The Mighty Texan

iTrader: (4)

I've already got a thread going in here on a problem I'm trying to find on my car, story short fuel consumption and bad performance. I've been doing about all I can so far and the only thing I've got left is to take it into a shop. There aren't any reputable shops around here, most of the places aren't that great and are extremely over priced and lazy so I haven't wanted to take it in. I was calling around and getting quoted a ballpark of $300 typically to find the problem on my car they claim. This seems pretty ridiculous to take 5 hours at $60 an hour to find out why my car is misfiring and having a big enough problem to be burning 14 gallons in 160 miles of grandma driving. I don't know much about analyzers but seriously that much? I figure it should only take an hour at most to find the general source of a problem like that.

LS6427

iTrader: (2)

There's only so many things that will call misfires. One of the most commonly overlooked thing is bent valves. Fuel injectors, plug wires, spark plugs and coils are all free to check.

A leak down check will find a bent valve.

Also, don't overlook a bad or failing PCM. They get old and burn out. Mine did.

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The Mighty Texan

iTrader: (4)

I have heard kind of a buzzing or electric sound coming from the glove box area and it also has been taking a bit to long to turn over when I start it but I don't think it's the battery.. Is there a way to check the PCM? I've checked all the above, except o2's and the valves. I replaced the plugs and wires, and PVC valve ect.. I checked the injectors and the spray looked normal from what I could tell.

It just seems that a quick look on a engine analyzer would show a big problem fairly fast. I understand if it's a bunch of things adding up here and there and finding them all.. Any suggestions? Do I really need to send it in for $300 when I've done most everything already? Thanks for the help again ls6

LS6427

iTrader: (2)

I think it would take a tuner to let you know if the PCM has a problem, not just a regular scan with an OBDII. Maybe if there's someone around you that has EFI Live or HP Tuners or the like, they can help you there.

I'd also make sure there's no corrosion on any of the battery cables, check them at the starter and alternator too.

Also, the ground wire that goes from the PCM to the engine might be corroded or loose. It attaches to the back of the passengers side head....I THINK........

An OBDII scanner can tell you if the 02 sensors are going bad.........

and NO.....just get someone like a tuner to hook it up, no need for a $300 inspection.

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The Mighty Texan

iTrader: (4)

Ok I will check all of that thanks! As far as a tuner, I don't know of any
in the tri cities area, what would be the best way to locate the nearest? I don't know of anyone with hp tuners or any ls tuning software, I think there's 3 camaro's in this town haha

01ssreda4

iTrader: (96)

O2s or Maf starting to go bad can really tank gas mileage. I had a MAF out and my mileage was down to about 75-100 miles a tank

The Mighty Texan

iTrader: (4)

The Maf sensor? Yeah I figure I should replace the o2's next.. 94k there Gunna be bad soon if they aren't already.. The thing is the ones on there aren't stock so I don't know how good they are.

The Mighty Texan

iTrader: (4)

I unplugged the PCM to give it a look, looked great but after plugging it back in I tried to start the car and it just kept turning over, it got flooded so I came back later and tried. It ran but sounded horrible and not good to drive on at all, also threw a service engine light, ses light was on also however it is usually on for secondary air. Any ideas what this could be?

samson_420

iTrader: (1)

Man, slow down. I know it's tough.

Check out all of the connections specially on the PCM.

There are only so many things you need to check on your car.


You should be alright, just check everything twice.

The Mighty Texan

iTrader: (4)

Problem Fixed: replaced ignition relay. Thanks guys!

The Mighty Texan

iTrader: (4)

I spoke to soon listen to this,

After i switched the ignition and starter relay i went for a drive to reset the pcm and everything was running great, no problems starting, strong power, little gas used.

Afterwards and after the car had sat for a while i went to start it to go to the store and get a new ignition relay, it had the same problem and took forever to turn over. Once it did start it ran horrible and was shaking and flashing SES. After pulling the 0300 random misfire code i bought bought new relays and started the car up, no change.

I noticed the ignition relay was very warm where as the starter was not.

With nothing fixed and it still misfiring, i did the usual checks around the engine bay with nothing standing out.

The car would not start and just kept cranking, so next, i switched the ignition and starter relays again. This time turning the key did absoultly nothing. Switched it back and it cranked all day again. Since i was wondering if it was fuel pressure i let it sit for 30 min and did the same procedure with the same exact results.

Now, i'm figuring it is an electrical issue and more than likely a fried relay. Any suggestions?

I've been reading up on all of the possibilities and going through the search, still any help does go a long ways and is much appreciated.

My next course of action is to start reading up on the ignition and such and try to narrow down the possibilities.

LS6427

iTrader: (2)

I was getting ready to tell you its a stripped plastic gear in your headlight motor.....but you have a Camaro.....

Glad you got it figured out....now go get a ticket.

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HAZ-Matt

iTrader: (8)

Does the ignition or starter relay have anything to do with the operation of the engine when it is running? You have a problem that started with poor mileage and now the car is hard to start and idles poorly right? It seems that what is causing the poor engine performance is what is probably making it hard to start.

MAF will mess up all the fuel calculations if it is bad. I haven't had any O2 sensors go bad enough to make the engine run poorly before they set their error codes. Obviously if spark is screwed up it will misfire. If the plugs and wires are new then it could be coils, although a random misfire code doesn't really fit a coil being out.

Was the 0300 the only code you have gotten? Is this car stock or has it had any codes disabled? List all of them that are showing.

