Spark plug

Ok I need some help with this one.

Spark plug #5 on the spark plug wire and 2nd on from the fire wall

I have 1 spark plug not firing...I disconnected the spark plug wire and the engine had no reaction. I turned the engine off and I found the spark plug wet with gas. The rest of the plugs are firing.

I changed the spark plug wire with a spare one and I have no change didn't make a difference. I changed the the coil aswell no change.

would it be just a faulty spark plug?

will the TPS have any affect on the spark plug firing.

I have fuel
I have air
just short 1 plug for firing

1989 m20

Thanks


Later on that day...........................................

Put a new plug in, I swaped out the rotor and cap and still have the same problem. that one plark plug not firing.

-changed the spark plug
-changed the spark plug wire
-changed the rotor
-changed the cap

still plug number 5 (2nd from the fire wall) not firing

Question? will the TPS or the AFM send signals to the computer not to fire that plug?

I have a spare AFM and throttle body that I will try tomorrow.

I did change the CPS 2 twice and no change in the engine

I have all new hoses

What about ICV will that send signals to the computer?

Thanks

Do a compression test on that cylinder.... no compression=no combustion=wet spark plug.

No , the tps and afm will not single out that one cylinder and the computer won't shut it down either.. not until much later, obdII cars have that capability on some models

Quote:

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Originally Posted by specialguess

Ok I need some help with this one.

Spark plug #5 on the spark plug wire and 2nd on from the fire wall

I have 1 spark plug not firing...I disconnected the spark plug wire and the engine had no reaction. I turned the engine off and I found the spark plug wet with gas. The rest of the plugs are firing.

I changed the spark plug wire with a spare one and I have no change didn't make a difference. I changed the the coil aswell no change.

would it be just a faulty spark plug?

will the TPS have any affect on the spark plug firing.

I have fuel
I have air
just short 1 plug for firing

1989 m20

Thanks


Later on that day...........................................

Put a new plug in, I swaped out the rotor and cap and still have the same problem. that one plark plug not firing.

-changed the spark plug
-changed the spark plug wire
-changed the rotor
-changed the cap

still plug number 5 (2nd from the fire wall) not firing

Question? will the TPS or the AFM send signals to the computer not to fire that plug?

I have a spare AFM and throttle body that I will try tomorrow.

I did change the CPS 2 twice and no change in the engine

I have all new hoses

What about ICV will that send signals to the computer?

Thanks

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If the injector for cylinder #5 is spraying wide open or in a stream, the spark plug can't stay firing from the excess fuel.

Swap the injector from 5 into another cylinder and see if the problem travels with the injector.

Good thinking... if it were the injector driver in the ECU, you'd lose three at a time. The coil wouldn't single ot one, only the wire could do that. Is it the plug? An inobvious crack might cause a short- or it may simply not work or be faulty. New ones can do this ;)

A compression test as Bill already suggested might be the best place to start tho. How long has it been doing it?

Is it possible your spare plug lead is also duff? Switch no. 5 with one of the other cylinders to confirm

Thanks guys I am going to try your ideas as I am stumped.

I will switch the spark plug with another cylinder
try a different plug
switch the injector to another cylinder
try another spark plug wire

Thanks Guys. I really appreciate the input

Quote:

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Originally Posted by Bill R.

Do a compression test on that cylinder.... no compression=no combustion=wet spark plug.

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The OP said "wet with gas." Your theory holds with compression leaks from both worn rings and bad valves, right?

I figure bad rings would leave oily, blackness on the plug which should be very easy to see that it isn't 'gas.' Unless the OP's car had 'virginal' oil...

Either way, a compression test followed up by a leakdown test for the weak cylinders tells much.

so I have some time now to try and figure out my problem.....Happy New Year eveyone

I tried another spark plug with a spare spark plug wire and I have spark from the Cap to the plug. Took out the new plug I put in and tested it and I have spark. All plugs are now sparking. I put back all the plugs and wires and I still have the same problem. cylinder 5 still not gettting aything from it.

took the spark plug back out and it is dry with slight traces of gas on it. it's got to be that injector. I have taken the injector power bar off and I have found the connections to be a little pushed in. I fixed the connector and I am still going to switch the no 5 injector with another one and see if makes a difference.

