectors, I've been following the advice of this video: . In particular, the part at timestamp 1:39. In that video, the test light turns on and flickers when it is touching the control wire and the engine is cranking. In my test, the light turns on when it is touching the control wire and the engine is not cranking. Later in the video, the guy states that the battery on his car is pretty dead. The battery on my car is relatively new (<2 years). I believe my test light turns on immediately because of this difference, so, to avoid damaging the fuel injector circuit, I did not try cranking the engine with the test light touching the control wire. I'm assuming that the fuel injectors are getting a signal from the engine computer and there is not a problem there.

Secondly I looked at the ignition (spark) system. I hooked up my test light to ground, and placed it inside one of the ignition wire boots. The wires are brand new, and their resistances all check out. With my test light inside one of the ignition wire boots, I had someone crank the engine, and I tried to see a spark. There was no spark.

I checked the resistance of the distributor cap and rotor, and both have very low resistance (as expected). They are both brand new, so I don't expect a problem there. Next, I checked for a spark at the ignition coil: with my test light hooked up to ground, I placed the other end of the test light near the ignition coil, and had someone crank the engine. There was no spark. Following the advice in these videos, (timestamp 4:48) and (timestamp 5:29), I tried to see if the igniter positive and negative terminals were still good.

With the key in the ON position and the test light hooked to ground, the light is very bright on the positive terminal and less bright on the negative terminal. With the light on the negative terminal and the engine cranking, I see the light dim, but I'm struggling to see the flicker seen in that video. With the light on the positive terminal and the engine cranking, the test light dims slightly, an there is no flicker. I'm assuming the quality of my test light might just be worse than the one used in the videos, and my igniter is fine.

I wanted to get the thoughts of this forum: do you think replacing my ignition coil will resolve the no start condition? Is there something I missed, or are some of my assumptions inaccurate?

Thanks for reading the long post.

TomCat39

It could be you get no spark and no fuel due to the ECU not getting the proper signalling.

Coils do go bad as do ignitors.

However, before replacing parts randomly, check your G101 ground and make sure all wires are in good shape, continuity to ECU from G101 as well as the Distributor to G101. If that ground is not well, it affects both systems.

Twalker

I replaced the ignition coil yesterday, but the car will not start. Thanks @TomCat39 for the advice. I will check continuity from G101 to the ECU and from the Distributor to G101. I'll reply when with those results.

Two components lie upstream from the ignition coil: the ignitor, and the ECU. These two are connected by a whole host of wiring and it's possible the problem could be a faulty wire somewhere. The wiring I moved around when I replaced the intake manifold gasket. (For details on that replacement see P.S. below.)

I believe the cause of the no-start existed before I did that repair. As my OP states, I was getting misfire codes long before the intake manifold gasket repair. Some additional symptoms included rough start-ups and a sort of gurgling or engine fluttering noise at around 2000rpm. I'm sorry I cannot give a better description than that. The sound was most audible on accelerating, but would also happen on decelerating. One source of rattling was definitely a partially mounted exhaust pipe, but there was another noise source from inside the engine bay. Once that sound started, I knew it was only a matter of time before something like this no-start would happen.

Anyway, the point is I am leaning toward agreeing @TomCat39 suggestion that there may be trouble in the connections between the ECU and the distributor. It would also explain why my fuel-injector test-light diagnostic result wasn't quite the same as those in the videos.

P.S. For the intake manifold gasket replacement, there was little room to work with in the engine bay, so I had to pull the fuel rail off, and ended up taking off the entire intake manifold. Gave it a good clean and scraped every bit of the old gasket off and was able to get everything back together. After that repair, the car started just fine, and I was able to drive it around for a 10-15 minutes. After that time, I had a slight overheat condition, but I remedied that by purging the air out of the coolant system (i did not refill the coolant system properly). After I purged the system, I was able to drive it around for 10-15min again, without any overheat.