I'm also not clear on what all you have done.

You replaced plugs and wires and the PCV valve. How did you check the spray pattern on the injectors? Did you also check the fuel pressure when you prime it and when it is running?

The Mighty Texan

iTrader: (4)

Good question, i don't think the starter does but i figured the ignition might keep the engine running.


Correct.

Only the 0300 code and a secondary air injection system code that occurs when i drive in rain and the air pump gets wet is what seems to be. The secondary air code is intermittent and has been going on for about 2 years and has never been a problem. The 0300 is the only other.

I replaced the plugs and half of the wires, the other half were bad and i'm currently waiting for the replacements which should be here in a couple days. I replaced the PCV valve, changed the oil, tested the voltage on the injectors and when i looked at the spray pattern i took them out and lifted them up and observed while starting the car. It wasn't the most thorough or safe way probably but i noticed they all looked about the same as each other.

I have not checked fuel pressure yet because i have not found a place that will rent a pressure tester or know anyone that has one.

The Mighty Texan

iTrader: (4)

Since yesterday: I switched the one good relay i had left with the "bad" one that i just bought and i believe is fried now and the car started first time and ran great. It did this for about 7 consecutive starts last evening and this morning. I figured the problem had been solved now. After what i believe had been the same operating time though (about 10-15 min) just about how long it ran well yesterday, i started the car up and it started idling bad and shaking. No codes yet, however, if it goes down the same as yesterday it will shortly and soon "fry" this relay as well.

I don't know why my car is burning through these relays or if that is what it is doing, i've been trying to find information on this but haven't been very successful. I'm wondering is my pcm or the wireharness is causing this also..

HAZ-Matt

iTrader: (8)

Yeah I dunno what I was thinking when I posted the above, it needs a good ignition relay to run when the key is on. The starter relay only works when you try to start the car. As above, if they were rated the same and you switch a bad ignition relay for the starter relay nothing will happen when you turn the key because the starter won't get any power.

Do you have any of the old ignition relays? If so do you have any way to test them to see if they were really dying? I don't know what the correct amps are for the control and load side for that relay. But I don't know why a little relay should be continually dying if you use one with the correct rating.

It seems odd that an ignition relay problem would cause the loss of gas mileage initially. That seems to me like it was probably a fuel trimming issue. Potentially if their was a leak in the AIR system check valves you could get bad fuel trims from the ensuing exhaust leak (or more precisely air leaking into the exhaust pre-O2).

P0300 is like the worst misfire code because it hardly tells you anything except the engine is running crappy.

Tim94gt

iTrader: (2)

Get a spray bottle and spray the plug wires/coils and see if it starts to misfire. You should be able to see it arcing.




Where did you get half a set of wires? Anyways, you should replace the other 4 plug wires.

Have you replaced the fuel filter?

Stock Tune?

The Mighty Texan

iTrader: (4)

I've noticed that when i would reset the pcm things would be good and work fine and then after running time or so many starts then the car would start acting up and misfiring and running bad until the pcm got reset again.

Alright here's what happened today:

I decided to do everything in the general area at once. First, I wanted to check the condition of the rockers and springs, as i have recently heard some valvetrain sounds (most likely the common piston slap), but after reading up i found some that experienced a broken spring throwing a misfire and causing the car to run in an open loop. I checked them out visually and by hand and they are fine, i noticed a couple rockers had a very very tiny amount of side-to-side movement probably 1/32 or less didnt seem like it would be a problem at all, however some were absolutely solid. Other than that everything seemed great.

Then, well actually before that, i pulled the plugs and wires. The spark plugs have about 500 miles or so and i'm guessing they should be very clean, however the car hasnt been running good and also i didn't run the car hard as is ideal from what i've read to "clean off the good cylinders". I took pictures of them too, but yeah they had some build up, not too bad, but in no way clean like they were new. Mainly, there was nothing shocking, which is what i assumed was all i was going to be able to determine from this, but since i wanted to check the springs..

I tested the coils, i don't know if i did it right though. I tested them on the secondary site i believe, not positive. This was more sketchy as i didn't really know much on how to, but i was looking for something that stood out. They all came to be around 12.3 Kohms however one cylinder was 12.14 Kohms which comparatively doesn't seem outstanding but 200ohms is a bit. Also i remembered that particular cylinder seemed not as warm on the manifold as the others, not too accurate but something.

Lastly, i inspected that which was easily accessible that wasn't before, the PCV hoses in the back and some other things i believe.

I also switched over my new 4 MSD wires over to the passenger's side so when my others arrive i can do a quick swap.

When i go to start the car after i had gotten everything back together and reset the pcm with unplugging the battery, the car cranks but doesnt start. I noticed the security light Edit: Not the security light the service vehicle lightstays on, and also you can't hear the fuel pump prime, just the relay click up front. Tried many times and nothing. Probably a bad fuel pump im guessing.. Edit: posted thread: No Prime From Fuel Pump

The Mighty Texan

iTrader: (4)

There is a way i believe, and i do have the old ones, one i know for sure is dead because when the car would start i would swap it in and it wouldnt turn over at all, then swap back and worked every time. I don't think there continualy getting blown now though, i believe all are in working order now

I've checked for air getting in and leaks and i don't believe there are any. And yes this code is the worst haha

The Mighty Texan

iTrader: (4)

4 were damaged in the mail and had a resistance of ~1000-2500 ohms so new ones are on the way.

Replaced it around 500 miles max ago. And yes, it does have a stock tune currently.