misledxcracker Posted March 31, 2007 Share Posted March 31, 2007 alright im sure most of you know my car by now, if you dont, it's an '86 SPFI, non-turbo. oh yeah BTW i tried searching... nothing seemed to fit my specific "problem" I've been having an idle problem... Go out in the morning to start the car, idles... wherever it wants. anywhere from 300rpm to 3000rpm. drive car some, idle fluctuates from 300rpm to 1000rpm, never goes high while driving, having the AC on does affect it at times, makes it drop. the car NEVER stalls, even sitting at 300rpm for 10 minutes wont kill it stop car, put 'er in Park, idle goes to 1500rpm instantly, cold or warm oh yeah, and it has the shakes really bad... i'm used to that though what are some common causes of this problem... i'll start replacing stuff now, money's finally coming in EDIT: ALSO... the secondary fan is ALWAYS on.... even with the car shut off and the key in the "ON" position... Link to comment Share on other sites More sharing options...
hooziewhatsit Posted March 31, 2007 Share Posted March 31, 2007 First thought is a gummed up idle air control valve ("IAC " with space if you want to search for it). -Dave Link to comment Share on other sites More sharing options...
daeron Posted March 31, 2007 Share Posted March 31, 2007 Run a D-check again.. You already checked the Idle Air Controller, right? If not, its the little cylinder mounted horizontally on the front of the throttle body. You would probably benefit from picking up a cheapo fuel pressure gauge and mounting it under the hood to make sure your FP is adequate.. I think I am nearing that point as well. With a carbed car, its easy enough.. if the pump is on and pumping some fuel up there, its probably good enough. FI *needs* that high pressure, at a very RIGIDLY pre determined pressure level, to function right. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted March 31, 2007 Share Posted March 31, 2007 D-Check. GD Link to comment Share on other sites More sharing options...
misledxcracker Posted March 31, 2007 Author Share Posted March 31, 2007 I ran a D-Check... and nothing. I've cleaned out the IAC twice already, if I have to, I'll get another one at the junkyard... Link to comment Share on other sites More sharing options...
GeneralDisorder Posted March 31, 2007 Share Posted March 31, 2007 Did you follow the procedure - holding the pedal down, return to half throttle for 2 second, and then start and drive for at least 1 minute? Then after you have driven it, let it idle for a while and see if it pulls a code. GD Link to comment Share on other sites More sharing options...
misledxcracker Posted March 31, 2007 Author Share Posted March 31, 2007 ran d-check correctly, got VSS and TPS codes cleared codes, now i only get VSS... my speedo cable is making noise daeron suggested making grounds... i'm going to do that tomorrow Link to comment Share on other sites More sharing options...
GeneralDisorder Posted March 31, 2007 Share Posted March 31, 2007 Probably an intermittant TPS issue then. I would test it. GD Link to comment Share on other sites More sharing options...
daeron Posted March 31, 2007 Share Posted March 31, 2007 he has gone through a great deal of testing and swapping with TPS units, he has tested the wires from the TPS connector to the ECU harness, Im pretty sure he has tested proper resistance values directly at the CPU... he says he has wiggled the wires all sorts of ways while the engine was idling low, he also had a problem with one TPS lsoing the idle contact when fully screwed in. He mentioned to me that he currently has his negative battery cable connected to a chassis ground, and no engine to chassis ground beyond that. I told him to ground the engine to the chassis battery ground point. That is what he is doing next, at least... I am stumped on how to help him further. If you say he needs to do what you say to get into D check mode, then he needs to do it; I've never done more than run it uver the RPMS for the prescribed time in my driveway. are the different ECUs slightly different in that regard?? Link to comment Share on other sites More sharing options...
daeron Posted March 31, 2007 Share Posted March 31, 2007 bump for an answer on "are different years' ECUs entered into D-check through different procedures?" I am now curious for myself, since I am trying to isolate my own odd mid-throttle hesitation. I've run D-checks in the past simply by warming up the engine , turning it off, connecting my connectors and running at over 2K RPM for the prescribed amount of time, my CEL starts flashing and I get code outputs. If this is all happening, then the fact that I;ve done nothing with the pedal doesnt have any bearing??? right? CEL flashing after a minute of non idle engine operation means D check mode has been achieved? Link to comment Share on other sites More sharing options...
daeron Posted March 31, 2007 Share Posted March 31, 2007 Cracker, YOU need to go to chapter 2, section 7, page 20 in the partial FSM, and examine the troubleshooting chart. at the top of the chart, there are a couple of asterisks.. *, *1, *2, and *3. I think your CEL behavior might be related to one of those, and that might help you with your diagnosis. These Japanese FSMs are like a special tool in their own right. it takes ALOT of working with them before you can FULLY understand, and utilize them. Link to comment Share on other sites More sharing options...
