accord96lx

My 96 accord lx 4cyl with an Automatic transmission is having trouble after I have tried fixing a rough idle.

Recap on everything I have done. All because there was a rough idle. First I tried re setting the idle screw, I got the idle closer to 750, but it still vibrated more than usual at idle.

1. Disconnected the Idle Air Control Valve and cleaned it out
2. Removed the throttle body and cleaned it out
3. Cleaned out the Fast Idle Thermo Valve and tightened it down snug
4. Checked the spark plugs, thats when I found oil on the plug wires
5. Removed the valve cover and rocker assembly
6. Replaced the o-rings
7. Tightened back down the rocker assembly
8. Did a valve lash adjustment- following the instructions from a sticky on this site
9. Replaced the valve cover gasket and spark plug tube seals
10. Removed and cleaned out the EGR chamber
11. Disconnected the fuel rail and fuel injectors
12. Cleaned and tested the fuel injectors- 2 were bad
13. Replaced the injectors and seals rings
14. Replaced spark plugs (NGK ZFR5F-11 2262)
15. Put everything back together
16. Bleed the coolant system
17. Cranked the car and it barely cranked and sputtered alot
18. Finally began to run but not that much smoother at idle
19. Drove to work
20. Engine light came on
21. Went to Oreilly and they read the code P0171
22. Took it to a local garage with a punch list of all I have done so far
23. They replaced the fuel filter-code cleared
24. Still runs a little rough at idle, even noticing what feels like a slight misfire
25. Removed the map sensor to see if it might be clogged somewhere, it wasnt
26. Replaced the Plug wires (its been over 72k since the last time I did the wires, distributor cap and rotor also)
27. Drove it and its still got the same slight vibration and slight misfire feel

When sitting at idle with the brake pedal depressed I tried all gears just to see how the vibration felt and its the same in all gears except neutral, not sure if thats useful to know.
Im waiting on the distributor cap and rotor to be delivered in the next few days and Ill install those too.

If anyone can help Id appreciate it.

ColeCooper90

I'm willing to bet it's the spark plugs. Replace them with new NGKS and make sure they're gapped properly.

I just realized that it says you replaced the spark plugs, but I cant stress enough that if you used anything but NGk,s, itll cause problems like such. Mine even did it with denso plugs.

accord96lx

Thanks, I did use NGK ZFR5F-11 2262 and gapped it to 1.11
Ive updated the post.

brakedrum

It could be something else, but bad motor mounts will cause vibration, but not necessarily only at idle.

At least you should visually inspect the mounts, especially the front one. A bad one will be visibly deteriorated and easy to spot. Even in daylight, use a bright flashlight so you can get a good look at the mounts.

There could also be some slack that has developed over time in your balance belt (if your Honda has one). My 93 does, and a vibrating idle would be symptom of that belt having too much play in it. Something to check.

accord96lx

Thanks Brakedrum, In 2013 I had very similar issues with idle vibration and went through a bunch of stuff then. I did replace the front mount myself but had a garage do the rear and side mounts. I remember replacing the mounts first and it didnt seem to fix the problem. Shortly after that I cleaned out the throttle body and idle air control valves and such and it didnt stop the idle vibration right away but seemed to have broke in and stopped idling rough after a day of driving. But its back now, so I started with what I remembered doing with the cleaning. Ill double check the front, but how do you check the others..what to look for? On the rear one, the mechanic that replaced the fuel filter the other day had told me he checked the rear mount and it was fine..but Id like to know how to myself.

On the slack in the belt..is there a best way to check for that? A tension gauge?

Also someone mentioned the main relay as a source of the problem here, but I assumed that it was a pass fail type part. Working properly or not at all. I had replaced the main relay about 4 years ago when the engine wouldnt turn over.

AmericanPie

Sounds like the car has had this issue for some time. Is it possible that the balance shaft is out of phase by a cog or two, causing an out-of-balance situation? Maybe the last person who did the timing belt service didn't get it sequenced correctly. Heck, for that matter maybe the timing belt itself is off.

Another possibility is that the harmonic balancer is damaged. My '97 Accord was idling rough for years until a Honda tech discovered that the rubber lining separating the inner and outer rings had sheared and the outer ring had moved, thus throwing off the balance. My theory is that somebody damaged the rubber section when trying to remove the balancer (again, maybe during a past timing belt service?).

