1990 Accord EX. 4 door. 245,000 miles. AT. No CEL on. Motor is stock.

Gave her a long needed tune up. Ran fine before but now she idles/runs rough. Rough meaning it starts fine and seams to drive fine. It idles ~1500 when cold and ~800 when warm. At freeway I’m in the3K range. For sure at idle and i suspect even at speed the whole engine is cutting out. The engine shutters along with the whole car at idlebut this shuttering hardly registers in the Tach. It picks back up immediately and has never stalled or altered the overall RPM. Hard to feel at speed but i think it is there. It seams like the electrical is cutting out and coming right back. Happens continuously with the interval between micro seconds to a few seconds between. Gas mileage is terrible. (Was ~22, now ~ 16)

what i did:
New plugs. NGK V groove gapped at .044". Old ones were NGK with the very eroded gap of .070"
New NGK wires
New fuel filter
New air filter
New cap & rotor.
Checked the timing. It is @ 15 degrees but i noticed the timing light cutting out in sync with the engine cutting out. (My Electrical clue)

New coil but this was done the week prior and did not cause any issues.
Whole electrical and temp system were checked professionally a few weeks ago.
New Battery and Alternator prior to the check-out above.


Put old cap/rotor and wires back in to see if they fixed it and they did not. Also noticed that to do the fuel filter i had to disconnect and invert the vacuum control box. The 2 hoses I took off are back in the right spot and are in good shape. Would inverting the vac box do this?

Woudl like to do some troubleshooting before i through in the towel.

Thank you for your help.
Matthew

 

When you changed the rotor, did you try to start the engine with the distributor cap off? If you did that, then you could have fried the coil.

I would check that all the wires in the distributor are clean and secure, since you did work in there. Check the coil and ignitor wires.

 

To start with, you have enough miles on your Accord that you could have a burnt exhaust valve. Start by performing a compression test.


If compression is ok, here is few possible things to check out.

1. During your tune-up, when you pulled the spark plug wires, was there oil in the spark plug tubes? If so, you need to start by cleaning the oil out of the spark plug wells and the spark plug wire ends. Then you need to replace the plug seals under the valve cover as well as the seals between the rocker assembly and the head casting. The Honda Part numbers are 12341-PT0-000 (x4) and 91301-PT0-003 (x4).

2. What kind of spark plug wires are on your Accord. Use only Genuine Honda wires.

3. How many times have you replaced the distributor sub assembly on this '90 Accord? These dist. sub assemblies were known for their issues withbushing failure. If the sub-assembly is not a Genuine Honda part, replace it with 06301-PT3-A10. This part comes as a new sub assembly, cap, rotor and Hitachi Ignitor. The only thing you swap over is the coil, which again, needs to be a Genuine Honda replacement and not anaftermarket.

4.One final possibility would be the intake manifold gasket is leaking vacuum. Your car is old enough that this could definately be the problem. With the engine running at curb idletake some carb cleaner and spray it between the intake manifold and the cylinder head and see if idle improves. Be careful performing this disgnosis!!! Have a fire extinguisher with you and wear eye protection.

If you do find that the intakegasket is leaking, you will need to replace it ASAP because the vacuum leakage will cause a lean mixture which causes higher combustion chamber temps whichcan burn exhaust valves.

Let me know how it works.

Ed Brian
www.accuratecars.com

 

Sounds like a miss to me. Verify that the wires were hooked up to the cap correctly. Also, with the engine running remove the wires from the plugs, one at a time, and look for the engine to run worse; if you take the wire off and there is no change then that cylinder is not firing. Use some dielectric grease on the wire ends if you didn't already and make sure the wires are not crossed or touching any part of the engine.

There are lots of reasons for a misfire, but if it ran fine before the plugs/wires/cap/rotor then I'd be looking there first.

 

Thank you all.

It ran fine prior to the cap/rotor/wires/fuel filter and air cleaner. Ran just as bad once i re-installed the old cap/rotor and wires which should rule them out.

