PonchoCatalina Posted January 11, 2007 Share Posted January 11, 2007 I have gotten a lot of help from the folks on the board here, and it has allowed me to make progress on my 91 Loyale, but I still can't get it to idle. I was getting a code 23 and 24 (MAF and IAC), but I've gotten both to clear (check engine light is off, O2 light blinking five short, happy flashes). The IAC problem was a bad wire in the manifold harness, and the MAF issue seems to have been a bad connection at the plug. I did briefly, after getting the other two codes resolved, get a code 21 (Coolant Temp Sensor), but I cleaned the contacts and that is now gone as well. Now for my problem: the car will not idle. When started it revs up to 1800-2000 RPM, then nosedives until it dies. Sometimes it struggles for a few seconds at 100-300 RPM before dying, sometimes (more often) it just dies immediately. I have cleaned the IAC and tested the solenoid - it seems to operate fully. The other piece of the puzzle: when I disconnect the MAF, it starts right up and idles at about 1100-1200 RPM in "limp home mode." Of course, then the check engine comes on and ECU throws code 23. When I reconnect the MAF, I'm right back to the rev and die cycle. Sorry for the long post, but this thing is driving me nuts - what else can I try? Thanks! Link to comment Share on other sites More sharing options...
silverhelme Posted January 11, 2007 Share Posted January 11, 2007 You are still having problems with the MAF. I had the same problem with one of my 88s. I found that there was a broken wire IN the MAF and had to replace it. It has run and idled almost perfect since. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted January 11, 2007 Share Posted January 11, 2007 #1 have you CLEANED the IAC and hoses? They get caked up with carbon and won't allow the needed air to flow. #2 Does it change once it's warmed up? If so I would say you have a fualty CTS that's reading hot when it's cold. #3 you may have to adjust the IAC air screw to bring the idle up to normal, but don't touch it till you are sure you have to, or unless you have already been mucking with it, or somone else has. #4 NEVER, EVER, under any circumstances touch the throttle body stop screw. Just telling you so you know. It's not for adjusting, it's only there to keep the throttle plate from jamming in the bore when it's closed. It should have a white paint mark on it from the factory, and is NEVER to be touched. The FSM doesn't even have a procedure for setting it should you accidentally change it. GD Link to comment Share on other sites More sharing options...
PonchoCatalina Posted January 11, 2007 Author Share Posted January 11, 2007 #1 have you CLEANED the IAC and hoses? They get caked up with carbon and won't allow the needed air to flow. #2 Does it change once it's warmed up? If so I would say you have a fualty CTS that's reading hot when it's cold. #3 you may have to adjust the IAC air screw to bring the idle up to normal, but don't touch it till you are sure you have to, or unless you have already been mucking with it, or somone else has. #4 NEVER, EVER, under any circumstances touch the throttle body stop screw. Just telling you so you know. It's not for adjusting, it's only there to keep the throttle plate from jamming in the bore when it's closed. It should have a white paint mark on it from the factory, and is NEVER to be touched. The FSM doesn't even have a procedure for setting it should you accidentally change it. GD Thanks, GD. Here goes: #1 - Yep - removed the IAC, removed the solenoid, cleaned everything up, seems to move freely. #2 - Temperature doesn't seem to matter. This evening I let it run up to operating temperature in "limp home mode", plugged in the MAF, same problem with warm engine as cold (which to me helps rule out IAC and CTS). #3 - I haven't messed with the IAC air screw. Someone else may have - this vehicle has been in "limp home mode" since I got it. #4 - See #3. I hope no one else messed with it. The car did get a new MAF at Pep Boys just before I got it...of course they missed the fact that all of the radiator contents were in the oil pan, so there's no telling what they screwed up! Link to comment Share on other sites More sharing options...
azsubaru Posted January 11, 2007 Share Posted January 11, 2007 [quote name=GeneralDisorder #4 NEVER, EVER, under any circumstances touch the throttle body stop screw. GD[/quote] a slight highjack, with apologies - why is it that you shouldn't touch it - what happens? and how do you set idle speed without adjusting that screw? Link to comment Share on other sites More sharing options...
daeron Posted January 11, 2007 Share Posted January 11, 2007 NEVER, EVER, under any circumstances touch the throttle body stop screw. Just telling you so you know. It's not for adjusting, it's only there to keep the throttle plate from jamming in the bore when it's closed. It should have a white paint mark on it from the factory, and is NEVER to be touched. The FSM doesn't even have a procedure for setting it should you accidentally change it. GD This is a screw that impedes the motion of the throttle.. in other words, its the little screw at the end of the bit on your TB that the cable attaches to.. you know, the part you grab and rotate to rev the engine when youre under the hood? there is a screw that limits how far you can push that thing open. this is not any sort of idle adjustment. I went ahead and quoted GD's entire statement on the matter, just to be perfectly clear. re read what he said, and then think about what you are trying to adjust.. you probably are not thinking about the right screw. Link to comment Share on other sites More sharing options...
