Engine sporatically shuts down, then restarts itself...

Engine sporatically shuts down, then restarts itself...

Postby chevyfreakster [OP] » January 11th 2017, 10:36pm

'95 Astro, 2 WD, base unit, 264,000 miles. About six weeks ago, the van began "thumping" at cruising speeds on the interstate. By thumping, I mean total lose of engine power for a split second, then continuing on like normal. This only affects the engine and not the lights, radio, wipers, etc., and happened about twice/day. Being an obvious issue, it's tough to diagnose when it happens intermittently...AND cures itself in seconds. In city traffic, if I'm going under 40 and it occurs, the van stalls, but starts up immediately like nothing ever happened (upon shifting to neutral, that is).

I did the usual web research and it seemed this issue is not linked to Astro vans alone, or even GM vehicles. All makes and models seem to be susceptible and each post explained what "they" did to rectify the problem. Trouble is, there was no common denominator, nothing there that made sense on a large scale...nothing that led me to a specific part. All these drivers reported this occurring after closed loop, never before. Basically, fuel or ignition had to be the cause (most of us can rule out 'air' as the cause). I read remedy suggestions ranging from: new fuel pump and/or filter, map sensor, bad PCM, spider injectors malfunctioning, pinched/loose wire, and of course dist cap, rotor, plugs, and wires, and more. Any of these could cause a myriad of problems, but an engine shutdown for a second? Hardly. Then the plot thickened.

The thumping increased in frequency over the next few weeks. One day, the van thumped, didn't recover, and I had to pull over. The engine remained running, but just barely; it would ping if I touched the gas pedal and not rev up. I turned it off, waited a minute, then it started up and ran just fine. So this new routine became necessary for me to get to work each day. Again, no way to test anything because it all began working perfectly shortly after. This continued until the van refused to restart and tow trucks became involved. My spark tester then revealed no spark.

All over the web, you can read about ICM's (ignition control modules) overheating and going bad. But I'd just installed a brand new distributor in November, with a new ICM and Coil Pickup included. After all this, the "new" ICM was defective. It finally tested negative and I had something that made sense. After replacing it (and the ignition coil, not the pickup coil), the van has been fine. My new dist also had 3 tiny holes (on each side) where my old dist had the screens. I decided these holes (toothpick sized) would get clogged soon and drilled them out to larger than the old dist ones. That should help to cool the ICM.

Once I narrowed this down to the pickup coil, ICM, or ignition coil, I began to read articles concerning those exclusively. Turns out: a failing ICM and/or pickup coil will exhibit the SAME SYMPTOMS. And once the 1st symptom is felt, the unit is toast and will completely fail soon. I also discovered it's a good idea to replace the ignition coil and ICM together, since they rely on each other. Gosh, this is long. Hope it helps someone. (Yes, I know the "gas" pedal is actually the "air" pedal on these vans.)
Original Poster [OP]
chevyfreakster
Fueling (3/8 tank)
Fueling (3/8 tank)
Years of Membership: chevyfreakster has been a member for 1 full year
Posts: 45
Topics: 15
Joined: March 2016
Gender: Male
Year: 1995
Van Make/Model: Chevrolet Astro

  • Similar topics
    Replies
    Views
    Author
  • So many engine options!?
    by Echo » December 4th 2016, 11:15pm in Engines
    25 Replies
    2293 Views
    Last post by Mmusicman View the latest post
    May 9th 2017, 5:11am
  • GM 4.3 Engine manual
    by Astrophile » February 8th 2017, 4:01pm in Engines
    1 Replies
    69 Views
    Last post by AstroWill View the latest post
    February 8th 2017, 7:14pm
  •  
    7
    85
    Last post by AstroSafari.com View the latest post
    May 23rd 2017, 11:43am

Re: Engine sporatically shuts down, then restarts itself...

Postby chevymaherchevymaher is online! » January 11th 2017, 10:41pm

Check the coil test it and move on to the module second. Test to make sure all the leads to the distributor are doing what they should. Ground power partial power etc. Find a diagram that tells you or search You Tube for someone that has a documentary basically. Telling you how to test each part and circuit. Do a google serch to find test as well.

That is what i got to do.
User avatar
chevymaherchevymaher is online!
Team Leader
Team Leader
Firing on 8 Cylinders (L7)
Firing on 8 Cylinders (L7)
Years of Membership: chevymaher has been a member for 6 full yearschevymaher has been a member for 6 full yearschevymaher has been a member for 6 full yearschevymaher has been a member for 6 full yearschevymaher has been a member for 6 full yearschevymaher has been a member for 6 full years
Posts: 13235
Topics: 83
Images: 94
Joined: November 2010
Gender: Male
Alias (AKA): chevymaher
Year: 1994
Van Make/Model: GMC Safari
Extra Info: SLE RWD Mercruiser

Re: Engine sporatically shuts down, then restarts itself...

Postby Lumpy » January 12th 2017, 1:11am

Sounds like an EMP hit.


