MrGiggles

I have recently acquired a 1990 Accord LX for a family member that I'm fixing up.

A brief history on the car: A good friend of mine's mother had the car since 2009. She drove it daily for a year (did the basic maintenance I think), until the transmission went out (5 speed.) Then she sold it to another friend of mine, who changed the tranny, and did some other small things. He drove it for a week and the timing belt broke while it was idling in his driveway. Out of frustration he was ready to send it to the junkyard so I stepped in and bought it for 300.00, to fix it into a reliable beater or part it out/scrap it and make money either way.

I threw a new timing belt on it and to my disbelief it had good compression and hadn't bent any valves. I threw it back together and it runs pretty well, but not like it should.

It doesn't like to start easily after it's been sitting for a while, it cranks fine but just pops until it takes off after some cranking. Once running and warmed up, it has an intermittent miss or stutter, but once it gets up to speed it smooths out and runs like it should. The plugs and wires are new so I don't believe these are the problem. However I think the rotor is old but I didn't see any signs of it arcing. I removed each plug wire while it's running and its firing on all cylinders but the idle is rough and sounds like an intermittent miss somewhere. I will be seafoaming it tomorrow to see if that helps at all.

The CEL is not on now, although it was last night. How do I check the codes on this?

I also have a problem with speedometer not working. It doesn't register any speed at all (needle doesn't move) and I don't believe the odometer works either. Any ideas?

Thanks

night

speed sensor

valve(s) are bent

MrGiggles

I don't think any of the valves are bent for a couple reasons.

1. All of the valves are still adjusted within spec and are all close to each other. I've read that a bent valve could have very excessive lash.
2. It has even compression on all 4 cylinders from what I can tell when it's cranking. I have not tested it yet but I don't think it's an issue.
3. If a valve was bent I think it would have a constant miss. My car misses intermittently and the engine runs smooth and strong after it gets past the stumble.
4. The car was idling when the belt broke. I understand that these are interference engines but I think it'd be much more likely to bend a valve cruising at 70mph.

Is there any way to test that sensor before I replace it?

night

just change it.

a tweaked valve can give weak compression at idle and usable compression at higher rpm.

phootbag

Graph the signal wire coming from the speed sensor. There is a specification for frequency measured against vehicle speed.

To retrieve the DTC, look under the glove box. There should be a 2-pin connector that isn't connected to anything. Jump the two terminals together with a wire or paper clip. Turn the key to the 'ON' position and watch the D4 and Check Engine light. The blinks will indicate the DTC.

As for the miss, there are a lot of things that cause misfires. A bent valve is not likely. You stated the valve lash would be excessive if a valve were bent. That is correct.

Does the engine miss more at idle or more at RPM, while under load or when cruising?

MrGiggles

It misses mainly at idle I think, and has a mild stumble if you try to floor it. Once it get running at a higher RPM, it doesn't miss at all and runs strong until you let it idle for a few seconds.

quickster

I think its...
#1 - Bad quality plugs
and/or
#2 - Improperly gapped plugs

Check to make sure they are NGK or Denso plugs. If they are anything else, swap them out.

These are good plugs and are affordable,

http://www.carpartswholesale.com/v5/...isting+Page:14

MrGiggles

It has NGK plugs in it now, I believe they are a platinum of some sort. There were some old plugs in the trunk so I think they are fairly new.

I will do my best to do a compression and possibly a leak down test today. Although I think the problem is ignition or fuel related.

MrGiggles

Just did a compression test. All cylinders were between 150-175.

When I took the plugs out I noticed each one had a different gap and one had a bent electrode. I ordered a new set that will be here this afternoon.

MrGiggles

I put the new plugs in and it ran 100% better until it got warm.

The first time I ran it I left the radiator cap half loose (so it wouldn't build pressure). After that run I tightened it up and ran it again. Then it started the miss again on the cylinder closest to the distributor. Switched plugs and it still wasn't firing on that cylinder. Out of curiosity I loosened the radiator cap to release the pressure and it started to smooth out and fire on that cylinder again. I did this twice and had the same result (when the cooling system has pressure, the cylinder stops firing. starts firing again when pressure is released). Now I am suspecting a cracked head or head gasket.

Does my reasoning make any sense? Could a faulty head gasket cause those symptoms? The oil looks good and doesn't have obvious coolant in it.

phootbag

Sounds logical. On a side note, a leaking headgasket doesn't automatically mix oil and coolant.

MrGiggles

I'm going to get some of the headgasket fixer stuff to try out in the car. It doesn't overheat and runs pretty strong if I can get it to stay sealed somewhat.

TexasRedCD5

i forget if honda runs an oring or a felt/metallic head gasket. You could be having an EGR problem. Your coolant intake line runs through the EGR before it enters the engine. Maybe the coolant pressure is causing the EGR to overload that one cylinder. Then again it could be an EGR manifold having multiple ports clogged. Caused an intermittent misfire on my 96 accord almost exactly described by your post.

