QuestionQUESTION: John,
Hey, thanks again for your time. Working on the '99 tonight, I am now finding that the starter will work if I pause and wait for a few seconds after turning the vehicle on. I also found I have fuel pressure, but no spark. Does this indicate, in your experience an immobilization? Have you seen/heard of the spider bypass (AMR4956), and would you recommend trying that? I understand your point about connecting to live data, but with all due respect, that is easy for you to say - you own the equipment. I am a home mechanic for a reason - to avoid paying dealerships/big time shops whenever possible.
Thanks,
Michael
ANSWER: First of all, the part number you gave me is a wire harness in the dash. On the face of it I don't see how that would help you.
I understand you are trying to fix this car without factory level test gear. That begin the case, you are going to have to take the wiring book (they call it an Electrical Troubleshooting Manual) and test all the relevant circuits manually. You will have to look at the engine sensor data to see if the crank signals are reading the ECU. If the ECU is getting the crank info. and it's powered on, but the ignition is not firing there is not much left but a bad ecu or immobilization.
The problem is that it's very time consuming to try and make those determinations manually without the ability to look at live data. So I'm not being coy or evasive, I just do not know if you can solve this problem effectively without good test data. The fact that the problem appeared only after swapping alarm units suggests immobilization for sure.
I trust you have already checked your work carefully for things knocked off or loose
---------- FOLLOW-UP ----------
QUESTION: John,
I appreciate your candor. I have been thinking about this and reading as much as I could all day and am about to head back down to my shop this evening. Of course, I would love to find in checking my work that I have simply bumped a relay or connection, etc.
With that said, if all I am lacking is spark, is there a basic, temporary fix to verify and isolate the issue, such as running 12+ from battery to --- ?
Do you mind clarifying a couple of points for me? You say it sounds like immobilization for sure, but that conflicts with the symptom vs. what I have read. I have read that immobilization disables the starter and fuel pump. The local dealer said I would have no crank if it was in fact immobilized. Also, I have read about "EKA" or emergency key access. Is that something that works on US models? I have no code as I never had an owner manual, being the 3rd or 5th owner of this vehicle. How do I get the proper code?
Thanks again for your assistance.
Michael
AnswerThe ECU reads the signals from the key, the security system, and engine sensors and makes three decisions:
1 - Turn on fuel pump
2 - trigger fuel injectors based on mass air, temp, and crank speed signals
3 - trigger ignition coils based on engine rotation signals and throttle position
It does other stuff but those are what's relevant to your starting problem.
I agree that the immobilizer supposedly disables cranking and fuel/ignition. However, having seen trucks that cranked while immobilized for various reasons I would not take what you say as a sure sign.
Rather, I would take your statement that the problem started after you swapped alarm controllers as a very strong indicator that the security alignment was lost.
On a truck of that vintage I'm not sure if you can get a security misalign separate from a immobilization. If so, that would explain why it cranks but does not start. It's not immobilized but it's not aligned and therefore will not start.
The only other explanation is that you have a coincidental failure (improbably) or you knocked something loose doing the swap.
EKA is not configured for the US vehicles. You could set it up if you had a test system but if you had the tester we would not be circling this problem anyway.
Sorry I don't have a better answer
