ckuske

I didn't see this thread before, so I thought I would throw my hat in: My name is Chris. I'm 42, and I think the term "Oregon Trail generation" works well for people my age. Depending on where you look, technically I am a Millennial but I roundly reject that label. If anything, I feel more kinship with the Gen X'ers. I was born kind of straddling the analog and digital worlds. I grew up with both computers and carburetors and record players, but I have first hand knowledge of using 4 MHz processors, 5 1/4" and 8" floppies (360 K), etc. I think that's why these trucks resonate for me as well. I live in Ventura, California. Born and raised locally. I've been married for 19 years now to my lovely wife, and I have a son (16) and a daughter (13) that keep me happily busy. They are understanding of this project even though it is a mild obsession at this point... I went to college and got an MS in Computer Science, and I work in the aviation sector for a company called Teledyne as a software engineer. I've seen the posts here about people working in digital imaging - a different business unit of Teledyne makes pretty fancy sensors especially in the microwave and infrared spectrum. I make software for these things called ARINC Data Loaders - they basically provide "Windows Update" for commercial aircraft that are essentially flying networks these days. I was originally an airplane geek before I got into computers in the mid-90s as a teenager - so I have a nice blend of the two worlds. I get to travel to some pretty neat places for troubleshooting, lab testing, and play around on aircraft and their systems. I am working on restoring my Dad's 1984 F-150. He bought it new, I rode in it as a kid (in a car seat even!) and it was my first car when I was 16. I fixed it up (well, I thought I was doing good things but my wiser self would disagree now), and drove it for a few years but sold it. I found it and bought it back about 4 years ago now, and I am trying to get it back to stock condition as closely as possible. It still has the original motor (rebuilt) and transmission. I am also trying to get it ready for my son to drive, so it will be a 3rd generation truck. I would be lying to myself if I didn't say there was some sentimental value (my Dad passed away 17 years ago now), but I do appreciate these trucks for what they are as well. I've been learning as I go - making some mistakes, learning the hard way, finding parts from all over the places, but lately I feel like most things are doable and I've been more confident diving into things and finding out that its pretty hard to really screw things up too badly. Just like in tech, it seems like the last 5% of a project takes the majority of the time. I am basically shaking out bugs (why is my life all bugs!?) and trying to get money together to get it painted the original color. Thanks if you have read this far!

Yep, back to basics! Hopefully things are clearer with a test light. A test light is coming tomorrow, but I’ll be on a work trip this week. (First one since COVID, and I was flying home on my last trip one day before international flights got shut down!) I hope to post findings again next Friday or Saturday.

Hi Dane, This is the one I have. I’ve had it for a few years but have been using it more lately trying to get these last things closed off: https://a.co/d/bi62gOr I’m conflicted whether this is a valid theory since the KOEO seems to work well. It’s less traffic to analyze than KOER though. I’m almost wondering if there is a maybe a grounding issue on the EEC? As a person at my work says, I am starting to look to “moonbeams” as theories…

I got a smoke machine and ran a smoke test. I taped the carb up, and ran the smoke through the brake booster line. I found one 'T' vacuum fitting that had a leak. Fixed that leak. OK, I took the truck out to warm it up for a KOER test, and drove it around tried to see if the hesitation was better. At first it wasn't... same as usual. After about a minute of driving, it was essentially gone. The stumble at fast idle is still there when in park (even after pulling back in, putting it in park, then revving to 2000 rpm). It's not there when driving... Moving on to try to KOER test again: I got the cylinder code (8) just fine this time. Ok, great... maybe I didn't warm it up enough last time. A little bit went by, then got the goose code (10). Hit the gas, codes started coming out. Some puzzlers still: 31,35,82,4,41,47,92,94 I turned everything off, ran the test again. Same results up to the codes coming out. I got code 32, then 35. Another code was being read, and my scanner display went completely blank. Like dead. Batteries are fine. Disconnected it and turned it back on... lit right up. So now, I am not sure what to trust. Is my reader bad (maybe)... is my ECU bad? Maybe. KOEO still works fine every time, no issues there. So, I've fixed one vacuum leak and the hesitation in drive is better, but my KOER tests are goofy and the stumble in park is still there. I am getting a little frustrated - I feel like I am reaching my diagnosis limits. But, the one guy I've taken the truck to before hasn't been able to address the hesistation issue in drive after he's seen it three times (it was lower on the list compared to other problems). He's kind of the "go to" guy around here for this vintage of car, and I don't want to start shot gunning and trying random people. I'm not sure where to go from here to be honest. I suppose buying a new reader or just getting a test light is the next step...

