Need help diagnosing what's wrong with my car...

[DisCrete]

Just got my car back out of impound... don't ask long story.

In either case.. check engine light came on. prior to the car being tow'd.

Took it to autozone they checked the codes... The error code it was giving, "Multiple cylinder mis-fire"

Need suggestions what could be wrong how to fix the problem.

I've heard a few things from the schmuck at autozone.

1. plugz
2. plug wires
3. injectors
4. compression
5. too much fuel
6. not enough fuel

Anyone have any suggestions and solutions to my problem please let me know

1996 Chevrolet Impala SS LT1 stock engine

Thanks,

-DisCrete

[Zboner]

start with the plugs man. see if its a easy fix

[Breech]

I'd put opti at the top of that list, hopefully something cheap though like plugs, wires, etc

[DisCrete]

Question...

17-32159 MSD 8.5mm Super Conductor Spark Plug Wires, 1994-1996 Impala SS, RED $79.99 $79.99
50-TR6-IX NGK TR6-IX Iridium Spark Plugs, One heat range colder than stock, gapped at .035 $6.99 $55.92


ignoring price.

is it ok to put these on my car?

I was thinkin about putting an MSD 6A ignition box as well.

Any thought as to a start for fixin my car.. figured plugs, wires, and ignition.

Also.... My check engine light went off.

This is the 2nd time in a year it has done this... stayed on for a couple weeks.. then just went off.

[grandkodiak]

Congrats on your 1000+ you post whore

I'd think that it was electrical for starters, if the car was fine one day, then it went sour, fixed itself, then it comes back, sounds like a loose connection somewhere thats causing the sparks to not ignite, or fuel not to spray. check the wires first, opti second, then move onto plugs, coil then injectors i'd say. if you know someone with an obd2 check the injectors see if they are going off.

if its not the injector/wires/opti/ignition/plugs/computer and you are getting multiple cylinder missfires, you might aswell toss the engine cause you've got some serious issues but unlikely since a stuck valve or a serious enough amount of piston "blow by" from ring damage or gasket leak would create a good deal of audible noise and/or vibrations.

[grandkodiak]

Actually, werent you having a bunch of problems before with the motor just randomly dying on you? what ever happened to that?

[DisCrete]

It still is doing it... but I think it's all related.

As for the starter... not possible.. brand new starter.. not even 6 months old.

The last one I shattered into about 4 or 5 pieces.

New fuel pump as well... last one just quit on me.

I have nothing left to check outside of the list above.

I was asked about resetting the computer.. but I don't want to do that yet.. as I don't think that is the problem.

[DisCrete]

Believe me I want to dump this block... more than anything in the world.

But, I need $4000 to do it

then I'll take it out back.. with and elephant gun and shoot the sum bitch.

[grandkodiak]

Screw that, get yourself a REAL LT1 car like a Tranny or Z28 bwahaha

[Breech]

If it's not a constant issue then you might check the ignition controle module. Especially if the problem occurs after the engine has warmed up. That is assuming that it's mounted in the same location (on the front of the driver's cylinder head) as the f body. They are prone to heat soak which can cause them to heat up and work poorly.

[DisCrete]

I'll have to check that... but how would I test for it?

Or should I just take it in and find out.

Last time this happend.. my engine died... i stopped.. started it up... hit the gas pretty hard... and then the check engine light came on...

the same day.. my car got tow'd... it sat for 2 weeks.. till I got it out of impound.. the light was still on... and went off the same day I got the car back.

I've been having bog down problems at low RPM for the longest time.. sub 1200rpm It seems fine once i get above 1200 rpm however.. high rpm feels strong... and consistant.

and usually if I feather the gas... example.. stop and go traffic... it bogs down the most.. and once in a while dies on me.. but it's only died 2ice since I had a new fuel pump put in... prior to that the condition was the same.. bog down problems...etc... fuel pump died.. replaced.. ran good for a few months..and started bogging down again.

It's just this time I took to autozone.. to find out what error code it was giving.

and that's what the guy told me, "Multiple Cylinder mis-fires"

[Breech]

It may not be bad, some people have solved miss problems by spacing the entire heatsink unit containing coil and ICM away from the head with a couple washers (on f-body's).

You may be able to pull it off and take it to NAPA, Autozone, etc. and see if they can test it for you. If not, here's one way.....

The first thing we will do is verify the optical sesnor is working correctly. and here is how..

unhook 1 fuel injector connector. with your testlight check for pulsing ground on the NON PINK wire while cranking the engine(different years use different color wires but all year have pink wires for the positive voltage side of the connectors) The other choice you have is to use the noid light noid light AZ OEM part number 25143, plug the noid light into teh connector and crank the car. The light should flash..

Do you have a flashing ground while cranking?

Yes, the optical sesnor is sending the signal and should be ok, continue to to test the ign system.

no, the optical sensor is not working see testing opti section.


next we will see if the coil and ICM are causing the no spark.
first on the ICM connector with key on engine off check for hot on the pink wire. do you have hot?

yes, next step
No, check ign fuse, repalce and retest.

Nect check for ground on the black wire. do you have ground?

yes, next step
no, repair ground

next test for a pusing ground at the green wire at the coil coming from the ICM. Do you have a pulsing ground?

yes, next step
No Replace the ICM *note, I have seen a bad coil burn up an ICM. It might be a good time to replace or upgrade your coil*


next with your testlight check for hot on the Pink wire at the oil. do you have hot?
yes, Replace your coil *note, High resistence from bad plug wires can burn out coils. You can Ohm test plug wires or replace them if wanted*

No, Check and repair ign fuse

[DisCrete]

Thx breech... I'll check that out... and post back when I can.

[DisCrete]

Breech,

U know what man.. I just talked to my friend... and including him I've had 3 or 4 people tell me to have the TPS checked

Throttle Positioning Sensor.

Friend said to take it to autozone and they would test it out... thing is I gotta take it out to do that lol... and I dunno how

[Breech]

http://shbox.com/1/component_location_views.html

Check out #2, it shows a pic of it (again on an f-body). Really pretty simple.

[DisCrete]

Cool thanks again.

[Breech]

No prob