95 Camry Acceleration

[JennyDee]

My 95-2.2l Gen 3 Camry with 143K is giving me a slight hesitation during acceleration from 25-40 mph. The hesitation/loading is only when I press the gas pedal hard to acceleratel. When I back off the problem goes away between those speeds of 25-40 mph. The hesitation or vibration/shaking goes away above that speed even when I press on the gas pedal for a quick acceleration.

Rev the engine up to 3500 rpm when in Park, and there is not problem or loading of the engine.

This problem was evident before I replaced the following and still is there.
1.Timing belt/water pump and oil pump seals
2. Plugs with OEM standard, Spark plug wires, rotor and dist cap
3. fuel filter canister next to the front left wheel well
3. PVC valve
4. No oil leaking near the distributor
5. No error codes jumping TE1, TE
6. Vaccum throttle linkage moves smoothly, port P E R no vacuum at idle, vaccum at PE other than idle.
7. Throtle position sensor set correctly
8. Air cleaner changed, inspected intake
9. cleaned throttle plate with B12 and Sea Foam through brake vacuum hose.
10. fluid exchange with the transmission.
11. Checked all vacuum hoses.
12. Reviewed the Matrix Chart for proglem symptoms 5S-FE engine.
13. Did not check the Switch Condition signal circuit EG1-396

Same problem feeling the acceleration lag and vibration if the gas pedal is pushed to hard..... .problem smooths out when backing off the accelerator pedal.

Side note... front motor mount and dog bone changed. C-V joints replaced and rear stabilizer bushings....

Love this Gen 3 engine... but this problem has stumped me.

Any suggestions.
Jenny

[Mike Gerber]

I would check the coil with a DVM. There should be specs for the generation 4 in the manual at the top of this forum. If that comes up in spec, I would check the fuel pressure with a gage. You may have to take it somewhere for this test, but it is quick and shouldn't cost that much.

Mike

[JennyDee]

Hello Mike:
I have to mention that I was looking for the coil but some where along the line I was told that the igniter and coil were the same thing and I was told that there was no coil on the Gen 3 engines.

So after your note, I looked up the specs on the Ingition coil ( IG-10) and they read primary at .36-.55 ohm cold and secondary coil resistance of 9-15.4 K ohms. I will check it tomorrow morning.

I have a feeling that it is the coil. With the cool mornings here in New England the car runs much better before it warms up. Last Sunday I was on the highway and it was 20 degrees F outside. I did not feel the acceleration problem getting onto the highway within 10 minutes of start up. The car ran fine even with the temp gauge at normal, but the ambient air was low 20's which now leads me to suspect that the resistance will show up higher on the primary and secondary coil specs.

If that does not prove out, I may through $40 at it and replace the coil.
Will report back...

Thanks
Jenny

Originally Posted by Mike Gerber

I would check the coil with a DVM. There should be specs for the generation 4 in the manual at the top of this forum. If that comes up in spec, I would check the fuel pressure with a gage. You may have to take it somewhere for this test, but it is quick and shouldn't cost that much.

Mike

[JennyDee]

Is the coil under the distributor..... ( non calif) I have not been able to find it in the docs online as to the location and process to remove it.

thanks
Jen

Originally Posted by Mike Gerber

I would check the coil with a DVM. There should be specs for the generation 4 in the manual at the top of this forum. If that comes up in spec, I would check the fuel pressure with a gage. You may have to take it somewhere for this test, but it is quick and shouldn't cost that much.

Mike

[Mike Gerber]

Jenny,

First, I miswrote when I said the manual above is for a generation 4. I meant to say generation 3 (92-96). That should be a good guide for you. Go to section IG. The info you want is on page IG-30.

Second, the coil is inside the distributor on all 5SFE engines, except those sold in California.

Good luck.

Mike

[JennyDee]

Mike:
I had a chance tol check the resistance in the primary coil and it came out at .09- 1.0 ohm cold which is well above the .38- .550 as specified in the ignition test. The secondary coil resistance was not in spec at 1.0 ohm.

The signal generator pick up coil resistance was in spec.

I do not have a timing light, so I was planning on scribing the distributor near the two bolts to replace the distributor as close to the position that I had taken it out. I am also going to sketch the position of the rotor position and I hope this will insure that I put the distributor back the same way it came out.

I am going to test the new coil before I purchase it to compare my ohm meter reading in case my meter does not read well below 1. Ohm.

Do you have any suggestions other that what I have thought of to insure that I do not ruin the timing when replacing the distributor.

Thanks.
Jenny

Originally Posted by Mike Gerber

Jenny,

First, I miswrote when I said the manual above is for a generation 4. I meant to say generation 3 (92-96). That should be a good guide for you. Go to section IG. The info you want is on page IG-30.

Second, the coil is inside the distributor on all 5SFE engines, except those sold in California.

Good luck.

