Hows it going everyone? Im having some trouble with my camaro this summer, and cant figure out the reason. It was idleing very rough, and once i drove it, it had no power and wouldnt be able to get past about 3k rpms. I would have my foot pinned to the floor and nothing. I took it to a shop close to my house and the mechanic said he was unable to retreave the codes becuase it wasnt accepting the scan tool. i then took it somewhere else and that mechanic said the same. So he suggested swapping the computer. $300 later i have a new computer in my car.

I picked up the car and drove it home. It ran normal. I then had to wait a week to get to the dmv to re-register it. I got home that day and it started rough. It then ran good, and i drove it for about an hour. I parked it and did some things. My dad suggested i get fresh gas in it becuase it sat all winter, i tried to get to the gas station but it half-way there it bogged down real bad and again very sluggish with no power, jus bucking down the road. At this point in fuming so i get a ride home and let the car sit a few hours. My father and i go back and try and crank it over.

Took us about an hour but got it to start. Again sprung right to life and i drove it home like it was new!. WE knew we had to go back to the guy and have him look at it. So he suggested we try anouther computer and it was under warranty so it was free of charge. Again picked it up that night and came home great. The next day went to go to work, got stuck on the side of the road with the same problems, bucking and juping running like crap and couldnt get it over 2500 rpms. Let it sit picked it up after work and strated right up. Drove it home. One more time i went out to drive around, and ran great. Parked it in the house took a shower ate, and came out and wouldnt start.

Again back to mechanic, he suggested MAF sensor. So i did that, $250+ labor. Today i was able to put the MAF on and started up beautiful. i was very impressed. Drove about an hour, in town, and up nd down the highway... Pulled into hess for gas shut her down and when i started up, same ****! Running rough bucking. i was kinda clasoe to home so tried to limp it, but died. Walked home and went back tonight around 9. So it was sitting for a good 5 hrs. started it up and bllasted back down the highway home, like nothing was wrong. Not only am i dumping in money but i dont know where to go now.

Heres what the basic sympthoms are in a nut shell (shortend version of my post lol) Car ran like crap. Replaced comp. Ran good on way home parked it. Started up a week later SES light came on. Went away after third restart. Drove a good 45 mins parked it. Then went out for gas and died on the way there. Bucking, jumping, backfiring, very little power. Got warranted computer droive it home great. Next day got stuck after 15 mins of driving. Went back to mec. suggested MAF. So i got that drove it for 1 hr. ran fine. Shut it off for gass started it up ran like crap. Let it sit for a few hrs. came back ran fine.

So basicly if it sits over night i can get 30-45 mins of drving out of it. Then if i shut it off, either wont start or will start but run like complete crap, it varies. other times, it will jus die, or loose power while im driving. other times if it dies while driving, i let it sit for 5-8 hrs go back nd it fires up. Any thing is greatly appriciated if you can help me. Thanks albert III

 

I'm not a great mechanic by any means, but it sounds like it may be the fuel pump. See if you are getting consistent fuel pressure at the fuel rails (I'm assuming its TPI since you didn't put what engine in your post).

When my fuel pump was going out, the car would sometimes start ok and sometimes not. Then randomly drive badly with stumbling, etc.

Hope this helps!

 

I would check your codes, and your fuel pressure.


It sounds to me like either the fuel pump or, more unlikey, the ignition module.

 

Before the fuel pump, I'd check (might as well replace it too) the fuel filter. This one can catch you by surprise sometimes, very often overlooked. Also how are you tune up items? (plugs, plug wires, air filter, cap, rotor, ignition compontents) Might as well eliminate the obvious. You're mech. is obviously just throwing parts at it, that sucks. You could also have a coked up intake or something, so maybe using a can of seafoam or GM top engine cleaner would help as well. These are all cheap maintanence things that needs to be addressed first before going much further into this problem.

 

It sounds like your problem is occurring only after the engine warms up ie. goes into closed loop. I would try to pull codes using a wire to jump the two terminals under the dash in your aldl port and see if you can interface with the computer at all. If that doesn't work, even after the new computer was put in, its probably related to your problem. Another easy thing to do is use a multimeter to check the proper voltage and resistance, where appropriate of all of your sensors and see if any one of them could be throwing your engine off.

 

Where are you located? I think you have a few injectors bad. I've seen this recently one one of our corvettes. After a while the injector would heat up, and the car would leave you stranded.

-- Joe

 

Thats another good suggestion!

I have heard about cases where injectors being bad caused the injector driver in the ECM to overheat and shut down. (Whether or not this is accurate remains to be seen )

Check the resistances of all th injectors with a multimeter... They should be between 14 and 17 ohms.

 

I agree with the above posters. Ohm your injectors. You can have one marginal with low ohms and when it heats up it will get worse and draw down the voltage and then the others will act up.

I have seen one case where the motor would either not run, run OK, run on seven cylinders or 4 cylinders on the opposite bank of a bad injector. It can drive you nuts.

 

Ive seen injectors over heat, and not CLOSE. Weird stuff.

-- Joe

 

wow all great suggestions, im going to be busy this weekend lol... sorry for not replying, but i have gotten all your posts and read them all multiple times, but i am very busy this time of year (HVAC) so i only got saturday nights and sundays to work on the car or really do anything besides work hah... we will see what i can find out, and ill be back with an update.. thanks again for your help everyone!!!

 

its been a while, and honestly i havent done anything with my baby (lol) all winter. Combo of not having time/becoming very frusterated with the car. I did take it to another mech. and he actually ohm'ed out the injectors like stated above. You guys were exactly right, the injectors had very little resistance. The highest one i believe was like 11 and the lowest was at 7? not exactly sure on that becuase it was awhile since i even touched on this subject. He also said the reason the other mechanic suggested the computer was becuase when there is little resistance in the injectors it goes back to the computer and then screws up the computer. I have tomorrow off for good friday so i am hoping to tackle the injectors tomorrow. I was hoping the information i have given might have made it alittle clear-er for you guys to understand. Do you think this is it, have i (actually the mechanic) finally found the problem? Would i just have to change the injectors and clear out all my problems. After reading everything i posted and heard my symthoms (s.p) does it make sense? Thanks again for your help it saves alot of headaches and money! lol Al III

 

This is a possibility. The ecm has transistors that control the ground circuit of the injector. If the reisistance were to change to a lower number, the amount of current flowing through the ecm would increase. More than likely if this was the problem, it would overheat the ecm causing the car to run like poo. Could be a root of lack of communication also.

 

When you get new injectors in it will run like new. Any injector that ohmed under 10 is done.

People here, me included, have had good luck with bosch/ford. I gambled (auction) and got a low mile set of 24# m9593-a302 for $60.00 shipped to my house. The 19# you need sell real cheap.

 

Word. I got a set of Ford 19# injectors off fleabay for $50 shipped. They work great, but read up on the fitment if you go with Fords... they're a tad shorter than the factory pieces.

Dave