86 EFI truck just shuts off when running
#47
07-12-2016, 12:40 PM
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Looked this morning at my trucks ECU. No wires in pins 3 and 6 on the plug in my case which coinsides with whats shown in the charts at "Old Fuel Injection.com" for an 85 and 86. I have diagrams too that do show VSS being input to the ECU on those pins for an 86, but also that same diagram shows the O2 sensor as being a heated multi wire sensor. Mine is a single wire. So the diagram must be something other than an 86 5.0 or some engineers plan that was not implemented as was mentioned. Not the first time Haynes and Chilton has included incorrect/incomplete info. But moving forward and the input is very much appreciated.
#48
07-12-2016, 01:19 PM
You're getting into too many conspiracy theories, these computers don't even have a CEL much less any notion of vehicle speed.What conspiracy theory? Although did you notice the VSS was made by Allied Signal, the same company that made the cameras used in the so-called "Apollo moon landings"?
#49
07-12-2016, 01:36 PM
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So this kind of makes sense. My ECU is receiving signals from a camera with dying batteries on the moon. Explains the intermittent cutoff problem!
#50
07-12-2016, 03:54 PM
Do the TV news anchors spy on you, too? And you can talk back to them through the TV?
#51
07-12-2016, 07:47 PM
Fleet Mechanic
If we're heading for outer space,
Apollo 11's Source Code Has Tons of Easter Eggs, Including an Ignition File Titled 'Burn Baby Burn' - ABC News
Apollo 11's Source Code Has Tons of Easter Eggs, Including an Ignition File Titled 'Burn Baby Burn' - ABC News
#55
07-13-2016, 08:46 AM
1) Does the engine have an Idle Air Control (IAC) valve? I would think so, but didn't see that on your list of parts that have been changed. A sticky IAC could certainly cause stalling.
2) You've mentioned how stepping on the accelerator seems to cancel the problem. (That's what made me think IAC just now.) You've changed the TPS several times. What if you tricked the TPS into thinking it was slightly open when it was really at idle? Since the problem seems to be predominantly at idle, tricking it to think otherwise might help for troubleshooting purposes. Not sure what other effects this might cause, but it might be worth considering to see if it helps with the shutdown problem. You could either rejigger the orientation of a spare TPS, or maybe add a resistor inline if that would trick it.
#56
07-14-2016, 10:16 AM
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Two non-conspiracy thoughts:
1) Does the engine have an Idle Air Control (IAC) valve? I would think so, but didn't see that on your list of parts that have been changed. A sticky IAC could certainly cause stalling.
2) You've mentioned how stepping on the accelerator seems to cancel the problem. (That's what made me think IAC just now.) You've changed the TPS several times. What if you tricked the TPS into thinking it was slightly open when it was really at idle? Since the problem seems to be predominantly at idle, tricking it to think otherwise might help for troubleshooting purposes. Not sure what other effects this might cause, but it might be worth considering to see if it helps with the shutdown problem. You could either rejigger the orientation of a spare TPS, or maybe add a resistor inline if that would trick it.
1) Does the engine have an Idle Air Control (IAC) valve? I would think so, but didn't see that on your list of parts that have been changed. A sticky IAC could certainly cause stalling.
2) You've mentioned how stepping on the accelerator seems to cancel the problem. (That's what made me think IAC just now.) You've changed the TPS several times. What if you tricked the TPS into thinking it was slightly open when it was really at idle? Since the problem seems to be predominantly at idle, tricking it to think otherwise might help for troubleshooting purposes. Not sure what other effects this might cause, but it might be worth considering to see if it helps with the shutdown problem. You could either rejigger the orientation of a spare TPS, or maybe add a resistor inline if that would trick it.
