My 86 GN frequently dies or will not start / Code 42

[madmax_1]

My 86 GN, after years of no real major problems, has started to just shut down while driving during the Summers (sometimes once or twice a day), usually on deceleration; sometimes it will not start at all after parking it for a few minutes. On occasion, on heavy acceleration, it will stumble and set a code 42. It will set no other codes. This is really frustrating, not to mention dangerous when it just dies in heavy traffic. Has anyone has this happen to their 86/87 GN, or know what the likely cause of this is? I'm not sure where to start looking for the problem.

[Keller]

http://www.gnttype.org/maint/malf.html#42

That might be a good place to start.

Any mods on the car? Details regarding mileage or modifications would help in narrowing down the issues. But right now I'd say it is likely going to be something regarding the ignition system. Anything changed or altered there? Non-GM / AC-Delco parts used for the ignition module or coil?

[theevii]

Is there a difference between the silver and the black colored ignition modules? I think I have not been having good luck with the modules I have been getting from NAPA and LEE. I am not sure what other 87 Regals had the distributorless ignitions.

[Keller]

Aftermarket modules, in general, are JUNK. 100% junk. I know people that have had the same experience. And parts stores will not stand behind failing electronic parts.

Highway Stars / NOS4GN is selling some aftermarket ones now that seem solid. However, theirs will NOT support an aftermarket tach. If that is not an issue, I would suggest theirs. A very good value. Unless going GM.

The difference between black and silver (i.e. aluminum) is paint. The original ones were painted, the ones that are not on a car from the factory genearally aren't. You can paint to make it match if it bothers you. Don't paint the wiring, though.

Coils are somewhat touch and go. The new GM coils are from China and not like the old ones. The Highway Stars / NOS4GM ones are just like the old GM ones and are very well made.

[Keller]

Originally Posted by theevii

I am not sure what other 87 Regals had the distributorless ignitions.

None. Only the TRs and then FWD cars after that. And the FWD cars do not use the same modules.

[madmax_1]

Originally Posted by Keller

http://www.gnttype.org/maint/malf.html#42

That might be a good place to start.

Any mods on the car? Details regarding mileage or modifications would help in narrowing down the issues. But right now I'd say it is likely going to be something regarding the ignition system. Anything changed or altered there? Non-GM / AC-Delco parts used for the ignition module or coil?

Thanks for the link to the diagnostics by code - I'll go through the list for code 42 one by one and check for open circuits. I guess it has to be one of those causes listed, if it's setting that code. I have the original Buick service manual when I need it - it has been my bible for 24 years.

The car has 320,000 km (about 200,000 miles); for routine replacement parts since 1987, all parts and sensors have been original GM purchased through GM initially, then through Kirban Performance for about 10 years now, after GM parts were no longer available from the dealer. This includes the coil pack and module, cam sensor, crank sensor, TPS, Oxygen sensor, etc.

Although the coil pak has been replaced 4-5 times, the ignition module itself has only been replaced twice in 24 years (maybe this is my problem!!). The last time was about 8-10 years ago, and I went with Kirban's module made by Wells for AC Delco - even at a $35.00 cost difference, would this not be the same AC Delco module sold by Highway Stars / NOS4GM, or is there a difference? Plug wires are the aftermarket ones made for the GN, also from Kirban. They are supposed to be the best fit and better quality than anything available in the auto parts stores.

As far as mods go, yes there have been a few; the ones that could affect timing include ATR's air intake system /w K&N filter/housing, refurbished MAF sensor, 3" downpipe, Tomco green stripe injectors, adjustable fuel press. regulator, Kenne-Bell Ultra Chip (although I've had this chip for 22 years with no issues), 160 degree stat. The ECM is original.

Over the years, I've had engine mechanical work done as well (rings, valves, rods, pistons and turbo replacement), consisting of original GM parts and a refurbished turbo from Limit Eng.. I have run with Mobil One or Amzoil synthetic 5W30, or 0W30 when 5w30 is not available, from day 1.

That's about it; I'll let you know what I find. If I find the module is bad, I'll go with Highway Stars / NOS4GN if the quality is better. Question: if that is the case, are there any other parts or components that could have been damaged by driving the car with a bad module for 3 Summers?

Thanks again - it's appreciated.

[Keller]

Any dealer should be able to get any part still in production. TR sources should have many others that are not in production stored up and for sale.

Your mods sound very low key and safe. likely why it has held up so well. Frankly, a more modern chip might make the car run even better. KB was not very advanced at the time they worked with the Buicks.

Anything Kirban sells will always be advertised as the "best", "largest", "fastest", "tallest", or "best smelling". Not sure about the Wells and AC modules being the same, but both have a fairly substantial cost compared to what they were ten years ago!