Question-------------------------
Followup To
Question -
My car wouldn't start when I tried to leave the corner market. No previous problems. I pulled it home and started checking under the hood. The spark looked weak so i put a new coil on it, good spark but it still won't start. I put 12vdc on the injector and it fired. The fuel pump is pumping but the injector is not firing. I used the key switch to get the diagnostic codes...12-27-55. I did have the battery disconnected so 27 is the only significant code. According to the repair manual I have 27 = an injector driver fault. This sounds to me like a bad PCM. I bought a used one and slapped it in but I still have the same exact problem. I have checked all of the wiring between the PCM and the injector, MAP sensor , and the o2 sensor. What else could be giving me this code 27?
Thank You.
Answer -
Hi Devery,
When you get that code I believe that the controller has detected a failure in the current that is supposed to be drawn by the injector when it has both a 12V supply from the ASD relay on the dark green wire and the other end of the injector's coil is ground by the PCM (white/dark blue wire) to pin 16 of the PCM. I am assuming that you have the throttle body fuel injector set up on a 2.5L N/A engine.
So if you have spark and you have verified that the 12V dark green/orange wire is connected from the ASD to the injector, then either the injector coil has opened, or the white/dark blue wire is open between the injector and pin 16 of the PCM. When you say you "put 12vdc on the injector and it fired" do you mean that you weren't getting 12V on it when you were cranking it? If you have spark then you have to have 12V also on the injector because both are supplied by the same output wire from the ASD. Have you checked the resistance across the terminals of the injector? It should be around 1 ohm. So other than that possibility, the wiring of the injector is the only other reason for no injector pulse if the PCM is doing its job to pulse the injector for a controlled length time pulse to ground in synch with the spark pulse from the PCM. The throttle body injector tends to last about 10-15 years so it is possible that yours has gone bad. So check those possibilities and let me know what you find.
Roland
Hi Roland. Thanks for your quick response. You are correct on the assumption of single injector, 2.5L engine, sorry I didn't mention that earlier. I have rechecked the wiring after you straightend me out on the power coming in on the dk grn/orn wire off the ASD relay contact. The ASD relay appears to energize for a second or so when the key is first turned on, I have power on the injector plug at that time, and also during cranking. I put the meter leads across the injector plug while cranking and recieved the same pulsing signal as I got on the coil plug, which tells me the PCM is good. OK, now I have fuel in the throttle body while cranking, but the car still won't start. I ohmed out the fuel injector; 2 ohms. I double checked the settings and zeroed out my meter it is reading 2 ohms. Is this too much? It is one ohm higher than what you said it should read, one ohm isn't much, but that is double the resistance. As for the spark, I checked it two days ago by removing the no.1 plug and laying it across the A/C compresor, it looked OK then. Now, however, I used a method which you suggested to someone else in a response I found in the question archives: I pulled the wire from the spark plug inserted a phillips screwdriver into the wire held the shaft of the screw driver 1/4 inch away from engine ground and had someone crank the engine, the spark seemed strong, but it was reddish orange in color. I have already replaced the coil, plugs and rotor (not the cap, just the rotor). Thanks again for your time.
Devery
AnswerHi Devery,
I don't believe that the 2 ohm reading is a problem. I can't recall where I got the specific value of around 1 ohm but I doubt that a reading of 2 represents a questionable coil resistance. What I would suggest is that you take a look at thefuel pattern when you are trying to start the engine as it hits on the throttle plate. It should be a very fine spray and when your helper stop cranking make sure that the spray stops and that there is no afterdrip. When the injector fails it often results in excess fuel which floods the intake and produce a too rich mixture.
The other thing to check isthe egr valve to make sure that it is not ajar. That is located on the firewall side of the engine near the passenger side corner of the head as I recall when I last looked at my 2.5L engine. Under the round top of the valve you will see as saddle like support and inside the support is the valve stem which has a slot. Take a flat blade screwdriver and use it to lift and release the stem of the valve. You may find that it is sticky in its operation which can be relieved by squirting WD-40 on the stem. The valve stem should go down into the base of the valve and firmly stop. Otherwise it will be ajar when you try and start and the returning exhaust gas dilutes the mixture severely enough to prevent starting.
So those are my best shot at the no start. I have had both the injector and egr cause no starts in my engine. The spark seems to be o.k. But take a look. Also, try disconnecting the battery for a few minutes to erase the old codes and see if the 27 comes back after a few attempts to start it. If it does, then the controller is seeing something to be wrong with the driver circuit for the injector. And then I guess I might bite the bullet and buy a new injector just because of the persistance of the 27 and the 2 ohm reading. But look again at the spray pattern during a 5 second crank period.
Let me know what progresses.
Roland
