My Daughters' 2001 Pontiac Sunfire - engine wont start on 30% of the keycycles

Maintenance/Repairs
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1

I’ve had 2 repair shops give me different answers, I don’t believe either of them… Here’s the issue-
For the past two months, 70% of the time, turning the key results in start-up, car drives away and runs fine. The other 30% of the time, turning the key to start, it starts for 1-2 seconds and then shuts off. I let the car go to sleep (close door, let BCM shut down) and repeat process and it will repeat the failure. 3rd, 4th and 5th attempt usually results in start-up, but its never consistent on which one of the preceding key-cycles will produce success.
NOTES-

  1. During a no start event, I’m noticed the cluster appears dead, no MIL’s and the dial gauges aren’t moving to their proper position. So I can tell before starting that it’s not going to succeed.
    1.1) Colder temps seem to make it worse
  2. Sitting between key-cycles for hours vs minutes seems to increase chance for success.
  3. First mechanic (on first visit) changed fuel filter (didn’t fix…) on second visit said I needed a fuel pump. (I called BS on him and took to the second mechanic)
  4. Second mechanic had the car for days, witnessed this no-start but couldn’t find any codes being set that would help me root cause this… The only help he gave me was that the fuel pump was working good. Had pressure and flow even when there was a “No-start”…

I’m starting to lean towards a bad ignition module, any thoughts on this?

Help…

2

Not an ignition imodule but maybe an ignition switch. Next time this happens just leave the key on and start checking other electrical devices that should be “live” with the key in the on position. Heater fan, turn signals, hazard lights, wipers, radio, etc. Take note of any items that are dead. If there are any, I’ll bet you could trace them all–including the instrument cluster and engine computer–to a common power source like an ignition switch.

3

Here’s a recall notice for the 2001 Sunfire that says the ignition switch contacts can be damaged by excessive current:

4

This behavior is typical of GM’s Passlock system so you might consider that. Among the dash indicators someplace is a security light, and if it goes to blinking then there is a pssslock system issue. Luckily - for me - I have never had to deal with one of these problems. So, unluckily - for you - if it is the problem I can’t tell you what to do about it. I can tell you that the web is full of various explanations for how to bypass or otherwise deal with this system.

It obviously may be other things, but starting and stalling immediately is a classic symptom.

5

Thanks All for feedback so far! The recall- I called dealer and the work was performed back in 2004. There were 3 options they were able to preform, depending on how the diagnose, change switch, add a wire harness change, and/or to add an additional module which would inhibit high-voltage from getting to the ignition switch contacts.

I’m kindof liking the idea of this option, because it acts like an intermittent contacts issue, wonder how I determine what changes might have been made?

6

cigroller- I will check tonight, but I dont recall seeing any Passlock MIL ever light up on this cluster. Additionally, when I plugged in and checked codes, none came up regarding entry. I do have a DTC on the chassis buss for a bad wheel sensor on left rear wheel, but this shouldnt cause no-start?

7

I think the recall work isn’t particularly relevant anymore. That was 10 years ago. Anything can wear out in 10 years. You could very well need another ignition switch.

Ask your friends, coworkers, neighbors for a recommendation to a competent local independent shop that has electrical capabilities. With the aid of a wiring diagram and a decent voltmeter this problem should be easy to diagnose once reproduced.

8

I’ll go into the Underhood BEC during a no start condition and to voltage checks on the circuits and try and find any that might not be live. I can pull the wiring mechs and determine if the dead circuits are of importance.

9

All- I got an OBD2 reader on the car tonight and found the following codes set: P1626 P1632
Which as I read up, have to do with theft deterrent. I also pulled up freeze frame and can see that during the last incident, the fuel pump and injectors, were off. Also- batter voltage was at 11.32v… Did I mention before that the car might have had a kinda weak battery? Oops… Also can see looking at the service bulletin that the repair work at dealership for the recall, they added this additional module which limits the amount of current being sent to the ignition switch.

I’ll get a new battery tomorrow and will clean the bad ground contacts to see if maybe this was my only problem? What do you think?

10

11.32 v is a very low battery, unless that is measured during cranking. I’d say you are on the right track. I wonder why your prior shops didn’t find those codes? It seems like you had no trouble sussing them out.

11

11.32V is far past dead. It’s even dead at 12V. So it’s certainly the case that there’s no point in chasing anything else until you know that the basic power system is in order. So a new battery, test of the alternator, and complete once over/cleaning of the cables is certainly the place to start. As long as you’re working on them you might want to peel back some of the insulation on the battery cables to look for hidden corrosion underneath.

12

If the recall was for contacts subject to damage by current, and the existing key cylinder was installed 10 years ago, I think it’s extremely likely that this key cylinder is shot. I doubt seriously if the replacement key cylinder was redesigned so thoroughly as to not be subject to wear failure over ten years. Chances are that they just put contacts that were a bit more robust ni the replacement cyllinders.

I vote for the key cylinder. Emphatically.