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A friend came to me with a 03 impala that has a starting problem. Firstly it has a 3.4L engine, he had the car scanned by a local parts store and was told Camshaft and Crankshaft needed to be replaced, he replaced both sensors but the car sometimes is still hard to start . I did a check on the car when it wouldn’t start and found : There is spark at the plugs when cranking, there is good gas pressure in line, however when i removed the plugs they were bone dry. I should mention at this point that the brand sensors he bought from a parts store was Duralast (no comment!).Sprayed starter fluid into intake at butterfly which starts the car for a second then it dies. I’m thinking that the computer is shutting down the injectors, when it starts it shows no problems at all, i have scanned the car myself and found only P0141 (pending) and in the eodb P0620. At one point i was thinking about the coolant sensor, as i had a mazda 626 that had the same problem and that was the cause of the problem, Any advise guys?
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One of those codes is for the o2 sensor, the other is regarding the alternator demand signal – I don’t think they would cause a starting problem.
You already know it’s a fuel problem, so the question is, are the injectors being pulsed and is there adequate fuel pressure. Did you actually measure the fuel pressure? What happens if you cycle the key from off to on (not start) 3-5 times before you try to start?
You can use a noid light on the injector connectors to see if the ECU is firing them or not. I’d start with checking fuel pressure though.I don/t have a NOID light to check the injector , at the moment the car is running, as soon as it starts acting up i will check the fuel rail and inform u of the actual psi
+1 on checking for the injector signal with a noid light but you didn’t mention HOW you checked for fuel pressure, if you just pushed on the schrader valve that’s really not enough you should check the actual fuel pressure with a fuel pressure gauge and c
UPDATE :
First of all, HAPPY NEW YEAR & THANKS YOU, JOHNZCARZ, TRCUSTOMS719, & ERICTHECARGUY. ok the car acted up today, this time i went prepared. I checked the gas pressure at the beginning of koeo reading peaked to 60 psi……BUT within a few seconds the pressure started to drop, i also smelt gas, after further inspection i found that the gas regulator was leaking gas, will give an update as soon as regulator is replaced.Quoted From oilythumb:
UPDATE :
First of all, HAPPY NEW YEAR & THANKS YOU, JOHNZCARZ, TRCUSTOMS719, & ERICTHECARGUY. ok the car acted up today, this time i went prepared. I checked the gas pressure at the beginning of koeo reading peaked to 60 psi……BUT within a few seconds the pressure started to drop, i also smelt gas, after further inspection i found that the gas regulator was leaking gas, will give an update as soon as regulator is replaced.Yup, a leaky regulator can sure cause problems.
Thanks for keeping us posted.Im sure this applies to you –
http://www.youtube.com/watch?v=AKtR_yF7bi8&feature=plcp&context=C398a51eUDOEgsToPDskKoDtzptGtAApTHvj3Rd2vX
I have replaced one on the same vehicle as yours for the above condition.
Nice you gathered evidence and now you have something real to go on well done! Keep us posted on what you find after you replace that part.
The latest update on this problem is the after a day the problem still exists, however my friend sent his car to a garage to get it repaired, he got the car back BUT (this is were i’m a little disappointed W-| as i would have loved to know what was the cause of this problem ) when i questioned him as to what was done he cant give me a sensible answer ( i will have to put him in my integration room L:D). He was told that he would have to take the car to a dealer to remove the codes the computer has stored in it as they couldn’t’ erase them, which to me (please tell me if i’m wrong as i’m not a PRO) has nothing to do with the problem at hand, i will be trying to get more info from him today, once again THANK YOU ALL 4 YOUR INPUT
Most generic scan tools can erase the codes and there is other methods also.
It would be interesting to know if the vehicle is actually fixed or not.
OK, here’s the latest, i question my friend, found out that they had changed the Camshaft sensor, as far as codes he could not remove he said the mechanic used a shop scanner and said that there was some (body) codes which he can not delete, which the dealer had to remove. He also said that (my interpretations from the interrogation) that the ignition switch and the curtsey switch has some incorrect/over voltage in the system (according to his scanner). The curtsey light does not work automatically or any of the dome lights (never had this problem before visiting the garage).As for the original problem , so far the car starts ok but we shall see
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