dkmcgowan

So I did some additional work tonight. First... The OEM Mopar O2 sensor switched faster and the engine ran better than with the NTK, I believe the O2 sensor is now working perfect. I could watch in on the MT2500 and it seemed perfect. I was able to find a dealership that had two of them in stock, I bought both, I might look for another one to have just in case. There are not many left out there anywhere. Next, I did more tweaking with the butterfly stop. .003 is the official number I believe. You want to open the butterfly and set the gap between the butterfly and the throttle body to .003. It should move up and down and slide out with a little resistance, but pretty easily. The .004 you insert will also slide out, but it should have a good amount of resistance. If you place in .005, it should feel like you have to pull on it hard to get it out, it should definitely feel pinned against the throttle body completely. At this point you are at .003 and that is where I believe it is supposed to be. I verified on 2 other Comanches, so that's 3 of them now. Second, I believe by default, at least in 1989 Comanches, verified on 3 now, the air bleed should be tightened all the way in by default, so all the way tight or clockwise. My ECU wants to keep my idle at 600 RPM. I wish it was a little higher, but that is where it wants to keep it and it works. It doesn't matter if I'm in park, drive, A/C on, A/C off, breaking hard, or whatever, it will settle at 600 RPM. It will go up when you go into park, but then adjust itself, it will go down when you turn on the A/C, but adjust itself, the IAC is in control and wants 600 RPM. So here is what I learned. If you want to get the benefit from the IAC, you want it to be in control. If you want a higher idle, you can use the butterfly stop to "manually" set your idle. You need to re-adjust your TPS after adjustment, but you can set the idle like an old carb engine by using the butterfly stop. When you adjust to open the butterfly, you will reach a point where the IAC loses control and closes itself all the way and cannot lower the idle anymore, then you have taken over. If you do this, you will have a constant large RPM difference between park and drive, because the IAC cannot compensate. You will have an idle drop with A/C on because it cannot compensate, essentially if you open it up enough, the IAC will shut itself closed trying to max compensate by removing air, it will not be enough, and then it's no longer in control of the idle your butterfly stop screw is. That is not the correct setup. I was able to adjust the butterfly stop to completely closed while the engine was running and watch the IAC shrink and let more and more air in. I was then able to start opening the butterfly and watch the IAC push out and cut off more and more air to compensate. You start to lose the ability with a warm engine, for the IAC to compensate effectively, at about .005 gap from butterfly to throttle body. It also starts to lose the ability to keep the RPM high enough if you close it all the way. The .003 setting let's it adjust up and down as needed with enough room for compensation and keep my idle at 600 RPM no matter whats happening with the motor. Will see how it does on the way to work tomorrow, but I think I understand now how it all works.

Then I think my idle speed issues are solved now as well. It is idling well, cold, warm, drive, and park. So that's two main issues gone, cranking and idle speed. Now there is still a slight miss and roughness. I got in two oem mopar o2 sensors today, plan to try one tonight. I also did a seafoam this weekend in the intake. While it didn't really help, it did show an exhaust leak at downpipe, I put on a new donut seal and that seems to be fixed. I got another set of plugs I plan to install in case the old ones got worn out when I drove around for 3 weeks in open loop with a bad o2 sensor. More to come but knocking out things slowly I guess.

I think the correct number for the throttle butterfly is .003 - .004. I had a friend measure two Comanches he has and both were around .003. I set mine to .004 because it ran better there. I also have the air bleed all the way clockwise, both the other Comanches were this way. This can be used for some adjustments later. I go it so that the .003 will slide in and move easily back and forth, the .004 will slide in but it's difficult and it will move, but it's pretty tight. The .005 will not fit at all. So I imagine it's probably around .0035 give or take. This should be a good starting point. This puts my idle in 650 rpm in drive and around 750 in park. Do other peoples idle change between park and drive?

I found an exhaust leak on the downpipe today, where it mates with the exhaust manifold. I'm hoping it's just the donut gasket and that's all. So I went and picked up a new one today. First question, the computer at the store said the vehicle needs 2 of them, but I don't see how? I just picked up one because that is all they had, but I figured it would need 1 donut style and one for the cat side, which is a different gasket. Second question is how do you line this thing up? In the past there was usually metal on one side that slide into the manifold, then bevel piece would tighten into the downpipe, this one is just flat on one side, so it could slide around. I will be tackling it tomorrow and all my questions may get answered as soon as I take it apart.

I'm looking for those two nuts to hold the relay cover on, anyone have some or know of something to use to replace them?

