92 Civic VX stumbling/hesitation

[benfrogg]

Well, sounds like at least your EGR ports are clean enough to work. That probably rules them out for now. Not a bad idea to use the foamer either way at this vintage/mileage.

I agree it's worth some investigating into electrical gremlins. Grounds strike me as a stronger and stronger possibility..... I added grounds to my VX (search my vids on youtube, "65 + mpg") using red amplifier wire. Easy thing to do really. Didn't change much for me, but it can't hurt. It might be worth thinking about for you, given the circumstances.
Did your tach move without a corresponding actual rpm increase of the motor? If so, I think the sensor for the tach is in the dizzy. It's possible the ignitor and related sensors inside the dizzy are bad, even though you replaced the ignitor. The sensor I'm thinking may be shot is the camshaft position sensor. That could possibly give some of your symptoms, what does everyone else think?

If, on the other hand, the tach revved and the engine did too, that sensor is likely not the culprit.


Did we ever get confirmation about the coolant temperature sensor or the throttle position sensor? I'm still leaning heavily to those if it's an electrical problem....

B

[bcfromfl]

Hi Ben --

As I recall, the engine continued to accelerate (mostly) smoothly (maybe a slight pause), but what the tach did is stop at 3k, then play "catchup" when the RPMs were closer to 5k. We're talking a split second, here...the car accelerates nicely in 2nd...as you know!

I asked the mechanic about the camshaft position sensor, and he said it's one of those things that if it's on the fritz, the car basically won't run at all.

I'm not sure about the coolant sensor or the throttle position sensor. I'm making a list for when I go back to the shop. As I was looking at the diagram on Majestic's site, I saw an air temperature sensor on the back of the IM, below the throttle body. What does this do? Critical component?

I'll check out your video. I had a grounding problem with my first car, an old '68 LTD station wagon. What happened is the bumper joints rusted and no longer conducted enough juice, and the turn signals (mounted on the bumpers) wouldn't work. I think they just turned on and stayed on while the switch was engaged. That was when I lived in upstate New York, and rust was a major issue. I don't see the rust on this car like that, but I'll make a note of it.

That's really helpful of you to have done those videos. I can't seem to translate well instructions out of a manual, but to see someone actually doing something is much better!

-Bruce

[add|ct]

^IIRC, the air temp sensor on the IM is for getting a reading for the air temperature coming into the intake? Not sure exactly what it functions as, but my thoughts were relative to determining ambient temp somehow but I vaguely remember hearing it's manfiold temperature.

No need to be discouraged my Bruce, hang in there. By the way, mine wasn't really messed up. I'd say normal for the age, perhaps not changed religious oil changes, poor gas or some other maintenance slips/driving or service conditions and there, well...there you go. Going to do my valve-lash soon so I'll post pics of the valve-train area.

By the way I had an RPM tach reading related issue recently. It was during the last 'cooler' weather before the temps starting being spring/summer-like again. Since, I haven't noticed issues. Here's what happened:

Coming into Neutral and approaching/at a stop during this time twice back-to-back days my RPMs would be idling like normal from the cold start idle for 1500 trying to 'settle' as the engine got to near operating temp. I had probably driven 2 miles. The RPM tach 'dropped' to the stall mark with no actual engine RPM change.

??? I put it in gear and started driving again and the RPMs immediately started reading accurate again.

Ben, could that mean also camshaft position sensor or in that area for the dizzy relative to the RPM tach reading? I'd like to know more, even for my '92 VX if this could help Bruce as well as myself. Thanks.

I had a mechanic have the car stall on them twice with difficulty restarting but it hasn't stalled on me without a bad takeoff in first, etc. Ignition switch or stuck closed IACV? Never issue restarting. I get a lugging idle issue once at full temp, otherwise no idle problems. This IACV had the rev up/down issue before and cleaning via the TB helps, but I may remove it physically and clean/inspect gasket as well. Good chance to bleed air from cooling system since it has coolant running by this mechanical valve.

It sounds like an ignition miss perhaps for Bruce, of course the reason is in question. When the mechanic checked the belt was timing right and belt tension still fine? Otherwise, igniter and coil were replaced; so with which brand?

I have a similar 'hesitation'...a pause, at times, and it takes a split second for the car to 're-try' to keep moving. I'm not talking from lean to non-lean driving at 50-60 in 5th either, but the FEEL seems like its lean then not-lean. Sorta herky/jerky and not smooth, almost like the timing is retarded severely for a split second.

