ezone

You gotta check that during the two seconds the pump is running

What color(s) are on the wire you checked?

Also, what year and trim level is this car--so I can check the right wiring diagrams


One is for the ECM, and the other relay is for the fuel pump.

Well, it's not under the distributor. You gotta find the thermostat housing, there should be a pair of wires bolted to it. These are the grounds for the ECM, the main relay, and probably 80% of the things related to running the engine.

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DaBrother

1999 Civic DX
Yellow wire with green stripe, the other is black at fuel pump connector.
Guessing the 4 V relay is for ECM and !2 V relay is for fuel pump.

DaBrother

OK Checked voltage again. Get 12 then it drops of. Crank engine and voltage is 12 V then just drops off while cranking.

Well the ground looks OK. But the only way to really tell is if it is taken loose and cleaned.
Instead connected test light to battery. Light came on when touching thermostat housing, the bolt head with ground connecter and the connector itself, if that means anything.

ezone

Which battery post was your Test light clipped to?

Okay that's a problem, it should keep the pump running during cranking. Is it the entire problem? IDK yet.

Will the engine try to run on carb/throttle cleaner spray ?



Do you have a set of wiring diagrams for this car?

I'd go to the main relay, pull it out, and do the next series of checks from that connector (backprobing) Keep the main relay plugged in, stick the probe up the wire side of the connector to contact the terminals

Connector picture:



Connect test light to chassis ground
Probe

#2: 12v+ only during cranking (starter signal)
#4: 12v+ out to fuel pump whenever pump is supposed to be running
#5: 12v+ with key in ON and START
#6: 12v+ with key in ON and START (power out to run the ECM, injectors, and some other items)
#7: 12v+ all the time


Now connect test light to positive post of the battery (or use a jumper wire if you have to), so when it lights up you know you have a ground
Probe

#3: should turn on the test light at all times, make sure to check it during cranking too (ground wires on the thermostat housing)

#1: should turn on the test light whenever the ECM turns on the fuel pump relay (ECM supplies ground to turn on the pump relay)





#1 is the one I wonder about, since you said power to the pump dropped off during cranking I am suspicious that the ECM quits grounding the pump relay

DaBrother

Just to try, cranked car, got lucky, timing mark lined up with timing belt cover mark. So removed distributor cap, rotor button looks like it is lined up for No. 1 cylinder pick up in cap. Therefore, should be getting spark to number one plug at the right time.

DaBrother

Clipped test light to positive terminal.
Sprayed some starter fluid in throttle body, jumped in car. Believe it tried to start running with that little dab of fluid.
Have a Haynes manual with diagrams. Have been looking at them. It said to connect to pin 4 on relay and there is no pin four on relay. It does not have the diagram you posted of the relay connector. Thanks for that.
The pins are numbered one through eight but there is not a pin four on board as I remember. Will definitely use your diagram.

ezone

There have been a few different configurations of the relays over the years and they are not all pinned alike.

The relay terminals could be marked with numbers and might be given for testing the relay itself .....but those numbers do not correspond to anything in the wiring diagram.

If I mention a terminal number it will correspond to the harness connector according to Hondas wiring diagrams, like in the picture above. Most of the time I try to tell the wire colors instead, it's usually easier to follow.

Confirmed it needs more fuel than it's getting.

DaBrother

Made all the checks listed above at relay connector. Each time the test light came on.
Was dim during cranking but still on. Believe I have about killed the battery with all the cranking.

ezone

Wellll you might need to put a charger on the battery for a while then. Gonna be tough to test for 12 volts if the battery is dead.

So do you still only see 4 volts at the fuel pump connector while the pump is running?
Is that same wire getting 12 volts at the main relay?(yel/grn #4 in the connector diagram above)
Do we need to figure out where it's dropping from 12 down to 4 volts?

Have you run 12v right to the pump to see if that brings fuel pressure up?

DaBrother

Listened to fuel pump while cranking. Believe the car was actually about to start.

Please clarify. Ezone typed gas should spray out when cracking a fuel line connection after cranking.
When I broke the connection at the top of the fuel filter gas just ran down the side of the filter. Should I have heard a hiss sound and gas spew out?

Could the ten percent or less ethanol clog the filter after setting for so long a time?

Some little something must be missing some where.

ezone

Depends on how much time passed from the moment the fuel pump turned off until you got the fitting broke loose. (I'm thinking of either the top large bolt on the fuel filter hose OR the bolt for the same hose on the end of the fuel rail)
If it was a matter of 5 seconds I'd expect a brief and strong spray of fuel that was at almost 40 PSI to spray from around the banjo fitting bolt head the moment you got it popped loose.

If it was a few minutes that might have been too long.

If you had a real fuel pressure gauge that would be a lot better (much more accurate) to work with.

DaBrother

I am either crazy (some may say that from reading my posts) or the car is haunted.

Fuel filter never replaced so thought I would replace it anyway.
It felt like it was vibrating so put the stethoscope on it and thought the pump was running even though the negative cable is disconnected. Then check the pump and it sounds like something is running. Unplug it and sounds like something is running. Guessing there is a major short somewhere. Would not think the earth vibrates that much.

Changed the plugs too. the electrodes where worn way down and the gap was way more then 0.39-0.43 In.

ezone

Then it's can't be anything electrical on the car.


Loosen the gas cap and see if it was vapor pressure relieving itself


You can hear stuff if you keep your ear to the ground.

DaBrother

Replaced plugs. Installed new fuel filter tonight.
Turn switch to ON position, heard relay click and fuel pump run.
For a few seconds it sounded touch and go but started and ran fine for several minutes.
Sounded just fine. Then it would idle slow and then fast and repeat. After about eight times cut it off.
So what could that be? Cannot drive yet because remembered have to add more coolant since some was split and add more steering fluid.

ezone

Low coolant level could cause that, for one.

