I have a 95 Corolla I just picked up for a quick flip. It has a severe misfire, bucking, jerking under moderate load and even in neutral sitting still at about 2500 rpm it cuts out and runs really rough. The previous (one) owner put on new distributor (includes G sensor and coil), cap, rotor, plugs, wires. They had it at several shops but never could find the root cause. Here is what I have done: confirmed fuel pressure (ok), confirmed EGR operation (ok), mechanical timing (timing belt, ok), ignition base timing, TPS (IDL, VC, VTA, E1) with ohm meter, confirmed these with Toyota handheld tester, ECT, TPS, KNK, IAT, ISC. I also threw these parts on for good measure, MAP, Igniter, another distributor assy, crank pos sensor, and alternator. There was some corrosion in the wire harness at the battery so I put on new terminals and cleaned up the battery. The engine starts and idles fine and runs fine until about 2500rpm no load (8%ish throttle) and stumbles horribly until about 3500 to 4000 it suddenly clears up and runs fine. On the road, it runs ok under light accel or full throttle but cuts out violently in between. In top gear you can ease up to 60mph ok but between 65 and 75 cuts out really bad. I am to the point now of thinking it is the ECU but I have no logical reason to think that I just don't know what else to try. I have tried disconnecting the EGR completely and no change. I also checked and cleaned the ground wires at the front and rear of the engine. All of the parts put on are Autozone quality not OEM but I hate to shell out thousands unless I know for sure what the issue is. Any help is greatly appreciated!
Could be your fuel injectors sticking on you. I'd also check the fuel filter can, as you can easily access it. Did you do a compression check? Sure it is not an accessory (A/C compressor, Alternator, etc.) that is excessively loading down the engine at higher RPMs and loads?
Fish, Thanks for the quick response. I know the accessory drag is not an issue because the alternator is new and AC is off (I confirmed the clutch is not engaging). I was going to replace the fuel filter but I would think the fuel pressure would be low under load if it were clogged and it is dead on with specs in Toyota RM. I also confirmed that the fuel pressure holds after stopping the engine so I would think that rules out both the injectors and pressure regulator. I will see if I can find a good salvage yard and locate some injectors and ECU. So far parts for this car seem scarce. Any ideas for online salvage yards?
149 posts
How much can you make flipping a '95 Corolla?? .....
Maybe time to move on.
Online salvage parts are hit or miss, quality wise, especially for the likely electrical/critical parts you are looking for. Fuel pressure may still hold and be within spec even with bad injectors.
Model year was made right just before OBD-II adoption, so you will likely not be able to get much info from running a datalogger to the ECM. A faulty O2 sensor could describe the problem you are seeing - probably be the least expensive piece to swap and see if performance improves. This is more likely if the car runs well at WOT - as the feedback information is not generally used at that point.
Fish, Thanks for the advice. I used the Toyota Handheld Scanner 02/rpm function to see the graph. The spec is 8 or more fluctuations in 10s after the sensor has been heated by running the engine at 2000-2500rpm for at least 90s. It passed with a nice smooth graph and 10 fluctuations. I also graphed the sub 02 sensor to for the heck of it and it had a nice flat graph indicating normal sensor and catalyst function. If I run the engine up to the point it begins to stumble the 02 graph goes crazy but I think it is just reading the misfires of the engine not actually causing them. I can't say for sure though so I will probably put one on for good measure. I just got the information for inspecting the fuel injectors today so I will check them out per the RM troubleshooting procedure tomorrow and see what that shows. I was thinking the fuel injector 12v was supplied directly from the battery and the ECU switched the ground open and closed for operation but per the wiring diagram both + and - are provided through the ECU so I will confirm those circuits. My past experience with injectors has always been that they stick open and bleed fuel into the cylinder causing it to flood and run rough at idle/low rpm or they clog and cause a lean misfire at high rpm/load. This engine is as smooth as silk at start up, idle, and 75%-WOT. At this point though I am considering everything so I will hunt a new set of injectors also. I bought a salvage yard ECU off ebay for 50 bucks that is guaranteed so I can try that out when it comes in. Wish me luck!
That's a lot of parts replaced. Don't rule out the possibility of a bad part right out of the box...especially the plugs and wires.
Good luck,
Jay in MA
.......new distributor (includes G sensor and coil), cap, rotor, plugs, wires, MAP, Igniter, another distributor assy, crank pos sensor, and alternator.
Old Toyotas are going for crazy money here.
A friend's gave his well used 2000 Camry to his older daughter. She drove it for a long time and then gave it to her sister.
290K miles, V6, auto, stuffed in the front, tree fell through the back window. They advertised it in Craigslist for $600 and ended up getting $1800.
How much can you make flipping a '95 Corolla?? .....
Maybe time to move on.
Update on the Corolla. Got in the ECU from eBay but it didn't help anything. So I got a .pdf copy of the Toyota RM and followed it step by step. The only thing I could find that didn't meet the spec was the ignition coil. The primary side resistance was more than double that listed. I tried another Autozone part but it had about the same resisitance. I ordered one online from a Toyota dealer and should be here in a week or so. I will update again once I put the new coil in. If that doesn't fix it I will have to find an oscilloscope to check sensor and igniter function. Wish me luck!
Just want to let everyone know. I put in the new OE coil from Denso and it fixed it!! The car is running great now!! Instead of flipping it I may drive it for awhile to wait out these crazy gas prices. I hope this post helps some other poor guy struggling with these type issues and it is a reminder to us all that you get what you pay for!!!
