94 LE 4CYL Auto, Vibration Problem: EGR Questions

[snafu9t9]

I have been chasing down a gradually worsening vibration problem for 2-3 years. It is worst at stop lights after the engine is warmed up while the car is in gear. Going into neutral or park almost eliminates the vibration. Prior to changing the transmission mount the vibration would get so bad it would visibly shake the steering wheel 1/8-1/4 inch at times.

The engine is fully tuned up, and I have replaced all the mounts, cleaned the throttle body, etc., etc. My most recent theory was the EGR valve. I was testing it using a vacuum pump, but the result I got is not discussed in my Haynes manual. The manual says that the engine should run poorly when applying vacuum. When I apply vacuum my engine shuts off. The valve doesn't seem to have any problem holding a the vacuum once applied. Does anyone know if this indicates a bad EGR valve, or an EGR valve that should be removed and cleaned.

The only other theory I have is that the bushings holding the steering rack may be sufficiently worn that too much vibration is getting through, but I kind of doubt that. If anyone has any other theories about the source of the vibration, I am all ears. I have searched and searched, and have tried almost everything I have read about the on the internet (or in the manual), but nothing has worked. Gas mileage is fine, and otherwise the car runs great, 112k miles and I think if I can cure this vibration it is just getting broken in.

[fenixus]

your EGR valve is good. make sure filter in EGR modulator is clean and facing hard/coarse side up
you may also have a dirty fuel filter or dirty injectors that might cause some slight fuel pressure or rare/random misfire that never gets diagnosed by ECU because it's not constant.

how are your engine RPMS at idle at both Park/Neutral gear and then in driving gears (either of R/D/2/L) at full stop with e-brake only (no accessories running)?

since you replaced all enginemounts, have anyone checked the flex pipe for any signs of cracks ? it usually goes shortly after mounts go bad. it may cause an exhaust leak and lean out engine at idle a bit too.

on my car i noticed also the tranny differential vibrates excessively at idle in Driving gears at full stop, not sure why yet as it was flushed in SEP '09 and should be good. tranny itself works great though.

[JohnGD]

You don't need a lot of vacuum to shut the engine off. See if you can just pull .5-1".

Did your tuneup include new spark plug wires? What type of plugs are you using?

Originally Posted by snafu9t9

I have been chasing down a gradually worsening vibration problem for 2-3 years. It is worst at stop lights after the engine is warmed up while the car is in gear. Going into neutral or park almost eliminates the vibration. Prior to changing the transmission mount the vibration would get so bad it would visibly shake the steering wheel 1/8-1/4 inch at times.

The engine is fully tuned up, and I have replaced all the mounts, cleaned the throttle body, etc., etc. My most recent theory was the EGR valve. I was testing it using a vacuum pump, but the result I got is not discussed in my Haynes manual. The manual says that the engine should run poorly when applying vacuum. When I apply vacuum my engine shuts off. The valve doesn't seem to have any problem holding a the vacuum once applied. Does anyone know if this indicates a bad EGR valve, or an EGR valve that should be removed and cleaned.

The only other theory I have is that the bushings holding the steering rack may be sufficiently worn that too much vibration is getting through, but I kind of doubt that. If anyone has any other theories about the source of the vibration, I am all ears. I have searched and searched, and have tried almost everything I have read about the on the internet (or in the manual), but nothing has worked. Gas mileage is fine, and otherwise the car runs great, 112k miles and I think if I can cure this vibration it is just getting broken in.

[snafu9t9]

Fenixus: Some good thoughts in here. I have checked the filter before, but I'll take a look at it again. I changed the fuel filter when I did bunch of work somewhere between 70-80K (timing belt, waterpump, etc.). I could change it again though, as I recall it wasn't that tough a job. I have also considered the fuel injectors. Given the car's 112K miles over 16 years, virtually all short trips and city driving, that seems like a possibility. Do people have a preferred technique of removing them and cleaning them, or do they just replace them? I have a hard time believing that those chemical cleaners work, though I would be willing to try it if others have had a good outcome.

As far as RPM, I would say I am at about 750 in gear with the brake on, maybe a little lower. It definitely bumps up a little bit in park and neutral, which is why I think it smooths out. I would suspect the transmission, but it performs great otherwise.

Flex pipe. I've had that replaced twice. Lasted just over a year (just outside warranty), but luckily I was able to convince them to fix it for free the second time. I would have to figure out the timing of the repairs, but I want to say that all the motor mounts were replaced between the first and second flex pipes. I just recently did the transmission mount myself. I should probably check the flex pipe again, though I doubt that is it. As I say, this has been around forever, gradually getting worse, and every time I get something repaired I hope that was it, but so far I haven't found it. I may have to break down and take it somewhere. I generally do repairs myself.

I have always assumed that the vibration is coming from the engine, but maybe it is a transmission issue. It's probably due for a transmission fluid change, I guess I could give that a shot.

