Sonia's Driver

Hello everyone,

I have a D15B7 in my Sol, which died suddenly at a light last weekend.

Troubleshooting Steps:

Cranks fast and steady, no start
CEL: Light checks OK, no CEL
Pulled plugs - no spark x4
Pulled Distributor cap - wear but nothing that would cause no spark.
Tested resistance across Ignition coil - within specifications.
Tested BLK-YEL wire - 12v with ignition on.
Tachometer reads 0 while cranking.
WHT-BLU to BLU resistance checked - within specifications.
WHT-BLU to ground - less than 12v

YEL-GRN to BLK-YEL tested with ignition on - ~3v.

Although I am pretty sure that the igniter is faulty, I do not feel that I have sufficiently confirmed that the ECU is good.

My next plan was to test the YEL-GRN to BLK-YEL with the ignition on, but the YEL-GRN disconnected from the igniter.

Any suggestions?

Thanks,
Sonia's Driver

CivicxTree754

You can test to see if the ecu is good by checking the ref. voltage to the MAP sensor. If its below 5volts then its bad. Search to double check that, I just read it somewhere.

thecruzs2007@yahoo.com

check your grounds..especially the one on the thermostat for the ecu

Sonia's Driver

OK, I had an idea.

When I get home, I'm going to crank for 20 seconds straight and see if the ECU pops an igniter code.
That would assure me that the ECU is good, but it would still leave the YEL-GRN wire as a possible culprit.

Sonia's Driver

OK, did some more troubleshooting. I ruled out a lot - closing in on a probable bad ECU.

The two ground wires between the ECU and the thermostat are good, <1 ohm and ~0v with ignition on.
Crank, TDC, and cyl sensors report 330 - 360 ohm at the ECU, no connection to ground.
The wire that supplies 12V to the ECU to maintain the memory is good.

Additionally, I have replaced the igniter with a genuine part, cranked for 25 sec, and read the codes from the ECU - 8 and 15 reported.

When I turn the ignition to run, the CEL comes on for two sec and goes out. After cranking, a code is set. Cycling the ignition resets the light. Not sure about the code.

Can anyone give more details about using the MAP reference voltage to troubleshoot the ECU? I couldn't find that in either of my service manuals.

Does anyone live anywhere close to the Hampton Roads area and have a running D15B7 engine or a working ECU for one? I don't want to blow the money for an ECU if that's not the problem. I'm already $120 in the hole for the igniter.

Thanks!

Former User

When you turn the key to ON(II), does the fuel pump prime for 2 seconds?

If your reset/clear the ECU and then crank the engine for about 30 seconds, are any codes still thrown?

What was the resistance measurement for each of the three distributor sensors. They should be 350-700 Ohms, so at least one is out of spec.

Have you resistance tested the coil? If so, what were the two readings?

Sonia's Driver

I can't hear the fuel pump prime, but I live near a freeway, and I'm doing the work outside, so I was just going to buy an adapter that would fit on the service connection and measure the pressure, but I haven't gotten to that step yet in the troubleshooting.
Spark first - then stuff to burn.

I will clear, crank, and check for codes tomorrow.
BTW, does the ECU clear the code memory when you cycle the ignition? Is the CEL supposed to stay on after a power cycle if there are stored codes?

I can't remember which one is which, but the resistances are 330, 335, and 355 in the order that the Honda service manual writes the test. I know that's a little low, but I think it's close enough. I assume that value changes as the crankshaft rotates? I'll try turning the crankshaft a 1/3 turn and see if the values change.

I have tested the coil - it was within spec as listed in the Hynes manual.

Thanks!

Former User

This method is easier than measuring the fuel pressure. Remove the gas gap and put your ear to the fuel fill hole. Cover the other ear with your hand. Then have a buddy turn the key from OFF to ON(II). You should be able to hear the buzzing noise of the fuel pump priming for 2 seconds.

No. Remove the 7.5A hood Back UP fuse for three minutes or more.

Yes, but they can be lost if you turn the key OFF. So once the CEL turns on, leave the key on and immediately jump the service connector to pull the codes.

If you continue to throw a distributor sensor code for one of the low readings, consider that the resistance may not be close enough. The reading is not affected by the positions of the cylinders.

Post the two resistance readings. For an accurate primary winding measurement, you must subtract the resistance reading you get from touching the two meter probes together.

Sonia's Driver

FIXED!

When I cleared it and I cranked, I only got code 15.
(I'm used to ECUs where the light stays on when a code is stored. I don't like this whole 'stealth code' business. No big deal now that I know it, though...)

When I took the dist. cap off again to check the coil, it became apparent that I hadn't properly reconnected the ECU signal wire to the igniter. The prong was probably between the connector and the vinyl insulator, instead of positively engaged.

Thanks for your help RonJ! Next time I'll trust my diagnosis and double-check everything.

For everyone else's knowledge: if your distributor sensors measure at 300 - 350 ohms, which is below spec, they aren't necessarily bad. (Also, the spark gap testers at AutoZone are trash. Just sayin')