86 vette running great then failed to start one day ( turned over ok just wouldn't fire ). GM mechanic diagnosed problem to distributor and said most likely part is the small ( approx. $50 ignition module inside distributor ). GM service manager then proceeded to try to rip me off by over quoting replace of the entire distributor. I pulled the car from GM, had the ignition module replaced, timing set, which got the car running. After that the car ran a little rough, hard to start hot, and experienced a code32 mass air flow and a code 42 electric spark timing. When cleared the codes resurface. We swapped out the ignition module again and also tried a new mass air flow sensor. Mechanics cannot figure out the problem. It just recently started running better and starting a little easier ( I'm suspicious that GM tampered with my gas or the car since it's strange that I got a new weird problem all the sudden after it was in their shop - esp. since the service mgr got pissed at me bc I didn't let him rip me off ). I'm wondering if bad gas could cause this including the service engine codes. ... or if anyone has any ideas on what could cause this. Any input is greatly appreciated.
Robert

 

well, let me see if you can set something straight for me first...you have an '84 and it has a mass air flow sensor? Is it still a crossfire induction system?

 

thanks for your ques. I'm not sure if it is a crossfire induction system or not. Also, it's an 86 vette. sorry for the type. Maybe it being an 86 answers the ques.

Robert

 

Is the EST wire from the distributor connected? That may give you a code 42, if I'm not mistaken.

 

Hmmm. Sounds to Me like the problems are all related.

Before I started suspecting some sort of conspiracy I would determine the Exact issues (root cause), and Then decide if those are in fact Related or something that could have been deliberatly "sabotaged". Then, if appropriate, call your lawyer...

Meanwhile, regarding those root causes...

A faulty ignition module is a fairly routine issue in HEi ignition systems of this vintage. Also an easy and relatively inexpensive repair. The real question is - Why did the module fail. Could just be it's Time. But -
Often the cause is more than just a defective module itself, and that cause will continue to cause problems until found. This is one reason why folks that Sell replacement modules will NOT warranty them..

Bad grounds will quickly kill a module. A bad Pickup coil will do the same thing. One (of many) Possible scenario is a distributor with shaft bushings worn badly enough that the rotating reluctor (for lack of a better word) ring on the shaft is hitting the stationary core of the pickup coil, grounding it and mechanically Jarring it - causing, eventually, a short in the insulation of the fine wire winding. This will kill a Module, in time, and will cause a weak or non-existent pickup signal To the module. This is one possible root cause of both a module failure AND for a code 42.

If a replacement module got the car to Run (when it wasn't before), then the old module was dead, and/or there was a bad connection to it. Wiring harness and connectors are the most common electrical problems that this '86 model car will have. Never believe that a connection is "good" until you have positively proven that to be the case.

In particular.. The 4 wire harness connector from the module to the body harness (it's about 6" in length and connects to the module inside the distributor at One end and to the engine/ecm wiring harness at the Other, right behind the distributor) is a Notorious cause of ignition system ills. The connectors at Both ends of this connecting harness are likely candidates for the problems you are having.

It's Never simple - something I have seen over and over. Replacing the distributor, Might not have been a bad idea. At Least pulling it out of the motor and having a really good look at it on the test stand! Might not have found anything, but you don't know if you don't Look.

BTW - My guess is that the MAF code, #32, that you are also seeing is a Result, not a Cause. Code 32 is MAF signal Low, meaning that Air flow is low. (or the air flow thru the MAF is low, not necessarily the same thing - vacuum leaks..)

This code can/will set immediatly after starting if the car fires slowly and tries to run poorly at a lower than normal idle speed. If you clear codes, start it up and the SES sets almost at once, That's probably your code 32. If The car was fired up and idling (or fast idling) normally, and that code set, Then you likely have a "real" code 32 issue. If it fired up poorly, barely running, and the code 32 set it's a code you can disregard - it's setting Because the car is barely running, not the Reason it's doing so.

With the code 42 happening That could/would be the cause, the reason, for the poor running and low rpm - which in turn means low airflow which trips the code 32. Viscous circle.

Like I said - it's never Simple..

