Code 32 causing no-start & performance issues! 94 k1500 5.7

[someotherguy]

Weird, because that is what comes with the Standard Ignition modules when you buy them from Oreilly or Rockauto. Never used anything but that compound for the last 20 years. I cannot think of a single module I have had fail, save for the one that shorted out when the tachometer shorted out on my old TBI. I have used that on all my TBIs, TPIs and Vortecs when I changed the module and even on the high-performance DUI modules that have more dwell time built into them for a hotter spark.

Oh believe me I know, lots of people use that stuff and like I said I'm sure it's worked for many of them. Even the tube of plain silicone dielectric grease I've got in the toolbox for spark plug wire boots says right there on the tube you can use it on ignition modules. I still don't. Call me paranoid if you want.

Richard

 

[Maui_chevyk1500]

Hey so besides my no-start Condition which I haven’t been able to trigger again, my truck is stumbling at idle now seemingly after I did the new spark plugs. I double checked everything I touched and found a spark plug wire not fully seated on the spark plug. I plugged it in and thought for sure that would clear up the stumbling idle but it made no difference.
I have new cap, rotor and spark plugs, the only thing that isn’t new is the wires, should I suspect them as they are well over 5 years old? Or should I go back and test all my spark plugs since that is the only change I made to cause the change in idle? Never had a new spark plug be bad but I guess it happens? I guess I should be honest and admit my spark plug wires are bundled together with zip ties in a few places . Probably not helping the situation…

 

[Maui_chevyk1500]

Also want to add my idle stumble is not at a particular rhythm it comes and goes almost as if the truck is about to run out of gas (just trying to describe best I can). God how I miss good old carburetors with adjusting screws!!!

 

[Schurkey]

You may have a code 32 but it's not the cause of your intermittent no-start condition. Be ready with spark checker and fuel pressure test gauge, because it'll be one or the other, no spark or no fuel.

...or both.

No spark AND no fuel spray on a TBI is often due to a failed pickup coil or a failed ignition module in the distributor. Could also be an intermittent wire in the wire harness between distributor and ECM, or a defective ECM. But usually, it's in the distributor.

thanks for the reply @someotherguy.
Ok so say I determine it’s no fuel or no spark. What would the next step in diagnoses be?

Connect a scan tool, look for RPM signal when cranking. No RPM signal = no fuel pump, no injector pulsing, no spark.

I don’t see any priming spray happening at the TBI with key on or starting.

Injectors don't spray until you actually crank the engine. Just turning the key to the ON position, should be no spray at all.

Now you say when you get the no-start: even while cranking, you're not getting spray from the injectors? That's good information.

At that point I would be hooking up the fuel pressure test gauge. IF you have sufficient (9-13 psi) pressure, but no spray, my immediate suspect is the ignition module. They can fail in several ways. No spark, no injector spray, or both. They can be intermittent. Also, the harness connections to the module can fail from age/heat, so if the wiring there looks brittle and damaged, it will need to be addressed.

Yup.

Actual heat sink compound has extra ingredients for better heat transfer.

"Real" heat sink compound is probably "better", but not needed. Dielectric silicone grease is fine.

I've heard of folks using wheel-bearing grease. I'm not saying I recommend that. We used to laugh at them, and then hand 'em a tube of dielectric silicone grease for the next time.

let’s say the fuel pressure is below spec when checked, would low pressure be enough to not allow the priming spray to happen?

There is no "priming spray".

Also would the low pressure be caused by a tired fuel pump? Or something else in the wiring possibly?

Failing pump motor, failing pump. Plugged fuel filter, or filter sock. High resistance somewhere in the wire harness between battery and pump, including the contacts within the fuel pump relay. Poor ground for the pump motor.

I won't replace a pump without testing voltage as close to the pump as possible, and testing amperage draw of the pump. Both tests need to have the pump RUNNING.

'Course, if the pump has voltage but won't run...sometimes y' gotta replace it without doing an amperage test.

Weird, because that is what comes with the Standard Ignition modules when you buy them from Oreilly or Rockauto. Never used anything but that compound for the last 20 years. I cannot think of a single module I have had fail, save for the one that shorted out when the tachometer shorted out on my old TBI. I have used that on all my TBIs, TPIs and Vortecs when I changed the module and even on the high-performance DUI modules that have more dwell time built into them for a hotter spark.