DaBrother

Added Coolant. Went for a test drive.
Noticed idle variation was only when in park after making a stop.
Heading for next stop, car hesitated then CEL came on.
Was jerking at times like it could not decide which gear to be in.
Got code P0505.
Saw a post that that could be one of a multitude of different issues.

ezone

P0505 is because it can't control the idle speed where it wants to.

Idle surges from 2000 to 1200 repeatedly? Get it to act up then:
Remove the tube or breather lid to access the throttle body and use your fingers to block the open ports visible in the opening of the throttle body. If that brings the idle speed down to normal or lower then ......
A stuck IAC valve is a good possibility. Tap test?

DaBrother

Did so.
Covered both holes. Engine sounded if it was about to stall. Did so about three times.
Covering the one round hole alone nothing changed. Covering the oblong hole alone, towards front side of engine, a couple of times, engine just about stalled.

After wards the idle changed. Instead of going up a short time and down a short time, it starting going up and down continuously. Just up down, up down. The change was not as great from high to low and was lower overall, engine not as loud as before.

Any thoughts on a good throttle body cleaner?

ezone

IAC valve is probably stuck open.
Tap on the IAC valve while it's surging. Use a screwdriver handle or tiny hammer.....hit the valve hard enough to jar its guts but not so hard you dent the flimsy metal. Knowwhaimean?

Also...got a pic of the throttle body and where the holes are? Can you follow the path from the hole that made a difference, see if that one leads to the IAC valve?

DaBrother

This must be the throttle position sensor under breather housing.
Guessing the IAC is to the right.

The oblong hole is on the front side of throttle body or towards the front of car. Air flow into IAC.

Looks like a hose goes to a coolant hose that loops back to the intake manifold. Yea, coolant hose to IAC.

Got to loosen that strap around the Breather to remove. 8 or 9 mm screw head???

Both pictures made standing on the right side of car.

ezone

First pic with the blue arrow it the TPS. DO NOT hit it.


8mm or 10mm..... There is no such thing as a 9mm fastener on a Honda unless you are in the rust belt. LBVS



Googled some pics, came back to this forum
IAC location, yes you have to get the filter housing lifted up.









And this thread has good pics too, give it a good read

https://honda-tech.com/forums/tech-misc-15/question-regarding-cleaning-iacv-d16y7-engine-2254464/

^See pics in that thread^
The goal is to free up the little barrel shaped thing inside the housing, it is a rotary valve and it is supposed to oscillate in the housing to control the air volume passing through. That valve inside must be able to rock back and forth freely, usually carbon buildup makes it get sticky. The little electric coil on the end of the valve is like the windings for an electric motor and it just isn't always powerful enough to overcome the sticking.

Sometimes just smacking it and getting it to work again then soaking it in carb spray is enough to keep it working for quite a while.
.
.
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DaBrother

Sprayed throttle body cleaner into oblong hole. Tapped on The IAC.
Believe it is OK for now. May have to take it off later for through cleaning.

Now to put everything back in place. Which may take awhile.

Many, appreciative, thanks to ezone. You da' man!

ezone

So did that bring the RPMs down to a better range?

DaBrother

Yes. RPM's reduced and idle going up and down stopped. The CEL even cleared on it's on after driving down the road and making two stops.

But wow unto me. This evening started surging again, if that is the right word, after driving awhile at 55 and driving in a near by town.

Need to spray some more or bite the bullet and take of the throttle body to get to the IAC.

Is cleaning one as shown in video's enough or will it just have to be replaced eventually be replaced.

ezone

So the tapping got it to free up temporarily....probably stuck again because it's still got carbon and goo in the passage getting in the way of the rotary valve.

More cleaning is the free way (I'm all about free LOL), keep after it until it works consistently.
If you don't want to remove the IAC valve, turn the TB on its side so your cleaner can fill the IAC chamber and let it soak for a long period of time.
Periodically rinse, if you have an air compressor you could blow it out, and repeat the soaking , you should see the fluid come out dark as long as there is still goo in the valve.
You can use carb and throttle cleaner...I've also seen water based solutions that worked on other manufacturers' valves.

I've taken the windings off so I could rotate the valve by hand during cleaning...the bolt holes are probably slotted, try to mark it so it goes back together in the same position it started in.


If you can get it cleaned enough to keep working, I don't see a need for replacement unless the windings are damaged or bad.

DaBrother

Tried using brake cleaner tonight to no avail. Could not get IAC unstuck tonight by tapping.

Hope I am not damaging the new CAT with these cleaners. Tonight bought a can of WD-40 just to get the longer flexible straw. But the nozzles are male and WD uses a female nozzle.

With your new encouragement will try cleaning more.

Now have to deal with Ford's TB issue.

Delicieuxz

I have a bag of oil plug washers, but I've never changed the washer on my 2007-purchased EM1, and it's never leaked. Part of why I don't change it is because it has never leaked, but part of it is that I want to find out if it ever will leak.

DaBrother

Sprayed more cleaner in last night.
Looks clear to me. Need a way to stop up hole to hold cleaner in valve and soak.

DaBrother

Took it all apart. See that spraying done before would not have got the job done.
Wondering if it is just enough to clean the IAC.

Cannot find a IAC gasket at parts stores online. Found a TB gasket at Advance Auto.
Would form a gasket be OK for the IAC?

ezone

Price a brand new IAC valve from a dealership and you'll be scrubbing that sucker spotless with your own toothbrush inside and out.


Because the coolant passage is exposed and is sealed by the rubber gasket, I would only use the correct OE gasket. You do not want antifreeze seeping into the throttle body and air stream!

Get the correct IAC gasket from a Honda dealer. Should be less than ten bucks.