Gary Lewis

Ok, I'll drive it a few times tomorrow. Maybe it'll dial itself in. But I won't tweak it any more for a while as my grandtwins arrive tomorrow night and will be with us for about 10 days, so there won't be much work done on the truck during that time.

Someone on here bought an MC with that valve on it from the parts store, and it wasn't terribly expensive. But I'd head to a salvage and put a used one on before going with the old-style MC. I say that because I don't like bleeding systems, especially with the old-style MC's. So I'd rather put a used one on and bleed once rather than having to bleed twice. And since I have a cap for placing pressure on the new-style MC's, bleeding them is MUCH easier.

Do some searching on here as others have done the swap and have the name and part numbers for that valve/connector. And some have bought the master cylinder with that valve. Direct swap.

Yes, with the exception that you need the residual pressure valve - at least that's what I think it is called. It adapts the threads in the master cylinder to your brake line. And you have to reverse the lines, which is really easy.

That is really, REALLY nice! Let's preserve those pics:

If it was me I'd go with the later model master that has an aluminum body, plastic reservoir, and a single cap that doesn't leak.

Well, he may tell me the same thing as I just emailed the triumvirate asking what I'm doing wrong. And yes, if I pulled Fuse 9 it would make it easier, so thanks. That way the radio wouldn't lose its time setting. As for the AFR, does the ECU figure it out out after several drive cycles? So I shouldn't start changing things? I think we are "there" on the idle, and here's the proof. This is a 41 second snippet of the end of the datalog of a 20 minute drive, so the engine was good and warm. The yellow line is Desired RPM, and under it is Actual RPM in green - take my word for it. The purple line is the Idle Speed Control Duty Cycle. Where it drops for several seconds is when I turned the A/C off, and then where it goes back up is where I turned the A/C back on. Basically the RPM does not vary when that happens, and you certainly cannot tell when the compressor comes on or goes off. I love it!

Thanks, John. It was a really good feeling, especially today. But I'm not quite sure I know what is going on as I went back two steps in tunes and wrote one in that had the proper parameters in for both the dashpot as well as lower limit to go into RPM Control. And when I fired it up the closed-throttle flag wasn't set. So I pulled power for 10 minutes and then fired it up again and then the closed-throttle flag was set and it ran well - save for going quite lean just before going into closed-loop. So something isn't working right when I write a new tune in. Binary Editor says it is resetting the ECU but that doesn't appear to be happening. So maybe I'll have to do it manually? Anyway, we need to run to Owasso so are going to take Big Blue for that run and we'll find out how well it does.

Yippee!!!!!!!!!!!!!!!!!! It WORKS! I had a thought last night the maybe I just needed to pull the battery cable for a bit and let the computer forget something. For instance, Decipha's writeup says that if you ever open the idle stop screw up that you'll have to pull the TPS connector, start the engine, shut it down, and reconnect. I'd done that but it didn't do the trick, so maybe pulling the battery cable would do it? IT DID! In the log below of the startup from cold there are several things to note: RPM vs Desired RPM: Look at the green line, which is RPM, vs the yellow line, which is Desired RPM. Save for the start and then right at the end it tracks perfectly! And while at the start the actual is a bit below desired, it is much better than the 1400ish it has been going to on a cold start. And the bit at the end where actual goes below desired is right after the throttle blips I did and is surely due to having the dashpot disabled. AFR: The blue line is the actual AFR and just before the vertical red line it is running about 18 - 19:1. But that red line is Fuel Source and when it goes to 0 the system goes into closed-loop mode. At that point the AFR goes into the high 14's and stays there. ECT: The red trace that goes up to the right is Engine Coolant Temp, which starts at 82F, climbs to 185F where the thermostat opens, and then drops to 178 at the end. But across all of that change the RPM is pretty much holding right where it is supposed to. So now I need to put some parameters back that I've taken out, like the dashpot, and then start it up again and see if that sorts out some of the issues. But the lean bit before going closed-loop shouldn't be part of that so it'll take a bit more research.