My VX @ 261,000 miles: Probably still has the stock igniter/coil/dizzy/map/iacv/egr on this car. Replaced have been Sumitomo wires with more brand new original Sumitomo, and I use the NGK plugs with the correct heat range(4043s is box code with the correct NGK part, just easier to remember for me, lol). I have replaced the dizzy cap and rotor, timing service etc. No coolant temp touched, but if things inside the dizzy are present like camshaft sensor that'd be an awesome find if it fixed hesitation. Replaced fuel filter twice, haven't tested for fuel pressure at the filter test port, thouhg.

Is it possible the replaced injectors for Bruce are of a different size/type somehow, on the other hand?

For the coolant sensor. If the readings on the 'dash' are accurate the one that sends information to the ECU could be 'slow'. The mechanic just needs to use equipment to test the voltage readings at the correct wire from the senor that goes to the ECU, unless the one on the dash is reading funny. IIRC, our car has 2. One for the ECU and one for simply the tach reading. Not sure which is where? I know for my car one is near the thermostat, is that the ecu relative sensor or the 'gauge' reading to tach sensor? I'd imagine the one with fewer wires is the 'gauge' and the actual sensor has more wires to ECU. My other is located on the front side of the cooling system on the 'upper' hose from the engine block back to the radiator. The thermostat housing one is from the 'lower' coolant hose.

I don't believe TPS go out often on these era and I'd think it'd be more of a problem if the RPMs stayed high in Neutral while moving instead of settling down. The delay during acceleration in 2nd for tach reading, I'm not experienced enough.

Changing aftermarket timing belts by 60,000 is good practice. If I don't drive it hard much and the mileage is before years I replace by 75,000 or 5 years on an aftermarket. Original dealer quality belt perhaps 80,000/7 years. Just to be safe.

I wish I could contribute more, but other than functional I'm only here to talk through certain issues related to mechanical, not so much electrical. Though, I know my IACV has stuck and idle has lugged low down to near stall before for me. At least, that is the culprit for now. I sorta hope so, even for the price of a new one if cleaning doesn't keep symptoms away long enough, it's just so easy to replace a mechanical part like that vs having to test various sensors.

Sometimes, the sensor can be fine but wiring back to the ECU or at the harness itself can be damaged some.

I had a 99 stratus I sold last year in family, immediately(like same week) it developed stalling issues soon after. ...great.

No code for this but it wound up not starting. Cranks all day, no start. Starts with starter fluid, at times, other times not. Culprit? Wiring from Crankshaft Position Sensor had detached from the secure routing back to ECU and were now touching the hot exhaust piping. This lead to frays/burnt wires. Spliced in the same gauge 18 wire, replaced about a foot/3 wires each, and the Crankshaft PS still worked fine. The car still starts now to this day.

Regarding shifting: I don't typically push the gas while I also have my foot on the clutch pedal or in gear? I usually just disengage the clutch(pedal in), then while in Neutral(cluch pedal out) I rev to desired rev match to aid the synchros then clutch pedal in(clutch disengaged) and drop it into the gear I want/ease of the clutch until it catches, and apply brakes during engine braking/coming to a stop. Or proceed to apply gas if I dropped it to pass someone.

OTOH, I usually just get to where I need and shift immediately into higher gear during normal acceleration. There is occasionally 'notchiness' and cold weather shift feel issues as well, but Amsoil MTF improved that. Currently, on Honda Genuine MTF Type-II post-clutch job but want the Amsoil MTF again.

SUM:

Map is probably fine. Check all wiring from harnesses externally mounted back to ECU, such as MAP/IACV/EGR/VTEC/IAT/TPS,etc. (though VTEC and EGR appear fine)

Worst case scenario is damage wiring that is hard to find, doubtful. Fuel system is fine? Okay, then. Even pressure at test port with a gauge test(top of fuel filter test via manual?)? Doesn't appear to be fuel related, though.

You mentioned one symptom(stalling) being fixed with a replacement IGNITER but other symptoms becoming worse after. This sounds like an issue inside the distributor/dizzy. Could be along the lines of a sensor, as ben brought up camshaft(i think crank is located inside the timing cover on some honda's, lower part but I'm not sure about our model?)

If the replacement internals are fine another 'worst case' would be distributor (which all new internals are needed, since I believe a replacement from a dealer/dealer item does not come with igniter/coil/rotor/cap, etc, just everything behind that. Worst case is a distributor. First, check wiring and sensors.

