Sid51x Posted October 11 Share Posted October 11 Gents, I know a few of you are gonna shake your head in disbelief, but this rig is the first one I've had with a carb (if you don’t count a motorcycle about 15 years ago). In my research, it happens to be one of the more simple ones, but has the added "benefit" [complexity] of the feedback system. As far as I can tell, that system is still in, and functioning, so for the time being I am going to stick with it. TLDR; I have only a basic understanding of what I should be doing, I am a little lost spatially, and the stuff I’m reading is assuming that everything is 100% stock, or is from non-feedback systems. Any help would be appreciated. As I've been taking out large chunks of the to-do list, I finally got my hands on a timing light and checked timing as everything just felt sluggish, and there was just no power at all. Finding that base timing was set to ~6 degrees ATDC, instead of the prescribed 10 BTDC leads me to believe that the last guy in there set the timing with the sprout (?) connector connected, which advances the timing a deal, and then set idle to 'that'. Now that I have the base timing up where it is supposed to be, the i6 starts up very quickly, and runs great, but is idling at what I would consider too high (no Tach to verify, will check with one I’m picking up today). It sounds like it is up over 1k RPMs, and now 1st gear is just not an option without what I would consider force. With all of that context out of the way. I've read the notes here, I have read what I can find in the service manuals from 84', the Haynes manual, and every forum post I can find here, and over on FTE. Unfortunately, what I keep running into is a nomenclature divide, "Adjust <insert completely foreign term here>" or it has statements of “This is set from the factory.” To add additional headache, most of the posts and videos I've run into are for the non-feedback units, so I do not know how much cross over there is. I'll get pictures up this afternoon when I’m digging around get some bearings to work with, but if someone can explain this to me like I'm a particularly bright 5 or 6 year old, I'd be very grateful. I will have a multi-meter with an RPM reading, a timing light with an advance dial (Harbor Freight), a vacuum gauge (Harbor Freight), and your standard tool assortment at my disposal. I’ve attached the excerpt from the FSM, and my emissions label, stating that it should be running in the 1.5k range after a handshake, and that completing this will drop it, but considering it is currently running up there, I have my doubts ‘that’ portion of the feedback system is still functioning. Link to comment Share on other sites More sharing options...
Sid51x Posted October 12 Author Share Posted October 12 (edited) Update, I dove in. I found 3 adjustment locations, and ignored the feedback procedure for the time being. I started with the one to the lower right of the tag in that tube. Tightened until I felt resistance, and brought it to 1.5 turns open (the common adjustment starting point I see mentioned a lot). This did basically nothing to the idle. Coming to the driver side, I found these two screws beneath the choke (lower right hand) one was all the way tight (left), so I started with that one. As I backed it out, RPMs dropped from the 1.5-1.7k to ~700 in quick order. Hot starts are consistent here, and it will settle between 640 and 700. (This swing might be the multi meter I'm using). I'll verify timing at this RPM, and I'll try a cold start tomorrow. Edit: Looking through the literature some more, the screw on the driver side (LH) that I adjusted is the curb idle screw, and the one on the passenger side (RH) is the fuel air adjustment screw, which originally would have been under a protective cover. Based on the reading I've done, I should eventually get around to adjusting 'that' with the vacuum gauge to get it into a reasonable range. Edited Saturday at 03:29 AM by Sid51x Clarification Link to comment Share on other sites More sharing options...
Sid51x Posted October 12 Author Share Posted October 12 Timing needed a tweak, just a degree. Did a road test. Have first gear again, and still plenty of power up through 70 mph. Cold start tomorrow, should be about 25°F by me. And we'll see how that idle does. So, this all being said.. I still don't know the nomenclature here, so I don't actually know what I've done. Link to comment Share on other sites More sharing options...
85lebaront2 Posted October 12 Share Posted October 12 Sounds like you have it pretty close. They can be a royal pain to set. The Idle speed actuator should go in or out to hold the speed where it is needed. Link to comment Share on other sites More sharing options...
Sid51x Posted October 12 Author Share Posted October 12 3 minutes ago, 85lebaront2 said: The Idle speed actuator should go in or out to hold the speed where it is needed. And, now that makes sense to me, and why there is that specific tuning that starts with unhooking the coolant temp sensor. I'll keep an eye on it the next time I'm futzing with it to see if I can catch it moving. Link to comment Share on other sites More sharing options...
85lebaront2 Posted October 12 Share Posted October 12 Unplugging the CTS apparently is to put the system in a "limp" mode so the computer isn't trying to adjust things while you are trying to set everything. Link to comment Share on other sites More sharing options...
Sid51x Posted Saturday at 04:20 PM Author Share Posted Saturday at 04:20 PM (edited) Digging further into the literature, there appears to be a propane enrichment function to set the fuel air mixture screw. Anyone have any idea where I can find this chart that is referenced? Scrolling through the FSMs I have I cannot seem to find it. (3rd Image) Edit: Digging further, This should be a TSB "Special Specifications" which may be TSB 84-1A. Edited Saturday at 04:53 PM by Sid51x Clarification Link to comment Share on other sites More sharing options...
ratdude747 Posted Saturday at 05:08 PM Share Posted Saturday at 05:08 PM Good luck setting the idle screw... I winged the adjustment on mine since I didn't have the tooling to set it "Correctly"- pretty sure I put it on the intial setting (1.5 turns out??? I can't remember). To some degree the feedback will compensate for an off adjustment... Hence why I don't lose that much sleep on it. Link to comment Share on other sites More sharing options...
Sid51x Posted Saturday at 05:14 PM Author Share Posted Saturday at 05:14 PM Fair enough, I found a hardcopy of the specification on eBay. I'll pick it up and see about getting it scanned for reference. But the overall procedure doesn't seem too bad. Warm up, unhook the idle speed controller, add propane, until the RPMs stop rising, adjust until the rise is in range. it's just finding 'that' range.. Link to comment Share on other sites More sharing options...
ratdude747 Posted 7 hours ago Share Posted 7 hours ago On 10/12/2024 at 1:14 PM, Sid51x said: Fair enough, I found a hardcopy of the specification on eBay. I'll pick it up and see about getting it scanned for reference. But the overall procedure doesn't seem too bad. Warm up, unhook the idle speed controller, add propane, until the RPMs stop rising, adjust until the rise is in range. it's just finding 'that' range.. Missed this. I'm pretty sure it also calls for reconfiguring the thermactor (smog pump) controls as well. Good luck... let us know how it goes. Link to comment Share on other sites More sharing options...
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