Aaauuuuuggghhhh!!! I Need Help!!!!

[zbugger]

Ok, not the mental help some of you think I need. I'm getting tired of my sisters car. I'm trying to figure out why it won't go past 1/4 throttle without falling flat on it's face. The plugs say it's running damn lean. The O2 sensors aren't really reading at all, and the damn thing isn't throwing any trouble codes at all!!!! I'm going nuts!!! I've already replaced the TB, TPS, and the ECM. The car died on me leaving a light, and I had to change the fuel pump. It's giving me a headache, and it's my only form of transportation. I would love to just blow this thing up and get a new car, but I can't afford a stick of gum at the moment. Ok, I guess I can afford the stick of gum, but not a car payment. I don't know. I guess I'm just getting pretty frustrated because the car is doing this to me.... and I really want to it. I just wanna drive it now. This sucks. I'm gonna just walk over to the bridge and jump. See ya'll on the other side.

[Flynlo416]

What kind of car is this Allen ?? Do you have a way to read the codes the car is throwing to see what the real problem is?? I'm assuming this is a much newer vehicle.

[zbugger]

Yeah, it's a '95 Geo Prism. I changed the engine earlier this year, and everything was fine. I've also got the Service Manuals and they've helped a little. I think being educated in the stuff helps too, but it may be something basic that I'm forgetting. Maybe a stuck EGR would have that effect? I don't know at the moment. I'm just pretty frustrated at the moment. The only reason I've changed some of those parts is because I still have them on the old engine. It's easy to just swap some questionable parts off the old engine that still worked. I'll figure something out. I hope....

[Flynlo416]

I agree!! EGR valve would be the next thing I looked at. It's always good to BREATH.......lol. Take a break and go look at it later .You never know what you might have overlooked.

[Zefhix]

Ok, not the mental help some of you think I need. I'm getting tired of my sisters car. I'm trying to figure out why it won't go past 1/4 throttle without falling flat on it's face. The plugs say it's running damn lean. The O2 sensors aren't really reading at all, and the damn thing isn't throwing any trouble codes at all!!!! I'm going nuts!!! I've already replaced the TB, TPS, and the ECM. The car died on me leaving a light, and I had to change the fuel pump. It's giving me a headache, and it's my only form of transportation. I would love to just blow this thing up and get a new car, but I can't afford a stick of gum at the moment. Ok, I guess I can afford the stick of gum, but not a car payment. I don't know. I guess I'm just getting pretty frustrated because the car is doing this to me.... and I really want to it. I just wanna drive it now. This sucks. I'm gonna just walk over to the bridge and jump. See ya'll on the other side.

Hey Allen, is this a static issue or does it only occur once the car warms up? Also, will it rev past 1/4 throttle while in neutral or not even then...is it just when it's under load? I suspect the 02s are more of a problem than you know, replacing them would be *cheap* insurance (okay so maybe the 02s aren't cheap; try the old ones). Also, even though you swapped the TPS you need to ensure that it is getting the required voltage range (your service manual should have the correct rates for the car) Also, you need to check fuel PSI at the rail and make sure that the fuel filter does not need replacing since you already replaced the pump. Good luck guy....

[zbugger]

Keith, I actually replaced all that as cheap insurance. With the new fuel pump I installed a new filter and pressure regulator. It will hardly hold an idle, and that's in neutral. I have to see how much the new O2's will run me. If I get it going in gear, it stumbles really hard. I'm not sure what to do after that. I hate throwing parts at something. I think dynamite should do the trick though.

[MrQuick]

I can't believe you keep forgeting about me, I was a Toyota diagnostic tech for 3 years...
An EGR and O2's alone won't cause this problem. A stuck open EGR will give you a bad/rough idle but will run fine at top end.Stuck closed EGR will just give you the pings. O2's can do it if it runs rich enough to kill a catalyst, but unlikely.
I do a comp check then a idle vac test.This would tell you if its mechanical or an input/output problem.This would be a good place to start.
What were the problems that prompted the engine replacment? Oil consumption or bearing failure,I can't remember? If it was a fluid loss through the engine it maybe a partialy plugged catalyst.A jumped t- belt would give you the same sympoms.

