carltonmat Posted February 5, 2005 Report Share Posted February 5, 2005 I have a 91 sevile, with the 4.9L. i love my car when it is running right. but i have been haveing problems with one or two injecters. they have blowen out fuse or just not fired. any ideas what maybe the cause? Link to comment Share on other sites More sharing options...
MAC Posted February 5, 2005 Report Share Posted February 5, 2005 Do you have any diagnostic codes? I believe you can enter the diagnostic mode by simultaneously pressing and holding down the Climate Control panel OFF and WARM buttons. I don't know your car so I hope I'm giving you the right information. Link to comment Share on other sites More sharing options...
adallak Posted February 5, 2005 Report Share Posted February 5, 2005 Yep, turn the ignition on and press simultaneously Warmer and Off for a few seconds until codes show up on the driver information center. Take them down. The codes looke like, say ECM 026. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
carltonmat Posted February 5, 2005 Author Report Share Posted February 5, 2005 nope no codes, runes great then out of the blue just starts to run rough and gets real bad fuel econ. Link to comment Share on other sites More sharing options...
MAC Posted February 5, 2005 Report Share Posted February 5, 2005 Do you know for a fact that fuses have blown? Because I have the GM Service Manual for 94' and it states that blown fuses in the 4.9L can indicate a short to ground at certain fuel injector circuits. I assume the 91' 4.9L will still be the same in 94'. You may have a voltage drop in certain fuel injectors caused by a shorted fuel injector harness. I'm just throwing out some food for thought based on what the Service Manual states as a possible cause. Again, have you actually replaced blown fuses? Link to comment Share on other sites More sharing options...
carltonmat Posted February 5, 2005 Author Report Share Posted February 5, 2005 yes twice in two monthes, i just reinstalled all the injectes today. the store, i bought the car for two hundred. the owner before slid it into a curb and thought it was totaled. but only need a new strute. it ran great for three monthes and then it begain. the service maniual says what to try? thanks for the help so far Link to comment Share on other sites More sharing options...
MAC Posted February 5, 2005 Report Share Posted February 5, 2005 The Manual has 6 pages of diagnostics instructions. The bottom line is that a fuel injector test should be done to determine if the injectors are pulsing within specs. Any injector that is more than 2 psi from the others is faulty and needs to be replaced. Idle quality should get worse if an injector is disabled. Next Question: Which fuse blew? Was it Fuse A5 and/or Fuse A7. The engine compartment fuse block will indicate which fuse. Fuse A5 is for injectors 2, 3, 5, and 8. Fuse A7 is for injectors 1, 4, 6, and 7. Link to comment Share on other sites More sharing options...
carltonmat Posted February 5, 2005 Author Report Share Posted February 5, 2005 a7 the first time when i moved the injectes it moved to a5. i moved them to see if it was wireing or injecter. so i think it is injector, because it moved from one cirect to the other. that make sence. how do you test the injecters. it has to be one to the four. thanx, again Link to comment Share on other sites More sharing options...
MAC Posted February 5, 2005 Report Share Posted February 5, 2005 There is a procedure outlined in the GM Manual for checking injector flow through the computer (PCM) but it’s somewhat complicated. Based upon the results there are instructions to continue or to move on to another procedure. Eventually, the procedure leads to an answer. Below is an example of the start of the procedure: 1. Key ‘OFF’ 2. Install J34730 Fuel Pressure gage 3. Key ‘ON’ Enter Diagnostics 4. Jumper Fuel Pump Prime Connector to battery voltage for 5 seconds to energize fuel pump to build fuel pressure 5. Select the PCM override PS10 (Injector Flow) 6. Press ‘Cooler’ Button until desired injector is selected 7. Press ‘Warmer’ Button -- note gage and record pressure drop on chart; repeat above for all 8 injectors. It would seem that you are probably right that you have a faulty injector(s) somewhere. It's possible that you could have a faulty injector harness. But, again, since the problem jumped from fuse A5 to A7 after moving the injectors, it would seem likely that you have a faulty injector(s). It's just a matter of narrowing it down to which one(s) and replacing it/them. Link to comment Share on other sites More sharing options...
MAC Posted February 5, 2005 Report Share Posted February 5, 2005 By the way, GM Service Manuals are on sale for $30.00 plus shipping. Click on the link below for details: http://caddyinfo.ipbhost.com/index.php?showtopic=4748 I bought my 94' Service Manual through Helms. It was a great buy as it was about $100.00 prior to the sale. Link to comment Share on other sites More sharing options...
MAC Posted February 5, 2005 Report Share Posted February 5, 2005 Interesting reading: http://www.asashop.org/autoinc/sept99/techtotech.htm Link to comment Share on other sites More sharing options...
carltonmat Posted February 15, 2005 Author Report Share Posted February 15, 2005 two new injects and all is well, they had only 1ohm not 12 to 14 like new thanx Link to comment Share on other sites More sharing options...
Scotty Posted February 15, 2005 Report Share Posted February 15, 2005 Your car sat for 6 years didn't it? I wonder if its possible that someone used injector cleaner and the solution sat on your injectors for 6 years dissolving the wire insulation, just a though. If they are drawing too much current, that could be the reason you are blowing fuses... Link to comment Share on other sites More sharing options...
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