Car idles rough, has a miss to it..., Fixed! Close. Options

[joeladam02]

Just put to a new 5sfe engine in my 98 GT...Running absolutely terrible!
Tried O2 sensor, Tried plugs, Tried Wires, Tried Cap and Rotor, Tried Resetting the Timing.

I've been told that the timing is controlled by the computer. Is this true?

Also, someone told me that since the old engine hadn't run for a while and the battery was unhooked for so long "it might just need to run for a while so the computer can reset/recalibrate itself". This sounds like bs to me, but hey, at this point I'm willing to try almost anything. But at the same time, won't it damage my engine by running with a miss if the timing is off?

All input greatly appreciated!
Learn me!

This post has been edited by joeladam02: Aug 13, 2008 - 5:08 PM

[Batman722]

are you getting a CEL ?

[joeladam02]

Eh? CEL?

Someone also told me this could be a vacuum problem...but I don't think a vacuum problem would cause this amount of a miss...

Anyone?

[D-Man]

CEL = CHECK ENGINE LIGHT

(IIRC) The computer programs itself over the course of the previous most 20 "drives" Primarily the data used at startup. Misfire is always a bad thing.

EDIT: the EGR malfunctioning would have nothing to due with it, as it's not a "required" system. it's more of a fine-tune thing.

This post has been edited by D-Man: Aug 12, 2008 - 8:34 AM

[joeladam02]

Ah ok...
No Check Engine Light. And not a vacuum problem.
It really sounds like a timing issue to me. No?

[D-Man]

what year is the new engine?

[joeladam02]

I believe it was out of a 95

[D-Man]

the ignition coil for a 95 is diffrent from a 98. Are you using the stock 95's internal ignition coil?

This post has been edited by D-Man: Aug 12, 2008 - 8:56 AM

[joeladam02]

only thing I took from the 98 was the throttlebody...it was in much better condition.

[D-Man]

I suppose timing could be culprit in this case then. Provided that everything is wired correctly, (ect.) Unfortunetly i wont be able to help you with timing issues, as my knowledge is rather limited in this area, and don't want to steer you the wrong way . PM pressure2 or Dr. Tweak, or continue to wait for someone who will know. G/L

This post has been edited by D-Man: Aug 12, 2008 - 9:01 AM

[joeladam02]

Awesome thanks very much!

[Rayme]

Get a timing light to check if your ignition system is good...then if that's all ok look further (injector clogged..timing belt skipped a tooth, etc.)

[Batman722]

You would need to swap the distributer, egr, and one other little thing (I just can't remember what it was) from the 98 to the new motor. Presure2 and lagos should remember, me and lagos helped presure2 put a 98 motor into his 94 and I remember we swapped those things.

did you change the timing belt ? rayme could be right, could of skipped a tooth.

[joeladam02]

Put a new timing belt on it...maybe it is the EGR after all...
Does anyone know how I can find out the year of the motor?
I couldn't seem to find it on the receipt and the papers that came with it.
Would this be stamped on the block somewhere? I kind of want to make sure its not the same type before I go ripping more things off...

[D-Man]

PM sent

[mnwolftrack]

Does a '98 have the air idle control valve on the underside of the throttle body, and if yes, do you know if the new throttle body's air idle control valve was any good? I've only owned a '94 and a '95 and don't want to assume the '98 has it as well. Is it plugged in? Is the TPS adjusted properly? Is it that the car just doesn't idle well but runs ok if you step on the gas, or does it just run overall like garbage at any RPM? Perhaps the belt is off a tooth or the tension isn't set right.

What I do know is that regardless of how long the battery was unhooked, it shouldn't cause the car to run like garbage for more than about a minute if even that long. It should run ok even after a long battery disconnect. All the computer is going to do is fine tune itself once it's back online.

Just put to a new 5sfe engine in my 98 GT...Running absolutely terrible!
Tried O2 sensor, Tried plugs, Tried Wires, Tried Cap and Rotor, Tried Resetting the Timing.

I've been told that the timing is controlled by the computer. Is this true?

Also, someone told me that since the old engine hadn't run for a while and the battery was unhooked for so long "it might just need to run for a while so the computer can reset/recalibrate itself". This sounds like bs to me, but hey, at this point I'm willing to try almost anything. But at the same time, won't it damage my engine by running with a miss if the timing is off?

All input greatly appreciated!
Learn me!

[joeladam02]

Fixed it!!! Had the vacuum hose to the EGR hooked up wrong...nice.
So simple, yet so hard to find!
Thanks for all the help dudes...runs like a dream now!