Do I need tuning or is something just bad?

[NoRiceInside]

Alright well Saturday I started tearing my engine down and I got it completely back together Tuesday. Just in case everyone forgot, I have a 3.4 and I ported some heads to match the gaskets and bought a Comp 260H grind (212/212, .440/.440 (.469/.469 after 1.6 rockers), 110 LSA).

It idles okay but when I go for a drive it hesitates and misfires a lot. I'm thinking maybe the TPS is bad and that causes the hesitation and maybe a coil is bad and that causes the misfiring.

The reason I'm thinking this is because I brought it to a shop where they hooked the scan tool up to it and it showed no voltage in the TPS, even though it was hooked up. Then we unplugged one spark plug wire at a time, and for 2, 3, 5, or 6 the rpm dropped like they were supposed to, but for 1 or 4 (which are on the same coil) the engine would completely die. Now I have no idea why this does this and why it would mean a bad coil, but I can't think of anything else.

Also we unplugged an injector or two and the rpm dropped, meaning they were working, but then we plugged a noid light into the plug and it showed no pulse. He tried several more, no pulse.

This is where I got to thinking that maybe the computer needed tuning. The scanner said the A/F was at 14.7:1 so that's perfect, yet it also said the O2s weren't plugged in, yet they were getting readings.

Very mysterious things that even confused the technitian. I double and triple checked every connection, the plug wires are installed right, the injector harness is installed right, everything was put back in the right spot. Anyone got any ideas???

[l1tech]

Sounds like you forgot to hook a ground back up when you put everything back together

[Jerriko]

Originally posted by l1tech:
Sounds like you forgot to hook a ground back up when you put everything back together

x2!!!

[StudlyCamaro]

am i allowed to x3 ?

[NoRiceInside]

that doesnt make sense. if a ground wasnt hooked up it wouldnt start at all. but anyway everything was hooked up right. i went and got some new spark plug wires, its running good now.

[Jerriko]

I don't think you understand. There are several grounds that connect to the engine block. Disconnecting just one WILL make your car do strange things. It's not an on-and-off switch when you are dealing with multiple connections. I would into it more. Spark plugs would not cause the problems that you described.

[wasjo6431]

i 4th the ground thing. the miss fire could be a coil they might be working but when at higher rpms they wont work. the timing might need to be retarted or advanced for your new cam, which means u need to contact super chips or fast chips or a custom place to make a tune for you to put it on your pcm with the 3.4L's there wasnt very much out there. if u want to retard it a bit just gap the plugs a lil more. and see if that helps you out. run 93 also with your setup and see if it makes any diference.
i couldnt get my car to start the other day come to find out some how we ended up getting the distrubutor 180 off on the engine. ahd to take the damn thing off along with the valve cover put it back at top dead c3enter see wehre the rotor was pointed wow oposite direction it was supsoed to fliped it got hte timing to 16 degrees advance fro teh cam break in. going to prolly end up between 12 and 20 all depnds how its on the the road. but the most comon thigns are the most over looked.

['94firebirdv6]

distributor???????

[Jerriko]

Originally posted by '94firebirdv6:
distributor???????

What distributor? I'll send you $20 when you find a distributor on your stock ignition 3.4L 94 bird.

[98Camaro3.8]

Originally posted by Jerriko:
</font><blockquote>quote:</font><hr />Originally posted by '94firebirdv6:
distributor???????

What distributor? I'll send you $20 when you find a distributor on your stock ignition 3.4L 94 bird. </font>[/QUOTE]He was referring to the post just before his. ;)

[NoRiceInside]

well yeah i understand the ground thingy...but you guys dont understand...all ground are connected. there was one chassis ground that bolts where the power steering pump bolts...then a couple more that bolt to the intake manifold studs. so yeah theyre all connected.

[wasjo6431]

check your coils take them in and get htem tested at the dealership witht hem on the car. only thing i can think of then. did u put new wires on it? with new plugs the plugs are gapped right?
fuel injectors arent cloged/ your gettign fuel trhough? the throttle position sender/sensor might be shot its worth a shot to replace what uc an its better to giwth new anyway. and slwoly ull find your problem.

[Jerriko]

Originally posted by NoRiceInside:
well yeah i understand the ground thingy...but you guys dont understand...all ground are connected. there was one chassis ground that bolts where the power steering pump bolts...then a couple more that bolt to the intake manifold studs. so yeah theyre all connected.

Then you need to disconnect them, make sure the connectors and mating surfaces are clean, and reattached them.

A lot of people will throw money and parts at the car right now by mistake. There is not one single part on the car that would cause all of the problems that you described. And the odds of multiple parts failing at the same time are very small, if nonexistent. You have to look at what all of the problems have in common since you just r&r'd the engine. I would suggest that you use the cheap but timely method of rechecking the work instead of using the expensive but timely method of throwing parts at the car and hoping that solves the problem.

[ April 12, 2005, 04:22 AM: Message edited by: Jerriko ]

[Jerriko]

Originally posted by 98Camaro3.8:
</font><blockquote>quote:</font><hr />Originally posted by Jerriko:
</font><blockquote>quote:</font><hr />Originally posted by '94firebirdv6:
distributor???????

What distributor? I'll send you $20 when you find a distributor on your stock ignition 3.4L 94 bird. </font>[/QUOTE]He was referring to the post just before his. ;) </font>[/QUOTE]As was I, it was just easier to quote the one word post instead of the paragraph. Sorry, forgive my sickly hands.

[BiH]

hey NORICE are you planning on dyno when you get it fixed? Im planning doing the same thing