MAD_MIKE

What is your idle speed in Drive?
Verified the rear engine mount control is not stuck. On A/T cars the mount should operate in a way that when the car is in drive(stopped) the mount should allow the engine to 'float' for smoother operation and then the mount stiffens under acceleration. If the mount is stuck in the 'stiff' mode the car will vibrate much like when inserts or solid mounts are used.
What is your fuel pressure?
Verified the FPR is working correctly?
Done a compression check?
Verified base timing is correct?(yes 97/97 is not adjustable, doesn't mean it is spot on either).
Backprobed the TPS and verified linear voltage change with throttle opening/closing?
Tested MAP sensor with vacuum pump to verify linear voltage output change?
Verified thermo sensors are all within spec?
Verified the HO2S is not lazy or malfunctioning?
Verified non of the belt driven components are sticking or dragging?

accord96lx

I wouldnt be surprised if there was some damage done from the last timing belt replacement.
Here is my thread from 2014 when the garage I took it too messed up
https://honda-tech.com/forums/honda-...ement-3197780/
In the end they agreed to redo it, but in the process of the mess up something could be off.



Madmike, I need to learn a lot more to do all of whats on your list here.
For now I can say that the fuel pressure after I tested today goes like this after watching this video

When running in drive and parked at idle the RPMS look like this



With the fuel pressure regulator vac line off the regulator and pinched - 44 PSI
When reconnected to the fuel pressure regulator - 35 PSI

Also I did check the front motor mount and from what I can tell it looks fine, here are pics






Something I noticed after running a test from park, reverse and to drive today.
With a buddy in the car running and a foot on the brake the car was placed in reverse and drive from park.
When going from park to reverse the engine side closest to the firewall dropped, the same for drive. Placing it in park brought that rear side of the engine back up.
Is this normal? Or does that indicate the rear motor mount is shot?

accord96lx

The RPM pic in drive

accord96lx

Motor mount pic that didnt go through in the first post

DCFIVER

Start the car and sit in it for about a minute or so,then shift to neutral.

Does the vibration noticeably decrease?

Shift into drive,does it increase again?

accord96lx

Thanks for the reply!
I cranked it up and let it run a few min and then shifted to reverse and it started vibrating, then neutral with much less vibration if at all, then to drive which brought back the same level of vibration as reverse. Vibration that rattles the keychain a bit.

colonelcorto

DCFIVER

The mounts are bad.

Id try replacing the front and rear ones first. If it doesn't solve it,then do the sides.

Aftermarket mounts are horrible. Even when brand new. We don't even offer them here at our shop unless there are no dealer mounts available.

The cheaper the mount,the worse they are. OEM mounts are the only way to eliminate the vibration completely.

However if you cannot get dealer mounts,We've had moderate success with Anchor brand mounts.





Thats my internet diagnosis with no direct access to the vehicle....

accord96lx

There has been improvement lately after I noticed that the negative battery cable was not on snug. The shim that was added to the post had been deformed so much from all of the disconnecting I had done during repairs. So I bought a new set of shims and tightened it all up and it runs a bit smoother now. Still though the idle...it wants to hang lately at 500 and a bit below at times. Ive tried different adjustments on the idle screw but it hasnt helped yet. I think the further its threaded out it seems to be closest. It does though wiggle a bit since its so far threaded out. When its wiggling though I can pull towards the passenger side with it and the idle increses more. But because its so far threaded out it doesnt hold in that position when I let go.

Is there a way to modify that post a bit to increase the idle? Im sure theres a proper way to get the idle back to around 750 where it behaves, Ive tried a bunch of stuff already and had no luck.

In fact I took it to a garage Ive had good success with. They are fair and been able to trouble shoot very well. I left it with them for a week with all of the notes to show whats been done and see if they can track it down. They came up with nothing though. I asked about the motor mounts and balance shaft belt and they said everything checked out fine on all those.

MAD_MIKE

Warm the engine up to full operating temp, let the radiator fans cycle. Turn off.
Open the hood.
Connect a tachometer to the white speckeled blue wire with the big rubber cover on it over by the main wire harness connectors.
Disconnect the IACV wire connector to disable ECU input.
Make sure all accessories are off, HVAC/Fan/lights/radio/etc.
Start the engine, it may need some help starting/stabilizing. Hold it at a 1Krpm for a few moments, then slowly close the throttle and allow the engine to idle.
Idle speed is 550 ± 50rpm with no load in neutral.