Please, find your PCV valve and report back. ONLY buy dealer item at the dealer or if forced into aftermarket get one like Beck/Arnley offer.

Some part links relative to discussion(not advocating buying any aside from PCV valve, I bet yours is SOL but try dealer first):

http://www.rockauto.com/catalog/x,ca...Z1%255D%2BSOHC

http://www.rockauto.com/catalog/x,ca...Z1%255D%2BSOHC

http://www.rockauto.com/catalog/x,ca...Z1%255D%2BSOHC

http://www.rockauto.com/catalog/x,ca...Z1%255D%2BSOHC

[add|ct]

^Ha, I figured it out. The 2-pin coolant sensor is to the ECU, the other has a snap on 1-wire that feeds the gauge at the dash, like the oil pressure switch above the oil filter, so that is the 'switch/gauge' there.

I just remembered, I heard some suggest cleaning the injector's grounding wire? Is that located under the thermostat housing with 2 or 3 wires?

[bcfromfl]

Wow, thanks add/ct! It's going to take me a bit to sort through all your great comments, but I wanted to be sure to tell you how much I appreciate you taking the time to say all that!

I've gone through four or five coils in the past 10 years or so, three within the past two. The most recent one two months ago I was told that it's a "known issue"...whatever that means. Apparently it's a plastic part that can't take the heat so close to the engine. They recommended next time it happens to replace with an aftermarket part.

I just checked out the price on a new distributor. Yikes! When I checked the diagram, I didn't see a camshaft position sensor. Is this included in the distributor?

I don't know which parts diagram is associated with the coolant sensor. Would like to find it...if nothing else, so I can take a look on my car and inspect the wires. That's good info to know about testing the right wires!

Before coming here this morning, I was Googling TPS issues for this car, and found this interesting comment on a messageboard:

"I read somewhere that a few years of the Civic had a semi-faulty wiring harness above the starter, where the grounds for the EGR, TPS, O2 sensor, etc. were held together by a metal clamp, but not soldered. If this clamp came loose, it would cause a whole bunch of aggravating, nearly unsolvable problems that may or may not set codes."

Don't know if this has any validity or not, but it seems relevant at least to some of what you and ben have suggested. I have a good imagination about this sort of thing, and wonder if the mechanic not choosing a good spot to lean on when working could have damaged an old wire or connection. This problem became worse after having the igniter changed, and perhaps a wiring problem occurred when switching things out?

The changing of the igniter was based on my recommendation. I was having the stalling problem I described, that couldn't be replicated in the shop. The mechanic showed me how to disconnect the ECU plug near the passenger kick panel when it stalled, leave the ignition key in the on position, and bridge two pins to get the Engine light to flash the code, which came back "15". After some reading, I decided to take a chance on the ignitor, which fixed the stalling.

When the mechanic checked the timing, he said that it checked out right on spec, and didn't give any indication that the belt had otherwise stretched or worn to the point of allowing the timing to change.

Sounds like you're a double-clutcher! When I was younger I used to drive really hard (but not like the kids today), and just never got the hang of double-clutching and heel-toe stuff. In the interest of fast shifting I punch the clutch and blip the accelerator when doing a 3-2, or 5-2. The way this car is geared, 5-3 isn't usually useful. Very rarely use 4th. Accelerating to highway speed (55-60mph) in this car is 1-2-5, or, if I'm getting onto a 75mph highway from a rest stop, I'll do 1-2-3-5.

-Bruce

[add|ct]

Ha, show 4th gear some love.

I noticed a frayed wire near my starter, I'll try to snap a picture and post in a bit and also of where the two coolant sensors are, and the location where I believe the injectors ground.

[add|ct]

Some pics.

PCV Valve

Hollow elbow, not the PCV valve!

Engine grounding wires

Transmission ground wire

Frayed alternator positive wire ugh!!!

That Intake Air temp sensor...thing.

What I believe to be the injector's grounding wire? Also, one of the coolant temp sensors.

The other coolant temp sensor

...and what is the sensor next to it seen here, 1 wire?

EDIT: Hmm, the last 2 images...1 may be for the cooling fan's switch at a certain temp and the 1 wire for the dash gauge? That crossed my mind just now.

By the way, another thought occurred. Perhaps there is an exhaust manifold crack or clogged cat(partially?)? Might explain the pop sound if it was exhaust pop sounds from the engine area to confuse as an engine pop?...but just a guess.

