96 3.1 Check Engine Blinking

Once the Lumina warms up the check engine starts blinking and it starts missing badly. Similiar to a faulty ignition module and losing a couple cylinders. It's making a poping noise at the tailpipe. I had the codes checked an a egr code came up. I changed the egr valve but that wasn't it. Any suggestions? It mostly acts up in town stopping and starting.
Thanks,
Rob

Once the Lumina warms up the check engine starts blinking and it starts missing badly. Similiar to a faulty ignition module and losing a couple cylinders. It's making a poping noise at the tailpipe. I had the codes checked an a egr code came up. I changed the egr valve but that wasn't it. Any suggestions? It mostly acts up in town stopping and starting.
Thanks,
Rob

Engine transmission and mileage and tune up history would help us help you.
Is the EGR problem fixed or what code no is it throwing?
A blinking check engine light is a missfire problem.
MT

It has 205k and is an automatic transmission. The code was a misfire code. I don't have the code on me but can get it at lunch time. The O2 cat sensor sent a code also.

Like MT-2500 asked, what is the age of the plugs, wires, fuel filter, etc... Start with simple tune-up parts, especially if the code is P0300 (random mis-fire). Don't over analyze if you haven't done the basic maintenance.

The codes are P0401 EGR flow, P0300 Random misfire and P0141 Cat O2 sensor. I have replaced the EGR valve and that didn't help.
I'm considering the Ignition module or a faulty coil.
What do you think?

It was tuned up less than 10k ago.....

It was tuned up less than 10k ago.....

What brand of spark plugs did you feed it?
Are the plug wires good?
If you have a missfire or miss find out which cyliner it is.
Check for good hot spark to all plugss first thing.
MT

Two of the front (3) plugs were hand tight if that. I bought new plugs and wires and have installed the front three. I will finish tackling the back three hopefully tonight. I took the serpentine belt off and noticed the tensioner has alot of play in it side to side. The belt is only about an 1/8" from hitting the block. I'm taking the altenator out to have more room to get at the back plugs. The two plugs that were loose had the white porcelan turning gray. I'll give an update when I get the back three done. Broke two of the three wires pulling them off the old plugs.

A liberal application of silicone dielectric grease inside the spark plug boots AND on the terminals can help prevent them sticking again. Been there...

Car is running much better after changing plugs and wires. Still getting the P0300 random misfire. Only seem to have a slight miss now from time to time. I added two cans of injector cleaner to the gas. The car is driven mostly in town so maybe it just needs a good road trip and a new tank of gas.

I put new plugs and wires in the car. Still getting the P0300 random/misfire. I'm currently driving it about 5 miles one way. About every other trip it will misfire and the service engine light will flash for a few seconds and then straighten out. One person mentioned it was not burning some of the fuel. I was thinking about changing the fuel filter and if that's not it I have a spare module and coilpacks from another lumina. What do you think?

I put new plugs and wires in the car. Still getting the P0300 random/misfire. I'm currently driving it about 5 miles one way. About every other trip it will misfire and the service engine light will flash for a few seconds and then straighten out. One person mentioned it was not burning some of the fuel. I was thinking about changing the fuel filter and if that's not it I have a spare module and coilpacks from another lumina. What do you think?

A misfire is a misfire.:grinyes: :lol2:
Obd 11 should tell you what cylinder is missing.
And can cause engine damage and ruin the cat to.
See if you can find out what cylinder the misfire is on.
Then check for good hot blue spark to plugs.
But remember new plugs or wires can be bad.
What kind of spark plugs did you feed it?
MT

It doesn't tell me what cylinder. It's just a general (P0300) misfire. I'm changing the fuel filter next and if that's not it I'll try a spare module and coil set I have. It's spuratic, not a steady miss, it just comes and goes. Loss of power and then it picks right back up. Sometimes shudders at stop signs, but you hardly notice it if your on the highway doing 55........
Later,
Rob

hey bud it sound like to me you got a knock sensor problem, the engine is trying to determan when to fire and its causeing a po300 missfire, check and see if your having a egr threshold insufeshint code if your useing scanner dont do a global obd2 scann do a full pathfinder test with the vin.....

Where is the knock sensor located? I changed the fuel filter and it was plugged. I drove it about 20 miles and had No problem and then it has started again. Would a coil or an ignition module send a random misfire?
Thanks,
Rob

I don't know what brand of plug wires you are using. I have found on a lot of new wires that the ends weren't crimped on properly. I have a plug wire crimping tool and have repaired many of these as most people won't pay for new wires a week after they installed new ones. It is mostly on the plug end.
Your better off with delco wires.