Just ran it again - maybe it's not warmed up enough? I waited until the thermostat opened etc.... about 4 to 5 minutes of running time, about 90 seconds at 2000 rpm. Choke was fully open. Anyway, the code this time (with no Cylinder ID again...): 20 47 2 5 47 3 85 2, 5, and 3 are out of bounds. 85 doesn't seem to apply to trucks at all. I am out of time today, I will drive the truck before posting again. Thanks for hanging in there.

Well, not fixed. I ran the KOEO test first, it came back clean (phew). I ran the KOER test next, and got all sorts of goofy codes, some of which weren't even in the reader manual. I convinced myself last time when this happened that I didn't set the reader up correctly. (I use https://a.co/d/aW87eVS) I thought the procedure was: 1. Warm truck up, then turn ignition off 2. Connect test connector and single (ground?) wire to terminals on code reader 3. Turn code reader on 4. Turn ignition on, start engine 5. Press Test button on reader 6. See Cylinder ID code 7. Wait for 10 code 8. Press accelerator In reality, I ran the test several times - most of the time the Cylinder ID code didn't come out, the 10 code came out sometimes, and got odd codes such as 3, 4, etc. I had this happen before, but altered my steps and it was much more coherent (got Cylinder ID test, 10, and then only one code, 35). Most of the steps I find online relate to a test light, maybe I'm getting something wrong in the translation. Apart from my KOER problems here (likely my fault), the stumble is still there at fast idle. I didn't back probe the EVP connector to check the voltage differential between pins. Maybe that is next. One other note, the first time I ran KOER, the engine died during a part of the test where I assume the EGR is opened. After the engine died, there was a repetitive sound of a "click" (but deeper than that), about 8 times a second. Constant, no variability in timing etc. It sounded to be coming from the EGR, but that doens't make much sense. It was definitely from that area, I tried to stick my head close but couldn't isolate it exactly. I kind of thought maybe it would have been the thermactor solenoids, but they were silent.... I still have the truck on jack stands from bleeding the power steering, I'll lower it and take it for a quick drive in a day or so to see if the main problem is addressed.

Thanks, will try it out shortly! I realize I ask questions that are fairly obvious, but I try to not assume too much. There is a lot of tribal knowledge that you only acquire through the School of Hard Knocks, and I rely on you guys to hopefully steer me in the right direction.

Got the new EVP in. The new NOS Motorcraft one registers less resistance between pins than the one that was on the truck. It still doesn't match the Haynes guidance though... Old One: 692 Ohms between SIG RTN and EVP SIG, and 4940 Ohms between VREF and SIG RTN on the old one. (the RTN/SIG was reading 1200 ohms the other day, so not sure why it is reading 692 now. I did however push the sensor rod in a few times, maybe it has a problem not returning fully out?) New One: 520 Ohms between SIG RTN and EVP SIG, and 4440 Ohms between VREF and SIG RTN on the new one. Now to try it and see if anything is different after starting... Also, the new one came with two different gaskets... I am unsure if both are needed? It seems the wider one would work. Maybe due to different vehicles? I would put both on, the smaller one sites on top of a flat region of the wider o-ring, but I since this sensor is based on depth into the EGR, I am worried it might throw it off.