Bill - I think there is yet another way. That mask I found has a bit for Purge, so it could be turned off and the MIL wouldn't light even if there was a code for Purge. But your way is the better way. However, I'm confused. Your system is vented as well as having vapor canisters? How does the vapor get to the canister instead of going to the atmosphere? Mine is just vented, right at the rear of the cab. And when a tank is full and you've driven the truck the heat from the exhaust causes some fumes to come out. I dropped Janey off at Walmart recently and when she got out she said "It smells like gas out here." Yep, and I knew why.

Nice clean truck. Says it is a CA truck and a 351W, so it should be the EEC-V system with MAF & SEFI. And it appears to have the E4OD. So the combo should have good power and get decent MPG.

If you adjusted the rear brakes after filling the master then that could account for the master overflowing. When you adjust the shoes out the pistons come in, displacing fluid back into the master. So maybe there isn't a problem? With the pedal going down a bit when you start the engine is sounds like at least the booster is working. And save for the spill from removing the cover everything looks dry.

Well, I missed something when I looked at the logs earlier. And remember, Throttle Position Relative (TP_REL) = Throttle Position (TP) - Throttle Position Ratched Min Voltage (RATCH). These are the readings at idle, and the "0504....../...." is the date and the time stamp: 05042022/10-21-52: TP = 1.1 & TP_REL = .03 05072022/13-12-14: TP = 1.08 & TP_REL = .8 And today's log has TP = 1.1 and TP_REL = .8. So RATCH changed dramatically from 1.07 to .3 between May 4th, when the ISCFLG was getting set to -1 for RPM Control and May 7th when it wasn't. So maybe it isn't another parameter I changed but something to do with not clearing RATCH? Might this be mechanical, like the throttle not returning?

Thanks, Bill. I'll give it a try tomorrow and let you know. As for the vent, I do smell gas at times from Big Blue. But I don't don't want the complexity, although I can see that where you live the humidity mixes all too well with the ethanol.

Well, it depends on your definition of "bullet". In RED Bruce Willis throws a bunch of rounds, which some call bullets, in a frying pan and turned on the burner. And they smoked a bit until they went off. So in that sense a smoking bullet isn't good. As for the differences between tunes where closed throttle works and tunes where it doesn't, I don't have a good answer. And that is because I didn't keep good enough records. I have a tune file called "05042022 Misfire Dashpot for MPH and Idle Changes" and I have several log files with that name plus a time stamp, and they all have a working APT, meaning it goes to -1 for Closed Throttle. But it looks like there were changes made to the original tune file without saving it under another name. And then there's the tune file called "05072022 Manifold to 3 and Idle Change plus 96", and none of the log files with that name and a time stamp have a working APT. So, I think what I need to do is to write the 05042022 file into the ECU, fire it up, and see if the APT goes to -1. If so then I can write the 05072022 file in, fire it up, and see if it doesn't work. If so, then the problem is either Intake Manifold Size in Liters, which I set to 3, or Idle Air Adder for ECT, which has two of the temps set to +96 RPM. But, if the 05042022 file doesn't "work" then I'll have to back up file by file until I find one that does work and then find the differences. Does that make sense? However,

I'm using the BBK throttle body. But these EEC-V's don't exactly use the startup TPS voltage as closed throttle. There's a function that BE calls RATCH that captures that startup voltage and then TP_REL is calculated by subtracting RATCH from TP. And the ECU then uses TP_REL. I've gone through Decipha's instructions on checking to see that the TPS is working and it is. It is within the min and max voltages that are allowed, and it is varying. But APT never goes to -1 indicating closed throttle. However, I had the thought that maybe it has never gone into closed throttle so went back in the logs. Sure enough, a month ago it was working! On May 6 at 10:21 I logged a run that had it working fine and the idle speed was close to "desired". But on May 7 the first log never went to closed throttle, and I'm pretty sure that no log has since, although I've just spot-checked several logs. So now I'm trying to figure out what changed. Unfortunately I didn't save a tune file each time I made a change, so there are a lot of changes in there that I'll have to work my way through. But the good news is that I have found a speeding bullet. Now I need to find the smoking gun. (Is that a mixed metaphor? )