Oh - Like GW962 said - when the EST Bypass wire is disconnected to adjust the timing a code 42 will set. This is normal and that code can/should be cleared after the timing is set and the the bypass is Re-connected. Was the bypass wire even Re-connected? If not you have no ECM timing advance happening, That would cause it to run poorly...

 

There is another thing that will kill an ignition control module. The use of incorrect dielectric grease which will dry out and not transfer the heat in the module to the distributor housing I am sure has caused many failures. Many think regular heat sink compound will work in a pinch. It will not work.

Gary

 

Hmmmmmmmmmmm!!!!!!! unless an 86 is different than a 87 code 32 is an EGR code. Where's Agent 86 when you need him?....lol. When I threw a code 32 it was a simple EGR switch, once again I'm not sure an 86 has a EGR switch, but alot of guys have posted that as a problem.

I'm also wondering if the dealer didn't diconnect the EST to check timing and forgot to reconnect it,?

 

Never assume stuff... I'm guilty. For an '85 the code 32 is MAF low. Now I'll have to look it up for an 86, I guess

OK - per Mitchell (since I haven't any other handy source for the '86 codes other than MitchellOnDemand online) - a code 32 in 1986 was EGR. Did the '86 Really use a MAP sensor? I thought that '86 was a straightforward MAF car.. Mitchell shows codes 33 and 34 as being MAP codes for it?

Sheez... It gets Better. Mitchell says the two MAF codes for an "85 are #'s 33 and 34. I was looking in the FSM last night when I typed the above, and I would Swear that I was seeing it as code 32.. Must be Me

It Is friday, right? Tell me it's really Friday..

 

Gary,
What is the correct grease to use? And why will heat sink compound not work?

Thanks

 

No MAP on an 86, or 87. I can't really say about the grease aspect, but it seems to me that my ICM came with dialectric....and I used it, haven't had a problem (knock on wood) for 2-3 yrs.

 

http://members.shaw.ca/corvette86/Code%2032.pdf

http://members.shaw.ca/corvette86/Code%2042.pdf

 

Ahhhh, now that's Dan

Since he's confirmed there is an EGR switch on an 86 I'd be replacing it, here's why. When I experienced the code 32 someone here posted that 95% of the time it was the switch, others concurred. $10. part, 10 minutes to change it, disconnect the battery for a few minutes and my 32 was gone.

As for the 42, make sure the EST wire is connected, it's a single wire between the windshield wiper motor and brake booster, think its brown/black. If that's not the problem pull the ICM, ignition control module, located in the distributor, take it to any Autozone and they'll check it for free.

 

Just saying thanks to all the great input. I will be checking into some of these possibilities and will let you all know what we find out.

Thank you, Rob

 

I'm now 90% sure my gas tank was contaminated. The car's been running sometimes perfect ( at start up when it's been sitting for a while - i.e. after the contaminants sink to the bottom or float to the top of the tank ) and then after I drive it 10-15 minutes ( when the gas sloshes around ) it starts stalling but then intermittently runs great. I finally ran the gas out to about 1/8 tank and the car started stalling bad, died and wouldn't start. Put some good gas in, let it sit overnight then it's back to the same problem where it runs fine intermittently as above.

The engine service codes might be another problem ... i.e. a loose connection etc. related to the distributor EST wire, etc. but I think it's smart to address the gas issue first.

Can anyone comment on least expensive way to address the contaminated tank ? gas treatment to absorb water ... if that's what it is ... is there a way to flush the tank without removing it ... ?

Thanks Rob

 

I've had contaminants (moisture) in fuel before. I used a product called Heet or Heat, can't remember the spelling, but almost all auto stores carry it. As far as draining the tank goes, I don't think I'd bother, just run it down and add new fuel with the Heet. Water or moisture in the tank or fuel system looks like tiny clear marbles. You could pump some or syphon some of the fuel out and look for this condition.

 

Thanks again. I put heat in the tank ... it ran good for 30 min. then died and wouldn't start. Then, as normal, it started right up after I let it sit overnight. I still think its bad gas and that when it sits the contaminant settles or floats so the car gets some good gas upon morning startup ?? I welcome any comments as to if this makes sense. I plan to try it again and try to cycle the heet and gas through to see if it will start running better. I don't look forward to removing and replacing the tank if that's what I end up having to do.