So here is a video of what I have been doing to set the throttle stop and keep trying to adjust it. Right now it's at .005 with my feeler gauge. I also set the air bleed 1 full turn out, so I could have it as a future adjustment. When I adjust the air bleed screw, it now works and makes a difference. I'm not sure I have it setup right. The car runs best, if I can get idle to 700 rpm, in drive. When I do this, the idle in park is like 860-880, which isn't that bad. With an IAC is there still supposed to be a difference between park and drive or should it go up when you put it in park and the IAC should bring it back down? Also, now when I turn on the AC, the idle drops a little, not bad, but before it would raise the idle, like the IAC would kick in and raise the idle up when it detected the AC, now it drops, does it the idle going down with AC sound normal? The idle still shoots up when I crank the car, so I know the IAC can rev it if it wanted too. Here is the video, you will see my ST fuel trim when up as well as the o2 sensor doesn't show going all the way to 0.xx as much, maybe it's going faster? thoughts?

I will make a video tonight and post it later...

When I said gap I meant feeler gauge

I actually just got it to run pretty good. I decided to adjust the butterfly stop. When I first got the Comanche, it was pretty open. So I adjusted it pretty much all the way closed, I used my gap, and I got it to where there was resistance pulling out a .0015 gap. I just now adjusted it two more sizes up, so there is resistance pulling out a .003 gap now. It's the 3rd smallest on my gap tool. It's still like the size of a piece of paper, super small. I kept adjusting it, and fixing the the TPS to keep it at 17%, until I saw my ST fuel trim get close and stay around 128. With the little bit of extra air, the o2 seems to be switching faster between rich and lean, the idle in park is about 800 rpm and more steady, and the idle in drive is over 700 RPM and really steady, needle not moving at all, right on the second line. The miss is pretty much completely gone and the idle feels pretty smooth. I plan to drive tomorrow and see for sure. Not sure why the adjustment wasn't working on my air bleed, it should have accomplished the same thing and is the correct way to fine tune, it's still all the way closed, maybe it's clogged or something? It just needed some air. I'm feeling pretty good, will see for sure tomorrow in a real world drive. This still might mean something else is wrong, but it feels much better.

I will try that later tonight if I can get the wife to hold the pedal while I film, otherwise I will get her to help tomorrow. The idle really isn't that bad and never feels like it's going to die, maybe my car likes to idle at 600 rpm and that's fine. Maybe I've been tracking the wrong issue. Let's reset and help me with this description of the issue. What would cause the vehicle, when warmed up, at idle, to have a slight miss or stumble? Not that bad, but you can feel it, and at times it can make it when your holding the steering wheel you can feel the vibrations. This stumble is not really there at all when the vehicle is cold and in open loop. The stumble is not there during accleration or at higher RPM's at all. There is no hesitation or lack of power at all. It also stumbles less with a bad o2 sensor when warm, one that is stuck in open loop, so running rich, which you can smell, but it's stumbling less. I have proper indexing on distributor, new cap, new rotor, proper gap on new ntk plugs, new wires, cleaned all electrical connections, all new relays on the passenger side, cleaned ignition coil connections, and fuel pressure seems good, about 3 psi low, but that could be the gauge. should I try a new ignition coil?

here you go, what do you think?

I did the vacuum gauge test, it seemed fine, I posted a video earlier, will try to find it and get it on you tube as well. It was around 17 hg, took it to 2k rpms, let it settle and it seemed to do what it was supposed to. I ran some bg44k through the system, then went ahead and got new cleaned up 746 injectors. I adjusted idle screw in half turn increments, all the way to 4 turns or almost all the way out. The IAC adjusts for it and idle still rough. I did pull the ccv off the manifold, let it just suck in air then my idle goes up to maybe 750-800. It runs so much better in open loop when you first start it for those few seconds. I was thinking about messing with butterfly stop to see if I could raise idle temporarily since idle bleed doesnt, I know I shouldnt. Not sure what the signs are telling us.

I backed it off just a little, it's the same... It might actually be idling lower and running a little rougher set at 17% as opposed to the 14% before. I'm out of ideas now... I'm going to try and track down an OEM NOS O2 sensor, and order a intake/exhaust manifold gasket and replace that. I'm considering just rebuilding the head or at least having it checked out while I have intake and exhaust manifold off. I also considered a last ditch use of seafoam to see if something is clogged or not seating.

I adjusted the TPS and made a new video The numbers changed slightly. I'm at a perfect 17 not on throttle position. It seemed to be idling slightly higher. I tried to increase idle with idle bleed screw, if I adjust it out, the idle goes up, then the IAC or something compensates and tries to keep it at 600 rpm. So I left it screwed all the way in like it was when I popped the cover protector off of it. When I drive it might be a little less rough now and smoother. The idle is a little lower actually when driving and at a stop light, it's down closer to the first mark, maybe 550 rpm, in drive, with foot on the brake. So adjusting TPS made it smoother but maybe idle even a little lower. I just keep reading about people having idle around 750 and that's where it should be, and it seems like that would feel great, but not sure how to get it there. Thoughts?

