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Car wont misfire when the valve cover is cool (when engine is cold)

Replace the cas its on its way out.

i know this thread is kinda old but i have the same exact problem. just wondering if you got the CAS and it fixed the problem.

92GSXBaltimore said:

i know this thread is kinda old but i have the same exact problem. just wondering if you got the CAS and it fixed the problem.

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ditto

Im having a similar problem too. I re-installed my TPS and i get intermittent CEL's related to it. It pops up, then goes away. It usually came on during idle after my thottle body swap/repair and at WOT. Under normal street driving it spits and sputters, mild to moderate, but enough so that when you try to give more gas, it gets worse unless you let off the gas, ease back onto it, or downshift and keep it close to 3000rpm's at all times I changed my plugs, didnt change. I've thrown every ignition part at it, coil, transistor, homemade grounding kit(which helped very slightly coming from someone other than me), fixed vacuum leaks, recirculated bov, the fuel filter has very few miles on it, changed at 77,000 before i swapped into the 4g63. The car had 80,028 when the new engine was installed and fired up. I looked at just about all the trouble shooting trees and what not to try and cure this problem. The combustion chambers were not heavily carbon caked. I have Nology hotwires, hks 264/272(undegreed) stock fuel running @ 9psi. It only does this at light throttle under 3000 rpms off boost. Under boost, nothing signifigantly annoying, slight slight hesitation when cold out. It's only a problem at part throttle under 3000 rpm. Thats the end of my long essay that I can remember. You can bash me, ridicule me, whatever just as long as you have useful input so that when my engine is finished being re-rebuilt(long story) i wont start out with this problem. Thanks in advance

sounds like an injector problem to me.

update: i replaced the CAS and it totally fixed my prob

92GSXBaltimore said:

update: i replaced the CAS and it totally fixed my prob

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THANK GOD! my plague might actually finally come to an end

doodie said:

sounds like an injector problem to me.

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replaced those too

So, the CAS and injectors fixed all mis-fires and sputtering (both on and off boost)?
Ju$t one question, a new CAS is like uuhh $700 dealer new. Injectors are dirt cheap. Where can i get a CAS for a good price?

check with Gary from www.mitsubishigraveyard.com

CAS????
I am having that same problem....More when the car warms up and is idleing for about 15 mins.....and then under light accell

Lee

Hello DSM'ers,
Alrighty, I have a problem with my '90 Eclipse that is driving me bonkers.

The car will not idle without missing and will miss to a smaller degree while under power.

Things I have done:
OK This is a newly rebuilt Naturaly asperated motor. I have removed the balance shafts and it has new gaskets all around, new rings, new bearings, adjustable cam gears, Polyeurthane motor mounts, and everything else is pretty much stock.
I've replaced the MAS which cured a problem of the idle all over the place.
I've replaced the Idle Air controler which also corrected some of the problem with the idle.
all the injectors have been cleaned and checked, new fuel filter, new fuel pump, origional fuel pressure reg (I doubt that is the problem).
I've changed spark plugs, plug wires, coils and power transistor with three sets that i have of all with no change.

NOW HERES THE REALLY WEIRD THING.
If I pull any one of the plug wires off the plug and just leave it like that, It idles like a dream, not missing and constant perfect idle all the way down to 400 rpm (I adjusted it down that far just to see). But as soon as I plug the wire back in it starts missing again and idle jumps between 700-1100 rpm.

the car will also miss under power with the following symptoms.
1. cruising down a city street at 35mph(2800 rpm in 2nd, or 2000 in 3rd) it will miss and cause the car to bounce back and forth rather violently.
2. Cruising on the highway at 80mph (3800-3900 rpm) you can feel a really small tug every once in a while when it misses.
3. under acceleration it is very smooth throughout the entire RPM range.

this problem has been driving me nuts for a long time now and I'm about to lose patience with this car (and I'm a VERY patient person).

