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It is a 1988 Chevy Beretta 2.8 V6 (MPFI)... Alright so today I bought a new, Throttle position sencer, and a new (map) sensor... After putting it all back on the car, jumped in and tried starting it.. It wanted to start!.. After 3 trys i gave up.. I want to know if the fule pump relay and or fuel pump canister would cause this not to start!.. Im getting fule to the engine i looked at the coil packs and all three are getting fire! I worked all this damn car all day, and back to the same problem i started at!.... ANY IDEAS???? :smash: :smash:
 

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Hey, usually a tps or map won't keep the engine from starting. If one of them was at fault, you could unplug it and it should start. What have you done so far? Codes? Fuel pressure? Some of these will still give you spark if you have a bad crank or cam sensor, but it may not be timed right. One of the major inputs is coolant temp sensor. If it's reading too high, the pulse width of the injector's won't be enough(not enough fuel), the engine might try and start but not have enough fuel. Unplugging it should give the computer a -40 degree reading. If you haven't tested this I might be able to find a test for you to do with a volt meter. Fuel pressure is obviously very important, you could have fuel, but not enough pressure and it may not start. Let me know where your at. On the flip side, if one of your sensors failed telling the computer to add too much fuel, that could also cause your almost start. How do the plugs look? Are they wet from fuel? Hope this helps or doesn't add too much confusion.
 

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Did you try the crankshaft position sensor like the previous guy asked? I had a jeep that exhibited the same signs as yours and that was the problem. It could be running fine one day, you shut it down, go back out the next day and it won't run. These sensors tend to get soaked with heat and short out when they're cooling down from a run session.

I'm impressed that you're so young and gung-ho about repairing this car yourself. If I could make a suggestion: go buy a book on the car, and one on fuel injection. To be perfectly honest, there are many components, but the outputs of the sensors are very simple. Usually most of them just send "yes or no" signals to the computer. Don't be afraid to crack open a book and learn about this stuff, the knowledge you gain may help you to assess your problem more carefully.

Your problem could be any number of things. From the above however, I respectfully disagree with the cat/o2 sensor. Generally a cat will cause problems at RPM/create smells. O2 sensors may cause the car to run poorly, but I've not seen one cause a car not to run.

The reason I asked you to check your fuel pressure is that on fuel injected cars the fuel rail has to be at a set pressure for the injectors to open and fire. Generally most of the setups on regular driver cars are "batch fired" which means many injectors fire at one time, and the charge just sits in the intake port until the intake valve opens for the cylinders that aren't on the intake stroke when the batch goes off (less dramatic than it sounds, we're talking a fraction of a second). What it does mean, however, is that the fuel rail is more sensitive to say a somewhat plugged fuel filter, because fuel is drained in pulses rather than steadily. Therefore the fuel pressure needs to be adequate and steady.

Do some reading, its obvious you have the drive to fix this problem.

K
 

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I have seen several cat's plugged so bad that the vehicle won't run. Last one I had was just last week, 1999 Dodge Ram 2500 w/5.9. Looked at the plugs and they were soaked. Disabled ignition and cranked it, sounded like it had even compression, cleaned the plugs, still no start. Pulled the rear plugs out #7 @ #8 and it tried to start, tried to start with o2 sensor out. finally pulled exhaust off of manifolds, and it still wouldn't start. Held gas pedal to floor and finally got it started. It was fuel fouling the plugs so fast, made it hard to start, run fine once we run it and it cleaned itself out. Pulled the cat off, the rear looked just fine, the front looked like it lost a fight with a really hot blowtorch. Completely melted down. Don't see these very often, but I've probably seen 1/2 a dozen. I agree with pulling the 02 and trying it. Good luck.
 

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Doc here, :pimp:

Start with the basics first..

Go to the fuse panel, check ALL the fuses with a DVOM, (don't just eyeball it and call it good, a fuse can open at the foot, and not be visible)..

Pay special attention to any marked: ECM, ECU, COMP, CRK SENSOR, IGN, AND INJ...

Rule those out FIRST, then go here:trouble shoot flow charts and follow the procedure..

It has a simple "Yes/No" flow chart as well as remedy for the "No's"..

Doc :pimp:
 

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# 1 Stop buying parts until you know what the issue is
Did you check the fuel presure or just see a little at the valve or something.
Fuel presure is critical on most cars. Get a gauge and test it. The parts you have already replaced will almost never cause a no start. Also it may be flooded, hold the pedal to the floor while cranking, this will turn off the fuel and let in plenty of air to dry the plugs. I agree with the above on the cat, I have never seen one keep an engine from starting, I suppose it may be possible. Just randomly changing parts is never a good idea. I would look at the plugs also. Those are real picky about plugs.
 
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