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Full Version: Alsmost a whole new car, still runs like a dog
6G Celicas Forums > 6th Generation Celica > Engine/Transmission/Maintenance
GordonR
Hi, it's my first post here. I've been reading for a while, but I'm at the end of my rope and trying to reach out to some folks who may have some good insight. I'm in west central Florida and I have a 1994 GT 5-speed ST204 that I bought back in 1998 when it only had 60K miles on it. After about 5 years and around the 140K mark the engine blew (my father in law, a professional mechanic thinks it threw a rod). The plan back then was to simply throw a used engine in it, but plans have a way of getting derailed. 12 years later we got back to it and got it running, but it never ran well at all. Those problems don't matter now because the second engine blew (rear main seal gave out while driving, lost all the oil and ruined the engine). At least this time we opted to have the engine completely rebuilt (cleaned, machined, bored out, all new seals, pistons, rings, etc.) and got a re-manufactured cylinder head (lifters are used but in good shape). Since then (about 2 years now) it's been a never ending hell trying to get the engine running right. At this point we've replaced almost everything under the hood and it runs mostly ok now. The engine is a 5sfe that probably came from a Camry or something because some of the brackets were different, but everything is as right as we can make it according to the factory service manual (the 2 volume green book). It think it's running pretty well now, but I still have some problems that are driving me nuts. It runs rough after a cold start until it warms up (idles high and makes sort of a chugging noise). After it warms up the shaking mostly goes away (not entirely) but it still shakes at idle and the shakes get heavy every once in a while (no discernible pattern). It seems to be worse under load (AC and headlights). It also shakes pretty good in neutral with the RPMs around 900 to 1100, so shifting into first is always less than pleasant (could also be part of the cold start problem because it idles in that range until it warms up). I do have a code 25 (running lean) that pops up every once in a while, so I think there may be a slight vacuum leak (vacuum leaks have been half the battle with this car, due to all the old rubber parts). And the gas mileage is still pretty bad. I get about 200 miles out of a 12 gallon tank (all city, lots of stop and go traffic), so roughly 17 mpg. No misfires as far as I can tell, and the tach holds steady (maybe wobbles a hair once in a while but it's hard to catch). When it vibrates it really rattles the passenger door. It stops if you hold the handle assembly, so it might just be a matter of the screws in the back of the panel being a little loose - I think I can fix that when I have time to take it apart again. It don't have the numbers, but the compression is good. My father in law has always suspected a problem with the head, but we keep finding things to fix outside of the engine and then it runs better, so I'm not convinced.

Some of what's been replaced: ECM (got one with matching numbers), water pump, oil pump, alternator, ignition module, distributor, plugs/wires, injectors and boots (OEM replacements), idle air control, knock sensor, timing belt, O2 sensor, IAT, MAP, and ECT sensors, TPS (tps, throttle cable and throttle body were precisely calibrated by the book), EGR modulator (EGR valve has been cleaned but not replaced, likewise the PCV), various hoses, all four motor mounts (got the kirkosaurus inserts for the front and rear), vehicle speed sensor, idle up VSV (used but works), EGR VSV (new), radiator and cap, temp sensor on the radiator, radiator and condenser fans, AC compressor, condenser, dryer, evaporator and pressure switch, and a new battery. Also replaced the brake master cylinder, brake booster check valve, the clutch master/slave cylinders, fuel pump and fuel filter. Fuel pressure regulator has not been replaced but looks ok. A heavy duty clutch was put in just before the engine blew the first time, so it's still pretty new. I tried to list everything, but I probably missed a few things. It needs struts and a muffler, but it still drives pretty well. I think the cat is ok.

I know the inserts can cause some vibration, but it seems to be more than that, plus the inserts wouldn't vibrate intermittently. I just want the car to not shake like a bucket of bolts so I can talk to some body shops about getting it painted and having the seats redone without getting laughed at. I know my diving conditions aren't ideal, and maybe the 10% ethanol is a factor now, but I used to get 300+ miles to a tank under the same conditions. I could have just bought a new car for all the money I've sunk into this, but at the time it seemed better to start with a known quantity and fix the problems rather than buy something that has who knows what wrong with it. But now, after replacing everything I can think of and it's still an embarrassment, I'm almost thinking about just taking it to CarMax to see what they'll give me for it. I still like the car, but I'd like it a whole lot more if it ran right. I know stock is lame, but I didn't know anything about engine swaps when I started this project, and after all the trouble I've had even having the Toyota service manual, the thought of wandering off into uncharted territory is too much for me. I just want the car I used to have (with a few upgrades) and I don't know what I'm missing, so I'd really appreciate some ideas. Thanks.
Smaay
without seeing the car i really cant help much. if you did put a camry engine in there, did you use all your manifolds and sensors? the camry is a little different than celica 5S-FE.

you could have swapped to a better engine for the money you put in rebuilding.
GordonR
Agreed. I definitely could have done a swap for the money I have into it, but honestly I'm more interested in getting everything running right and being able to find parts in the future. The whole point of this project was to make everything as close to new as possible to squeeze as much lifespan out of the car as possible. Stock horsepower isn't bad (should have got a little increase from boring out the cylinders, but I'm still trying to get everything dialed in), and I just like the feel of the car, so I think this is the right path for my needs as a daily driver. It's just had a lot more surprises than I ever imagined.

