donljacobs Posted October 9, 2011 Author Report Share Posted October 9, 2011 IAC has a shaft that has a black ball thing on one end with a shaft going to electronic part. you can take the black end and move it right left about 1/4 inch. Also, My radio all of a sudden is intermittent with each start of the car......and I have an intermittent security light. Is there something in the ingnition, key switch, that could cause a intermittent misfire???The key has been sticky since I owned the car. Link to comment Share on other sites More sharing options...
BodybyFisher Posted October 9, 2011 Report Share Posted October 9, 2011 Ok, that might be your problem you IAC pindle should NOT move like that Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
donljacobs Posted October 9, 2011 Author Report Share Posted October 9, 2011 Oh, Lord love a duck, that part is like $15 wouldn't that be a hoot? Man, that would be so very fine! Should I just go get one or is there a test for it? The prindle wiggles in the shaft quite freely, I would call it sloppy. If that is it, you are the MAN! Thanks! Link to comment Share on other sites More sharing options...
BodybyFisher Posted October 10, 2011 Report Share Posted October 10, 2011 All I will say is that when i cleaned my IAC pindle it was TIGHT..... if your pindle flops around it could be restricting IDLE air and causing your problem.... GOOD LUCK I hope this does it.... This could also be the reason it does not occur at highway speed, as the majority of air is drawn through the TB's throat Since this is a mechanical problem it would not set a code either. I think this could part of the problem but it would not explain the misfire on the front bank if it still exists Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
Ranger Posted October 10, 2011 Report Share Posted October 10, 2011 PCV is fairly new and rattling freely. You have a rattle can PCV? Mine is a metered orifice. I thought GM went to the metered orifice in 2000. Link to comment Share on other sites More sharing options...
donljacobs Posted October 10, 2011 Author Report Share Posted October 10, 2011 Yea, my PCV looks like all I have ever had on every car, if it rattles, it is good. Well, I kind of read the price on that IAC wrong. I said $15 but forgot the $200 in front. I will try to get a used one, if it works, I will then get a new one. Thanks again! Link to comment Share on other sites More sharing options...
donljacobs Posted October 11, 2011 Author Report Share Posted October 11, 2011 First day on new job! I commute about 40 miles a day. My last report, I had cleaned IAC and saw a difference. Today the car misfire all the time, but no where as bad. It is like one cyclinder misfiring vs. 4. I stopped on the way home and bought a used IAC at a salvage yard. The first thing that I noticed is that this one moves left to right about 1/4 inch like the old, but the shaft on this one is shorter that my old. I cleaned it thoroughly installed it the car idled somewhat better, but still a miss. I had no time to further test, but commute will tell tomorrow. So, the intermittent is GONE, seem to misfire all the time, but better? Different IAC, but still appears to be misfire???? Oh, how does this accuate? I assume up and down? My MPG are way down. Anymore suggestions out there, I do appreciate all. I think we will know more tomorrow after a run........Thanks again Link to comment Share on other sites More sharing options...
BodybyFisher Posted October 11, 2011 Report Share Posted October 11, 2011 If I recall there was NO play in my IAC valve, none. no side to side, no up and down, it was solid. It moves in and out via a motor to allow the necessary air to maintain the idle on closed throttle. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
donljacobs Posted October 11, 2011 Author Report Share Posted October 11, 2011 First day on the road with the replacement IAC......The car ran perfect to work, no misfire. Went to go to lunch, major misfire issues. Went to come home........Very little misfire!!!!!!!!!!!!!!! I don't know what to say! Link to comment Share on other sites More sharing options...
BodybyFisher Posted October 12, 2011 Report Share Posted October 12, 2011 You are getting close, as I said, my IAC had NO play, see if you can inspect a new one for comparison Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
donljacobs Posted October 12, 2011 Author Report Share Posted October 12, 2011 Great Idea, I will see if the parts store will let me check one out! thanks! Link to comment Share on other sites More sharing options...
donljacobs Posted October 13, 2011 Author Report Share Posted October 13, 2011 I have not had a chance to check out a new IAC, but he car was terrible going to work..........and perfect coming home! Like new, this is just crazy! Link to comment Share on other sites More sharing options...
BodybyFisher Posted October 14, 2011 Report Share Posted October 14, 2011 You are closing in on this problem. Think about it, that IAC is a precision device that carefully meters the air if that pindle is allowed to move around it would vary the amount of air, have a look at a new one Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
donljacobs Posted October 16, 2011 Author Report Share Posted October 16, 2011 I went to all the local parts places and no one carries the IAC!! However, the one off my new to me 2002 Eldorado might fit. I pick it up tomorrow. I did not want to kill this dts driving it with the missfire, but I have to have something to drive to work! So tonight I bought a 2002 Eldorado ETC.........with 37,000 miles on it. Not only does it look new........it still smells new......the back seat has never been sat in....the drivers looks like it was never sat in. Now, I can park this DTS and finish fixing it right without putting more hurt on it. The TB looks the same as my 2000 and this Eldo runs absolutely perfect so. Driving the DTS this weekend, it is the same, one turn of the key perfect another not. I have noticed that I am getting a security light intermittently and the radio turns off intermittently. ???? I will report back after I try a known working IAC. Thanks! PS I was quoted $300 for a new IAC.... Link to comment Share on other sites More sharing options...