Silicone grease is all I've used in the past, although I think I've got a tube of heat-sink compound somewhere. I think the heat-sink compound is theoretically "better".

my truck is stumbling at idle now seemingly after I did the new spark plugs.

Connect a scan tool, verify EVERY sensor and computer output.

What is the cranking compression pressure of all eight cylinders?

Have you tried a cylinder-balance test to find weak cylinders?

the only thing that isn’t new is the wires, should I suspect them as they are well over 5 years old? Or should I go back and test all my spark plugs since that is the only change I made to cause the change in idle? Never had a new spark plug be bad but I guess it happens?

Inspect all of that. Quality plug wires can go well beyond twenty years, but most wires won't.

Run the engine in the dark. Look for corona glow around the plug wires. If you see corona, you should replace the wires. Test resistance of each wire with an ohmmeter. Anything over 4000 ohms per foot of wire is suspicious.

I guess I should be honest and admit my spark plug wires are bundled together with zip ties in a few places . Probably not helping the situation…

That's gotta change, in particular #5 and #7 M-U-S-T be separated so that they don't run parallel and close together. Either they cannot be run parallel, or they must be separated by at least 1/2 inch, preferably more.

 

[Erik the Awful]

I'd use regular dielectric grease or even wheel bearing grease in a pinch, but I have thermal paste on hand. It's a best practice to use it. It's so cheap that there's no reason not to keep some in your chemicals cabinet.

 

[someotherguy]

I'd use regular dielectric grease or even wheel bearing grease in a pinch, but I have thermal paste on hand. It's a best practice to use it. It's so cheap that there's no reason not to keep some in your chemicals cabinet.

And unless you're in some type of business that uses it on a daily basis, a small tube of it lasts practically forever. Hell I still have a couple tiny tubes I bought at a Radio Shack back when those places still existed.

Richard

 

[Maui_chevyk1500]

So I was able to get it to no-start again, unfortunately it happened at my job and left me stranded but I was able to verify no spark at least at the end of spark plug wire. I can hear the fuel pump running when I turn the key on (I wasn’t able to verify fuel pressure because I don’t own a pressure tester) so I’m assuming it’s an ignition related issue.
So now I’m focusing my attention on the coil, ignition module & related wiring Like @Schurkey mentioned.

My question is this:
why doesn’t the truck stall when the no start condition is present. Why does it run until I turn the ignition off, then wont start after. But then after sits over night magically it starts again?
This behavior makes me think that it has to do with temperature and my wiring being compromised somewhere. Obviously in the distributor/ ignition area.

I don’t really want to put a new coil and icm for $200 if my wiring harness is possibly the culprit. I don’t know how to proceed as I am lousy at using a multimeter and don’t really know where to start.

Does anyone have any other advice at this point that doesn’t involve a scanner? cuz I don’t have access to one…

Anyway you guys have been so helpful through this whole thing and I’m so thankfull!

 

[Road Trip]

My question is this:
why doesn’t the truck stall when the no start condition is present. Why does it run until I turn the ignition off, then wont start after. But then after sits over night magically it starts again?
This behavior makes me think that it has to do with temperature and my wiring being compromised somewhere. Obviously in the distributor/ ignition area.

Greetings Maui_chevyk1500,

For about 15 years I was buying/driving high mileage '89-'90 Honda Civic hatchbacks
as my DD. Every single one that I bought either had, or would eventually develop the exact
same misbehavior:

* As long as it was running, it would keep running.
* If I forgot & shut it off hot between work & home, it would NOT restart until it cooled off.

* When the no-start happened, I had a gallon jug of water behind the seat, so I would open
the hood, pour the water over the lower aluminum distributor housing (distributor was installed
horizontally off of the end of the camshaft on the passenger side) ...and the car would start right up.
(And yes, I got some strange looks when I did this. :0)

The root cause of the 'always fails to start hot, yet always starts once cooled off' was a thermal-sensitive
(hot fail) electronic Ignitor module inside the distributor. This is the electronic replacement that Honda came up
with for the mechanical points way back when. (See attached.) And after the original Ignitor accumulated enough
miles/thermal cycles, this is how they would fail. NOTE: Most would choose to replace the entire
distributor with a reman for ~3x the money, but nearly always the Ignitor was all that was needed.

