'62 is not happy (1 Viewer)

[Kleatus]

I will try and investigate further tomorrow, but if anyone has some similar experience, opinions/info in the meantime I am all ears. More brains are better than one..

The '62 started cutting out a couple days ago, for a few seconds at a time, in short random bursts. It did it 2 or 3 days in a row at the exact same spot on the way home from work (a pretty good grade uphill.) When it does it, it's completely off - not starving for fuel cut out, but complete loss of ignition cut out. It did it to me again today on another hill, seeks to happen after several minutes of sustained load then goes away. It doesn't do it my whole drive in to work, just the hill on the way home. It doesn't cut out at all when cold or not under sustained load - pulls fine up to 4K rpm just fine if I just punch it.

The CEL was on the past few days so I pulled the codes this AM before pulling the EFI fuse to reset things;
12- rpm signal
25- lean
26- rich
41- tps
42- vss
71- egr

After driving into town tonight it was back to the same business. Pulled the codes when I got home and got:
41- tps
51- switch signal
71- egr (not too worried, it's off and on)

Will start with electrical check of TPS.

 

[Prairie Swamp]

Boy that's an odd one. So it's downhill on the way to work? Definitely sounds like a heat soak issue. I can't think of anything on the ignition system that would get "tired" from working too hard. I'd have to look at the wiring diagram to see what has the possibility of completely cutting off ignition. I would think loss of Crank Position Sensor signal would throw a code but I don't know. By all means track down your codes and check AFM and TPS, but could be a flaky coil, ignition module or simply a marginal electrical connection somewhere, including grounds.

Sorry I can't be of specific help just thinking out loud. Good luck. Intermittent ones are the worst.

Eric

 

[Kleatus]

Suspect pickup coils in distributor..

 

[Kleatus]

I'm guessing these are not original. They check out OK on resistance though..

 

[Kleatus]

Ok. It's still being a pain. Of course, just when the weather turns to crap I have to leave the 4WD with new tires at home..

Played with a few things tonight.
Checked TPS and AFM. Both checked out fine.
It sure has the symptoms of heat soak ignition related issue, so I swapped the coil and coil wire out (they did check out OK.)
Changed the fuel filter since it's been a while anyway. Checked fuel pressure. 42 at idle, 65 with the return pinched.. I should also mention I did remove the EGR valve the other night and it wasn't dirty/clogged and seemed to be working normally. I did also drive it with the vacuum disconnected from the EGR and nothing changed.

Pulled the EFI fuse again and took it for a drive tonight. Same crap, and CEL came on exactly when it started cutting out. 41 and 71. I suppose I need to start checking grounds and wiring..

 

[LAMBCRUSHER]

your code 41(tps) is a common denominator...after verifying the TPS at the TB, verify the harness by doing the same tests, but at the ECU with the connectors unplugged...sounds like a loose connection/broken wire...

 

[Kleatus]

your code 41(tps) is a common denominator...after verifying the TPS at the TB, verify the harness by doing the same tests, but at the ECU with the connectors unplugged...sounds like a loose connection/broken wire...

I suspect you're right @LAMBCRUSHER , I spent some quality time Saturday morning at the crack of dawn leaning over into the truck in 35 degrees and rain checking wires and running the voltage and resistance tests in the FSM. I would have to look at my notes to see exactly which ones - but I did find one voltage at a hair over 3 instead of 4-5 as specified, and the resistance for the TPS goes to 100k ohms when tested at the ECU instead of the specified infinity (which it does show at the TPS) when opening the throttle. I also noticed that my engine harness had fallen from its clip on the firewall and was down behind the head, getting dangerously close to the exhaust manifold, but it looked to be fine upon opening up that spot. Retaped and tidied that up, but didn't see anything obviously out of place with any wiring or connectors. At any rate, after all the poking and prodding I took it for a test drive and it ran great. It's been about 300 miles since Saturday and hasn't skipped a beat. Lots of hills and even some 4WD action on Sunday. Maybe she just wanted some quality time with me? Frustrating that I don't know exactly what it was..

 

[cruiserfj45]

Could be the ignitor giving you intermittent grief. Is it still just a few seconds off or has it gotten longer?