I will adjust tps tonight and play with air bleed screw, it's all the way in. What about fuel trims and other numbers, map manifold, etc..? Any other indicators of what might be causing rough low idle? Brand new o2 sensor, ntk and new relay with voltage at the sensor when car running, anything else that can cause o2 to switch slow?

I just uploaded it to youtube, maybe it will work there so you can see the fluctuations. Try this link https://youtu.be/9VDnASuCys0 Here are the numbers though. RPM = 590 (fluctuates from 560 - 612) O2 (V) = 0 - 4.9 (fluctuating every second) ING (mS) = 4.9 Loop Status = CLSD Exhaust = Lean/Rich (every second rotates) ST Fuel Trim = 100 (fluctuates from 90 - 110) LT Fuel Trim = 130 (doesn't move) Map SNSR (V) = 1.7 (goes up to 1.9) Map (Hg) = 12.8 Man Vac (Hg) = 16.8 (goes up to 17) Baro Pres (Hg) = 29.8 TPS (v) = 0.72 (adjusted the auto way not manual, manual would put it 0.82, tried that ran about the exact same) Throttle (%) = 14 Throttle SW = CLSD Fuel Sync = rotates between - and + Coolant (F) = 195 Charge Temp (F) = 125 Spark Adv (BTC) = 15 (rotates 13-15) Knock = 0 A/C Switch = Off A/C Request = No EGR = Off Battery = 13.9

Thats working, how do the other numbers look in my second video?

It looks like the RPM's drop every time the o2 voltage goes down, then the o2 voltgage goes back up and the rpm's go back up... I assume that's why it ran better with a broken o2 sensor that was stuck at 4.98, it was at least more steady... I'm leaving the good o2 sensor in there, just need help on what to try next? Replace exhaust/intake manifold gasket? Rebuild the head because a valve is not seating or something? Compression was good, but didn't do a leak down test, only compression test.

With some additional research it looks like 118 - 125 on the MAT/IAT might be correct, so I plugged it back in.

I took out the MAT sensor and cleaned it, put it back in. When I crank, the MAT sensor shows 118 and just stays there, the coolant temperature goes up to 210, settles back down around 206 or so, but the MAT is just staying at 118. It did in the previous video go up to 125 and then 127. What is the normal temperature of the intake at operating temperature? I then unplugged it, the car still runs, maybe a little better, and it shows on the MT2500 247, which I assume is the max value, but probably just runs the same. Not even sure if it's the issue or not, just assumed it would be closer to the CTS temperature, but maybe not, maybe 118 is accurate.

So I did some more research. The o2 sensor being stuck at 4.98 and not moving meant it was dead. So we have an answer to the question about the original o2 sensor, it was not working. So I put the new NTK into the car, warmed it up, and took another video. The car did run better with a bad o2 sensor, stuck in open loop, not sure why. My "charge temp" is only 125 when the vehicle is fully warmed up, not sure if maybe that is the problem? Here is the latest video. https://photos.google.com/photo/AF1QipNQyb3mc66XAFMNI5uvqivjVTXi6NZ7WpvKv139

Reading through the manual it looks like my o2 reading is way high and should be closer to 2.5v, meaning it's lean... The man vac seems good at 59, or 17 Hg give or take, but the map vac is lower, not sure if that's normal... I always thought you got lower vacuum readings when leaking, but these seem normal. I'm thinking I have a vacuum leak somewhere, all the hoses are new, new injectors and o-rings, and I've tightened the exhaust and intake manifold bolts to spec, but it must be leaking somewhere on the intake and exhaust manifold, or somewhere inside, but my compression test was good. Any other insights will be helpful...

I got the MT2500 in the mail today and hooked it up. The vehicle had been driven home and was pretty warmed up. I let it sit long enough to unpack the box, figuring it out, and get it connected. It worked! So I made a video of all the readouts while they were happening, it was easier than typing them all out. I'm not sure how to read it all. It says the exhaust was lean, and I'm running with the air bleed screwed all the way in, so that implies a vacuum leak maybe, only thing left would be exhaust/intake gasket, replaced everything else. The o2 voltage isn't fluctuating like I though it would. I currently have the used OEM sensor in there not the NTK. So here is the video, let me know what you learn from it! https://photos.google.com/photo/AF1QipM9hLrBNavPSpk3zMdCFsJXVWlQxgU1WwAENptC

I see multiple people saying they use the jeep-1 adapter with success on naxja.org and jeepforum.com

What's the adapter look like or do you know model? Need to try and find one on ebay. I hope it has the correct cartridges.