Not always, the plugs aren't always oily from bad rings. With no compression its very hard to get the gas to light so you end up with gas soaked plugs, doesn't have to be oil fouled.

Quote:

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Originally Posted by bsell

The OP said "wet with gas." Your theory holds with compression leaks from both worn rings and bad valves, right?

I figure bad rings would leave oily, blackness on the plug which should be very easy to see that it isn't 'gas.' Unless the OP's car had 'virginal' oil...

Either way, a compression test followed up by a leakdown test for the weak cylinders tells much.

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new injectors are cheap from five O group, dont remember off hand the exact site. If you need it let me know most the people here know who I'm talking about. PM me if no one else chimes in, I don't check here all the time anymore.

Thanks for all your help and input.

I got a used injector from a friend who has a parts car (same year, same motor). I installed the injector, hooked everything elese back up and bang.....car started up right away and runs strong with no misfire.

The only issue I have right now is after the car reaches proper teperatures or gets to a stop light it stalls, unless I goose the gas pedal. I think it could be the ICV I have changed all the air hoses and I have tried 2 different AFM's. I installed a different throttle body aswell and have the same issue.

I am going to get and OHM meter tomorrow and check the ICV......but if anyone has any ideas it would be great. I did change the CPS 2 times and that did not resolve the issue. temperature sensor and sender have been changed aswell

Thanks

Quote:

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Originally Posted by specialguess

Thanks for all your help and input.

I got a used injector from a friend who has a parts car (same year, same motor). I installed the injector, hooked everything elese back up and bang.....car started up right away and runs strong with no misfire.

The only issue I have right now is after the car reaches proper teperatures or gets to a stop light it stalls, unless I goose the gas pedal. I think it could be the ICV I have changed all the air hoses and I have tried 2 different AFM's. I installed a different throttle body aswell and have the same issue.

I am going to get and OHM meter tomorrow and check the ICV......but if anyone has any ideas it would be great. I did change the CPS 2 times and that did not resolve the issue. temperature sensor and sender have been changed aswell

Thanks

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Progress!

How 'gassy' does your oil smell? It may be so saturated with gasoline, that the car runs too rich at idle due to the PCV system.

I've 'cured' idle issues by just changing very old or gassy oil. You know the bad injector sprayed too much gas for the spark plug to fire off, so where did all that gas go? Into the oil is my guess.

So for the cost of an oil change, she very well may run right. If not, you did her a favor anyway as the oil is probably thinned out right now.

Good advice... once warm the oil is supplying more fuel vapour to the mix so the car will run rich. The ECU wil take that the wrong way and react badly. If not the oil, yo'll be missing a vacuum leak somwhere. Check the hoses adn the conectors very very carefully, it is very easy to miss such leaks.

Quote:

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Originally Posted by specialguess

Thanks for all your help and input.

I got a used injector from a friend who has a parts car (same year, same motor). I installed the injector, hooked everything elese back up and bang.....car started up right away and runs strong with no misfire.

The only issue I have right now is after the car reaches proper teperatures or gets to a stop light it stalls, unless I goose the gas pedal. I think it could be the ICV I have changed all the air hoses and I have tried 2 different AFM's. I installed a different throttle body aswell and have the same issue.

I am going to get and OHM meter tomorrow and check the ICV......but if anyone has any ideas it would be great. I did change the CPS 2 times and that did not resolve the issue. temperature sensor and sender have been changed aswell

Thanks

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clean the ICV so that it moves freely. On the stalling issue, after you clean the ICV you need to reboot the computers to clear the codes and the computer will re-learn your engine again.

Thats exactly backwards... once warm the computer no longer richens up the mixture like it does for cold start and warmup. So if you have a vacum leak like a hose or gasket, its no longer getting extra fuel to make up for that leak and the extra air getting into the engine unmetered. The engine then tends to stall at idle because its too lean not too rich.

