Alsmost a whole new car, still runs like a dog Options

[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.

[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.