Mike

[Mike Gerber]

I think your plan is a good one. I haven't removed the distributor from my generation 3, but I have done one on the generation 2. The way that distributor shaft was set up it can only go back in either right on or 180 degrees off. It's not a gear like on old American cars; but looks like an upsidedown wing nut. The generation 3 is probably the same. I think you will see what I mean when you take it out. Scribing a line (or using a sharpie) should work fine.

Mike

[JennyDee]

Well, it looks like my coil is actually fine and that the meter I was using was not accurate to give me the correct readings in the low range. I brought my test meter with me before I purchased the new coil and tested the new coil before I purchased it. I came up with the same readings as the one in my car that I thought was bad. I ended up purchasing a new meter and went through the tests again. The primary and secondary resistance was right on target. So it actually saved me from installing a coil that I did not need.

I also checked the igniter voltage, signal generator pickup coils, throttle posiiton sensor resistance, and they were in spec. Then I moved forward and checked the O2 voltage pulses E1 and VF1 which were close to 8 times a second, but I had the RPM at 2000 rather than the 2500 as specified. Did not want to wedge anything more on the gas pedal. <g>

So now I am back to square one, still the hesitation seems to show itself in the 35-40 mph range just before it shifts. Then it smooths out fine. Looks like I will have to be easy on the gas pedal until I get up to that shifting point.

Still trying to understand why the hesitation ( maybe an injector can't keep up ) shows itself between that speed range. Car runs perfect on the highway and without any lag or problems (70 mph)

Back to the drawing boards.

Jen

Originally Posted by Mike Gerber

I think your plan is a good one. I haven't removed the distributor from my generation 3, but I have done one on the generation 2. The way that distributor shaft was set up it can only go back in either right on or 180 degrees off. It's not a gear like on old American cars; but looks like an upsidedown wing nut. The generation 3 is probably the same. I think you will see what I mean when you take it out. Scribing a line (or using a sharpie) should work fine.

Mike

[Mike Gerber]

Jen,

Ok, now I'm a bit confused too. I keep going back to a weak fuel pump. That's why I suggested having it checked with a pressure gage. Maybe it just can't deliver enough fuel under heavy acceleration. A gage should check the pump and the fuel pressure regulator. If you can connect it to the fuel rail and get a hose long enough, you can put it near the dash and take the car for a ride. Tape it to the outside of the windshield if you have to. Try noting the pressure at the RPM range where you are having the problem. Do you notice a drop?

Also, check the ECT (engine coolant temperature sensor) with your DVM. Check it hot and cold. It may be slightly out of spec and causing a rich or lean condition under certain situations. These have been known to be a problem on some Toyotas.

Your thought of one or two bad injectors is a good one also, but an ex-Toyota tech told me he's rarely seen any problems with Toyota injectors. The pintel they use is pretty large and rarely cloggs up. You can check the resistance of each injector using your DVM. The spec should be in the manual.

Another remote possibility is a small crack in the tube leading from the air filter box to the throttle body. It can produce weird problems. I'm know I am grasping a bit here but it seems you have taken all the logical trouble-shooting steps.

That's about all I can't think of that would cause a hestitaion.

Keep trying.

Mike



PS: Jen,

You might also try posting your problem on Toyota Nation's Camry Forum. A few new people looking at this may have some additional thoughts. Here's a link to their forum:

http://www.toyotanation.com/forum/fo...php?forumid=15

[JennyDee]

Hello Mike:
Well, I spent the good part of the day checking the Manifold Absolute Pressure Sensor, Throttle Positoin Sensor, Intake Air Temperature Sensor, and the Engine Coolant Temperature sensor. ( did not pull out the ECT as we had temps in the 20 F last night out side of Boston, so I got a good reading of 6K ohm cold and .2k when hot)

Your first suggestion of the fuel pump is getting stronger all the time. I will have to check the pressure regulater later tonight. The only thing I have a problem understanding is that once I clear first gear ( just under 40 mph, the problem goes away) Seems as if (0ne) cylinder is not firing... but it shifts at 40 mph the problem is gone. Now I can step on the gas pedal and accelerate up to 70 mph without any lag... so that is where I have seem to not quite understand how the fuel pressure would be taxed in the first gear range and not when I step on it above 40 mph and let it wind up to 70 mph.....

I will call around to see were I can get the fuel pump checked this week.
The good thing is that I have not spent any money on things that were not broken.... <grin>

Will also register with the other forum and see if there is any suggestions.

Jenny

Originally Posted by Mike Gerber

Jen,

Ok, now I'm a bit confused too. I keep going back to a weak fuel pump. That's why I suggested having it checked with a pressure gage. Maybe it just can't deliver enough fuel under heavy acceleration. A gage should check the pump and the fuel pressure regulator. If you can connect it to the fuel rail and get a hose long enough, you can put it near the dash and take the car for a ride. Tape it to the outside of the windshield if you have to. Try noting the pressure at the RPM range where you are having the problem. Do you notice a drop?

Also, check the ECT (engine coolant temperature sensor) with your DVM. Check it hot and cold. It may be slightly out of spec and causing a rich or lean condition under certain situations. These have been known to be a problem on some Toyotas.