Idle screw is an air bypass port. If it is coked up your adjusting is not going to affect idle speed much if at all.
If the idle is low, clean the TB throat and edges of the butterfly of coking to allow the expected air to get around the butterfly.
If the idle is still low, count the number of revolutions it takes to remove the screw from where it was.
Clean the tip and threads of the screw, it will have a bit of coking. Be careful of the O-ring around the screw.
Using some TB cleaner clean out the idle screw port, you might need a Q-tip or be very careful with a small pick to remove any built up hardened carbon deposits.
Reinsert screw the original amount of turns and recheck idle speed.
Adjust until the idle speed is correct, after cleaning it should have better adjustability.
Turn the engine off.
Reconnect the IACV connector.
Pull the memory fuse for 10 seconds.(to clear the IACV code that will have been set)

Restart the engine and let it idle for about a minute
Idle should be 700 ± 50rpm. (Neutral)

Turn on the headlights(LOW BEAM). Let idle for a minute.
Idle should be 770 ± 50rpm. (Neutral)
Turn off headlights.

Turn on A/C and fan to highest setting, let idle for a minute.
Idle should be 770 ± 50rpm. (Neutral)

If the engine is not raising idle with the load increases, there may be a problem with the IACV.

accord96lx

Thanks MadMike, I'll do this tomorrow or as soon as it stops raining..

Somethings definitely wrong. When I thought I had remedied the stalling issue that its now having by adding the shim to the neg battery post and tightening the cable snug isnt helping like I thought. Its at times suddenly sputtering while driving like its going to conk out and makes it unable to accelerate. 4 times tonight on my drive home it did this. Each time I pulled over, recranked and drove some more. It would go for a few miles and then act up again. I cant believe the garage didnt experience this.

accord96lx

Ran into a few snags, first I dont have a tach. Ive got a timing gun and a multimeter, fuel pressure test gauge, and a compression tester.
I wouldnt mind picking up one, but is there a best one to get? One thats good for several types of cars?


When I had removed the throttle body last month I gave it a good cleaning. All inside and out that I could reach. The butterfly area in particular.

I removed the screw but I didnt see any o-ring




I did clean out the port as best I could with a brush from a cleaning kit and alot of carb cleaner. I cleaned the threads real good on the screw itself as well.






I reinserted the screw and put it back to where I last left it, but really I have dinked around so much with it before this that its not in an actual position that it was set to.
I drove it around a bit and its still at around 500 rpm at idle, it didnt have that sputtering conk out feel during the drive. May be wishful thinking that thats gone.


Ill re do the test you outlined once I get a tach and can find the wire you mentioned.

Its going to be in this area?

DCFIVER

2 things.

1. I addressed a vibration complaint. The thread title is about a vibration problem. You said the idle was rough, you never said it was low. If you want relevant advice,you need to be concise with your issue.


2. That is not the idle screw.


DIYers ......

accord96lx

Sorry DCFIVER, I know Im all over the place. The vibration happens at idle. The 500 range is about where its at right now. I assumed 750 would smooth it out some, it behaves a bit better there at least.
On the idle screw..I was told it was so forgive me. Is there an idle screw? Or am I screwed at idle?

Also, the garage I took it to checked the motor mounts and told me they were in good shape. I specifically asked about the one on the transmission with the vac. They said it checks out.

DCFIVER

A service manual would help you out considerably here. Even the junk ones at the local auto parts store is better than going in blind. Better yet, Google/Youtube is a good place to start. Eric the car guy has a lot of "how-tos" on Hondas.

Where you charged for checking your vehicle over?

A free inspection is worth as much. Did you mention the idle issue?

accord96lx

I began with Erics video on idle issues for my model and it was great, he stepped through alot of what I did and followed his directions. The idle screw thing though I cant seem to get from him and the Haynes Repair Guide I have only has a pic like this..which I cant tell if its a different year or not. I cant find this thing on my 96. The manual says 94-97.





I was charged $30, they kept it a week. I gave them a prinout of the numbered list I have in post #1 and mentioned both the vibration and idle issues. They couldnt figure it out.

brakedrum

If it's like the prior generation Accords, that screw will have a clear rubbery seal over it that must be pulled or pried off to get to the screw. Generally, if the screw has never been touched, and your IACV is functioning properly, you shouldn't need to mess with the idle.

accord96lx

I have a few questions on the tach install.

With the multimeter I have I switch to 4cyl and connect the black to ground somewhere and the red gets probed into the white speckled blue wire?
Also, I have ordered a BlueDriver Bluetooth Pro OBDII Scan Tool that I should have soon. Can the Bluedriver tool act as the tach for the test you mentioned or is a direct connection to the wire best?



If I need to directly connect to this white speckled blue wire, is it under the fuse box under the hood? Or inside the car underneath the dash that I should be looking for?

hondaslave1342

I hope you get this resolved..i use my scanner on live data to check rpm..i believe its your balancer shafts are off a tooth..