Bad coils will normally throw mis-fire codes for the cylinders they fire, not a random mis-fire code (unless all the coils went bad at once, unlikely).
An ignition module can cause a random misfire code, but rarely.
Since jmiles says a bad knock sensor may trip a p0300 and p0401 (both codes you had), maybe that's your next thing to check.

the knock sensor is by the ac and the oil filter look in between there it's there look for singel blue wire i think ...

I'll give the knock sensor a try. The cel blinked all the way to work today. It's about 5 miles. It was cool and damp this morning. Ran great all the way home last night but it was about 80 degrees out then. When it acts up I have limited power but all the sudden it will just take off and the cel quits blinking.

Look for a corroded connector clean with electrical contact cleaner or brake clean. Normally an electrical part fails when hot.

Wouldn't the knock sensor send a different code?

yes it would if you got a bad coil pack it will,

get a ohm meter and check the current in each wire while running,

dont ever take off the wire while it running...

I'll give the knock sensor a try. The cel blinked all the way to work today. It's about 5 miles. It was cool and damp this morning. Ran great all the way home last night but it was about 80 degrees out then. When it acts up I have limited power but all the sudden it will just take off and the cel quits blinking.


A blinking light is a missfire.
Usually caused by bad plug or wire or weak coil or ign module.
Even new plugs or wires can be bad.
Can you pinpoint the missing cylinder?
What kind of plugs did you feed it?
Is it getting good hot blue spark to all plugs?
Run a spsrk test on coil.
Clear codes and see what code returns.
Is the egr valve code or problem fixed?
MT

The cel blinked all the way to work again today. It's about 5 miles. It was cool and damp this morning. It ran great again all the way home last night but it was about 80 degrees out then. Why is it running good when it's hot out but not when it's cool????? When a catalytic converter is plugged would that cause a P0300.
Thanks,
Rob

The cel blinked all the way to work again today. It's about 5 miles. It was cool and damp this morning. It ran great again all the way home last night but it was about 80 degrees out then. Why is it running good when it's hot out but not when it's cool????? When a catalytic converter is plugged would that cause a P0300.
Thanks,
Rob

When the light is blinking you have a missfire.
That is the time to check it for the miss.
Hot or cold or damp.
What about the other codes and whatkind of plugs did you put in it?
A plugged cat will not cause a missfire BUT A MISSFIRE CAN CAUSE A PLUGED CAT if you keep on driving it with a missfire.
You need to find that missfire.:grinyes: :lol: :grinno: First.
MT

What checks should I make? Pull a coil wire while it's missing? Check the spark going through the wires while it's running? I put champion plugs in it but it had platinum plugs before and it did the same thing. It had a P0420 code with the the P0300 the last time I had it checked. Previously it had a P0401 but it didn't come back the last time it was checked. It doesn't jar you or anything it's just a lack of power.

What checks should I make? Pull a coil wire while it's missing? Check the spark going through the wires while it's running? I put champion plugs in it but it had platinum plugs before and it did the same thing. It had a P0420 code with the the P0300 the last time I had it checked. Previously it had a P0401 but it didn't come back the last time it was checked. It doesn't jar you or anything it's just a lack of power.


The code 420 is cat code but it may be caused from the mssfire.
A good scanner would tell you what cylinder is missfiring.
I wold throw the champion plugs in the trash can and get the right AC Delco the good book calls for.
If you have a engine miss pull the spark wires off at the coils or plugs and see if you can find what cylinder is missing.
With a spark tester check for good hot blue spark out of coils and at the spark plug wire where it goesonto plug.
If good hot blue spark to the spark plugs check spark plug and cylinder compression.
To help narrow it down try to find what cylinders or cylinder is missing.
And remember you have to have good hot blue spark to all plugs first thing.
Another air if miss in damp or cold spray wires and plugs and coils with a water mist or raise hood after dark and look for fire jumping.
And if you have a good heart and no pacemaker run your hand around the wires.
Or safer way is to ground a screwwdrive with a ground wire and go over them.
Good Luck and let us know how it goes.
MT

You are better off using the OEM AC Delco spark plugs on a 3100.

But I would concentrate on the P0420 DTC. Your CAT convertor has less than ideal oxygen storage capability and is failing the efficiency test. Although typically other ignition components causes CATs to go bad and causes fixed cylinder misfires, a flaky CAT may cause a P0300 random misfire DTC. Due to excessive exhaust backpressure the crank sensor is sensing some sort of variation therefore triggering a P0300 DTC. See tech procedure at link below.