JohnGD: I have been using Bosch +4s. The current set probably has less than 2K on them because I replaced the old set when I was scared I fouled them after cleaning the throttle body. I replaced the wires when I did a tuneup. That was probably at about 80K. I just got a set from either autozone or parts plus. I wasn't terribly impressed with the way they fit into the cylinder head, but the boots seem to snap on the plugs fine. Do people have a preferred type of plugs/wires that they find work best? I would be willing to try that.

I may need to hand this over to a professional, but I am always cautious about doing that because I am often very dissapointed with the results, so I try and sort these things out myself. This one though ahs been going on for years, and I may have to give up.

[coffee-3000]

I was experiecing excessive vibration in my steering wheel for about a year with no trouble codes.
Eventually I recieve a trouble code indicating that I had a misfire in cylinder #6. My local mechanic cleaned the injector for cylinder #6 and the vibration stopped. I'm not sure if this helps. But it is worth thinking about.

I'm trying to figure out how to remove the injectors myself in order to clean the rest of them.

[fenixus]

snafu9t9, it seems you have a ~45k miles old fuel filter. it's due for replacement. get an OEM one from local or online dealer or WIX from Napa (Napa Gold). They last at least 30k miles, but other aftermarket fuel filters last ~15k miles tops.

here is a DIY on fuel injectors removal (5s-fe engine):
DIY Fuel rail & injectors removal - 4cyl i4 5s-fe gen4 camry - PICS !

I sent them for cleaning in California (RC Engineering), it cost me around $150 for all including shipping UPS 2 d day both ways, about a week turn around time (i'm in Jersey). they were only 72k miles old (10 years) and already out of balance (10%), after cleaning they are within less than 1% of balance.
New injectors cost (from online dealer) was $520 for just injectors.

If you don't want to touch them yet, Chevron Techron is a good injector cleaning stuff, but it won't solve dripping/restricted spray pattern problem if it's bad already. The RC shop puts them in chemical & ultrasonic bath, you can't do that yourself.

your tranny has nothing to do with it. computer controls fully engine speed in driving gears and will always try getting them into 700ish (norm is 700+/50rpm in Neutral gear, all accessories off). when Park gear causes RPM to go to like 800ish it's fine and normal, but anything above 900rpm in Park is NOT normal.
though you should drain/refill or flush it every 30k miles (including differential), that's what manual says. I did first flush at 60k at dealer as i was scared it's bad already (had some vibrations trouble like you do)

I think you can check vacuum ports on Throttle Body at idle to make sure you have zero vacuum reading from P & R ports confirming the throttle plate fully closes at idle. I don't remember which port exactly that was, but i can look it up, been there done that not long ago.

about your tune up items (plugs, wires and air/fuel filters). never use Bosch spark plug wires, if you have them, you can safely put them in garbage and get some decent OEM quality wires, like cheap japanese made NGK TE58 (~$40) from Advance Auto Parts or Amazon ($27) with free shipping. Bosch wires are horrible, i tried 3 sets and all of them were junk, they didn't last a month without some kind of a problem.

I don't think your Bosch+4 plugs are bad, but for future I could suggest sticking to Japanese NGK Laser Platinum or Iridium-IX plugs, this is great stuff!
those Bosch plugs tend to fail prematurely, for most people they do not last 30k miles as I heard.

is there any chance you can get a OBD2 scanner connected to your car and see live readings (fuel trims, MAP, o2 sensors, etc.) when engine idles ? this would be helpful to determine if your vibrations are somewhat related to what ECU does.

You can also try Sea Foam treatment in engine, tank and booster port (you will need to change oil after 50-100 miles). it can help smooth your car vibrations too if thats because of some dirt or carbon deposits.

EDIT:
NGK TE58 wires are for gen4 camry (yours is gen3), check here for gen3 camry wires:
http://www.ngksparkplugs.com/part_fi...uv/default.asp

[73sport]

Years of short runs in-town and no long freeway runs add up to more reasons to use chemical cleaners.

snafu9t9, I know you said your not hopeful of fuel additives but just like things accumulate over time, some of these cleaners can remove it over time too. Grab a bottle of Techron (Chevron product) and burn down a tank on the freeway doing some sight seeing and then a couple more in town. It won't hurt.

Does the car ever see bursts of wide open throttle operation? Ever? And how often are the oil changes?

A common mistake I've seen when people install engines, tranmissions and replace mounts is they tighten bolts as soon as they get a good straight shot at the bolt. This can be when the engine is still jacked up, sitting on blocks, held by a chain, has the Dog bone is in a bind, or things were not allowed to settle to a natural neutral resting spot. Bad idea. . .

Sometimes it helps to loosen mounts which have slots (start the engine for needed vibration) and allow the mounts to settle under load to that neutral spot and tighten them. This unloads the mounts so they're not bound up fighting one another as this causes vibrations to be transmittted to the chassis.

Has the CAR EVER BEEN WRECKED? Sometime mounts are bound up due to faulty collision repairs! Don't discount that! Mounts in a bind from collision damage can cause this too!