BodybyFisher Posted October 16, 2011 Report Share Posted October 16, 2011 Congratulations on the new car. With regard to the IAC, Rockauto.com has an AC Delco for $216, a Standard for $204 and an Airtex/Wells for $106 Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
donljacobs Posted October 22, 2011 Author Report Share Posted October 22, 2011 I checked new IAC, it also has play left to right. I am starting over. I sprayed plentum when it was trying to go rough and it evened out. I tried this several times. Again, because it is intermittent, it is so hard to tell. Could a vacuum leak be intermittent...or would it not be so prevelent at higher speeds. Is there something else to try for the plenum? What else to check? Link to comment Share on other sites More sharing options...
BodybyFisher Posted October 22, 2011 Report Share Posted October 22, 2011 Take a close look at it, a cracked plenum usually sets a 2 bank lean code, but since yours is intermittant, it may not reach the DTC threshold, who knows Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
donljacobs Posted October 22, 2011 Author Report Share Posted October 22, 2011 I rechecked everything for a vacuum leak. I poured a bucket of water over plenum, no change, while there I played with wire harness(new on (new) coil bank 1 coil(front)I could not tell a change, but ran codes again and got a 1359!!!! Front Bank!!! So, new connector, new coil bank, where do we go from here? This is where we started. I do believe this is a break through???? I hope Link to comment Share on other sites More sharing options...
BodybyFisher Posted October 22, 2011 Report Share Posted October 22, 2011 P1359 - Ignition Coil Group 1 Control Circuit Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
BodybyFisher Posted October 22, 2011 Report Share Posted October 22, 2011 Yes this is a big breakthrough DTC P1359 Ignition Coil Group 1 Control Circuit Circuit Description The ignition system provides the spark to ignite the compressed air-fuel mixture in each cylinder at the right time. There are two ignition control assemblies located in the camshaft cover of each cylinder bank. Each assembly contains a control module, and four of the eight ignition coils. Each coil connects directly to a spark plug using a boot, thus eliminating the need for the secondary ignition wires. The assemblies receive ignition voltage from a fused circuit, and connect to chassis ground. Four of the eight ignition control (IC) circuits and a reference low circuit connect each module assembly to the PCM. The PCM uses the IC circuits to send timing pulses to the ignition control module. This signals the ignition module to trigger the coil and fire the spark plug. The PCM checks the IC circuits for an improper voltage condition. The PCM is able to separately detect an IC circuit shorted to ground. However, the PCM cannot separately detect a short to voltage, or an open circuit. Therefore, the PCM checks the IC circuits for this condition in two groups. The two groups consist of every other cylinder in the engine firing order (that is: 1, 7, 4, 6 and 2, 3, 5, 8). If the PCM detects an improper voltage condition in the IC circuit group for #1, #4, #6, and #7 cylinders, DTC P1359 will set. Conditions for Running the DTC The ignition is ON. Conditions for Setting the DTC During PCM power-up, the PCM detects an open circuit condition in the IC circuit group for #1, #4, #6, and #7 cylinders. ORThe PCM detects a short to voltage condition in the IC circuit group for #1, #4, #6, and #7 cylinders. The condition is present for less than 1 second. Action Taken When the DTC Sets The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test runs and fails.The PCM stores the conditions present when the DTC set as Freeze Frame/Failure Records data. Conditions for Clearing the MIL/DTC The PCM will turn the MIL OFF after the third consecutive trip in which the diagnostic runs and passes. The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. The DTC can be cleared by using the scan tool Clear DTC Information function. Diagnostic Aids The Misfire Current Cyl # / Misfire History Cyl # displays on the scan tool provides information that may be useful in diagnosing DTC P1359. The Misfire Current Cyl # counter may normally display a small amount of activity (0-10 counts). However, the display should not increment steadily. If the Misfire Current Cyl # increments steadily for a single cylinder within the IC circuit group, the condition is isolated to the IC circuit for the specific cylinder. However, if the Misfire Current Cyl # increments randomly within the IC circuit group, the condition may be due to poor connections at the PCM or a faulty PCM. Also, if the Misfire Current Cyl # increments steadily for a cylinder bank, DTC P1360 may set. DTC P1360 may result from one of the following conditions: A loss of power or ground at the module assembly for the cylinder bank A faulty or disconnected module assembly connector for the cylinder bank A faulty ignition control module Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
BodybyFisher Posted October 23, 2011 Report Share Posted October 23, 2011 See if you can read this diagnostic chart, if not PM me your email address and Ill send it to you. Save it to your computer, open it with a photo program and zoom in, if its illegible PM me Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
donljacobs Posted October 23, 2011 Author Report Share Posted October 23, 2011 Thanks, I can use a magnifying glass and I will get right on this! Link to comment Share on other sites More sharing options...
donljacobs Posted October 23, 2011 Author Report Share Posted October 23, 2011 I went to move the car and the OBDII was connected, it gave new codes. PO308 number 8 cylinder, P0507, high idle, 1359 and 1360. I pulled on injector connector # 8 and it appeared to make engine run smoother. Again, hard to tell with intermittent condition. Link to comment Share on other sites More sharing options...
BodybyFisher Posted October 23, 2011 Report Share Posted October 23, 2011 NO NEED to use a magnifying glass, just save it to your computer, open it and zoom it Here is the remainder of the diagnostic chart from above, now that you have P1360, this appears to be pointing to a bad PCM Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
donljacobs Posted October 25, 2011 Author Report Share Posted October 25, 2011 Can anyone tell me what is usual cost to reprogram PCM? Is this a dealer only option? I see there are some services that rebuild your old unit, do you still have to reprogram or just learn cam settings? Which is best? Thanks much! Link to comment Share on other sites More sharing options...
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