The engine came from a boneyard, and they pulled it so I don't know exactly what car it came out of, but my mechanic thinks it was a Camry. Yes, there are subtle differences. There was a problem with the knock sensor because the engine had the mounting hole in the wrong spot, but he was able to get it mounted in the right place, and any other differences (bracket locations, etc.) have been dealt with. At least that's when I'm told. The manifolds are original to the car, but since you mentioned it, there was an issue with the intake manifold where one of the bolts fell out. Probably just a matter of not having enough Locktite on it. It hasn't happened again. All of the parts that have been replaced have been replaced with the right part for a 94 Celica GT, which would include almost all wearable parts outside of the block, except for the EGR, PCV, a VSV that has something to do the the cooling system, power steering pump, and minor stuff like that.

We did find something that may help. The radiator and condenser fans are causing some of the vibration, even though both motors have been replaced. So the next step is to replace them again (one is under warranty) but this time do the fan blades as well. Maybe the shrouds too if I can find them, or we might have to just repair the old ones (one's metal, one's plastic). That could be the source of the vibration that comes and goes, but I doubt it has anything to do with the shaking around 1,000 RPM because that's too consistent. We're wondering if there may be something slightly out of balance in the bottom part of the engine, maybe in the flywheel / clutch area, but can't think of a good way to test that without ripping the whole thing apart. The crankshaft didn't require machining (but it was polished), and the harmonic balancer was replaced with the engine rebuild.

We're still digging into it, but I'd love to hear any other ideas.
GordonR
Another thought about the manifolds... The cylinder head was purchased for the car it's being used on, just like all the other parts. But my mechanic has always had doubts about the head because it didn't look exactly like the one he took off the block. If the manifolds are different on a Camry, then the head is probably different too. And that that would explain why the new one didn't match. So everything should be the right part for this car except for the block itself and maybe some of the internal hardware (pistons, rings, etc.).
slavie
Sometimes you can get caught up in your own thoughts so much that you loose track of where you're at.

You really need to try to diagnose your car more. Throwing parts at it doesn't always work. Go back to the basics.

Lean condition at low RPM points to vacuum leaks - make sure you find any and fix them.
Checkl the IACV. They're known to cause issues when they get clogged up with carbon deposits, and can cause vibration at idle. Check to make sure yous is working fine. Idle RPM should be 700+/-500 rpm warm.

Check the resistance on your spark plug wires, check the cap, learn to read your spark plugs.
Next, check your cylinders for consistency. Compression test, maybe leak-down test if you can. With engine running, pull spark plug wires one at a time to see if the vibration gets worse: if pulling out 3 cylinders causes things to get worse, but 4th one isn't so bad, you may have a problem with that cylinder. Rebuilt engine doesn't mean perfect engine - rebuilders are human and make mistakes, too.

The Toyota FSM has fantastic diagnostic procedures for practically every component. Use it. Yes, replacing parts is much easier than actually diagnosing the problem, but it's too close to guesswork to be your only tool for times like these. Besides, new parts can be defective, too, and you'll never figure that out without proper diagnosis.

Look to see if your replacement block still has a VIN plate on it (bottom rear left side, in the corner by transmission - left side is the exhaust side). If so, check the VIN and you'll know what car it came from. There's P/N stamped on the cylinder head, too, if you're concerned about that.

Again, proper diagnosis is hard to beat with parts flying out of your wallet. Hope this helps.
GordonR
Thanks for the suggestions. So far, everything that's been replaced actually has been diagnosed and replaced because it needed to be, and yes, some of the new parts have been bad. I think it took three distributors (new) before one worked right due to bad parts and subtle differences where the parts store says something fits the vehicle but isn't quite right. Chasing down dozens of problems at once has been a nightmare, but I guess that's what happens when a project gets derailed for so many years. At this point I think we've identified the cause of the vibrations. The fans are easy to replace, and the low RPM shake is definitely coming from the transmission. Tearing into that isn't going to happen for a while, but we think it's either a bad machining job on the flywheel or something is throwing the pressure plate off balance. I suspect eliminating the vibrations may help the gas mileage because there won't be as much energy being lost before it gets to the wheels, but I won't know how much until it's fixed. That still leaves the occasional code 25 which I think may be an intermittent vacuum leak, and whatever else may be affecting the mileage, so a good recheck of everything is probably a good idea.
VavAlephVav
The first vacuum leak I'd look at is the big vacuum hose that attaches to the bottom of the throttle body. Mine ran real ****ty until I sealed that one properly.
Some suggest spraying something like throttle cleaner around the suspected areas to see if it gets sucked into the vacuum system.

Also for the sake of vibrations, did you replace the motor mounts? And if so did you use some aftermarket mounts or did you go to Toyota?
I can tell you especially the Front-right (front of the engine) is the most important one. It looks kinda like a tea kettle. But the Toyota mount is filled with oil to act as a damper to absorb the vibration of the motor. Toyota wants $160 for it or you can go into an auto parts store and get one for $40-60 But it will not be filled with oil, and it makes a Big difference in how much everything shakes.
The cheap motor mounts vibrate as bad as a solid polyurethane racing mount without being nice and stiff it is literally as loud inside the car as if you had a bad muffler.
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