random stall with easy restart
Here's the problem. My 30002 is stalling at random times, cold and hot, driving and at idle, no apparent common thread. It's a new install, it starts and runs fine, I'm still using the default tune, I haven't changed anything yet. I have double and triple checked the wiring and connectors. No fault codes. Idle is at about 800. IAC steps 1-3. sometimes dropping to 0. The stall is clean, no sputtering, just like someone turned off the key. But it starts right back up no problem. It seems to happen more at low rpms, but it's done it on the freeway, too. Anything anyone can suggest before I start bothering the help line? I'm not noticing anything on the dash when it stalls, but it's hard to be looking exactly when it stalls out. If I had to guess, it sounds ignition related, but that's just a guess.
Learn to catalog and retrieve. There are videos on Fitech.com.
Get a 2 minute log at idle and up to operating temp.
i can look at it or the techs can as well.
I tried to attach a log but I don't think it worked. I did get an error code of 64 for a few cells, I will go check my fuel pump wiring. I'm running a 50101 pump with 12 ga wiring to the rear from the relay. One long run, so I'd be surprised if it's grounding out anywhere. I also had a code of 105 before I started the truck...which is a bad ground? I'm grounded to the block, which is strapped directly the the frame on both sides, but I'll check just the same. I'll try again with the log.
My suggested grounding method. Battery ground should go directly to engine block. Frame and Body grounds should be at least 10 gauge directly to the battery. Not recommended to ground frame or body through the engine. Can cause issues with EFI. Especially on vehicles that weren’t originally injected.
changed the ground so it runs from the batteries to the block then from the block to the frame, both sides, and using #3 cable. On the latest log the only funny thing I see is the IAC count is a little low, 0 to three at idle, but the idle stays normal right to the stall. I'll try again with the log, stall is at line 478. I also have a bunch of "DASH" and "Tail" for the run status. What does that mean?
I'm heading out to see if I can log another stall now. Seems to run fine other than just completely dying on me from time to time.
Reread my ground recommendation. However, not seeing in any codes that would lead me to believe you are getting interference or ground loops.
Your log started long before it was up to temperature. Once it showed over 170, things looked in order. Log was about 20 minutes long.
i never seen a stall.
btw, dash and tail is when the engine is increasing or decreasing in rpm. Like acceleration and deceleration.
I get what you're saying about the ground. I'll take care of that, but I also don't think that's the problem, but it may be contributing.
On the old log, the stall was at line 478...the rpms drop to 0 and the run status goes to stall.
I apologize for the length of these, but it's hard to predict when it will stall, so I just keep the log running until it stalls out. On the new log it occurs at 835, and again from 965-1001. I noticed on the second one the vacuum drops much more than the first one. Other than that, I don't see anything indicating why it would stall out. The values all look almost the same. And when it stalls, it just shuts off like you turned the key, no sputtering, just off, right now. Turn the key, and it starts right back up again, no issues. And I can hear the fuel pump buzzing when it stalls, so I know that's not it.
I know you've been doing this a long time, and you're probably the most experienced tuner out there for Fitech stuff, what's your gut feeling on this...'cause I'll bet you're right. I'm sure you've seen whatever it is before............and again, skip to line 835 on the log...that's the first stall out. I'm sorry it's so long, but it only stalls when it wants.
You are correct. Nothing in the data shows that it is a Fitech issue. If it were fuel pressure, it would slowly go lean and die. That leaves ignition. Maybe the ignition switch itself. Could be losing contact with vibration or heat. When you restart, it establishes contact again. This would make sense why it is random.
Any thing else with the ignition system would likely fail to restart right away. However, the ignition system from key to coil to distributor is where I would be looking.
Btw, thanks for the compliment, but I’m still learning myself. Every day we see something new. Sometimes it is a new way a user can screw up an install.😆
It's been a while, but I've been chasing this problem the whole time. Here's what I've done:
Per our writings, I have grounded the block to the battery, and the frame and body to the battery. The block is not attached via ground to the frame, although I think it's still sharing the ground via the motor mounts.
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Rerouted the black wire from the Throttle body to the input on the MSD box, shielded the wire.
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Shielded the green and purple wires from the distributor to the throttle body. They obviously run under the distributor for some distance, however they are shielded and as far under the plug wires that I can get them.
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Ordered and installed new plug wires and routed them as far from any of the Fitech wiring as possible. The wires are 8.5 mm spiral core, 500 ohm per foot RFI supression wires with EDPM insulation.
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Spark plugs are AC Delco 41-803 resistor plugs valued at 3k-10k ohms.
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The O2 sensor wire crosses under the plug wires on the driver's side. It's about 12" between the plug wires and the O2 harness, and they cross at almost 90*. The other wires (H20 temp and ignition) both cross under the plug wires and are not sheilded.
- Replaced the ignition switch. Traced all the wiring from the switch to the throttle body/coil/ CDI box. everthing is soldered, and checks with continuity while moving the wires around. I know that doesn't prove anything, but it doesn't appear to be a short in that wiring.
Two possibilities that I want to ask about: could the noise be coming from the plug wires being too close to the actual ECU? It seems it's wrapped in pretty thick metal, and is grounded, but maybe? And second, there is a blank line in my datalogs before it stalls. Every once in a while, it also has a blank line, but it doesn't stall. I've never noticed these blank lines before. What's the story with them and could they be related to the problem? I'm attaching a log with a nice steady warm idle, a little drive, and then two stalls with restarts in a row. Stalls are highlighted in yellow.
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