Got a 94 Del Sol Si with maybe 140k miles, 1.6 SOHC engine. Noticed an odd noise on a quick trip to grocery store and after getting back and investigating, found it coming from one of the spark plug ports (No 1). Pulled the plug wire (while running) and saw a puff of smoke come out (not good). Put back on and did a quick check of other plug wires to see if similar activity and none showed. Pulled No 1 plug wire again and after a few seconds, it stalled.

Discovered the spark plug was loose (ACK !!) pulled plug and inspected and looks like it may have been loose for a while. Used boroscope and tried inspecting threads and top of piston best I could. Saw some wear on threads but not enough to even consider major repair. Cleaned plug and reinstalled, tightening very well. (will probably get a new plug sooner vs later) Checked other plugs and gave them a snugging. Reinstalled everything and now it won't start. Not hitting at all. I didn't disconnected anything else. HELP !!

 

Pulling a plug wire when running can kill the coil or the ignition control module. There is tests you can do to test each. Both reside inside the distributor.

Also. the torque spec for spark plugs is 13 ft-lbs. Anything more and you risk ripping out threads next time you pull the plugs. Don't over tighten them if you wish to keep longevity of the motor.

 

I am fearful that is what happened. I did start some of the diagnostic testing and confirmed there is 12vdc getting to the distributor. Started to take things apart but the screw holding the rotor in place is so tight that even with a well fitting driver, it has almost destroyed the Philips drive. Gonna have to drill it out and after being incredibly frustrated and cold, stopped for the day. I won't be able to get a new screw until next week anyway now.

If one of the two is bad, I hope it's the coil as that is the cheaper of the two. Stupid things are expensive. Are there any reliable aftermarket brands that will work in place of Honda brand ?

 

If it was an OEM screw on the rotor, it's not actually phillips but JIS I think it's called. Japan uses cross tip that doesn't have rounded inside corners but sharp 90 degree corners. The phillips tends to slip and chew up these screws.

This article shows the difference extremely well.
https://www.motorcycle.com/ask-mo-an...-phillips.html

I have struggled with that screw before too. I ended up using my small bolt extractor socket on it. Beat it on and then used my ratchet to break the screw free. Still wasn't pleasant but it did get me out of the jam without having to drill it.

 

I am aware of JIS drive but neglected to consider this screw likely uses that drive. I've chewed it up enough where I have to drill it. It was cold and windy when it happened and I was hoping for a quick fix so wasn't as patient as I might normally be especially after seeing I might have just blown a couple c-notes.

 

The bolt extractor used the outside part of the head of the screw.

This set, the smaller socket fits well with a little hammer tapping it bites in.

https://www.canadiantire.ca/en/pdp/m...w.ds#store=433

 

Drilling the hole then another go with a fresh bit got the screw out but now the stupid rotor button is stuck. I went ahead and broke the moisture shield away so I can do the diagnostic testing but still have to get the rotor button off. Sprayed a little wd 40 on in ystrdy but still won't budge. There was a little moisture corrosion on the screw. Pretty nothing has ever been touched inside the distributor. Hoping I can pull the coil after testing and then be able to get leverage to pry the button off without damaging any other parts. Something that should be so simple is becoming a major project.

 

If the screw is indeed out, then you can tap the rotor on a little to break the corrosion. Then you might be able to pry it off. I had one that was a real bear and that is the method I had to do to get it off. I also have plastic L trim pry tools I used.

 

Yea, already broke the rotor working on it. Metal core still stuck. Will put a small puller on it tmr. Problem now is troubleshooting. Coil resistance checks good but the diagnostic post is a bit unclear on checking for a grounded coil. Both resistances check good but the negative terminal on the coil measures direct short to the housing so I'm not sure if that is a short or if negative is supposed to be grounded.

Also, Supposed to get +12vdc on both the black/yellow wire and the white/blue wire. Got it on the blk/yel but not the wht/blu but the chart doesn't show what causes that. All fuses check good. Best I could find is that the wht/blu come from the ecu and I can't imaging I blew that. Check engine light is on just momentarily with switch on so shouldn't be any codes. I'm measuring the wht/bly on the plug going into the distributor. That should be the same as what is going into the ICM, yes ? Or is is different ?

Thanks for the continued assist.

 

Sorry for the delayed response. I'm going to have to dig up some info for the wiring. Our old wiring guru doesn't seem to participate much anymore.

I don't remember is your Del Sol SOHC v-tec or is it the DOHC v-tec model?

 

No worries. So here is my current status. When I first checked the coil, it was still wired in. Once I removed it and checked, it was not measuring any connection to ground. Resistances check relatively close so I don't think that is an issue. I took the ICM out and and was able to take it to an Advance Auto store and they checked it on their machine and it passed multiple times, even after it heated up a little bit. So I don't think that is the problem (Whew !). So, I'm going to try and reassemble everything and check functionally if the ICM is sending the signal to the coil. Probably won't get to that till tmr due an unrelated situation.

The only other unknown at this point is why the white/blue wire is not getting +12 vdc.

Will post back after I get all my other reassembly and testing done.

Thanks.....

 

Forgot to mention, mine is a 94 SOHC vtec, 1.6 liter.

 

Okay so tomorrow morning, I'll dig through my documents and pull all the wiring info for the D16Z6 distributor. Been really distracted recovering from my surgery last week.