It may not be *the* thing, but it’s definitely *a* thing. I just removed the EVP from the EGR and measured again. (I noticed that when removing it, it felt “spring loaded”, meaning the pintle was depressed just be being installed.) Anyway, with it removed the measurements are now 4880 Ohms and 683 Ohms. Still out of spec, but closer. Looks like I need to hunt for a new EVP…

Ok, I need to put my EGR/vacuum stuff back on so I can start bleeding the power steering and test it. So, I checked the EVP. My Haynes manual says resistance between VREF and EVP signal pin is supposed to be "slightly less than but no greater than 5000 Ohms". Mine is around 4550. So fail, I think. Next, EVP signal pin and SIG RTN should be "slightly greater than, but no lower than 100 ohms" but it is 1200 Ohms! I think I found the problem? I will take the EVP off the EGR and make sure the pintle isn't stuck somewhere... I imagine a reading this far off could really cause the ECU to do stuff that shouldn't be happening...

This isn't about fuel boil or choke settings. The truck starts just fine an hour (or a day) later. The float bowls evaporate completely when left all week. (ask me how I know!) The idea of an inline booster pump with momentary switch intrigues me. I doubt I'll implement it, but it is appealing. Jim, I had the same idea, and I implemented it. I tried to choose an electric pump that allowed pull-through from my mechanical pump, I had a push button switch wired, a filter installed between the tank and the electric pump, etc. It turned out that it seemed to help, but it ended up causing my mechanical pump to fail. There could be lots of reasons for this, so I'm not blaming the electric pump, but is something to be aware of if you start on making that change. Since I got a new mechanical pump installed and my carb rebuilt, my truck starts very quickly even after sitting for a week. Just an FYI.

Yep, I know eventually the problem will make itself known. On the power steering thread, I just got the old one off, and got the pulley off too. First time I've ever done that. I used my brake bleeder vacuum pump, that made it much less messy!

No such luck. There was a gasket there, not in great condition, but it was there. I've ordered two fresh ones from Amazon, they'll be here Tuesday. I took the cooler off and gave it a bath with hot water and Dawn dish soap. It looks much better. There was a fair amount of carbon, but not enough that I thought it would have caused an issue. But it just got Roto-Rootered, so it should be good for years to come. On Tuesday I'll put everything back together, check out the EVP sensor, and unless a miracle happens by then, go down the smoke test route. It still feels like a vacuum issue, so that's the track I'll stay down. Coincidentally with all of this, my original power steering pump gave up the ghost finally. So, putting a replacement on with the rest of my day today...

Agreed! Fingers crossed. To be clear, there was a gasket mating the EGR to the cooler. From cooler to the manifold is TBD ( an hour or two hopefully), it doesn’t appear so.

Ok, I pulled it. It basically looks brand new still. I pulled vacuum on it and the valve seems to move freely as well. I did notice that the EGR cooler should have a gasket on both sides. I didn't remove it off the manifold yet, but if there is a gasket there, I sure didn't see it. Either it's fallen apart or isn't there. That would be a red flag (I think). If you slide the cooler on the bolts and try to mate it against the manifold, there's a small "clank". You would think if a gasket was there, it wouldn't do that... It looks like the same gasket should be on both sides of the cooler in the drawing below. I felt inside the cooler with my finger and got some carbon out. I guess I'll pull that next (how deep is this onion?). Before I go down that rabbit hole I suppose I should measure the EVP voltage to make sure that isn't throwing the ECU off...

Well, jury is out for me to do another round of testing. First, I capped vacuum line that attaches to the EGR itself. The stumble at fast idle is still there, no question. After I tried each configuration a couple times, either I stopped noticing the difference, or the truck had gotten its way into a better state. I was never able to make it stall, so I suppose that is good. Also tried capping off the vacuum that goes into the solenoid to remove the EGR and solenoid both - again is seemed better but it is hard to say for sure. (Vacuum Source -> Solenoid -> EGR Vacuum Line -> EGR Vacuum Connector) I tried capping some other paths off, no improvement. I also hooked the vacuum gauge up to the EGR vacuum line, and verified there is only vacuum applied through the solenoid after the truck is warm, and you advance the throttle. I guess I should remove the EGR and check it on the bench etc, and make sure everything is clean, seats well (EGR fully closed?) etc.

