Running poorly after storage

[Drdestructo]

Uncovered my 91 to get it on the lift to do a timing belt replacement. Car hadn't been run in about 10 months. Stored with a full tank of non ethonal fuel.
Car started right up but seems to be running on 5 cylinders. Not intermittent. You can drive it but it's way down on power. Throws a check engine light after a few min if driven at higher revs. Light resets after shutting engine off.

Any ideas where to start? Anyone had similar? I plan to start by replacing plugs And cleaning injectors.

Russ

 

[Honcho]

Uncovered my 91 to get it on the lift to do a timing belt replacement. Car hadn't been run in about 10 months. Stored with a full tank of non ethonal fuel.
Car started right up but seems to be running on 5 cylinders. Not intermittent. You can drive it but it's way down on power. Throws a check engine light after a few min if driven at higher revs. Light resets after shutting engine off.

Any ideas where to start? Anyone had similar? I plan to start by replacing plugs And cleaning injectors.

Russ

Things to check based on your description:

* Fuel pump resistor
* Fuel pump
* Fuel filter
* O2 sensors
* Igniter unit

The fuel pump switches to high mode when the revs get higher, so it might not be switching over due to age/wear. I agree it's a good idea to at least check the plugs and send the injectors out for cleaning. I'd also warm the car up and perform a compression test- the 5 cylinder thing is a bit worrying.

 

[Old Guy]

Car started right up but seems to be running on 5 cylinders. Not intermittent. You can drive it but it's way down on power. Throws a check engine light after a few min if driven at higher revs. Light resets after shutting engine off.

I recommend that you use the service check connector to retrieve any stored error codes. The norm is that once the CEL lights, it stays on until the ECU is reset. Some of the error codes need the problem to occur 2 or 3 or more times for the CEL to stay illuminated and some of them have to have the problem occur within a drive cycle. I know that the misfire is one of those multiple events to trigger errors. On some cars the CEL will illuminate or blink when a misfire is detected ; but, the CEL will not stay on after a restart unless the misfire threshold was reached. I don't know the specifics of how the Honda pre OBDII ECU manages misfire error codes. Short answer is even if the CEL is not illuminated there may be error codes stored in what is sometimes referred to as a pending state. Those error codes may give you some clue as to what is going on.

All of those items mentioned by Honcho are possible candidates. If it turns out that you have some misfire codes pending I would add the following suspects:
- check the ignition coils for signs of deterioration
- examine the external insulator of the plugs for signs of flashover and look at the condition / color of the insulator tips. If you have an anomalous color on one or more of the insulator tips that could be a sign of ignition system problems on those plugs or a fuel supply problem on those cylinders (see dirty injectors)
- if the injectors have been untouched since 1991 your plan to have them cleaned and flow checked is a good idea

Finally, did the poor operation occur before you got around to doing the TB? If you did the TB and then started the car up the rough running might be due to a cam timing error.

 

[goldNSX]

Uncovered my 91 to get it on the lift to do a timing belt replacement. Car hadn't been run in about 10 months. Stored with a full tank of non ethonal fuel.
Car started right up but seems to be running on 5 cylinders. Not intermittent. You can drive it but it's way down on power. Throws a check engine light after a few min if driven at higher revs. Light resets after shutting engine off.

Any ideas where to start? Anyone had similar? I plan to start by replacing plugs And cleaning injectors.

Russ

This. Fuel can go bad too.
The injectors on a Honda don't seem to be as problematic after long storage as in other makes but there are exception of that rule of course.

 

[Bram]

Second on the Fuel.

Bram

 

[Drdestructo]

Hi Guys! Thanks for all the ideas! I have the car on a lift so getting the fuel out should be easy enough. My van could use that old gas! Got new plugs and will clean injectors. Don't have the injector seals til tomorrow so I can't do the injectors until then. I'll post whether this all makes a difference!

 

[Hugh]

Be careful when removing the drain plug. Loosen it slowly and carefully, slowly and safely collect the gasoline. If you remove the bolt completely you'll unleash a torrent of 18 gallons of misery and your garage will explode. Reinstall it with a torque of 36 lb-ft.

If you haven't blown up your garage or drained the fuel you might want to try adding some octane boost to your existing gas. Octane breaks down over time and your car might simply be pinging.

 

[tucsonsx]

If the gas is bad it will cause the same problem in your van and mixing it with new gas doesn't work either - just dispose of it. if it seems too thick or smells like varnish it is bad. Race fuel lasts a long time and Sta-Bil really does work.

 

[asylum]

I highly doubt that the fuel is the problem. After 10 years ok, but 10 month...

Checking fuel pump is a good idea. But I would first check coils and plugs after storage with humidity...

 

[goldNSX]

I highly doubt that the fuel is the problem. After 10 years ok, but 10 month...

I couldn't believe it at first too when I've heard it the first time. We have pretty good fuel here in Europe but it seems to be less durable in the US as I've heard of several stories over the years and all were located outside of Europe or in this forum located in the US. So I think it COULD BE a possible cause.

 

[Drdestructo]

Drained the fuel and changed the spark plugs. The three rear coil packs have rust. Does anyone know the difference between the fronts and the rears? Seems like all the aftermarket parts are all six the same. Acura has separate part numbers for front and rear but they look the same. Nobody seems to have any OEM ones.

 

[Old Guy]

I seem to recall that the difference between the front and the rear is the orientation of the base gasket on the coil and that you can turn a front coil into a back coil by spinning or flipping the base gasket. Take a front coil out, spin / flip the gasket and test it in the rear cylinder bank to see if it fits. There is a thread on Prime from at least 3+ years ago where this was discussed for the na1 cars and I am pretty sure the conclusion was, same coil with a flipped or spun base gasket (can't remember which). I will let you do the searching if you want to confirm.

I forgot, the other difference is the front coils have FF printed on the top and RR printed on the back coils. Very important if you are into concurs perfect.

 

[Drdestructo]

Okay. I drained the fuel, changed the plugs and all 6 coils, as the rear coils were rusty. I may experiment someday to see if it was a single coil causing the problems.

One spark plug was weird when removed. It appeared slightly loose in the hole and when removed it gave some resistance. Once out, with a bit of WD40, I was terrified that the threads were compromised. Amazingly a new plug with a bit of anti-seize went in like butter and torqued right up. Whew!

Started the car and it ran great. I bought all new injector seals so will probably do that job next time I'm working in it but I'm glad it wasn't the injectors. I suspect it was a loose plug possibly coupled with a bad coil.

Taking a road trip today/tomorrow and hopefully all stays well!

Cheers and thanks for the helpful suggestions.

 

[Old Guy]

A loose plug can cause two problems

- loss of compression issues if it is really loose which would show signs of leakage around the threads and plug body
- a compromised electrical connection at the thread interface can cause misfires or weak spark

Loss of compression on one cylinder or misfires on one cylinder would likely show up on the misfire codes if you had checked.

Which sparkplug was loose? There are not a lot of incidents; but, a loose plug on the middle front cylinder does seem to be a rare; but, reported occurrence with the NSX

 

[Drdestructo]

Loose plug was in Number 2 (Center rear) cylinder. Did a 300 mile road trip and all is happy now!