Twalker

I could not locate the G101 ground that @TomCat39 suggested I find, but that's probably because I have very little experience reading wiring diagrams. I would be grateful if someone could forward a wiring diagram for this model. Since I didn't want to mess with wiring I know nothing about, I instead did a simpler check outlined in the Haynes manual: I checked the battery voltage is reaching the ignitor, what the manual calls the "ignition control module" (ICM). Here is a link to a video of how I did this: https://photos.app.goo.gl/wS4XsZttEEKiPxdx8

I am pretty sure the battery voltage is reaching the ICM. I believe the ICM is responsible for sending an alternating signal to the ignition coil. Since the battery voltage is reaching the ICM, and the ignition coil is not producing a spark, does that mean the ICM (i.e. the ignitor) has failed and I should replace it? I've been advised that the ICM itself is not very expensive as long as I buy it without the accompanying heat sink, and I'm pretty sure I've found one online. I wanted to get the advice of the forum before I bought the part, since I already tried replacing the (more expensive) coil without resolving the no start condition.

CX-Adam

G101 is on the thermostat housing. There's an image here: https://honda-tech.com/forums/honda-...spark-3255464/

It's also PIN 3 on the main relay

Twalker

big thanks to @CX-Adam for the link to the thread that had the photo of the G101 ground. In that thread, I followed the link to the ignition diagnostic tutorial, and wound up on the ICM diagnostic page: https://easyautodiagnostics.com/hond...system-tests-5. I have done everything except this test, and have ordered some basic electrical equipment to complete that test. This test seems definitive, and will tell me if the ICM is receiving the proper signal from the ECU. If it is, I will replace the ICM and the car should start. If it isn't, then the problem is with the ECU or in-between connections. I will update this thread after I get those results.

If the problem is with the ECU or in-between connections, I will begin a new thread since I anticipate asking a lot of questions that have to do with the wiring and connections inside the engine bay. Perhaps a first place to start would be testing continuity at the main relay, since those have a notorious tendency to fail in these older Hondas.

TomCat39

Don't worry about a new thread, this thread can house all your questions as you go. Easier to keep it all in one location and helps prevent you from having to retype vehicle information and stuff you've done etc.

Twalker

Sounds good @TomCat39, I'll keep my posts here.

Okay! I'm pretty sure I have a dead ICM! I have verified a crank signal is being sent to the ICM, verified the ICM is receiving a battery voltage, and verified there is no spark at my ignition coil. This means the ICM is not able to take the crank signal and command the ignition coil to spark.

The steps I followed are outlined in this video (you can start at timestamp 1:29):
For comparison, here are some videos of my attempt: https://photos.app.goo.gl/VLgvDLcywZ8ASTx89

In video 1 (1min 10sec), I give my setup. In video 2 (40s), I've connected the battery, and the light does not turn on. In video 3 (22sec), I have carefully pushed my back probe deeper into the terminal of the yellow-green wire to be sure I am contacting that terminal. Without the key in the ON position or cranking the engine, the light turns on when I connect the positive terminal of the battery. In video 4 (18sec), I get an unambiguous blinking.

I will replace the ICM let you all know if that has fixed the no-start condition!

Twalker

It worked! I replaced the ICM and the car starts now. Here is where I ordered the part:
https://www.partsgeek.com/catalog/19...?brand=hitachi
Part Number: 6020-05105041

I actually bought two because I wasn't sure I'd get a quality part, but when they arrived, they looked to be in excellent condition and OEM quality (packaged in original Hitachi boxing). Here are some photos I took: https://photos.app.goo.gl/nuDrYQy7dT7YFfes8

Anyways, now that the car is running, this thread can come to a close. Now I hear a rattling sound coming from the distributor side of the engine (away from belts, around cylinder #4) while the engine is idling. This sound was there before the ICM replacement and intake manifold work. It does not sound as serious as engine knock, but could be a precursor. I will start a separate thread for that. In that thread, I hope to take a video with good audio quality so the people on this forum can have something good to work with. Perhaps it's possible the failing ICM caused improper sparking in the combustion chambers and ruined the rod bearings...? I'm praying this isn't the case; if I have to replace the damn engine I'm gonna be pissed.

Thanks again to the responders @TomCat39 and @CX-Adam. I hope this thread can help people with a similar issue!

TomCat39

You may just need a valve lash adjustment. Loose valve lash causes a noisy head.

94 Civic Si

Glad you fixed it! $146 each, eh?