Idle bogs with elec. load HF to D15Z1

[seeodywhy]

I put a D15Z1 into my 91 HF last year. If I plug in the cigarette lighter or turn on the turn signal or something the idle will bog down. But if I turn on the headlamps It will bog for a second or two and then increase back up to normal. It's been like this for over a year now. I'm averaging high fifties on highway road trips but I generally get 35 to 40 all city. I'm sure it is related to this problem. Also when I accelerate the car feels as though it is the timing is retarding at regular intervals. Kinda like pulsating or something. It is not the O2 as I had the hesitation problem when I first did the swap and a new sensor fixed it. I have Gone through the trouble charts but if anything is out of spec according to the charts the check engine light would be on. In other words the manual assumes the light is on. Other than that you have to replace parts until you find the culprit. Does anybody know what this could be.

[Christ]

Ditch the flow charts, and manually test all the sensors. You can find the test specs using Google.

Have you considered the likelyhood that you're entering/leaving lean-burn mode? Or that you're stuck switching between VTEC profiles?

[seeodywhy]

No its not that and i've tested the voltages and resistances of almost all the sensors. I have a volt meter to measure lean burn and it does the repeated retarding of the ignition timing whether in lean burn or not. I have put the timing light on it and it periodically retards at idle too. What about the idle fluctuating with electrical load.

[Christ]

Originally Posted by seeodywhy

No its not that and i've tested the voltages and resistances of almost all the sensors. I have a volt meter to measure lean burn and it does the repeated retarding of the ignition timing whether in lean burn or not. I have put the timing light on it and it periodically retards at idle too. What about the idle fluctuating with electrical load.

Idle is controlled by the IACV - it's the thing that has coolant running to it on the back of the intake manifold.

When there is load on the engine, it's supposed to open up some to allow more air in to account for the extra load at 0 throttle. If the wiring was soldered together, trace the wires back to the solder joints and re-wet them, they may have been contaminated at some point. If that doesn't clear it up, remove the IACV and soak it in a pail of ethylene glycol antifreeze, which will help remove carbon build up without damaging the sensor. Once you've soaked it for about a day, rinse it with clean water and then spray the hell out of it with WD 40 or something similar, plug the wire clip back in without installing it, and turn the key on, off, on, off, on, off and watch the plunger in it. It should cycle through full on and full off each time you cycle the key.

[seeodywhy]

I cleaned the hell out of it already but i'll try taking it off the manifold to see if the plunger moves. I just gave a friend a ride home and it is still losing power at regular intervals. Like every second i'll get a slight power surge. I think they are all related.

[TomO]

The electrical load issue would be related to the ELD (Electric Load Detector) found in your under-hood Fuse box. I'm not sure if there is a test procedure for the ELD but you might search on Honda-Tech as I remember there being and ELD specific tech thread in there.
ELD Thread 96-00 Civic related but may still contain useful info.
HOW TO CHECK THE ELD
ELD Search

The HF under-hood fuse box has an ELD in it as well as the VX one. My only concern would be if the wiring is the same to the pins on the ECU.

The ELD detects things like the blower fan or headlights putting more of a draw on the electrical system, it then tells the ECU to kick up the idle a tad (100-150RPM) by changing the position of the IACV.

I have personally seen the HF ELD go bad before and the symptoms were a weak idle and dying engine in idle when headlights, climate control, or radiator fans turn on.

Sometimes the idle will bog for a second as the headlights come on or the cooling fan turns on. Sometimes the system takes a second to catch up due to carbon buildup in the intake or IACV.

I find my VX "pulsating" as you've described while lightly accelerating. I believe it to be a measure of the ECU programming to save a little gas during acceleration. It may be more noticeable in your HF as it is even lighter than the stock VX.

The ignition timing will retard and advance under idle as the ECU is compensating for lean/rich mixture, this is normal.
In order to check true base ignition timing you must jump the service (CEL) connector on the OBD1 ECU and check timing that way. Since you've done an OBD0-1 swap you'll have to check to see which ECU pin to ground in order to get into diagnostic mode.

Have you cleaned the EGR passages? EGR Cleaning How-To

Hope this helps

[seeodywhy]

I checked the eld. But i was thinking about trying to get one anyway. My O2 sensor passed all the tests too. When I replaced that it fixed the problem. I cleaned the egr valve but not the ports. I put 8 inches of vacuum on the valve and the engine bogged down so that means the ports aren't clogged shut. What kind of flux is good for soldering the wires because my soldering looks like crap.

[bgd73]

fairbanks aK...driving a 1991 HF(?) what is an "HF"?

I could mention cold weather phenomonas that stay all year in unibodies. Ithappens after just 5 in maine...the electric bogs begin... Examine channels,and oil base paint. this could bneed grinding and welding.say bye bye to the juice killers. Ignore the water gas smell...the oil based paint wins.

I run a 23 year old sube, from alaska. moisture got everything, the sube is a springy little buggy and does starnge things. water gas is the survivor, at the expense of electrical hog. it was electrical madness, just boggy hog with the alternators. It is not just unibodies, I learned this years ago living in maine...and yes, I am serious.

you get very cold in places that cars are not from, its like feeding a tropical bird in the north pole to stay alive. A well known subject here, for anyone that keeps their machines for many years. (more than 10), and it is a strange subject for big heads in the warmth called "engineers"

[seeodywhy]

I actually drove it here last january from baltimore and it was doing this before during and after. You are right though. Things like my intermittent wipers don't work when it gets really cold.

[some_other_dave]

Originally Posted by bgd73

fairbanks aK...driving a 1991 HF(?) what is an "HF"?

CRX HF, the "High Fuel efficiency" model. Rated at 50 freeway MPG stock, without a lean-burn engine or VTEC or anything more advanced than fuel injection.

The problem you (bgd73) are describing is "bad grounds". Could be a suspect in this case, but I would be more inclined to check the solder joints as was indicated earlier.

-soD