The shop manual shows how to test the booster by pumping the brakes several times with the engine off the drain the vacuum reservoir. Then stand on the brake and it should be hard. But when you start the truck the pedal should go down some as the booster helps you. So if you do that and the brakes aren't hard with the engine off you'll know you have a problem that doesn't include the booster.

Mid-day report. I did two things this morn: 1. I set Lower Limit To Enter Dashpot RPM Control to 1.4 lbs/min. 2. I asked a question regarding this on Decipha's forum. Then I took it for a drive and did some data logging. And when it was warm and at idle the ISCFLG was still at 0, meaning it was in dashpot prepositioning, not RPM Control. And the idle was still too high. But by then Decipha had responded with "if your stuck in dashpot then your either not setting the closed throttle flag or you did something to prevent dashpot from decaying out." Sure enough, the parameter of APT was at 0 at idle, and APT is "Throttle Status" with a -1 signaling closed throttle, 0 meaning part throttle, and 1 = WOT. And APT did got to 1 when I ran it up through the gears, so I know it is connected. I'm not going into "closed throttle" mode! Now to figure out why that is...

You don't really need to check. The stator connection gives the same voltage regardless of whether you have a 1G, 2G, or 3G alternator. You can see the choke heater in the bottom center of the schematic below. And 5 psi is adequate. Most carbs are happy with 5 to 7, but Edelbrocks or Carters don't really like more than 6, so I usually set my regulator to about 5 and I've never run out of fuel due to low pressure.

It won't hurt to bleed the front brakes, but as it is separate in the system I don't think it will matter. But I do think it is time for a new master cylinder. I've included my own screen shot of that same Rock Auto page and included both the year/model info as well as all of the options. And personally I'd go ACDelco unit at about half the price of that Dynamic Friction unit. Just because the others don't say "4WD" they are. Looking at the info on this site (Documentation/Driveline/Brakes) I see that an '86 takes the same master cylinder whether it is a 2wd or 4wd.

John/Machspeed has the stickers, so I tagged him in this.

Glad you got them working, Larry. And I hope you are feeling better. Did you have the master off? The push rod to it is adjustable.

I don't think so Bill as it idles pretty well. About 17" of vacuum. The flag to go into computer control of the idle RPM isn't getting set, so the computer isn't bringing the idle down to the "desired" RPM of 648 that I've set. And it has plenty of room to do so as the ISC is running at about 35% for that 800 RPM idle, so it would be easy to drop the duty cycle and bring the R's down. I'm doing a lot of reading trying to figure out what the issue is. And I keep going around in circles. Decipha's writeup on adjusting the idle doesn't talk about that flag, which surprises me. But it does talk about a number of functions that I'm slowly mapping my way through. Anyway, I'm hoping to understand what sets the flag and then discover what I need to do to get the computer controlling the idle. And since I now have the mass airflow at idle down to 1.2ish I might set the lower limit to 1.4 again and see if that will do it. Somehow when I set it to 1.4 before the airflow had gone to between 1.4 and 1.5 so it never set.

Today I changed Dashpot Preposition to 0 @ all RPMs and one more culprit has been exonerated. In truth, the air mass value going through the MAF sensor went down from 1.4+ to 1.2+, so maybe if I set the Lower Limit to Enter Dashpot RPM Control back to 1.4 we'd go into RPM control. But even if that worked it would be masking the problem as the factory setting for this tune is .4 and Bill's is at .12. And the Idle Speed Control duty cycle is running at about 35%, so something is calling for more air which is causing the duty cycle to go up and, therefore, the air mass to be too high. The quest is still on...