Click here (http://www.obd-codes.com/trouble_codes/generic/p0300-random-multiple-cylinder-misfire-detected.php)

BTW - Don't get shocked. The high voltage off the coils doesn't feel good.

I had autozone and advanced auto both check the codes. I haven't cleared it since I replaced the fuel filter. I did disconnect the battery while changing the fuel filter and think that should have cleared it. This morning it ran pretty good but did blink a couple times. When I put it in park after driving to work it was idling really fast. I have looked and listened for a vacuum leak but haven't located one. I sprayed some wd40 around the throttle body area trying to find a vacuum leak but haven't found one. Saturday I'll probably try the spare coil pack and module I have and see if that makes a difference. I had a crank sensor give me some problems on a 91 lumina I had and others have mentioned it might be the knock sensor.

When looking a vacuum leak spray carb cleaner or wd40 around the intake manifold and use vise grips to pinch off the hose to vacuum booster. Also spray around the injectors as a leak can occur when an o-ring is bad. If you replace an o-ring use some vasoline to lube it. Also check for any cracks in the inlet air intake.

Well, I got home and it was missing so I pulled the coil wires off 2 and No fire. Put it back and pulled 5 and No fire. Then it started running right and I pulled them and both were firing. Coil, ignition module, crank position sensor or what. I'm guessing coil. Can a module fail on one coil? Would the cam or crank sensor cause this? Anything else it could be? I'll start out with the coil first I think.

Let me know what you'll think!!!!!

Thanks,
Rob

I would first ohm the sparkplug wires. Also check the gap and if any could have a hairline crack.I found one where one wire was bad and it caused both to not fire. You won't get full continuity but you should get a reading. Less than 30,000 ohms.I would ohm the coil. 5000 to 6500 ohms across the towers.
With the tower pack removed check primary 0.3 to 0.7 ohms this is across where the plugs go in the bottom. Use a 12volt test light and check for signal across the two prongs while an assistant turns over the engine.
Next check for 0 to 1 with an ohm meter on the camshaft sensor and crankshaft sensor. It may only have one depending on the vin. no.
I think it could be the module with a bad plug wire most likely.But I'm not sure so I would test and try to find the problem.

Well, I got home and it was missing so I pulled the coil wires off 2 and No fire. Put it back and pulled 5 and No fire. Then it started running right and I pulled them and both were firing. Coil, ignition module, crank position sensor or what. I'm guessing coil. Can a module fail on one coil? Would the cam or crank sensor cause this? Anything else it could be? I'll start out with the coil first I think.

Let me know what you'll think!!!!!

Thanks,
Rob

You are gaining by finding which cylinder or cylinders is missing.
Could be ign module or coil.
But I would go for the coil first.
If you still have the spare coils and ign module replace the 2/5 coil with one of your spare ones.
good luck
MT

why not get 6 pieces of vacuum hose all cut about 2 inches in length, put them all on the coil towers, and plug the plug wires on them. It may have to be tapered at the top in order to fit in the plug wire boot, so make sure it has good contact. Then start the car. It should run quite well with the hoses wired in the system. then you can get some sort of a test light with an insulated handle or some sort. Clam one side to ground, and short out one cylinder at a time by touching the test light to each piece of vacuum hose. Listen for engine RPM drop. If the RPM doesn't drop, you have found the faulty circuit. Just dont touch the vacuum hoses while the engine is running.

I'm not quite ready to condem a coil pack yet. you cannot just simply unplug a plug wire. This is a waste spark system. plugs 2 & 5 (or whatever are grouped together on the coils) are both fired at the same time, one spark is used for compression, the other is "wasted" on the exhaust stroke. So if you were to unplug cylinder #2 to check for engine drop, you would also be breaking the circuit to #5. Does that makes sence?

so in essence, if the plug wire to number two cylinder has an open in it, number 5 would also not fire because lake of a complete path to ground. This would make it seem like a faulty coil pack. when in all actuality the cheapo wires are junk.

When I started this post all the old plugs looked fine when I changed them out. No fouling and it still had the old wires also. I changed the plugs and wires and they are new. It is doing the same thing with old and new. I'm thinking coil and will try that tomorrow. I held the end of the coil wires just a 1/2 inch or so from the coil so it should still jump that distance as it did when it started firing and not missing again. I drove it this morning and it never missed a beat. I have a (3) spare coil packs and module so I can try it tomorrow.