Lump
Image
User avatar
Lumpy
250k+ Miles
250k+ Miles
Firing on 8 Cylinders (L7)
Firing on 8 Cylinders (L7)
Years of Membership: Lumpy has been a member for 7 full yearsLumpy has been a member for 7 full yearsLumpy has been a member for 7 full yearsLumpy has been a member for 7 full yearsLumpy has been a member for 7 full yearsLumpy has been a member for 7 full yearsLumpy has been a member for 7 full years
Posts: 11000
Topics: 261
Joined: April 2010
Location: Phoenix AZ USA
Gender: Male
Year: 1989
Van Make/Model: Chevrolet Astro
Extra Info: 11 in. lift Camo

Re: Engine sporatically shuts down, then restarts itself...

Postby chevyfreakster [OP] » January 12th 2017, 11:01pm

According to what I've read, an ignition coil can be in the proper ohmage range and still deliver a weak spark. As far as the ICM goes, same thing basically. If the parameters of ohms are within specs, it doesn't necessarily mean the unit is good. It only means that it's functioning. The tricky thing about the ICM's in our vans is: they can get hot and fail...then cool down and run perfectly. If the electronics get too hot, they will expand and lift off the circuit board, losing connections. As the unit cools, they shrink back into their original positions and the unit works again. I took mine (ICM) into Autozone twice for testing and twice they told me it checked out perfectly. A day later, it died its final death and finally tested defective. Can't wait to talk to the store manager at Autozone about the failed distributor...and my towing bills. This time, I installed a Borg Warner ICM. No more cheap crap for me!!! It's too expensive.
Original Poster [OP]
chevyfreakster
Fueling (3/8 tank)
Fueling (3/8 tank)
Years of Membership: chevyfreakster has been a member for 1 full year
Posts: 45
Topics: 15
Joined: March 2016
Gender: Male
Year: 1995
Van Make/Model: Chevrolet Astro

Re: Engine sporatically shuts down, then restarts itself...

Postby AstroWill » January 12th 2017, 11:20pm

Glad you got it fixed, and thanks for posting!

My guess would be that the ignition coil died because of a fault in the secondary ignition system. Spark then takes the path of least resistance, which in turn fried the ICM, then you replaced the dist/ICM without replacing the coil, and the faulty coil quickly fried the new ICM. Once you replaced the faulty coil, and installed a new ICM, all is right in the world. Now if you still have a problem with the secondary ignition system, it's only a matter of time before the new coil bites the dust and the cycle begins again.

If you haven't inspected/tested/replaced your wires and plugs, that would be the next on my list of preventative maintenance.
User avatar
AstroWill
Team Leader
Team Leader
Firing on 4 Cylinders (L6)
Firing on 4 Cylinders (L6)
Years of Membership: AstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full yearsAstroWill has been a member for 8 full years
Posts: 5408
Topics: 66
Images: 132
Joined: February 2009
Van Make/Model: Chevrolet Astro
Extra Info: 90TigerGTv8 03AWD

Re: Engine sporatically shuts down, then restarts itself...

Postby chevyfreakster [OP] » January 31st 2017, 12:00am

Sorry for the late response. Yes, the bad coil theory seems feasible and, since I bought a Duralast (Autozone) coil, even more so. The van is running better now and I switched coils (I have an old one) just to see. It runs just fine on either coil. That STILL doesn't mean the coil isn't the original problem; it could still be. I need to install an AC Delco coil, to be sure, right? My spark is kind of blue, but also yellow in spots. Does that make sense? Forgot to mention I observed the different colors on the spark tester.
Original Poster [OP]
chevyfreakster
Fueling (3/8 tank)
Fueling (3/8 tank)
Years of Membership: chevyfreakster has been a member for 1 full year
Posts: 45
Topics: 15
Joined: March 2016
Gender: Male
Year: 1995
Van Make/Model: Chevrolet Astro

Re: Engine sporatically shuts down, then restarts itself...

Postby chevyfreakster [OP] » February 8th 2017, 12:30am

Again, I can't keep up with all the internet things I love. In lieu of that, here's this: I was having mental issues with the AC Delco ICM and pick-up coil in the new Duralast distributor (I swapped the originals with the new GM parts). This particular unit never completely failed, but kept doing the "jerking" thing, at any given time...actually did stall at idle once, but cranked right up. So, I ordered an Autolite distributor. The reason being: The AC Delco ones did not have the copper shield over the pick-up coil, just like the Duralast didn't (which we all know failed). The Autolite had the coil cover AND the two breather holes with screens, just like my original distributor. I also ordered an AC Delco ignition coil as per the recommendation. So last evening, after work, they both got installed. What a nice blue spark from that coil! WOOHOO!

This morning, the van ran quite well. Not as much pep as the day before, but I figured the computer would adjust to the new parts. Then leaving a toll booth, I had to floor it. The van fell on its face, power-wise, and didn't run decently for the rest of the day. The pep got snuffed somehow, BUT...no power loss episodes. It reminded me of another time when I installed a Duralast dist. cap/rotor and had the same results. So I got home from work and took the brand new cap and rotor off, then replaced them with the GM ones (still fairly new). All the pep returned...and early shifting...no hesitations...etc. It ran like a completely different vehicle. These lessons are costing me a small fortune. I share them on this site because all of you help me every day with your tips and suggestions. This thread isn't over yet, not until I drive for a few weeks. Seems like something always happens to send me back to square one. Hope I'm wrong.