MrGiggles

I will look into this.

Its only a last ditch effort.

MC Slide Hammer

I've read that air in the coolant system can cause various idle and operation problems.

Check the inlet thermostat housing (near the injectors and not the outlet housing by the exhaust manifold) and look for a bleeder valve. When the car is at op temperature, open it up (bleeder should take a 12 mm socket) and bleed the cooling system of air. Cooling system is bled when a continuous stream of coolant comes out of the bleeder valve. Close and tighten bleeder valve when done, and make sure you have your temperature setting set on the hottest setting and have your blowers going too during the process.

As for MIL, the service connector on my car was located somewhere in front of the passenger door panel on the side. Look for a green plug - I believe it's a green although I'm not sure. Short it out with a paper clip with the car off; turn the key to the on position, and if your car has trouble codes, you'll see a series of blinks. Long blinks = 10. Short blinks = 1. If for example you have code 14 and only that code, you'd see one long blink followed by 4 short blinks and then it cycles and repeats.

But maybe the rotor or distributor caps are bad.

Edit: I don't believe it's the EGR because from what I've read they definitely cause misfires when the ports are clogged unevenly, but AFTER the car is warmed up not before, and when you're moving in higher rpms. But I might be mistaken about this.

MrGiggles

It does have the slight miss but only between 2500-3000 RPM. When the cooling system doesn't have pressure, it runs great. I'm not sure how fast I was going (3k in 5th, anyone know what speed?) but it carries itself well and has good power. I will see if it burns any water in the next couple days before I continue to invest in this car. When it's cold it runs great, no miss at all.

I did open that valve when I first filled the car with water, but I will try to bleed it again to see what happens.

quickster

I always fill it up then let the engine warm up completely with the cap off. open up the bleeder valve to make sure it full. close it. turn on the heater full blast and squeeze all the hoses. You will see bubbles come out the radiator. Making sure there is no air in the coolant system does wonders for bad idling and its usually the first thing I check since I find it the easiest to start.

MrGiggles

I've been messing with it for the past couple days without any major conclusion. I did put some block sealer in just to eliminate any problems there may have been with the head gasket. I think I have the coolant system bled all the way.

While running it the CEL came on. I checked the code and it was 43 which I believe is the fuel system. I cleared it, took it for a drive, it ran like crap (missed all the way until 4k, had no power until about 80% throttle then it would take off again). For the hell of it I shut it off and started it again. Miss is completely gone and it runs like new. Any ideas? Fuel pump going bad? Old gas?

I tried that a couple more times with the same result... Start it, runs great for awhile, starts to run like crap. Start it, runs great and cycle starts over. Idle has improved since the sealer. I blew out the fuel filter but it wasn't stopped up.

MrGiggles

Today I took out the VSS. How do I test this to see if it's okay or not. Not sure if this matters or not, but the when the key is turned on the Speedometer needle moves up just a little bit.

TexasRedCD5

My accord had a miss from 2500-3000 rpm when maintaining speed, reguardless of engine temp. 3 out my 4 EGR ports were clogged and after they were cleaned, never happened again. Because it is intermittent, makes ignition problems very unlikely. The problem occuring when the cooling system is under pressure stumps me. To be honest, maybe giving all of your electrical connections a good cleaning and a coat of dielectric grease can give you some results. Whats the worst that can happen, you got clean electrical connections and can check for possible loose or corroded connections. Do all the basics before you replace parts is my philosophy on diagnostics. I always wanna put fresh fluids and clean EVERYTHING before i start diagnosing broken parts. Sometimes you can find your problem in that process.


End of my semi-alcohol impared rant on diagnostics

MrGiggles

Is there any way I can bypass the EGR system temporarily to see if this solves my miss?

I tested the sensor and it just has 9 volts all the time on the pulse wire. Doesn't change when I spin it. I'm guessing this is the problem and I have a new one on the way. Power and ground at the plug.

"A"

How old are the engine/tranny mounts?

Do they look cracked or worn?

MrGiggles

I'm not sure but I doubt they've ever been replaced. If they have it's not been recently. They didn't look too terribly bad though.

MrGiggles

I replaced the VSS and the speedometer started working again. I also changed the rotor but the miss is still there, although not terribly bad.

It mainly misses on deceleration and when you give it a little gas to take off. Once you get up to speed it runs just like it should. Wires and cap are newer and not arcing, and the plugs are new as well as the rotor.

However I did notice that there was a little bit of oil in bottom of the distributor cap when I was changing the rotor. Is this a common cause of a misfire or a common problem?

I've also been reading that a faulty EGR system can cause misfires. Is there any way to bypass or troubleshoot the system without doing the whole cleaning process (it looks pretty tedious)?

BTW, there is not CEL on. Everything seems to be working correctly except for the intermittent miss.

Thanks

MrGiggles

bump