Your thought of one or two bad injectors is a good one also, but an ex-Toyota tech told me he's rarely seen any problems with Toyota injectors. The pintel they use is pretty large and rarely cloggs up. You can check the resistance of each injector using your DVM. The spec should be in the manual.

Another remote possibility is a small crack in the tube leading from the air filter box to the throttle body. It can produce weird problems. I'm know I am grasping a bit here but it seems you have taken all the logical trouble-shooting steps.

That's about all I can't think of that would cause a hestitaion.

Keep trying.

Mike



PS: Jen,

You might also try posting your problem on Toyota Nation's Camry Forum. A few new people looking at this may have some additional thoughts. Here's a link to their forum:

http://www.toyotanation.com/forum/fo...php?forumid=15

[Toysrme]

Take the plugs back out, ground them & check the spark across all of them.
Get your hands on both a vacuum gauge & timing light.
How is the EGR flow?

[JennyDee]

I am going to check the EGR flow based on the specifications EG1-157.

I also adjusted the stop screw on the Throtle Position Sensor to bring the resistance into spec. Seems that it has helped with the vibration between 30-35 mph, so I believe that the problem is associated with air flow rather than the fuel pump. I think I may have contributed to the problem as I had adjusted the "stop screw" on the TPS as I had thought it was the idle adjustment and moved the screw much to close to the vacuum plunger.

I am going to double check the Throttle Position Sensor, set the sensor based on the resistance, plus do the port check with the EGR flow tomorrow night.

Jen

Originally Posted by Toysrme

Take the plugs back out, ground them & check the spark across all of them.
Get your hands on both a vacuum gauge & timing light.
How is the EGR flow?

[Toysrme]

Ahhhh.
Ya EFI Toyota's don't have an idle adjustment. Sometimes you can open the throttle plate, or adjust the TPS, or adjust an air-flow meter's bypass - but the ECU is still going to try to run whatever it thinks it needs to try to run.



Let us know how it goes!

[JennyDee]

I opened the EGR vacuum modulator and cleaned the filter with B12 and made sure the ports were open. Did the same process with the EGR valve. Car seemed to run better the next morning, but always seemed to run better in cold weather until thethermostat opened. The next evening I started the car and opened the hood. Note, with the outside temp in the lower teens the hood struts can't hold up the weight of the 1995 Camry hood, so a good recommendation is to cut to lenght a block of wood to prop it up from the passenger side fender bolt. That way you avoid the hood crashing down onto you.

Ok, back to the main issue.

I replaced the set of spark plug wires again as they seemed to not stay in place. I had replaced them this past June along with the Denso plugs. For some reason the #4 cylinder plug wire was always pushed up. I re-seated the boot and top square cover and it always seemed to pop up the next time I opened the hood. The two piece wire set, ( boot and top) seemed to be a little on the cheap side compaired to the OEM that was on their for 10 years. They seem to be fine, but they seem to be cheap. So after talking to Autozone, they told me to pull the wire set and they would honor the lifetime warranty on the wire set. Perfect, I put on the new set, which was a molded boot and top mold square. When I pulled the plugs to check the spark, they looked good and the plug color was fine.

Started the car and noticed the #4 plug wire dancing up and down. I'm not a high tech mechanic, but I know that plug wires are not suppose to dance. <girn> What was actually happening I thought was that the threads were leaking and was causing the blow-by. Worse case I thought was that the threads were screwed up. I did put Never-SZ on them before installing them, so I thought the threads were leaking or it was the plug gasket. I am sure it would be $250 to have the head threads reworked.

So I pulled out the #4 plug and noticed that the porcelin top was loose and I could rotate it with my fingers. Went to Auto Zone and picked up a new set of Denso plugs and installed them. Kept my fingers crossed and the plug wires are not dancing. The hesitation seems to have dimininshed too so there may have been a few problems that were part of the original problem....

I guess the bottom line is to double check the basics..... I'm still spinning on the fact that the plug porcelin was defective.

Jen



QUOTE=Toysrme]Ahhhh.
Ya EFI Toyota's don't have an idle adjustment. Sometimes you can open the throttle plate, or adjust the TPS, or adjust an air-flow meter's bypass - but the ECU is still going to try to run whatever it thinks it needs to try to run.



Let us know how it goes![/quote]

[Mike Gerber]

Jen,

Many times, with engines and engine controls being so advanced today, compared to the engines of my youth, we forget the basics. They are still internal combustion engines. Think spark, think fuel and think timing and check those things first. That 25-40 MPH speed under hard acceleration must have been a point where the engine vibration started moving that plug/porcelyn around a bit causing a slight miss.

Anyway, glad to hear you have finally fixed the problem.

Just a thought on the hood struts. They are fairly inexpensive to replace. They probably run about $25 each aftermarket. Many techs will use a pair of vise grips on one side at the top of the small diameter rod (the one that goes inside the other piece when you close the hood) to keep the hood help upright when the struts fail. Most people have a set of vice grips in their tool box. It's probably safer until the strut rods can be replaced.

Mike