To me and if this was a car or truck someone brought to me with the stalling problem, the TPS would be something I would be suspicious of. I imagine it is the easiest sensor on the engine to suffer from mechanical wear. Replaced these on a few cars I have worked on with immediate success. I have not tested the new one on it now other to make sure it passed a little below 1v at idle and it had a clean sweep as I opened the throttle plates. But did this quickly last week when I put it on. Need to go back and focus on this. It's an OEM unit as has been suggested by others in this forum to use. So I just threw it on before work threw a meter on it and had to go.
#57
07-14-2016, 11:07 PM
Yup I did fail to mention that I swapped this out. First time was from a parts yard where I found one that looked almost new. Cleaned it and put it on. Was better than what I had previously! Eventually had idle issues again got one from Auto Bone. No difference but read that I really needed to go OEM on this part to be happy. So a few months ago, got one from NAPA. Was an improvement but by this time I was starting to have the stalling problem in its early stage. (Doing the cut out about once a month)
Still scratching my head over the whole situation. Short of the discovery of a smoking gun, I'm willing to gamble some of your hard-earned money and reemphasize trying Stabilant 22 on the various electrical connections. It's especially helpful on delicate, low voltage circuits like sensors and thermocouples. We use it at work (aviation) and it puts a dead stop to chronic intermittent faults that never seem to show when testing.
Might be worth a try, instead of continuing down your current expensive path of building a new truck piece by piece. The history of water immersion makes your truck a prime candidate.
#58
07-14-2016, 11:57 PM
Aye... these things are 30 years old now, and their ability to stand up to the elements by this point is going to really depend on how it was treated and maintained over its life. Nothing lasts forever.
#59
07-15-2016, 11:39 AM
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The "idle issues" you mentioned: Am I reading correctly between the lines that the IAC replacement predated the stalling problem? Were you running the Auto Zone or NAPA valve when the stalling first reared its ugly head?
Still scratching my head over the whole situation. Short of the discovery of a smoking gun, I'm willing to gamble some of your hard-earned money and reemphasize trying Stabilant 22 on the various electrical connections. It's especially helpful on delicate, low voltage circuits like sensors and thermocouples. We use it at work (aviation) and it puts a dead stop to chronic intermittent faults that never seem to show when testing.
Might be worth a try, instead of continuing down your current expensive path of building a new truck piece by piece. The history of water immersion makes your truck a prime candidate.
Still scratching my head over the whole situation. Short of the discovery of a smoking gun, I'm willing to gamble some of your hard-earned money and reemphasize trying Stabilant 22 on the various electrical connections. It's especially helpful on delicate, low voltage circuits like sensors and thermocouples. We use it at work (aviation) and it puts a dead stop to chronic intermittent faults that never seem to show when testing.
Might be worth a try, instead of continuing down your current expensive path of building a new truck piece by piece. The history of water immersion makes your truck a prime candidate.
Yes but the NAPA replacement went on after the stalling began as an occasional (once a month or so and has since become multiple occurances every trip) with no effect on the stalling problem but I did notice it seemed to control idle much better than the previous two I put on over the past 5 years.
Even though I sometimes jump around to different possibilities relating to this, I always come back to electrical. Found an intact engine harness from an 86 last weekend and will start by cleaning it then test all the connections. But yes will see where I can find Stabilant 22 give that a try.
Went ahead and replaced the O2 sensor only because I was not satisfied my existing one was responding as fast as I expected. New one is much better but not expecting this to resolve the stalling... seems to be running less rich after warming up.
#60
07-15-2016, 03:31 PM
Amazon carries it. I'm sure there are plenty of other online sources, too:
https://www.amazon.com/Stabilant-5ml...s=stabilant+22
Read the reviews. Interesting stuff, almost exclusively positive, even in spite of the seemingly outrageous price. Heck, it can't be cheap to harvest unicorn tears for the base ingredient. From what I've heard, the unicorns have to be wild, too. Doesn't work with captive unicorns.
Manufacturer's website, not the greatest info there, however. No mention of the unicorns, as this apparently a trade secret:
Product Sizes & Packaging