jeffcat

We have an '89 D15B2 that has zero trouble starting when cold. The battery, starter, and all that is fine. It starts right up with no problem....runs and drives great.....until it gets to operational temp, and then it ABRUPTLY and IMMEDIATELY dies with no stumbling or anything. Once it's warm, it will not refire. The starter will turn over, the fuel pump primes, and everything, but there appears to be no spark. If you leave the car cool all the way down, it will fire right up.

So, we pulled the main relay, and I didn't see any cracks in the solder joints, although it did show some signs of rust on the solder joints. So, I resoldered the main relay anyways. It did not fix the problem, so we are stuck here. Any help as to what else it might be? I thought maybe an ignition control module, but it runs great when it does run. You can take it down the road and gun it, and it runs perfectly fine...until operational temp comes.

jlicrx

any codes showing on the ECU? - sounds like a classic ignition control module (igniter) problem, which would be giving you a code 15

Former User

Does unplugging the ECT sensor or O2 sensor prevent the problem?

And as mentioned, also post the CEL codes.

jeffcat

Unfortunately, I didn't check the ECU code yet. I may do it tomorrow or Wednesday. The car is 50 minutes away. I didn't have much experience with Honda OBD0 or OBD1 or whatever the 1989 model is.

If it would be an ignitor, coil, distributor, etc., how interchangable would a D15B1 part or a 90-91 D15B2 part be? I was astonished at how many parts are different between the 88-89 and 90-91 models. Almost everything has a different part number.

Former User

Pull the CEL codes, and try the unplug tests before you start replacing parts.

jeffcat

Well I didn't take this video but here is what we saw. I don't really understand why the lights are different in intensity. I was guessing it would be code 15, but I can't even decipher this.


EDIT: I drove an hour down there just to look at the lights myself. It doesnt have a long pause light that would indicate 10 and then a series of quick flashes. All it does is blink 15 times consecutively, pause then blink 15 more times? I was under the impression that you needed a long pausing light then 5 quick flashes to get 15, but i guess not. Regardless, it's code 15.

jeffcat

Replaced the Ignitor and main relay today. After replacing the ignitor, code 15 away, but now the damn fuel pump won't prime. Now I only have Code 16. Even though, it's not running at all now, I think the starting then stalling issue is fixed as the old ignitor I pulled out had no thermal paste between the ignitor and heat sink.

When the car would temporarily drive then die, the fuel pump worked fine. You could turn the key, and hear the pump prime. I've tried soldering the main relay, with no change. I bought a new main relay...no change. It's frustrating as hell because you fix one thing, and now something entirely unrelated is failing now. Is there a fuse for the fuel pump somewhere. I didn't see one the interior or exterior fuse box. I can hear the new main relay clicking, but no fuel pump priming.

fcm

It is possible the problem is the fuel pump itself, test the fuel pump power lead, at the PGM-FI Main Relay for power, [should be a yellow lead]. 94

jeffcat

I'm just going to pull the fuel pump out of the car and hook it up to the battery and see if it works.

I find it quite miraculous if the fuel pump suddenly died in conjunction with whatever was causing the code 15(probably igniter that was replaced).

The fuel main relay clicked. Fuse 14 is good. I have seen previous threads where people speak of a loose ground on the thermostat housing, but I looked at the thermostat housing on this 89 LX and there is no electrical ground to be found. Where is the ground for the main relay?

Synopsis:
1st day: Purchased car. Car starts up, runs and drives great, until warm....suddenly dies. Fuel pump is audibly priming normally
2nd day: Car starts....warms up....dies....Car cools....starts again...dies again. Fuel pump primes normally....you can even accelerate full throttle down the road, before it dies after warming up. Code 15: Ignition issue
3rd day: Code 15 and Code 16 show suddenly despite no changes being made. Fuel pump no longer primes.
4th day: Soldered original main relay despite no noticeable problems. No change. Car turns over, but no longer even starts...even when juicing battery with another car.
5th day: Purchased new main relay and installed new Igniter/Ignition Control Module. Code 15 is no longer present. However, Code 16 is still present. Fuel Pump still will not prime with new or old main relay. Both main relays do audibly "click" though.

jeffcat

Well I went down and checked on the car....again. I found the thermostat ground and took it off and cleaned it. The car was doing the same thing and cranking but not starting and the fuel pump wasn't priming. So, I jumped the circuits in the fuel pump main relay like in this video.
https://m.youtube.com/watch?v=h_ArpwIYstA

Needless to say the car's fuel pump primed and started right up on the first try and ran. So, should I deduct that it needs a main relay or what? I soldered the original honda relay and it clicks when you turn the key over. I bought a replacement aftermarket relay which also clicks.....yet the car won't start with either one.

