doug791

Okay forget EVERYTHING i said before if you were following the thread i had.

Heres the story, car was running just fine and then all of a sudden started stumbling and backfiring like crazy. Now when i crank the motor it will only stay running if i give it a bit of gas as soon as i get off the throttle it bogs out and dies. The engine will stay running as long as i give it gas but if i try to drive it to the end of the street and back it will start stumbling and backfiring. Also when its running it smells rich as a pig.

On a side note when the car is cranking the oil pressure gauge goes all the way to the right when cranking like normal but then once it starts running it goes all the way to the left. As far as i remember it usually settled pretty quickly right in the middle as far as i remembered.

(to people who were following my earlier thread i figured out why my tach got messed up and it had nothing to do with my problem stupid wiring thing i messed up by accident but is fixed now)

raul.garcia

Even if the Chip Carrier is locked in, if the Hyper Chip isn't solder in the OEM carrier, vibration will cause it lose it's connections, and it's mind. Some use a ZIF (zero insertion force) socket to allow quick removal of the chip, this may be convenient for programming, but soldering is better.

Try tapping on the ECU case to see if it stumbles, (although could be the ECU itself.) The other thing you can tap on that's cause the same problem is the MAF, if you have one.

If all sensors are good then it sounds like a faulty connection, with age connector hold down tabs will break off and the connector will back itself out with vibration (this happened to me with one of the Dizzy connectors.)

doug791

ill try the chip carrier idea tonight that sounds like a viable explanation. The chip is right by where the fuses and everything are right? sorry for the ignorance on that one my car knowledge is limited to stuff ive already done on my car and im only 17.

And its a 90 car so it will have speed density

raul.garcia

No the chip is in the ECU (the ECU is behind the glove box.) It's a aluminum rectangular box about 1" thick. It has two connectors on one end blue, and white, or black I'm not sure. Might want to have someone who knows electronics take a look at it.

Rice Killer87

if its not that,sounds like it could be EGR valve related as well (except for the rich part... )

if ur car is TPI,u can see the EGR valve from the pass. side under the upper plenum...its a silver round thing and has a vacuum line going to it. Unhook the vacuum line and see if it will run w/o any throttle w/ the vacuum line off.

raul.garcia

Might be wrong, but EGR is negative backpressure type, will not open in idle, so removing vacuum won't tell you anything, need to rev to about 2k rpm, (or use EGR Diagnostic Chart.) The ECM uses TPS, CTS, among other things to decide when, and how much EG to recirculate.

doug791

i tried starting the car again. Now im figuring the best way to deal with this is forget what was happening when i was driving it just deal with the problem at idle or in neutral.

When the car was on i gave a pretty good knock on the ecu and the engine didnt do anything so it being loose is not the culprit, could still be bad though. When the car was running it was doing pretty descent just the car was completly flooding the engine with fuel.

aklim

Well, I once had my entire driver side of fuel injectors short out the fuse. That meant no injector firing while running. ECM took sensor readings via the O2 sensor and doubled the pulse width. Right side flood, left side has no gas. Check the O2 sensor for laziness.

doug791

explain pls

raul.garcia

Does it feel like it's only running on 4 cylinders? Check the exhaust, 4 cylinders can't burn all that gas, should smell bad, and blow dark smoke for sure.

If you can't find, or check the fuses, take a rubber hose and hold to the body of the injector and listen for clicking sound, no clicks - injector isn't working.

aklim

If you have a scanner, you can see O2 voltage. When the sensors get old, the move slowly. They should be changing all the time and pretty quickly too but if it moves slowly then it is lazy and needs changing.

doug791

Okay its definitly not running on 4 cylinders, i know what a dropping cylinder sounds like (lol my cars done that before too yay learning from experience, just wish it was on someone elses car for once).

As far as testing the 02 sensor aklim i dont have a scanner i was able to check the codes just using a paperclip and connecting the 5-6 pin method and it just flashes code 12 over and over.

I'm starting to think that since i know the oil pressure gauge is getting electrical power and i know the needle does move around (it moves while cranking) that i might actually not have any oil pressure. I need some way to verify this first but if i actually dont have oil pressure then its most likely because my distributor is messed and isnt powering the oil pump drive shaft.

Fastbird93

Just out of curiousity, what's your TPS reading?? My car when I got it back the TPS was not giving any voltage at all, and it acted like yours (I.E. had to give gas to start and keep running, let off gas car dies, runs REAL rough).

chriswtx

It could be an egr problem if it is stuck in the open position. Also could be a distributor problem. When the dist. module starts to fail it can cause this problem...