I also have a brand new AC Delco spider injector set (nut kit) sitting, waiting for the perfect weekend to install. This time, the plenum will get a good cleaning.
Original Poster [OP]
chevyfreakster
Fueling (3/8 tank)
Fueling (3/8 tank)
Years of Membership: chevyfreakster has been a member for 1 full year
Posts: 45
Topics: 15
Joined: March 2016
Gender: Male
Year: 1995
Van Make/Model: Chevrolet Astro

Re: Engine sporatically shuts down, then restarts itself...

Postby dramey » February 8th 2017, 12:56am

Why buy a Duralast distributor when you can get a Skip White distributor for less than half the cost of the Duralast distributor? The Skip White distributor is a much better distributor and highly recommended on this forum.
User avatar
dramey
Firing on 2 Cylinders (L1)
Firing on 2 Cylinders (L1)
Posts: 242
Topics: 7
Joined: September 2016
Location: Alaska
Gender: Male
Year: 1997
Van Make/Model: Chevrolet Astro
Extra Info: AWD Cargo Van

Re: Engine sporatically shuts down, then restarts itself...

Postby Coaster » February 8th 2017, 1:19am

have you read my thread about "'i'm stranded"

we have the same thing going on. to a T. same year even.

except mine cost $600 to get home.

i am waiting for some time to check fuel pressure/leakdown to eliminate that. i have the tools, i need the time.

i ordered a new ALDL cable because i wrecked my cable oops.

i strongly suspect the pickup coil, but i will not shotgun that. too much work
User avatar
Coaster
Firing on 8 Cylinders (L1)
Firing on 8 Cylinders (L1)
Years of Membership: Coaster has been a member for 4 full yearsCoaster has been a member for 4 full yearsCoaster has been a member for 4 full yearsCoaster has been a member for 4 full years
Posts: 947
Topics: 102
Joined: December 2012
Year: 1995
Van Make/Model: Chevrolet Astro
Extra Info: 4.3 cargo 2wd

Re: Engine sporatically shuts down, then restarts itself...

Postby chevyfreakster [OP] » February 17th 2017, 12:51am

No Coaster, I didn't read your post. Gen 1 diagnostics will not alert you to a bad pick-up coil, at least not my scanner. I've found no way to solve my issues but to experiment, and log the results. My data stream is quite limited in its ability to share engine info. I hope your solve your problems soon. If I can help, I will.
Original Poster [OP]
chevyfreakster
Fueling (3/8 tank)
Fueling (3/8 tank)
Years of Membership: chevyfreakster has been a member for 1 full year
Posts: 45
Topics: 15
Joined: March 2016
Gender: Male
Year: 1995
Van Make/Model: Chevrolet Astro

Re: Engine sporatically shuts down, then restarts itself...

Postby Coaster » February 17th 2017, 1:01am

scanning has shown me that my issue (and likely yours) is the injector stops firing during the trouble period. the question now is why. i have been out of town and working overtime so i have had very, very little time to troubleshoot and test but tomorrow i plan to test the signal and voltage to the fuel injector with two light bulbs. if both the 12V to the injector and ground pulses are firing when the issue happens then it is the injector or mre likely the connector on top of the injector.

if either bulb goes dead during the test than it is whatever is driving those wires.
User avatar
Coaster
Firing on 8 Cylinders (L1)
Firing on 8 Cylinders (L1)
Years of Membership: Coaster has been a member for 4 full yearsCoaster has been a member for 4 full yearsCoaster has been a member for 4 full yearsCoaster has been a member for 4 full years
Posts: 947
Topics: 102
Joined: December 2012
Year: 1995
Van Make/Model: Chevrolet Astro
Extra Info: 4.3 cargo 2wd


 
  • Related topics
    Replies
    Views
    Last post

Return to Engines

It is currently May 23rd 2017, 11:43am

Engines Forum
Engine Repairs, Modifications, Diagnostics, Tuning, Upgrading, Questions.
Moderator: chevy57bert
To create a new topic in Engines, click this button:
Previous topic Next topic
Recent Image Attachments
Attached by:
Attached by: paulbot
paulbot
in Engines
Views: 2130
Comments: 16
Date: Yesterday
Time: 4:30am
» Read last comment
Attached by:
alife2
in Engines
Views: 1869
Comments: 22
Date: May 20 '17
Time: 9:13pm
» Read last comment
Attached by:
alife2
in Engines
Views: 1869
Comments: 22
Date: May 20 '17
Time: 5:08pm
» Read last comment
Attached by:
alife2
in Engines
Views: 1869
Comments: 22
Date: May 18 '17
Time: 7:36pm
» Read last comment
Attached by:
alife2
in Engines
Views: 1869
Comments: 22
Date: May 17 '17
Time: 10:15pm
» Read last comment
Sponsors
 

Who is online

Users browsing this forum: No registered users and 4 guests