Struggling under acceleration

[Duds]

Just rebuilt my 7m everything sounds good engine idles great but as soon as you give it gas it stumbles, almost dies, then comes back. Timing was set when I put it all together but going to recheck in the morning. It has some old gas in it, thinking it might be the problem but would like some other opinions before I start siphoning a full tank.

Edit: The car also takes about three tries to get it to start, regardless how long you try each of those three times.

 

[grimreaper]

any codes?

 

[rawmk3]

Check your MAF. Non metered air getting into the system will do that. If your turbo, check your intercooler and piping for leaks, and them make sure your mass air is plugged in, and if your NA, make sure all your pipes are free of leaks, and then check the mass air. That would be my best guess. It can idle unmetered, but once fuel is given it richens up to the point it dies. Basically flooding the car. On start up do u get a bad gas smell out of your exhaust?

 

[Duds]

Did the timing made no difference, noticed my coilpack wasn't grounded but that also made no difference. Pulled codes 41 and 52, tps and knock sensor. Knock is probably from it starting as it barely starts but once it does it sounds smooth. All my pipes are tight and no cracks (most are new). No gas smell either

 

[rawmk3]

I just looked at another thread that made me think of this, but there is a brown wire that comes off E2 and goes all the way to the AFM with connections to the CPS, and ECU temp switch. I would check that. I had an issue similar and when I looked, i had cracks in my wire loom, and exposed and broken wires. Fixed the wires up, and no more spitting and sputtering, and ran just fine. Might be something to look into. Maybe run a continuity test from the CPS to the ECU e2 pin.

 

[Poodles]

Did the timing made no difference, noticed my coilpack wasn't grounded but that also made no difference. Pulled codes 41 and 52, tps and knock sensor. Knock is probably from it starting as it barely starts but once it does it sounds smooth. All my pipes are tight and no cracks (most are new). No gas smell either

You already know the answer...

 

[rawmk3]

You already know the answer...

He pulled the codes, but that doesnt mean that is exactly what is wrong. It just means the ECU isnt reading that sensor correctly. Could be in the wiring easily. And checking the wires is alot cheaper than replacing a sensor. And then do a test on the sensor while your there too.

 

[Poodles]

A bad or incorrectly installed and set TPS will give him EXACTLY the symptoms he's seeing. The ECU throws a trouble code for a reason and most of the time will tell you EXACTLY why the car is not running right...

 

[rawmk3]

You said you did a rebuild on the motor, did you do anything to the TPS such as move it, remove it, or is it exactly the same as it was when you pulled the throttle body off the intake? Reason I say possibly wiring, is he did a rebuild on the motor. The wires are prolly 18+ years old, and probably dry rotted, and cracked. Moving the harness around when pulling the motor could have broke a wire easily. So putting a continuity test to the wires first would be a good idea, to make sure the lines are reading correctly, then looking at the TPS and where it is set at. Added resistance in the wire from being broken or oxidized could send false readings to the ECU

 

[92TealSupra]

You said you did a rebuild on the motor, did you do anything to the TPS such as move it, remove it, or is it exactly the same as it was when you pulled the throttle body off the intake? Reason I say possibly wiring, is he did a rebuild on the motor. The wires are prolly 18+ years old, and probably dry rotted, and cracked. Moving the harness around when pulling the motor could have broke a wire easily. So putting a continuity test to the wires first would be a good idea, to make sure the lines are reading correctly, then looking at the TPS and where it is set at. Added resistance in the wire from being broken or oxidized could send false readings to the ECU

Hey lets all do what I just! Bought a brand new wiring harness for my '92, though I got the last one produced by Toyota, you can still find 87-90 I am sure. I paid $530.00


LOL


..

 

[stabbinkabbin]

Poodles ftw, if your tps is the slightest off it messes up. =( I have been trying to tune mine forever now it seems. Using shims and a continuity tester to measure resistance between throttle points.

 

[Duds]

I'll be doing the tps in the morning, adjusted once before a few years ago and was annoying to do, thanks.

 

[Supranforever]

The problem is either TPS, or AFM related.

Also, what is your complete mod' list?

 

[Duds]

Mod list on this car:

Stock lol, unless you count mhg and arp's to be mods, I've had this car sitting up where I work for the past 2 years just started rebuilding it this summer.

 

[test pilot]

Your problem sounds a lot like mine. Any solution so far?

 

[zachm611]

fixing the tps will help with idle and acceleration. and fixing the knock sensors most likely the wiring will help with acceleration as well. i had code 52 and as soon as i got to 3 or 4k rpm... instant limp mode. get your codes fixed and let us know how things are going.

 

[hvyman]

why would you be adding shims to the tps? all you do is move the sensor into the proper resistance range and tightin the 2 screws. if not as specified replace.

 

[Poodles]

Think he's refuring to the feeler gauges used...

 

[stabbinkabbin]

Yeah sorry, meant feeler gauges =D

 

[hvyman]

^ ooo ok that makes sense