mikeshoup Posted January 11, 2007 Share Posted January 11, 2007 This is a screw that impedes the motion of the throttle.. in other words, its the little screw at the end of the bit on your TB that the cable attaches to.. you know, the part you grab and rotate to rev the engine when youre under the hood? there is a screw that limits how far you can push that thing open. The TB has a little block cast into it that keeps the plate from opening past 90degrees. The stop screw is to keep the plate from closing too far. The stop screw should not ever be touched. Idle problems shouldn't ever need the stop screw adjusted. Link to comment Share on other sites More sharing options...
daeron Posted January 11, 2007 Share Posted January 11, 2007 Re reading all that, I kinda sounded a little condescending. It was unintentional, I was trying to illustrate with words. Thanks for the photo, mike. Link to comment Share on other sites More sharing options...
Prospeeder Posted January 11, 2007 Share Posted January 11, 2007 You know my car would do somewhat the same thing randomly, i knwo different fueling system, and turbo, but it would idle great then just slowly nosedive till it stalled out, somtimes tried to hang to life but just died, although it would start back up for me and idle fine. Hasnt dont it since i replace the intake manifold gaskets Link to comment Share on other sites More sharing options...
PonchoCatalina Posted January 13, 2007 Author Share Posted January 13, 2007 It's fixed!! I thought I'd share my findings in case anyone else has similar problems and is searching for answers. First, the back story: I bought this 91 Loyale back in September only to discover it had water in the oil. Naturally I assumed head gaskets were the culprit, but in fact it turned out to be a popped freeze plug. I replaced the head gaskets anyway, had the heads rebuilt at my local machine shop (cleaned, milled, new freeze plugs, valve job, etc.) and put it all back together. After everything was reassembled, it ran, but poorly: the exhaust smelled of gasoline, it would stall if you revved it, and the green diagnostic connectors would prevent the engine from starting if connected. Also, I was getting two trouble codes: MAF and IAC. First I fixed the IAC by replacing the solenoid (old one was dead), cleaning the valve, and running a new white wire from the valve to the body harness. After fixing that, the car would not run with the MAF connected - it would rev to about 2K rpm then die - but the MAF trouble code cleared. When the MAF was disconnected it ran (poorly) in "limp home mode." All the measurements (volts, ohms) were within spec at the MAF and it was brand new just before I bought the car, so I began to suspect the ECU. Just for the heck of it, though, I installed a junkyard MAF and it fixed my problems. Now the car fires up, runs, doesn't stink of raw gas, and even runs in D-check mode. It turns out that when she started belching milkshake out the PCV lines some months ago (since all coolant was going straight to the oil pan through the freeze plug port), some of the oily goo backed up into the air intake plenum and fouled the MAF (the sensor looks fine, it's clean, and the little wires are intact, but when I removed it and laid it on it's side, "latte" started weeping out the bypass port). So, until I encounter something new, the Loyale is finally operational. Thanks to all for the help I've gotten along the way! Link to comment Share on other sites More sharing options...
samneric Posted January 13, 2007 Share Posted January 13, 2007 It's fixed!! Thanks to all for the help I've gotten along the way! I like stories with happy endings Steve Link to comment Share on other sites More sharing options...
Petersubaru Posted January 13, 2007 Share Posted January 13, 2007 Thanks for sharing your FIXED solution...you never know what you can get into when buying used..always full of surprises Link to comment Share on other sites More sharing options...
azsubaru Posted January 13, 2007 Share Posted January 13, 2007 This is a screw that impedes the motion of the throttle.. in other words, its the little screw at the end of the bit on your TB that the cable attaches to.. you know, the part you grab and rotate to rev the engine when youre under the hood? there is a screw that limits how far you can push that thing open. this is not any sort of idle adjustment. I went ahead and quoted GD's entire statement on the matter, just to be perfectly clear. re read what he said, and then think about what you are trying to adjust.. you probably are not thinking about the right screw. (nooffense taken) I knew which one GD meant, but on a carbed car, that's probably the very screw I would think you would use for idle adjustment. Another lesson from the board! I've never touched either of them on my car, but after all these years of mechanics of unknown qualifications working on it, who knows? So, what would be a likely result of the wrong screw being adjusted? something really bad? Link to comment Share on other sites More sharing options...
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