Quote:

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Originally Posted by genphreak

Good advice... once warm the oil is supplying more fuel vapour to the mix so the car will run rich. The ECU wil take that the wrong way and react badly. If not the oil, yo'll be missing a vacuum leak somwhere. Check the hoses adn the conectors very very carefully, it is very easy to miss such leaks.

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I cleaned the ICV checked the OHM's "40-41 on the outer pins 20-21 on the middle and the other pins"

How do you reboot the computer disconnect battery or is there another trick to this.

Thanks

Just disconnect battery and turn key on to drain system completely of power.

Thanks I will do that before I head out this afternoon. I haven't driven too far since I fixed it. I will let you guys know the end results when I get back.


Thanks

still wants to stall at the traffic light.....can't find a leak in any of the intake hoses...what about that pipe that runs under the intake maifold to the engine block, will this cause my problem.


Thanks

Low mileage engine... can't be the engine... age is a factor so I would have to say it is the AFM.

Did you clean the ICV?

Quote:

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Originally Posted by specialguess

still wants to stall at the traffic light.....can't find a leak in any of the intake hoses...what about that pipe that runs under the intake maifold to the engine block, will this cause my problem.
Thanks

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need to find the source of the leak, sounds like everything else has been covered. The intake gasket could be leaking at the engine, spray carb cleaner in that area at idle. Without re-reading the whole thread did you pull the oil dipstick to see if it makes any change in idle quality? I'm still betting intake leak from the gasket due to age.

finally got some warm weather and the car has been parked for the last month. So I decided to install the new parts I ordered: sump tube, o rings, washers and new spring. Here is what I found
- no o ring in the top of the tube
- no washers used at all
- intake manifold gaskets worn
- dip stick o ring worn

So now I am off to the dealer to pick up and intake gasket and a o ring for the dip stick tube.

is there anything I should look for while I have the intake manifold off the car?

Thanks

http://www.bimmernut.com/forum/showt...ight=sump+tube

This link is what made me check out my intake tube

Of course, redo all the rubber under the manifold. Now is the time to tackle the stray vacuum leaks.

Have a gander at your intake valves, looking for differences valve-to-valve which will give you an idea about the health of your injectors.

Send the injectors for sonic cleaning? Replace their o-rings to prevent vacuum leaks...

See if the head gasket is leaking on that side (piece of mind).

Wash the engine compartment on that side. Remember, clean = fast! ;)

I am stumpped still wants to stall at traffic lights....Should I consider the oil pump? this only happens when car is at operating temperatures....could it be a bad sensor that will make the car want to stall?

Any ideas will help....I have to goose the gas pedal at the lights to keep it running.

Question what makes the car run rich? I have an M20

Thanks

Fuel injection engine temperature sensor

AFM. Disconnect your AFM and see if it idles.

This is really getting frustraighting. I have changed my AFM with one I got from a parts car, I have changed almost everything on the top end of the engine (Intake gaskets, sensors, ICV, hoses, cps and I even changed the CPU) There has to be something I am missing or did I put in a bad sensor somewhere.

Here are my issues that I am having:

1 - every day issue - car will start fine drive it for 20 mins or so to get to opersting temperature and get to a stop light and it want's to shut off unless I hold the gas pedal at about 1200 - 1400 rpm, engine light and oil light flash until I gas it.

2 - once in awhile I will start the car and it dosen't want to rev pass 2200 rpm and sputters, engine light and emergency light comes on. and flashes.

I know you guys must be getting sick of me by now but any help on my issue will save me from taking the car to a mechanic an spend money that could be used for something else.


Thanks

1989 m20 - 121,000km

Did you clean and make sure the ICV moves freely? Not sure what sensor yet but thats a real big possibility after the ICV.

I did clean the ICV and I have a spare one aswell and they both react the same way.

After read the forum......could the fuel pump or system cause the problems I am having. I had the pump changed about 10 years ago, I did do the fuel filter in October

Thanks

I'd have say change out the fuel pump... you covered everything else.