Any help and suggestions would be appreciated.
Roger

OOPs,
I forgot to mention a few other things I have tried without and changes.
NEW Alternator
changed the o2 sensor
Changed the ECU
Changed the MFI controler
It has a new Cat on it.
all cylinders have between 165-170 psi compression.
Tried three different throttle bodies. IE: 3 TPS and 3 Idle air motors
Hell I even changed the part of the wireing harness that connects to the engine and ECU.

The only explaination I can come up with as to why it works better with one plug wire off would be that the system cant charge the coils fast enough to put full voltage across the spark gap so when it is plugged back in it drops the voltage further and starts missing..

Oh yes, if I didn't say so already... All cylinders are missing at different times unless I pull one plug wire off.

the whole thing is really pissing me off.

I have sorta the same problem and was woundering what is the CAS? Sorry for my ignorance of this. And how can it be checked?

Seems like my problem also...but do you guys smell raw gas at idle?

My list to check right now(dont know if it will help)that I read my cause misfires..

Crank angle sensor, Ignition Module, Coil pack or coil, Coolant temp sensor? and air intake sensor? The last 2 I read and someone siad that they can cause misfire on here...so this is heresay. Who knows..

I have consistant clyinder #1 misfire. Under idle up to 2500 or so under excelleration causes the car to shake badly from left to right under lower rpms...otherwise through the powerband it seems ok....I can pass emission either

Zacksdsm said:

Seems like my problem also...but do you guys smell raw gas at idle?

My list to check right now(dont know if it will help)that I read my cause misfires..

Crank angle sensor, Ignition Module, Coil pack or coil, Coolant temp sensor? and air intake sensor? The last 2 I read and someone siad that they can cause misfire on here...so this is heresay. Who knows..

I have consistant clyinder #1 misfire. Under idle up to 2500 or so under excelleration causes the car to shake badly from left to right under lower rpms...otherwise through the powerband it seems ok....I can pass emission either

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My car a 1G 1990 AWD TSI had a backfire, misfire problem when run up to 6300 rpm+ I put in new plug wires and all is good, I can bounce her off the rev limiter anytime I want without a problem. I didn't think the old wires were bad only being 6 months old, but the bad head design with the boots way down in the head can make the wires go bad fast even if you buy the "expensive" ones. Tune ups are always a good thing, and are often over looked and way cheaper to try than a CAS

This thread has been a bit high jacked, so I'll ask. Where are we at with everyones problems? Don't post what fixed your problem yet. I want to see who still is experiencing something they need help with so we don't look like a bunch of 7 year olds playing soccer. Swarm ball is cool for them, but it sucks in tech forums.

dont any of you guys have friends with dsm's? barrow the parts off there car before you go spending 100's on parts that you dont need, i dont understand why you would want to just guess on stuff you dont know about its just like the dealership mechanics are, no diagnostics or anything, instead of finding what is in the system and just replacing every part in the system why dont you ask how do i test this or how do i cancil out this certain sensor, i think the first thing alot of the people need to do is go out and buy a chilton's manual, or get a alldata account/ mitsu disk, i mean it would save you lots of money in the long run, sorry this is so long winded but i just hate seeing people go out and spend money on things that are going to get them no where.... if you have any specific questions or want any help with a certain thing contact me and i will help you test and figure out the problem or atleast find someone that knows more than i do for you to get help from, i hate seeing you guys spend so much money and fix nothing, let me try to help or find someone that will...

good luck fellow dsm fallowers
sleepyGSX

budman, test your igniter/coil/cas for starters...


zack coil= random misfire usually
plug/wire/injector= that specific cylinder


hope that helps

for people with misfires run car and pull plugs one at a time untill you find the cylinder that makes no difference when plug is pulled, then check plug for gap and condition, resistance check wire for an open, check injector for an open power to injector (noid light), a single cylinder misfire is no spark or no fuel, simple good luck

Erok said:

........ic questions or want any hel....blah blah.... help you test and figure out the problem or atleast find someone that knows more than i.....blah blah blah.....from, i hate seeing you ....blah .....much money and fix nothing, let me try to help or find someone that will... ....BLAH!

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Thread started:
12-10-2004

Pay attention to post dates next time.