4drEF

Have had this issue twice.
Once with an old battery.
The other time was the main relay.

And from your newest post, it seems like a main relay.

fcm

The PGM-FI Main Relay should click three times, [when ign. switch is turned on] the first two clicks are very close together so it can sound like one click.
The first click is the fuel injector relay turning on, the second click is the fuel pump relay turning on, after no more then a few sec. there is a third click, it is the fuel pump relay turning off after priming.

The "bypass" you link is not telling you what the problem is, it is just a bypass..

There are 3 powers to the PGM-FI Main Relay, start by looking for them, unplug the relay and test
1- 12V+ constant, hot at all times.
2- 12V+ switched, hot in run and start
3- 12V+ switched, hot only when cranking to start..

Sorry I do not have the wire colors for an 89 Civic, but you do not need them to test for the powers.

There are two power outputs from the PGM-FI main Relay, one from the injector relay, hot in run and start, you will have to plug the relay in to test for it, the other power out is from the fuel pump relay, hot when priming, [no more the a few sec. once ign. switch is turned on and once engine is running].
The last two leads are the relays ground, [black] should have full continuity to chassis ground at all times, [test with multimeter] the last lead is the ECU fuel pump relay control lead, [ground] may be a green/black
To test it, once you have located all the other leads and confirmed you have powers and ground plug the relay in and turn ign. on and use a jumper lead from the black ground lead to the control lead, or jump from chassis ground to the control lead terminal.

If that makes pump run the problem is the ECU or wiring between the ECU and the relay. 94

jeffcat

Yea, the relay only clicks 1 time when turning the key to the "on" position, but the fuel pump won't run.

fcm

So fuel pump relay is not turning on, check ECU control lead to PGM-FI Main Relay, simply ground that terminal with a jumper, if the pump turns on the problem is the ECU or a wiring problem. 94

jeffcat

Electronics are not my friend, so this is a worst case scenario for me.

I actually found another relay in a junkyard....didn't work....so clearly it's not a main relay problem(the relay itself).

I did however perform these tests:
https://honda-tech.com/forums/honda-...-pics-2535047/

Mods should post this in FAQ!

1991 Honda Civic Hatchback L4-1.5L SOHC (16 valve)

Testing and Inspection

NOTE: If the car starts and continues to run, the PGM-FI main relay is OK. (My car doesn't start or run any longer in a normal state without bypassing the relay, so I didn't do this part as 2 OEM relays have not worked, and 1 aftermarket one also has not worked)
NOTE: Pay close attention to the diodes!!! This just bit me. Power can flow only one way through a diode. The diodes are the triangle arrow looking symbols in the Main relay diagram. The 'arrow' is the direction of current flow from positive to negative. Guess I should of read the directions more closely.
MAIN RELAY TEST


1. Remove the main relay.
2. Attach the positive battery terminal to the #4 terminal and the negative battery terminal to the #8 terminal of the main relay. Then check for continuity between the #5 terminal and the #7 terminal of the main relay.
a. If there is continuity, go to step 3.
b. If there is no continuity, replace the relay and retest.
3. Attach the positive battery terminal to the #5 terminal and the negative battery terminal to the #2 terminal of the main relay. Then check for continuity between the #1 terminal and the #3 terminal of the main relay.
a. If there is continuity, go to step 4.
b.If there is no continuity, replace the relay and retest.
4. Attach the positive battery terminal to the #3 terminal and the negative battery terminal to the #8 terminal of the main relay. Then check for continuity between the #5 terminal and the #7 terminal of the main relay.
a. If there is continuity, the relay is OK.
b. If the fuel pump still does not work, go to harness test.
c. If there is no continuity, replace the relay and retest.