 

hey tom.. surgery? Hope you get better soon! not thread hijacking, just saying hope ya get better soon!

 

No worries. A little more testing completed. After having the ICM tested good at parts store and coil resistances testing good with meter, everything has been reassembled (minus rotor button, on order). I connected one spark plug wire to the coil output and put a plug on the end and had no spark. I still have no power on the White/Blue wire coming into the distributor that apparently comes from the ECU which suggests an ECU issue. The diagrams I found indicate this wire goes to the TDC sensor. I will check again but the engine light is not staying on when the switch is turned on. I pulled the ECU fuses for a couple minutes to try and force a reset to no avail.

The only other oddity I have come across so far is that when the distributor is all wired back up, there is a direct to ground short on the negative circuit of coil and the ICM. It does not show when the ICM is disconnected, Can't find anything that shows that this wire should have a straight to ground connection. But thinking through the circuit, I guess it would have to in order to complete the primary coil circuit and then switch off when the coil is triggered to fire ??

 

Finally got the missing pieces to be able to provide FSM pages relatively easily. My Honda data DVD is scratched up so gonna need to figure out how to recover that data. Anyways, maybe these pages will help.

 

What I think I need to find is the wiring from the Distributor to the ECU. If there is a short there, that could be the problem you are seeing. I am not sure if your ground situation is supposed to be there or not supposed to be. My head really isn't in the game and it's been sometime since I've spent any real time trying to wrap my head around it.

What I can do is provide factory information on the car so you can see what is supposed to be. I do hope this helps.

Just taking a fast look at the Schematic, there is two different WHT/BLU wires, the one from ECU to Distributor and on internal of the distributor going from COIL to ICM. Which WHT/BLU are you referring to as having ground. If the one for ECU to Distributor, it almost seems like maybe the shielding (which is grounded) is making contact with the WHT/BLU wire, which would stop signaling to the ECU.

I can also get you the pinouts and color codes to all the plugs going to the distributor if you think that will help. I have the ETM for the 92-95 civic which used the D16Z6 and should be pretty much the same for your Del Sol.

 

Thanks for these docs. The plug pinouts would be great if you could manage those too. This is very helpful and will let me perform some more troubleshooting. Hopefully I can narrow things down this weekend. If I can't find anything, I am thinking I will pull the ecu and crack it open to see if I can find anything obvious. Likely won't find much as board level diagnostics are not my forte but sometimes I can find obvious issues.

 

The obvious and fairly common issue with these old ECU's is usually a blown catalytic capacitor (can capacitor). Many times it looks horrible but you can desolder and remove the bad cap, then clean everything with 99% isopropyl alcohol and solder a new cap in place and be back in business.

 

Storm front moving through today so not much troubleshooting options since I am out in the weather but did have time to pull the ECU can crack it open. Nothing blatantly obvious though upon inspection, it does appear a couple of the electrolytic's have leaked some. As cheap as they are, I am just going to be proactive and replace them all since there are only eight of them and it's a cheap fix. Whether it fixes it or not, will make me feel a little better. I am also going to up the voltage rating for each one by a step up. Will see what happens but will go into next week now by the time I get the replacement cap's.

 

Update, Finally got back to it. Got the replacement caps in. Used Vishay / Sprague caps all the way through. Up the voltage rating by a step for each one. Put ECU back in, still nothing. Finally did a different kind of test (that I should have done earlier) which was to test the actual signal wire from the ecu. My meter had a Hz setting so connected that and was able to read somewhere in the neighborhood of 650 Hz on the yellow/green wire (pierced the wire to get a connection). That would equate to about 325 rpm's assuming it's sending the signal 4 times per two revolutions. I then connected to the negative on the actual coil and got a reading of around 1600 Hz which doesn't seem right. It should have matched the signal wire from the ECU. I tried connecting the other test lead to both positive and negative and got the same result. The end result is that it appears that the coil IS getting some type of signal so even though it tests good, I am going to order $10 ebay replacement just to test it. Even if it runs for a few minuted before blowing up, it will tell me something.

While I was hoping replacing the capacitors in the ECU would somehow magically fix it, at least I know have new caps an the ECU is still functioning after my work. Coil won't get here till next week so another wait before I get to the next test.

 

Conclusion. I received the cheap 3rd party coil and popped it in. Car started up though a bit rough but I figure that to the computer going through a reset since I had pulled the fuses to force that previously. Have already ordered the actual Honda coil (HondaPartsNow seems to be the cheapest option for oem Honda parts) as I don't trust the cheap coil for the long haul. It came with no box, has a made in Taiwan label though is labelled with the correct generic part number (TC-08A). Minor rust on the lams so likely sitting on a shelf for quite a while. Who knows, could be a factory second that got pushed to the aftermarket. For $10 shipped priority, it's hard to see how they make any money on it but it has served it's purpose for me.

I can only conclude that there are some areas in the original coil where the insulation broke down, probably on the secondary side where it doesn't show up with the ohm check but probably shorts when it tries to generate the much higher voltage. The lams on the original coil have also generated some rust corrosion and are actually separating near the bottom from the rust buildup. So while it was damned inconvenient for the car to break down on me, at least it was in my driveway and I have repaired what could have been a problem at a later point in time. Now I just need to get the ambition to change the original timing belt. I figure I am really pushing it at 136K miles.