QuestionQUESTION: Hi Roland- I wrote to you on Thursday. We have fuel, spark and timing belt is fine. We replaced the cam sensor, crank sensor and we have back firing. It will crank but not turn over. You suggested we try the EGR and spray some WD40, which we did, we checked the voltage on the MAP sensor and it was low (under 3), so we replaced it. Still it won't turn over. Any other suggestions?
Sincerely, Sherri
ANSWER: Did you disconnect the battery and check for new codes after trying to start it? The MAP should show 5 volts on the violet/white wire that comes from pin 6 of the pcm. The black/light blue should be ground, and the dark green/red signal wire usually is around 4.6V with the engine at rest and then drops when you are cranking it over due to partial vacuum created by the cranking (so maybe 3 is ok?) , and then it drops to about 1.5 when the engine catches and idles. You didn't say at what instant you read the 3V. So check the 5v supply voltage too. Ideally you should get a code of some sort. You still have fuel/spark/ and compression I presume.
Roland
---------- FOLLOW-UP ----------
QUESTION: Yes, we reset the codes by disconnecting the battery and all we have now are 12 and 55. We had replaced the Map sensor, and we double checked compression, we have 145 psi on boths sides. BUT we found out that we are only getting spark off a NEW coil pack from cylinders 2 and 5. What could be causing this? Thanks for all your advice! Sherri
AnswerHi Sherri,
That is a good clue. That means only one of the three coils is working. I would begin by verifying that you have a connection between the coil pack plug (three of the four pins) and pins 17, 18, and 19 of the powertrain controller (pcm). You can just verify that one of each of those pcm plug wires is so-connected to a unique one at the power pack end, as it is hard to describe which is which, except that the wire colors are white, red, and black, respectively. Also verify that none of the three are shorted to ground when both plugs are disconnected. If that checks out, then I would suspect the cam sensor may not be reliably identifying where the cam position is located, either because it is not close enough to the cam sprocket or it is breaking down. If you want to try re-positioning the sensor, get a paper spacer from a dealer parts counter to put on the face of the sensor, then push it in until the face of the sensor hits the surface and lock it in place. Maybe this is the answer!
Roland