I did notice that the old plugs were covered in oil. New seals are on order but right now they are clean. Wires are in the right order. If i pull any of them you notice a change in the how the motor runs. The wires do touch the valve cover since some of the clips are gone. The old wires did that too.

Not sure it would be the valve or any sort of major leak as it started right after these parts were replaced. No doubt my compression is not as it was new though but it runs good and always has. Had it in the shop the prior week and they would have noticed how bad it is running now. Did not start or try to start the car with the cap/rotor off. The new coil is aftermarket and was replace to solve a faulty tach reading.

It feels like the entire engine electrical cuts out for a moment and then comes back. The whole car shutters like the engine is suddenly loosing power then getting it back.

Thanks for the ideas. I will try these out but if any other ideas come to mind i would apreciate it.

 

Your coil doesn't generate the tach signal. The ignitor generates that signal.

I have read about aftermarket parts failing out of the box, so the 'new' coil that you have might be bad. If you still have the old coil, I would put that back in there to see if the problem goes away.

 

PAhonda,

Thank you for the correction. Strange that the coil cured my dead tach. Probably i hit something else that made it correct. Will try replacing the old coil too.

 

if all this happened since you did the work i would double chk everything that you did.. all the connections, electrical wires ok ?? just for the heck of it chk the wires that go to ignitor and coil, make sure that they are not loose ,, also i saw this once,, make sure that the wires that go to the coil have the proper short screws .. i had it once where someone used a longer screw and was not tightening the coil wire properly and was causing the same issue as you are having..
Also chk the egr valve, disconnect the hose and pull a vacc on the valve engine off,, if it holds vacc valve is ok.. Then start the car and hose still off ( you will have a code but clear the ecu later ) remove the underhood fuse 7.5 amp ( back-up ) .. if engine dies or stumble .egr system is ok,, if engine does not change the egr ports are most likely plugged

Also you should always gap the plugs to the smallest setting ( .040-.044 ) you should gap them at .040,, plug gap gets wider as plugs wear ..
Asa Hondaed said,, if there was oil in the tubes you need to replace the seals,, I would do only the upper seals to start with, the ones under the valve cover,, clean everything up, chk later to see if there is still oil building up in the plug tubes if so, replace the lower rocker arm seals..
There is a write up on our DIY section should you need help to do so..



As for Hondaed.. I am surprised with some of the advices that you gave him,, doing a compression chk would be the last thing on my list and if it was a burnt valve it would do it all the time and engine would miss badly even ( especially ) at idle .

As for the distr bushings wearing down,, I have seen a lot of those , but first the distr starts to make noise ,, and if the sub-assembly were to fail ecu would register a code .
And it does not sound like a vacc leak either ..
it is nice of you to provide info and all the parts #s ..

 

Thank you again.

Put the old coil back in last night. Verified the screws to the coil are the stock short ones and are tight. (The front one, or taller of the two was oxidized) Verified the wires going from the coil to the Igniter were on. Found more oilinside of the distributor. Found this before and cleaned itup. Likely there is a seal i need to replace. Guessing it is on the shaft somewhere. Made sure none of the ignition wires were touching any metel.

It runs better now, but still stumbles. Not as harsh and not as oftain. Every second or so now. Still seams like the electrical is cutting out.

I doubt this has anything to do with it but i will put it out there. My dash is all apart right now as i also troubleshoot a faulty temp gauge. (Shoots up to hot right away even when cold) All the switches are plugged in and work but everything is hanging.

Will check the EGR and plan to replace those seals. (Probably check the timing belt at the same time) Will also probably pull the plugs and check them. May put the old ones back in if i still have them just to be sure....

Matthew

 

Problem resolved. Sort of ashamed to admit it was my faut. Two problems.

1 When installing spark plug #2, it must have slipped out of the socket and hit the cylinder head. It had no gap left.
2 Dirty plug top on spark plug #3. Left over from the old wires.

Hence my electrical issues.

Re-gapped all the plugs, cleaned up the wires, adjusted my valves and installed a new distributor shaft seal. Also fixed the temperature gauge and put the dash back together.

Thank you for all the help. My next project is the timing belt. I am sure i will find lot's on that so searching i will go.

Matthew