Hesitation at WOT - Toyota Nation Forum : Toyota Car and Truck Forums

giperbolic · 04-13-2009, 03:53 PM

I have 2001 solara (5sfe) auto. When I try to accelerate hard, it chokes at between 3-4k rpm and check engine light blinks but won't stay, so no codes stored.

I have:

Replaced IAC.
Cleaned TB.
Replaced air and fuel filter, spark plug and wires (NGK).
Checked resistance of ignitors as per factory repair manual.

Still having the problem.

I have not (but will):

Checked EGR system.
Checked for vacuum leaks.

Another thing I have noticed: sometimes, even during smooth acceleration needle doesn't go through rpms smoothly, it sometimes jumps 2-300 rpm forward, just the needle, car's acceleration continues to be smooth at that time. So I wonder if tach sensor is crapping out.

The problem is there even during revving in the "Park".

Any ideas?

***ASG14*** · 04-13-2009, 07:04 PM

If the CEL ever comes on,t he code IS stored untill cleared. Go get it read.

LUVLEXUS101 · 04-13-2009, 07:09 PM

Use to happen to me, it was a leaking upper air intake hose.
You might want to check that out.

giperbolic · 04-14-2009, 05:17 AM

I have a scanner on loan from autozone and there were no codes when I have done this the other day, I will check again.

Vacuum leaks are on my list.

Any other suggestions?

Mike Gerber · 04-14-2009, 01:17 PM

There should be a code present. Keep the scanner with you. Drive the car until the CEL light flashes on again and then immediately pull over and read the code. The code should be stored in memory on an OBD2 car until erased. Some people say that the code will be removed after a X number of key restarts if it doesn't return, but I'm not sure about that so try to read it immediately after it flashes on.

Mike

hill8570 · 04-14-2009, 01:32 PM

OK, I'm a lot more familiar with the Camry than the Solara, but IIRC, the mechanical parts of the 2001 Solara are equivalent to a Gen4 Camry (someone correct me if I'm mistaken).

The jumpy tach sounds like the camshaft position sensor or crankshaft position sensor (or the associated wires / connectors) is iffy, which could possibly explain the choking -- it's like you're getting an intermittent misfire, but not long enough for the DTC to be memorized (in a Gen4 Camry, the misfires must persist for at least 1 minute at 3000rpm in order to be memorized). If you can get the bogging to happen for at least a minute straight, you should be able to get a code you can pull.

If you happen to know someone with an oscilloscope, monitoring the output of those sensors (preferably at the same time) might give you some clues.

giperbolic · 04-14-2009, 09:47 PM

Mike Gerber,

I've tried to get CEL to come on while driving home, it only flashes for a second. I had it come on about 10 times on the way home. I got home, plugged in scanner - NO CODES. There may be a set period of time for CEL to stay on to get stored. I wonder if I can have it scanning while driving, probably not.

hill8570,
I was thinking in the same direction.
Another thing that I've noticed today - similar symptom happens when I go over bumps = could be loose connection.
I'm not sure where does tach gets its signal from.
I'm mostly using search on the forums before posting and from I've read tach signal comes from ECU, but ECU must be getting its signal from crank sensor since camshaft only turns once for 2 turns of the engine, i.e. (signal from cam sensor) x 2 = rpm.
I will check both of them.
I may be able to borrow oscilloscope from my former professor, but it may be easier to swap both sensors, since I have spare for both of them.

beingblueeyes · 04-16-2009, 09:03 AM

need more info
whats the car idle at when warm?
can you rev above the 3k-4k when in neutral?
Have you pulled the plugs to make sure they all have around the same wear? If one if different you found your problem cylinder and can go from there.

giperbolic · 04-16-2009, 11:56 AM

As I mentioned before, I put new NGK plugs.
I pull them yesterday - all looked good, car does smoke (grey/black = running rich) a little.
Idle at aroun 6-700rpm when warm.
I can rev to 4.5-5k rpm but after3k it's acting up.
I've replaced cam sensor yesterday - didn't help.
I'm trying crank sensor today.

hill8570 · 04-16-2009, 04:52 PM

Quote:

Originally Posted by giperbolic

As I mentioned before, I put new NGK plugs.
I pull them yesterday - all looked good, car does smoke (grey/black = running rich) a little.
Idle at aroun 6-700rpm when warm.
I can rev to 4.5-5k rpm but after3k it's acting up.
I've replaced cam sensor yesterday - didn't help.
I'm trying crank sensor today.

600-700rpm warm idle? Sounds a mite low -- 750 is normal for a 5F-SE.

Is the smoking at idle, or when you're having this stumbling issue?

giperbolic · 04-16-2009, 05:05 PM

smoking even during normal acceleration, but smoking so little, I can't see it during the day, only at night in the beam of the car behind me while leaving a stop light.

I will check warm rpm.

giperbolic · 04-19-2009, 10:22 AM

Replaced cam and crank sensors, both ignition coils - didn't help.

Luckynumber5 · 04-19-2009, 02:57 PM

Flashing CEL usually means multiple cylinder misfires, which also explains why the acceleration is funky when it flashes.

CAn you scan the fuel trims when it flashes, try to see if the car leans out or richens up before the misfiring. It can be caused by too much or too little fuel.