I'll hopefully get to that tomorrow! In the meantime, I took a video to show the vacuum and you can see/hear the stumbling at fast idle. This isn't the main problem, but it may be adjacent. This video doesn't have the EGR disconnected (that's tomorrows job) https://drive.google.com/file/d/1MZygufOC7WSG52hxLHgggvVgT7gncPex/view?usp=sharing The audio is a little different in person, but hopefully this adds a little more color to what I'm trying to describe at fast idle. But, this item is secondary (but annoying). It's odd, but driving, this isn't noticed in performance, the tach, or in listening to the engine. Driving, it's all good, or when you kick the idle down.

Yep, sorry I didn’t phrase my question well. At all. It looks like the only vacuum going into the EGR is from the solenoid on the valve cover. The line is smaller that I thought it would be, but I’m no expert. I just wanted to ensure that was the only line. I’ve pulled that line, will cap it, and drive the truck again. Also regarding the vacuum test, should the vacuum reading be steady? Or reasonably steady? It was jumping about 2” on either side of the 20” reading while running.

Here is my vacuum diagram. It's always a joy to read, but looks like the only vacuum is to one of the solenoids mounted on the driver's side valve cover?

I just realized that I got it backwards! I just edited the text above. Vacuum dips on the miss, it doesn't increase. I have never seen a gauge where 0 is on the right hand side of the dial! But, now I have. (That's how I got confused, just looked at the big number and counted the small hash marks from there, in the wrong direction!)

Thanks, I'll dive into that this weekend. I guess I should just pull the EGR off in general and see if it moves freely etc. Or should I leave it in place, ensure it is closed, and plug its vacuum line first to see if things improve? I also disconnected the HVAC vacuum line that comes off the tree on the firewall. At fast idle, the vacuum is at around 22". At normal idle, about 20". The missing at fast idle causes the vacuum to dip to 20" when you hear a "blip" in the exhaust. Hopefully this is all related!

I've been running more tests before blocking vacuum things off. KOEO is still clean, but have Continuous code of 22 (can't seem to get rid of this one, replaced MAP sensor, line, and redid wiring)? Just ran the KOER. Got one code (35). Looks like I'm back to looking at the EGR... I replaced the EGR and its position sensor already a few years back. (But very little usage) I will start with backprobing the EGR sensor voltage I think. I need to run out for a bit, but any other insight? If the EGR is acting wonky, I *think* it could explain my symptoms

Brakes were just worked on and checked out, and they are working well. I think I really need to have a full vacuum check done. Now that you mention it, I’ve been hearing some noise coming from the HVAC system. When I turned the fan off, the noise went away. I assumed it was wind noise in the ducts. But maybe not? Maybe I can plus the hose under the hood to try and isolate it?

I don’t know, I’m under the impression it does strange stuff. And it sounds like you’re on top of things, so I was trying to think of something that wasn’t checked. First thing I do on this era of vehicles is check for vacuum leaks. And with what it’s doing, the accelerator pump. Bill was mentioning a hairline crack in a carb he had in another thread. Thanks Dane, I appreciate the ideas! Keep ‘em coming! You never know what could be related to changing one thing. A truck is a system of systems with dependencies, knock on effects etc. like all “good” or “fun” problems, it’s typically not one thing that goes wrong. (Like in aviation) I’ll add these to the list, and just go by process of elimination. Thanks again!

Thanks Gary for confirming vacuum as one path. Dane, in my limited knowledge, I thought the TV rod only affected the shift points. How would it cause this issue? (I am not arguing, I’m asking because I’m curious!) I did happen to buy a pressure gauge, because if I bumped the idle up more than 50 RPM, you have to check the trans pressure. So, add that to the list! Also I forgot to note, no codes in the ECU. Codes are clean in KOEO and Continuous. I haven’t done the KOER test yet.