 

[60 toy ota]

If This comes back I wonder if there are cracked wires inside the insulation where it fell off the clip... Keep that part of the harness in the back of your head

 

[LAMBCRUSHER]

Your story sounds alot like when I first rescued my 62; had all kind of codes...just went thru systems one by one. changed o2 sensors, tested and calibrated TPS, tested and cleaned IACV, tested and cleaned dizzy. kept having trouble with both the o2 sensor circuit and the TPS...took the TB off and cleaned the TB with TB cleaner NOT CARB CLEANER, recalibrated the tps, tested the lines at the ecu and got good results...now that I think on it, the TPS and o2 circuit have been stable since...I wonder how much unplugging and plugging back in all the connectors does...(breaking up corrosion/making better contact)

 

[Prairie Swamp]

Nice rig and awesome pic. I hope you got it for good but I'm like you I would forever be waiting for that shoe to drop. Might be a blessing if it drops out and stays out for awhile. I'd be carrying an electrical schematic, multimeter and some jumper wire if you're not already. Good luck.

Eric

 

[Kleatus]

Could be the ignitor giving you intermittent grief. Is it still just a few seconds off or has it gotten longer?

It's been behaving fine since fiddling with everything. It was instantaneous to a few seconds at a time, off and on to the point that I was reduced to 20 mph on a 8-10% grade. But it only occurred after ~30 seconds of moderately heavy throttle going uphill. Flooring it off a light couldn't ever reproduce the effect.

 

[Kleatus]

Nice rig and awesome pic. I hope you got it for good but I'm like you I would forever be waiting for that shoe to drop. Might be a blessing if it drops out and stays out for awhile. I'd be carrying an electrical schematic, multimeter and some jumper wire if you're not already. Good luck.

Eric

Thanks. I hope it's fixed too. I always have a tools including a multimeter and wiring supplies, but your right- the FSM will need to take up residence under the back seat I think.

 

[Kleatus]

Your story sounds alot like when I first rescued my 62; had all kind of codes...just went thru systems one by one. changed o2 sensors, tested and calibrated TPS, tested and cleaned IACV, tested and cleaned dizzy. kept having trouble with both the o2 sensor circuit and the TPS...took the TB off and cleaned the TB with TB cleaner NOT CARB CLEANER, recalibrated the tps, tested the lines at the ecu and got good results...now that I think on it, the TPS and o2 circuit have been stable since...I wonder how much unplugging and plugging back in all the connectors does...(breaking up corrosion/making better contact)

I've had all that and more off/apart/scrubbed out/tested/replaced when I did the head about 25k ago. Just one of those things-it is pushing 400k and this is the first time since then that it's really acted up like this. The only other "issues" I have are concerning the EGR and air injection. Neither of which have really given me any issues from a reliability standpoint.

 

[LAMBCRUSHER]

I hear ya. mine, too is gettin on in age (366XXXm)... hopefully it is nothing.

 

[Kleatus]

Ok, after driving it for a week and a couple hundred miles including a low-range 4x4 trip in the snow, all was well.. starts fine, idle is rock solid right at 650, gets up and goes as good as it can, etc.

Well today, it's back. The difference now is that the "off switch" comes on and off at light-moderate throttle and goes away when above ~75% throttle, whereas before it was only under heavy throttle and wouldn't go away...CEL came on (and off) a couple times on the way to work...haven't checked it out yet. That will have to wait till Monday. I must have a connector or wire that's just not cooperating...or maybe the intervals between multiple miles in 4WD are just too long, and she needs more action.

 

[LAMBCRUSHER]

hmmmm, could be EGR related maybe- if the modulator was going south, or the valve is getting stuck open...

 

[Kleatus]

The issue occurs exactly under the conditions I would expect the EGR to be operating. However all the vacuum hoses to the EGR and modulator are bypassed at the moment and it makes no difference if they are hooked up.. I tried that then first round and again halfway home last night. I also took the valve out and tested it on the first go round, it opens and closes as it should and was surprisingly as clean as I remember it being when I actually cleaned it 25k miles ago. The modulator was pretty nasty before cleaning though (I clean them out by soaking them in simple green and pushing water through them.) Maybe the return spring on the EGR valve is weak and there's crap jammed in it now? Usually when they stick open it's a high-vacuum (idle) issue.

I may see about rigging up something to watch some critical voltages and vacuum while driving.. that would pinpoint the issue, since my troubleshooting sitting in the driveway didn't reveal any smoking guns.

It's just a machine, I'll get to the bottom of it..

I suppose it could be an ignitor or ECU issue too..

 

[LAMBCRUSHER]

fuel injector wiring splice...I hear they can get corroded...

 

[Kleatus]

I checked voltage and resistance of each bank of injectors at the ECU and it was spot on. I am running 4 hole Bosch injectors with pigtail adapters, so I've had my hands on that wiring fairly recently..