MAIN RELAY HARNESS TEST

1. Keep the ignition switch in the OFF position.
2. Disconnect the main relay electrical connector.
3. Check for continuity between the BLACK wire (pin 2) in the connector and body ground.(Didn't check...I'm going to next time)

Fig. 33 Main Relay Harness Test (pins 1 and 2)


Fig. 34 Main Relay Harness Test (pins 2 and 5)


4. Attach the positive probe of the voltmeter to the YELLOW/WHITE wire (pin 1) and the negative probe to the BLACK wire (pin 2).
a. Battery voltage should be available. (It was like 11.4v...close enough)
b. If there is no voltage, check the wiring between the battery and the main relay as well as the ECU fuse (15A) in the main fuse box.
5. Attach the positive probe of the voltmeter to the BLACK/YELLOW wire (pin 5) and the negative probe to the BLACK wire (pin 2).
6. Turn the ignition switch ON.
a. Battery voltage should be available. (It was like 11.6v...close enough)
b. If there is no voltage available, check #14 fuse and the wiring from the ignition switch to the fuse box, and the wiring from the fuse box to the main relay.
7. Attach the positive probe of the voltmeter to the BLUE/WHITE wire (pin 4) and the negative probe to the BLACK wire (pin 2).

Fig. 35 Main Relay Harness Test (pins 2 and 4)


Fig. 36 Main Relay Harness Jumper Test


8. Turn the ignition switch to the START position.
a. Approximately 10 volts should be available. (I only got 8.6v...possibly the issue, or just multimeter error as all the readings were lower)
b. If there is no voltage check the #2 (10A) fuse(It was ok...I even changed it) and the wiring between the ignition switch and the fuse box, and from the fuse box to the main relay.
9. Connect a jumper wire between the BLACK/YELLOW wire (pin 5) and the YELLOW/BLACK wire (pin 7).
10. Turn the ignition switch ON.
a. The fuel pump should work. (And the fuel pump does turn on)
b. If the fuel pump does not work, check the wiring between the main relay and the fuel pump, and the wiring from the fuel pump to the ground (BLACK wire).

So, now I am left here pulling my hair out here. Could it possibly be an ignition switch issue? I REALLY, REALLY don't want to go hunt through all that wiring. I went back yesterday and bypassed the main relay harness with jumper wires, and the car started right up and I drove it around for 30 minutes without an issue....it ran great.....but I'm limited by this stupid little problem. Every test on there gets power.....even if it's not enough. If not's not getting enough power, what would be the cause of that? It gets most of the power, but perhaps not enough to cross the threshold to click the relay I'm presuming.

I didn't check the ground continuity yet(missed it). My question is where are all the grounds pertaining to this system of the car? I aimlessly checked the ground on the thermostat and valve cover, disconnected it, cleaned it, and reattached it, but that's the only one I have done anything to really.

4drEF

How do you know the relay you got from the junkyard was good?

fcm

Use a jumper to ground terminal #8, ECU A12, 14 [with relay plugged in] you can jump from terminal #2 ground to #8, the ECU would normally supply that ground, it may not be, or there is a connection problem between the ECU and the PGM-FI Main Relay, [terminal #8] 94

jeffcat

I don't for sure, but the car originally started and ran fine when we first purchased it. It would at least drive around and the fuel pump ran. I resoldered the original OEM main relay....no change. Purchased an aftermarket brand new OEM replacement.....no change. Pulled the same OEM replacement from the junkyard....no change. Admittedly, I haven't checked them, but I would find it highly unlikely.

Former User

Did you ever do these simple tests? Start with the O2 sensor.

jeffcat

Sorry, for the confusion. So you are saying plug the main relay into the main relay harness, then use a paperclip or wire to ground terminal #8 on the main relay harness the the chassis?...then what? I know of the ECU pin points on the ECU, but I'm having difficulty interpreting what you are stating exactly. Sorry for my lack of understanding.

jeffcat

Not yet. How would they prevent the fuel pump or fuel pump relay from working?

Former User

Sorry. I was going off the thread title and first post where the pump was priming.

Have you tried a known good ECU?

jeffcat

It's all good....the problems keep changing lol.

I don't know anybody that has an ecu laying around although I could buy one for $35 from a junkyard, although I'd rather not spend the money for it if I don't need to.

Former User

With all other connectors plugged in, unplug ECU connector A.

Turn key to ON(II).

Use a piece of wire to ground pin A12 to the metal frame under the dash.

Does the fuel pump run as long as pin A12 is grounded?

Repeat test with pin A14.

Post the results.

jeffcat

I'll give it a try when I get back on Monday. We have to race the miata this weekend at NCM. I'll post the results. Thank you guys for the support.