Need Help Diagnosing Engine Problem

[wuzzyone]

Dear Club members:

Can someone out there please give me a hint as to what is wrong with my ride?

I have a very nice burgandy 1992 LS400 and recently the engine has been acting up, after the engine gets warmed up. When driving along, I feel hesitations as if the engine dies for a split second. Then after completely warm, it might even stall at a red light. When idling hot, the engines runs well, then several times a minute rumbles and then picks back up. I have replaced the fuel filter, have 93 octane fresh gas in tank, and added injector cleaner. The engine light came on, and my mechanic read the onboard computer which gave CODE 13. My mechanic then put on a CRANKSHAFT POSITION SENSOR. I drove it and found the problem was still the same. My mechanic read the onboard computer a second time and again the computer read CODE 13. My mechanic now says that I need to replace a CAMSHAFT POSITION SENSOR and that may take care of the problem. I don't want to throw money at parts replacing parts that are not needed. Has anyone experienced this problem and would you be kind enough to enlighten me. I miss driving the car.

Signed,

Wuzzyone

[LScott400]

I have not experienced that on my LS400, but my daughter's Mitsu did the exact same thing and turned out to be the ignition coil.

[sha4000]

check your air filter and the spark plugs and wires. does your car shake violentl when your at a stop light? i had a bad ignition coil on my 91 and the car sook so bad at a light that i had to put the car in park and take my foot off the brake

[Tote]

My wife had the same issue with her car. Well at least the stall for a second at the red light. Replaced fuel filter as well, with no results. Decided to changed spark plugs (figured I needed to change the spark plugs Anyway). Found that the ignition Cables were bad. The first one i tried to pull out broke. Part stayed on the spark plug. Replaced Ignition Cables (not Much of a choice). Problem Solved in My case.

Tote

[obergc]

Wht some of you gentlemen are overlooking is that a set of bad sparkplug wires will not set a code 13 in the ECM. While a bad wireset will certainly cause some of the symptoms described, they will not set an engine code. There is a single crankshaft position sensor and a camshaft position sensor for each bank. The relationship between the pulses coming off the three sensors determines ignition timing and an intermittent output from one of these sensors can give you the same symptoms as a bad set of wires. Your mechanic is simply using the shotgun approach to troubleshooting or rather repairing your problem. He is not troubleshooting at all. Troubleshooting this particular probe requires the use of an oscilloscope, checking for the output of the sensors at the ECM input connector under the dash on the passenger side, easy to access. However, this requires that your mechanic have an oscilloscope and that he knows how to use it. At least your mechanic is in the right ballpark, he just chooses to use a shotgun instead of an oscilloscope to troubleshoot your problem. There is no excuse for him to arbitrarily be changing parts, his approach costs you, not him. BTW, your problem could be just a loose/dirty connector to one of the sensors OR the wiring connections between the sensors and the ECM OR it could be the ECM itself.

[sha4000]

Wht some of you gentlemen are overlooking is that a set of bad sparkplug wires will not set a code 13 in the ECM.  While  a bad wireset will certainly cause some of the symptoms described, they will not set an engine code.  There is a single crankshaft position sensor and a camshaft position sensor for each bank.  The relationship between the pulses coming off the three sensors determines ignition timing and an intermittent output from one of these sensors can give you the same symptoms as a bad set of wires.  Your mechanic is simply using the shotgun approach to troubleshooting or rather repairing your problem.  He is not troubleshooting at all.  Troubleshooting this particular probe requires the use of an oscilloscope, checking for the output of the sensors at the ECM input connector under the dash on the passenger side, easy to access.  However, this requires that your mechanic have an oscilloscope and that he knows how to use it.  At least your mechanic is in the right ballpark, he just chooses to use a shotgun instead of an oscilloscope to troubleshoot your problem.  There is no excuse for him to arbitrarily be changing parts, his approach costs you, not him.  BTW, your problem could be just a loose/dirty connector to one of the sensors OR the wiring connections between the sensors and the ECM OR it could be the ECM itself.

←

your absolutely right i didnt overlook this i myself was wondering how the mechanic can go from crank to cam sensor when he has the code in his face and all he has to do is check the values for the circuit