Gloyale Posted March 31, 2007 Share Posted March 31, 2007 alright im sure most of you know my car by now, if you dont, it's an '86 SPFI, non-turbo. oh yeah BTW i tried searching... nothing seemed to fit my specific "problem" I've been having an idle problem... Go out in the morning to start the car, idles... wherever it wants. anywhere from 300rpm to 3000rpm. drive car some, idle fluctuates from 300rpm to 1000rpm, never goes high while driving, having the AC on does affect it at times, makes it drop. the car NEVER stalls, even sitting at 300rpm for 10 minutes wont kill it stop car, put 'er in Park, idle goes to 1500rpm instantly, cold or warm oh yeah, and it has the shakes really bad... i'm used to that though what are some common causes of this problem... i'll start replacing stuff now, money's finally coming in This could be a line pressure issue in the transmission? 3AT I am assuming? High line pressure will cause the clutches in the tranny to remain engaged so the engine is basically fighting the stopped drive train to stay running? This is just a speculation on a possiblity, not a diagnosis. EDIT: ALSO... the secondary fan is ALWAYS on.... even with the car shut off and the key in the "ON" position... The Fan thermoswitch may have failed? Or the relay? Has someone wired it "on" in the past? There's also a chance it could be the A/C switch assembly or the A/C relay failed? Does the A/C compressor clutch engage whether or not the A/C is on. Link to comment Share on other sites More sharing options...
daeron Posted March 31, 2007 Share Posted March 31, 2007 This could be a line pressure issue in the transmission? 3AT I am assuming? High line pressure will cause the clutches in the tranny to remain engaged so the engine is basically fighting the stopped drive train to stay running? This is just a speculation on a possiblity, not a diagnosis. I have wondered this same thing about his problem, and my own vehicle.. but this would be caused by.. overfilling the transmission? remedied by flushing? Link to comment Share on other sites More sharing options...
misledxcracker Posted March 31, 2007 Author Share Posted March 31, 2007 I put new grounds, as predicted, it didnt do anything. Jiggling the wires to the TPS does nothing, messing with the CTS doesnt do anything, and the TPS itself is just fine. There's NO hesitation anymore, it just idles like crap, which means NO passing emissions for me. Has to idle according to the sticker under the hood, and of course, it doesnt. I'll check the A/C clutch, but I have no idea what relays are what... I did the D-Check parked, and driving. I only get the VSS code. The transmission was flushed. It used to have a problem shifting when cold, hasnt had a problem since the flush. I'm going to read those sections in the FSM now. Link to comment Share on other sites More sharing options...
daeron Posted April 1, 2007 Share Posted April 1, 2007 i noticed that the troubleshooting chart I referenced you to says different things, about the CEL coming on in different ways, while doing a D check mode. That made me think about what you were trying to describe to me.. of course, by today I couldnt recall the EXACT situation you were having, but you said the CEL was just coming on and staying on, or something.. so read the asterisk'ed parts, and read them fourteen more times if you have to to understand them (good old translators) Link to comment Share on other sites More sharing options...
misledxcracker Posted April 1, 2007 Author Share Posted April 1, 2007 im going to ask this.. and it may be completely irrelevant to my problem... ...but can the timing slip out of nowhere and cause this erratic idle? i havent touched the timing belts on this car, let alone even touch the covers... they only have 34k on them (car itself has 94k with mechanic receipts since '89....) why i ask this? i was just looking at the emissions paper... and it says "incorrect timing" Link to comment Share on other sites More sharing options...
Gloyale Posted April 1, 2007 Share Posted April 1, 2007 I put new grounds, as predicted, it didnt do anything. Jiggling the wires to the TPS does nothing, messing with the CTS doesnt do anything, and the TPS itself is just fine. There's NO hesitation anymore, it just idles like crap, which means NO passing emissions for me. Has to idle according to the sticker under the hood, and of course, it doesnt. I'll check the A/C clutch, but I have no idea what relays are what... I did the D-Check parked, and driving. I only get the VSS code. The transmission was flushed. It used to have a problem shifting when cold, hasnt had a problem since the flush. I'm going to read those sections in the FSM now. The A/C relay is mounted above the pass side strut tower. The fan realy is next to it. Have you tried adjusting the idle screw? it may be backed out too far, and as it tries to die, the ECU compensates? Idle screw is on throttle body, just behind the IAC. right side off throttle chamber, between throttle bore and IAC. Warm it up and disconnect the IAC connector before adjusting. Also when you are setting the timing, are you disconnecting the TPS? Link to comment Share on other sites More sharing options...
daeron Posted April 2, 2007 Share Posted April 2, 2007 you dont disconnect the TPS, you have to make sure that the idle switch is on.... right? the FSM says to ensure that the idle switch is working properly, so I take that to mean that the TPS HAS to be connected Link to comment Share on other sites More sharing options...
misledxcracker Posted April 2, 2007 Author Share Posted April 2, 2007 No I didnt think you have to disconnect the TPS... ...I just connect the greens. Drove it 40 miles today, does awesome on the highway too Tomorrow I'm checking the relays, the timing, and I'm going to relubricate the speedo cable... Link to comment Share on other sites More sharing options...
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