First off, I'd like to say thanks in advance for any and all help.

My car is a 1988 Camaro SC, 305 TBI. I had the motor swapped out a little while back, since I completely cooked the factory 305. The replacement motor is an 89 305 TBI, completely stock, except for a 120 thermostat.

Basically, the car runs really rough, seemingly randomly. I've noticed it runs a lot worse when its in gear, rather than neutral, in these situations. Basically, I can feel the motor pulsing occasionally. Usually, this isn't too irritating, but on bad days, when the trans first gets up to overdrive (700r4) it shakes the entire car, making it nearly undriveable unless I pull it down to third.

My TPS had a coulple dead spots, so I replaced that, and the situation got a little better, but when it did act up, it was worse.

After replacing the TPS, the car actually started to backfire when it acts up, instead of just occasionally stumbling. At first, it was only if I got into the throttle heavily, but now its just about anytime. I replaced the IAC last night, and it got a little better, but its still doing these things occasionally, and it throws a check engine light most of the time now, as well.

Only problem is that I can't get any codes from it because apparently the 89 engines used a different computer, and my 88 computer just blinks ones and stays on solid when I try to get codes from it.

I'm completely out of ideas, so I would REALLY appreciate any and all help, and again, thanks in advance!

How does the car run when cold? Have you checked the IAC and 02? What is your feed line fuel pressure? What is your base timing set at. These are some of the things that can get tampered with or damaged when you swap engines.

would the 120* thermostat interfere with everything if the cars running a regular chip??

120* is too low. I assumed that was a typo but I geuss I was wrong. Anything below 160* requires chip work to make everything kosher. If you have a stock set-up it is much easier to just go with a 180* or 195* thermostat.

IAC is brand new. Haven't checked the o2 sensor, but it does this with the motor cold, too, so that rules out the o2 since its not used till the motor hits temp. I swapped the thermostat back today, drove it around for a while, still doing it, so thats not it. I'm gonna reset the timing this weekend; I think the computer might have kicked into limp-home mode, so to speak, with so many defective parts on the car for a while, so the timing may be off.

I noticed tonight that the motor seems to be either detonating or backfiring even at idle sometimes, so I think the timing is way off.

After you've replaced these parts, did you clear the codes by unhooking the battery for a few minutes?
I forgot to do this once, when I replaced my EGR valve.
Probably not your answer...

no i didnt, actually. I'll try it, just to be safe, though. Thanks, I wouldn't have thought of that! Anyone else got any more ideas?

This sounds like it could be a problem with the TCC switch.

Now this is troubling...I thought the engines were the same...sounds almost like you have a problem with either the chip and/or ECM. A bad chip could be causing all of your problems.

I don't think its the computer. I've just been told that the computers differ slightly enough to make it so I can't get anything but gibberish from trying to run diagnostics myself. Aside from that, they're apparently the same, but I dunno. Where could I even get a chip? Cuz I know I can't just goto the dealer and order them (at least here) cuz I called. :-/

Also, whats the exact name of this TCC thingie, and where can I find out how much a new one costs? heh. I assume its something like 'torque conveterter control' switch or something similar, but I haven't even heard of it till now, to be honest.

I was messing around under the hood today, and noticed I have a spark plug wire arcing up at the distributor. I've got new plugs and wires just waiting to go on, so those will be done soon. When I insulated the offending plug wire with a rag and ran the motor through the RPM band, it seemed to be alot less hesitant and didn't bog or backfire at all, too, if that helps.

From the outside the 8063 looks just like 8746 ecm to a scantool. The aldl stream is the same. If your still having problems try scanning it again to see if you can get anything out of it.

What did you say your base timing was at? If you hear ping I would go for that right away to see if it slipped or if the hold down bolt came loose.

Base timing is exactly at top dead center, which according to all my service manuals, is factory spec.

As for the computer, I can get the information with a scan tool, just not by using the jumper method to have it flash codes to me. Does that mean anything? Or does it just mean the issues I'm having the computer doesnt have a code to flash at me?

The timing specd for the 88 year is 6 deg BTDC. Try that and see if it perks up any.

It should flash codes. It should return a constant code 12 when pins A + B are shorted.

Yep, I don't get any codes. I get one flash, then on solid. Been doing this ever since I had the new motor swapped in, actually. I replaced the ECM, as I was told this was most likely the computer being damaged that would make it do this, but it's still doing it. Do I need to get new chips from somewhere to solve that?

I'll re-adjust the timing the first chance I get, which will most likely be this coming sunday, as this week is full of exams for me. :-/ I hate college sometimes.

The flash/solid on when the key is turned to the on position means that its not seeing that the pin is shorted and its starting up like normal. There may be a wiring fault somehwere.

oh cool. thats easier to trace. hah.

I got to thinking about the torque converter control thingie ... its not anything with my torque converter, i don't think, cuz it does the 'surge' thing in all gears, not just when it hits overdrive. So I think its just timing + plugs + wires, so I'll get that taken care of sunday, and we'll have an answer on that, at least.

ok, bit of an update. Got bored with studying math today, so I went out to start swapping plug wires. Obviously I went for the one that had the split in the boot up by the dizzy, first. I pull it off the distributor, and the rest of the wire, except for the boot where it attaches to the spark plug, came with it. It was literally in two pieces.



:-/ Car is running 100% better. Still has a bit of a 'pulse' to it sometimes, but not so much, and I think thats probably due to having mis-matched plug wires on the car right now. The rest (passenger side) will get changed on sunday when I can work in a heated/insulated garage and be able to actually lift the car up to get to that side. I would imagine my plugs are pretty fouled from having a cylinder completely non-functional, too, so I'll swap those at the same time, and back the timing off a bit, since it seems to be a little high from what you guys have told me. Thanks 100 times over for your help, everyone!

allways something really simple in the end...


have you put on a new cap n coil yet...that makes a difference in the smoothness of the engine..my car purrs since I replaced all that stuff.

Its actually making that arcing noise again under the hood, and I can't figure out where. I can't do the passenger side plug wires from above, cuz of all the damned AC stuff, so I'll see if its something over there on Sunday, when I get home, I suppose. Cap and rotor will get done at the same time. I hate tracing down problems like this.