[Little Bob]

Did you try the cam sensor? Did you check for pinched wires?

[zbugger]

I can't believe you keep forgeting about me, I was a Toyota diagnostic tech for 3 years...
An EGR and O2's alone won't cause this problem. A stuck open EGR will give you a bad/rough idle but will run fine at top end.Stuck closed EGR will just give you the pings. O2's can do it if it runs rich enough to kill a catalyst, but unlikely.
I do a comp check then a idle vac test.This would tell you if its mechanical or an input/output problem.This would be a good place to start.
What were the problems that prompted the engine replacment? Oil consumption or bearing failure,I can't remember? If it was a fluid loss through the engine it maybe a partialy plugged catalyst.A jumped t- belt would give you the same sympoms.

Hey Vince, I only knew about your Dodge days. Anyway, it was a bearing failure because of a lack of oil that made me replace the engine in the fist place. The most recent problem occured when the engine stalled as I accelerated from a stoplight. I've run the OBD test, and it's supposed to come up with a DTC 51 when I have the AC on or the throttle anywhere past closed. It's not doing it. I'm still sitting here reading the books on the damn thing, and I can't figure it out. The only time there's a problem is when the throttle is open. I can't get anywhere past 1/4 throttle. It's not throwing any codes, yet it is for some reason running extremely lean. I can't find any vacum leaks either. You can call me tomorrow if you want to talk about it. I'm just gonna punch the concrete till my hands bleed to take my mind off the car.

[Gonzostyle]

Allen, did you try the temp sensor (the one that sends data to the ECM)? My dad's geo started running like crap and it wound up being the temp sensor. Also, do the Geo's had altitude compensators? That might be causing a lean condition.

-Jeremie

[68LSS1]

what about the injectors? Got a set off the other engine to put on? Or at the very least a noid light to check injector pulse? I know nothing about Geo's so I'm assuming it has a 4 injector system.

[Charley Lillard]

Have you tried unhooking the cat convertor ? Maybe it is plugged.

[CAMAROBOY69]

I had the same thing happen on my 1989 Beretta and as Charley said, it was the cat. I just cut the cat off and put a straight pipe in.

[dennis68]

Allen, you need to find somebody with a scanner-not a code reader. Then at least you can monitor sensor readings while its acting up and figure out why. Take a look at ST/LT adaptives, they will usually tell story. If the GEO processor shows timing retard that is very helpful as well as O2 readings, of course don't forget CTS, TPS, and MAP-very important. A bad MAP sensor will **** up your world.

[TonyL]

A. Start with the cat. simply start the car and check the tail pipe for exaust while someone runs the engine. if none or too little is coming out, there you go.

B. toyota puts the coil packs right by the exaust mainifold on some of those engines, if you are one of those the heat could be affecting them and causeing bad spark problems at warmup, especilly on load

Oh, back to the cat, check it for a fresh air inlet valve, if there is one, unhook it. and let the air breath out. if it is the cat, sometimes you can beat it with a 2 lb sledge and break the parts up enough so they blow out.

[zbugger]

Ok, well, here goes. I know it's not the cat. The exhaust is blowing fine, and it actually is putting out a lot of water. Also, it has the California emissions package. It has a pre-cat, and a cat downstream. It also has the O2 sensor, and a sub-O2 sensor down stream as well. The timing looks fine. The ignition is still a distributor style. I do have to replace the wires, but they can wait. I am actually using the DLC to get the codes out, using jumper wires to get the thing to spit out any codes. I'm using the multi-meter to read the sensors, and what I've gotten seems to be in range. I don't see what could be going on, but I do think that it's just something right under my nose. It'll rev to 6k, but it won't let the engine run after it reaches 1/4 throttle. I'm going nuts. I'll try and post some of the readings this week. Any you guys want to know specifically?

[68LSS1]

What does it use for timing advancement? Vacuum or mechanical?

[zbugger]

What does it use for timing advancement? Vacuum or mechanical?

It's computer controlled electronic.