[mrmad]

If you have burned up that many ignition coils, I'm wondering if your engine grounds are corroded. Honda coils can fail if the engine is not grounded well. You don't want to test if the car has spark by holding a bare spark plug and touching it to the engine while turning the car over, that is a good way to burn up a coil. You might remove the ground wire that goes from the head to the radiator support and clean the terminals.

A bouncy tach can indicate the ignitor is near failing, but the tach output in the ignitor is a different output pin then the signal that goes to the ignition coil so I'm not sure if it necessarily means the ignitor is on its way out.

I don't have a VX, I have a CRX HF, and a 95 GSR Integra, so I don't have the exact manual for your car. I'm going by my Integra's manual, but I imagine they are very similar. The coolant temp sensor (the one to the ECU, not the gauge) is the sensor that has two pins on it. It is a thermister, or a temperature sensitive variable resistor. If you get a cheap digital multimeter and measure the resistance across it, it should be about 1500-2000 ohms when the engine it cold (at around 75F). When the engine is at operating temp, it should be around 200-250 ohms.

The throttle position sensor is a potentiometer that is fed 5V from the ECU. The honda-tech thread below shows you how to test it using a digital multimeter and how to replace it and calibrate it if you need to. I replaced the TPS on my Integra and it was not too difficult.

http://honda-tech.com/showthread.php?t=2830131

[bcfromfl]

I just got home from my trip last night.

Thanks so much, add/ct for those pics! I need to carry the computer out to the car (!) so I can match things up!

The sound I mentioned was most definitely detonation. I have heard another, very disturbing sound that I've never heard before, coming from the passenger-side of the engine compartment. It has happened a handful of times over the past few weeks during the worst of the knocking, and must be extreme detonation causing almost a "clanking" sound.

Thanks mrmad for those suggestions. I'm definitely adding that to the list of things to be tested. I just changed the ignitor because of a stalling problem, and the new one fixed that.

As I was driving on my trip (in our '98 Honda Civic sedan), I remembered that the mechanic I mentioned previously, the one who may have adjusted the idle, told me something else. I don't remember the exact reason I brought the car to him, maybe 1999 or so, but it may have had something to do with rough running and the tach needle jumping. He took the distributor apart, and cleaned and lubed the distributor shaft. He told me this was a "known issue" with some older Honda engines, that the shaft is not sumped, and will run dry...causing metal-against-metal issues when it tries to spin. He warned that this problem will keep occurring. His repair fixed the problem at the time, but I remember looking at it a few years later and realizing that removing it was beyond my knowledge and tools, so, I just sprayed some WD-40 as best as I could around the spot it goes into the block.

I'll do this again, and, if nothing else, try to eliminate another possibility.

-Bruce

[add|ct]

EDIT on my previous post:

The pic with the frayed wire is the hot/positive wire at the STARTER(not the alternator).

The PCV valve pic view is by leaning over the Valve Cover Gasket and looking down the engine block through the Intake Manifold runners, near the passenger side(from this angle, the 'hollow elbow' is on the right hand side or drivers side of the IM's runners).

PS:

Bruce, with the warmer weather down south settling in, wouldn't you know it I'm having more hesitation myself. It's this 1 or 2 second delay from a stop or slow speed while trying to move in non-lean, but it feels like the engine is stuck in lean(just for a feel description, I know this isn't happening at the RPMs I'm at + the throttle I'm requesting), but the delay to then make more power(not VTEC related) seems to point to a fuel issue(or an air/fuel ratio problem)/mechanical issue/OR ignition issue. That or timing is off or the computer is somehow retarding timing. If this car has knock sensors(not sure where, I think distributor or that area(perhaps a crankshaft area sensor as well), it could also explain this brief power 'delay'. Note, this usually is happening to me before VTEC(IIRC) or at least in 1st or 2nd gears mainly.

Going out to bleed the air from my cooling system to hunt down a low idle issue on the car, might clean the IACV today or later on since I also plan on switching the coolant over to a non-dexcool 'like' coolant(Prestone's 50/50 premix for all makes/models etc, is more for domestic vehicles that can use dexcool than this non-domestic Civic). I don't think the frayed wire at the STARTER I pictured before would cause an idle issue, but I suppose it's possible I just wouldn't think so since the starter isn't going to be turning over while driving, though I am new at the electrical portion.