Could a crank or cam sensor cause a coil not to fire? I had a 91 that would jerk hard from time to time and it was the crank sensor. It kept getting worse and worse....It ran like a new one after I changed it out.

When I started this post all the old plugs looked fine when I changed them out. No fouling and it still had the old wires also. I changed the plugs and wires and they are new. It is doing the same thing with old and new. I'm thinking coil and will try that tomorrow. I held the end of the coil wires just a 1/2 inch or so from the coil so it should still jump that distance as it did when it started firing and not missing again. I drove it this morning and it never missed a beat. I have a (3) spare coil packs and module so I can try it tomorrow.

Could a crank or cam sensor cause a coil not to fire? I had a 91 that would jerk hard from time to time and it was the crank sensor. It kept getting worse and worse....It ran like a new one after I changed it out.

It could be possible but not not very likely.
The crank and cam sensor is what actually picks up a missfire.
See what another coil does.
Coil first.
If the coil loses fire first step is replace the coil and then go for a ign. module if you still lose fire or have the miss.
When you get the missfire fixed clear codes and drive it a few miles and then recheck for codes.
Fixing the missfir should clear the 420 cat code if the cat has not been damaged from the missfire.

Here ia a little info on a code P0300
P0300
DTC P0300

SYSTEM DESCRIPTION
The powertrain control module (PCM) uses information from the ignition control (IC) module and the camshaft position (CMP) sensor in order to determine when an engine misfire is occurring. By monitoring variations in the crankshaft rotation speed for each cylinder, the PCM is able to detect individual misfire events. A misfire rate that is high enough can cause the 3-way catalytic converter (TWC) to overheat under certain driving conditions. The malfunction indicator lamp (MIL) will flash ON and OFF when the conditions for TWC overheating are present. If the PCM detects a misfire rate sufficient to cause emission levels to exceed mandated standards, DTC P0300 will set.

CONDITIONS FOR RUNNING THE DTC
· DTC P0101, P0102, P0103, P0107, P0108, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0315, P0336, P0341, P0502, P0503, P1106, P1107, P1114, P1115, P1121, P1122, P1351, P1352, P1361, P1362, P1374 are not set.
· The engine speed is between 525-5,900 RPM .
· The ignition voltage is between 9-18 volts .
· The engine coolant temperature (ECT) is between -7 and +125°C (+21 and +257°F) .
· The fuel level is more than 10 percent .
· The throttle position (TP) sensor angle is steady within 1 percent
· The Antilock Brake System (ABS) and the Traction Control System are not active.
· The transmission is not changing gears.
· The A/C clutch is not changing states.
· The PCM is not in fuel shut-off or decel fuel cut-off mode.
· The PCM is not receiving a rough road signal.
CONDITIONS FOR SETTING THE DTC
The PCM is detecting a crankshaft rotation speed variation indicating a misfire sufficient to cause emission levels to exceed mandated standards.

ACTION TAKEN WHEN THE DTC SETS
· The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
· The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC
· The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
· A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
· A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
· Clear the MIL and the DTC with a scan tool.
DIAGNOSTIC AIDS
· Excessive vibration from sources other than the engine could cause DTC P0300 to set. The following are possible sources of vibration:
· Variable thickness brake rotors-Refer to Symptoms - Hydraulic Brakes. See: Brakes and Traction Control\Hydraulic System\Testing and Inspection\Diagnosis By Symptom\Symptoms
· Worn or damaged accessory drive belt-Refer to Symptoms - Engine. See: Engine, Cooling and Exhaust\Engine\Testing and Inspection\Diagnosis By Symptom\Symptoms
· Spray water on the secondary ignition components using a spray bottle. Look and listen for arcing or misfiring.
TEST DESCRIPTION

If the actual CKP variation values are not within the learned values, the misfire counters may increment.

The misfire was the 2 & 5 coil. It is running like a champ again. Thanks to all the people who gave input on this problem!!!! That's the first coil I have ever had fail. Drove it all weekend with No problems.

Thanks again,
Rob

The misfire was the 2 & 5 coil. It is running like a champ again. Thanks to all the people who gave input on this problem!!!! That's the first coil I have ever had fail. Drove it all weekend with No problems.

Thanks again,
Rob

Thanks for posting back how it went.
Glad you got it going.
Keep a eye on it and make sure the cat code 420 clears up or does not come back.
Good Luck
MT