missfire under load?

[michael93LE]

I have a 93 Corolla LE 1.8L 7AFE.

background: girlfriend blew motor, so put another motor with 91k on it in, compression is good in all cylinder, they read as follows: 123, 124, 125, 124.

idles find, but when under pressure like when in drive or reverse, it seems to missfire. when the engine is cold it does OK at best, then gets worse at it heats up. I cut the cat off and welded in a test pipe til i get it fixed, and the cat was very clogged when i cut it off. tonight I drove it around for a few miles and let it get to temp, and when it did, it started running like $#!& again, and I brought it home, popped the hood, and when it rev it up a little to see what it would do, and it just stalled. When I got in to restart it I saw that the CEL had came on (first time I have gotten it to come on), so I jumped the terminals and got the code. The codes it gave were:

31 - Air flow meter signal
41 - Throttle Position Sensor

Also when i tried to restart it, it wouldn't start, didn't look into it any more tonight after that. However, for one, what is an Air flow meter signal? I have never herd of this? For two, I have another TPS, and put it on today, and it didn't change anything. I am going to test to make sure they are good tomorrow when I buy a new multimeter since mine decided to die today. but this morning it idled perfect (i didn't drive it), and when I just dump the throttle, all it did was spit and sputter for a second, then revved to the limiter. If i slowly eased into the throttle, it ran fine.

I changed the coil already as well, unplugged the MAP (almost died when i did this, so I plugged it back in, just wanted to see if it made a difference). The battery and alternator are good, all sensors and pluggs are plugged up, cat is removed. I am at a dead end here, anyone ever had this happen, or know how to fix it? its been a month since i got the motor in, and I haven't been able to drive it!

[Bitter]

bosch platinum plugs?

Could be a bad MAP sensor, did you calibrate the TPS?

[michael93LE]

The plugs are fine I installed the TPS correctly

[speedy25]

Originally Posted by Bitter

bosch platinum plugs?

Good one Bitter!!

OP- Did you dismiss this? Bosch plugs are CRAP and cause a lot of problems.

ANyway, your problems are typically related to normal maintenance items related to the ignition system. Write back when you have done that work and tell us if its running well again. Not all codes point to an exact problem.

-SP

[MirrorEyes]

I believe it's Bosch items that also have a really bad history with our cars as far as, you know, working.

[michael93LE]

Got it, i changed the plugs and wires, and it runs perfect!

[Bitter]

So were they bosch platinum plugs?

Also not a bad idea to change the cap and rotor if they haven't been done already.

[michael93LE]

N, they were aug light plugs, but I do believe it was the wires that were bad

[speedy25]

For anyone else reading this thread later... IF your car runs like crap DO THE MAINTENANCE!!!! Japanese cars are very reliable and while SOMETIMES there are parts that go bad that normally don't, most of the time its simple maintenance that makes your car run well again. DO that FIRST, then post.

-SP

[michael93LE]

Agreed, my car ran fine with these plugs and wires in the old motor, but did not in the new motor, so I suppose don't assume they are good just because they worked well in an older engine!

[jelly53]

what are the torque specs on the spark plugs?

[Kiwi-Corolla]

Originally Posted by jelly53

what are the torque specs on the spark plugs?

18 Nm (13 Ft-lbs).