NOTE: The replacement units installed with thermal compound would go on to last the rest of the
life of the vehicle. Replaced several of these, 3 for me, and the rest for my friends. Never had to
replace any of them a 2nd time.

****

What does this have to do with you? You are experiencing the same thermal failure that I was, right
down to it never stalling when hot, but by the same token there's no hot restart...it has to cool off.

Given the symptoms you've observed, it seems to me that your ICM has become thermally sensitive
& you should consider replacing it. Note: I've never had a spark plug wire set give me a 'bad when hot,
good when cold' failure symptom, so at this time I wouldn't replace them for this round of troubleshooting.

By the same token, coils are funky high-voltage devices, and I always distrust them just a little. For example,
if I were to claim that this *has* to be the ICM, it will turn out to be your coil instead. :-( That's just the
way it is when it comes to trying to predict the exact behavior of ignition coils turning a steady +12V input
to multi-Kilovolt output pulses. :0)

****

To summarize, based upon all of your troubleshooting, if it were my truck I would:

* Replace the ICM with the highest quality part you can source. (Others jump in with specfic recommendations, please)

* Also have a new coil either located or in hand to try on the 2nd pass IF the ICM doesn't cure this hot no-start issue.
By the way, some will recommend replacing both ICM and the coil. (Failing coils often make for nasty neighbors in the
electronic ignition circuit neighborhood, and can cause collateral damage on their way out.)

* Spark plug wires should only be changed if they fail the inspections that others have already noted.

* NOTE: If the new ICM comes with thermal compound, use it. Don't install it dry. (I've changed a few failing
Ignitors that had been changed before, and they were dry.) With electronics, the higher the heat, the shorter
the lifecycle. And if you have to supply the thermal compound yourself, please do, don't skip this step.

Can't sleep? Here's a nice article comparing a bunch of different thermal compounds: ZZZZZZZZZ

Hope this answers your question on how an electronic ignition system can run hot no problem, but
at the same time won't restart until it cools off.

Best of luck. Let us know what you discover --

 

[Keeper]

An ICM is only $30 or so. I know it's not my money, but it sure sounds like a likely culprit for the no start, until it's not of course. On the rough idle, have you separated the plug wires yet? Good luck with it.

 

[someotherguy]

So I was able to get it to no-start again, unfortunately it happened at my job and left me stranded but I was able to verify no spark at least at the end of spark plug wire. I can hear the fuel pump running when I turn the key on (I wasn’t able to verify fuel pressure because I don’t own a pressure tester) so I’m assuming it’s an ignition related issue.
So now I’m focusing my attention on the coil, ignition module & related wiring Like @Schurkey mentioned.

My question is this:
why doesn’t the truck stall when the no start condition is present. Why does it run until I turn the ignition off, then wont start after. But then after sits over night magically it starts again?
This behavior makes me think that it has to do with temperature and my wiring being compromised somewhere. Obviously in the distributor/ ignition area.

I don’t really want to put a new coil and icm for $200 if my wiring harness is possibly the culprit. I don’t know how to proceed as I am lousy at using a multimeter and don’t really know where to start.

Does anyone have any other advice at this point that doesn’t involve a scanner? cuz I don’t have access to one…

Anyway you guys have been so helpful through this whole thing and I’m so thankfull!

More troubleshooting leads to less parts-guessing, but if I were to guess, I'd say the best guess is your ignition module. This is based on your previous reported symptom of no injector spray while cranking, combined with current reported symptom of no spark while cranking. That's your combo of "no fuel, no spark" at the time of your no-start condition. #1 suspect for this is the ignition module, but that doesn't mean it's the ONLY suspect.

Coil is very low on the suspect list because they rarely fail (the factory original ones, anyway) and it won't be responsible for a no injector spray condition.

If you want to just shotgun replace a part, the module is the one to go with. As mentioned by several, be sure to use heat sink compound. A thin layer, after cleaning off the distributor base, is the way to go. Too much is not good. Just enough so that it bridges the air gap between the distributor base and the module, so that heat can transfer easier.

Richard