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Discussion Starter · #1 ·
Ok .. here we go .. This is yet again ANOTHER idle problem thread .. No worries .. I have read many of the other threads and have attempted to figure it out myself with many different actions but with out avail ..

I have the some what bouncy idle at warm operating temps .. when its cold it idles high as expected .. but after it warms up it tends to slowly reduce (while fluctuating) its RPM's until it eventually dies .. Sometimes not so slowly .. Like if Im clutching and braking going into a curve or at a red light .. and then the car may die and I lose all power everything .. Which is a lil dangerous when Im not always expecting it to die on me ..

Ok .. So now my set up .. Im running a full ZE with DE ECM, VAF and a Warm air intake ..

As for what Ive done trying to correct this .. I had a DE TB with a ZE IAC on there with the coolant lines hooked up and had this problem .. Ive had a different DE TB with DE IAC on there .. Ive had the DE TB on there with the ZE IAC plugged in without the coolant lines hooked up .. Ive had the DE TB with the DE IAC on there without the coolant lines hooked up and I still had this problem .. I had a DE TB with NO IAC AT ALL and still had this problem .. Each time I have checked the TPS and its sitting at .5v ... Yes I have checked the coolant levels but that really doesnt matter the times that I had NO IAC or the IAC wasnt hooked up to the coolant lines ..

so break it down ..

DE TB ZE IAC (with and with out being plugged in or with and without the coolant lines hooked up)

DE TB DE IAC (with and with out being plugged in or with and without the coolant lines hooked up and the vac port on the DE IAC blocked off)

DE TB NO IAC (nothing hooked up because there is nothing there)

and there was two different TB's during testing working with two different TPS's as well ..


Now during testing with and without the different IAC's and with the different TPS and TB's ... Its been the same every time .. Get it all hooked up as I want it .. then start the car .. as it warms up I have to continue opening the idle air screw to maintain the 1k RPM at idle .. If I dont it will slowly fall and die around 250 RPM .. Also if I bump the throttle after having continuously turned the idle air screw to maintain the 1k RPM the "real" RPM's will show .. Like I did this once and it immediately settled at 2.5k RPM so I turned it back down and quickly had the same problem of it slowing down till it died ..

So since no matter what I do with the TB or the IAC's I end up with the same results .. Im thinking i have another problem elsewhere on the car that is affecting the idle .. I just dont know for sure what it is that could be doing something like this ..

So anyone .. everyone .. toss out some ideas, thoughts or questions and help me figure this out !!! Thanks :)
 

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get your TPS recalculated at a shop. my shit did this a lot, till i messed with the TPS
 

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could your timing be off a little? i know mine had similar problems (and still do sometimes because I still think there's some air in my lines) and I adjusted my timing 3 or 4 times just to be absolutely sure. if you try a different tps or get your calibrated, although not sure how one would do that, and you still have the problem, most likely that your coolant lines still have air in them, most notably around tb. one guy tried filling his tb with coolant before hooking up the lines and made sure there was no air and it fixed his idle problems. i have yet to do this as it's been freakin cold outside
 

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Just wondering, why are you using a DE TB? I use the ZE TB on a ZE. If you have the ZE TB, use that and:

Use JE50 VAF
KL31/36 ECU or chipped to that
Use the right intake manifold
make sure all vacuum lines are hooked up right and no leaks

If you are mixing and matching things from a DE, you could be facing several problems all at once, not just one.
 

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Discussion Starter · #5 ·
Thanks for all the replies ... I have tried multiple TPS's and set them both at .5v (which is correct iirc) ..

As for the coolant .. I thought that at first too .. BUT when I removes the IAC for testing there is nothing there at all (imagine a TB without the IAC) .. So there is no coolant running though the TB due to the lack of the IAC .. and I was still having the same problems both with IAC and without one ..

Now as for the TB .. I had a ZE TB one on there at one point with a JE50 and a true ZE ECM and was still having issues (that was the original setup after I rebuilt the ZE) .. But really the only difference between a ZE/DE TB are the IAC's ... Other than that they are identical .. and by using a ZE-IAC , DE-IAC and NO IAC .. Ive essentially tested with three types of TBs.. ZE and DE along with a custom TB that removed the IAC completley..
 

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now just to understand because i dont understand.....
whats all these codewords? DE TB ZE IAC
man im fkn lost...
is there any page in the forums explaining these shortened words?
call me noobeh

Cheers:angel:
 

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Discussion Starter · #7 ·
I think there is an acronym list somewhere ..

DE is the letter code for the NON-JDM engine used in the US, Europe, and in Australia

ZE is the letter code for the Japanese "JDM" motor

TB is just short for Throttle Body

IAC is the Idle Air Control

TPS is Throttle Position Sensor
 
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I think it's safe to say that it's not a tb/iac issue at this point. I would lean towards a vac leak right now. You can spray starter fluid (or propane from a propane torch for plumbing) along all of the vac lines, egr, vc gaskets, im gasket, injectors, tb and see if your rpms raise any. If none of that works, then it could be a fuel pressure or injector issue I suppose.
 

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Discussion Starter · #10 ·
Hmmm .. I wonder injectors maybe .... Im fairly confident Ive check all vac lines and they are good .. It never hurts to look it over one more time though .. as far as fuel pressure I have a steady 40psi (iirc) being that I have an AFPR on there its easy to keep an eye on that..

anyone know of a way to check injectors ?!!? :)
 

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Did you cover / tape up the bottom of the throttle bodies you ran without an iac ? as they have vac chanels and would cause a leak, throwing doubts on the tests.

Going off your profile you are runing this in a probe with OBDII wiring .. yes ? and you get no CEL ? If the inof i have is wrong and you are running it in an OBDI car, will the engine start in diag mode ?
The ZE engine you dropped in, does it have a green and black water temp sensor or just a green ? either way, try disconnecting the green sensor when cold, and see what happens. Its been known for these to go out, but not report faulty to the ECU.
 

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Discussion Starter · #12 ·
I know a guy that is making IAC block off plates .. So I used one of those with a nice thick gasket to ensure no leaks would form there ..

AS for my Profile I really need to adjust that .. I havent had a probe in a yr or two now .. I have a 93 Mx6 now and yes it will start and run with the TEN/GND pins jumped .. and to be honest I dont recall which CTS is on the car .. Thats something Ill have to look at and see and maybe even try .. Thanks Odd
 

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If the car will start ok in diag mode when warm, does it show the same symptoms and die? if the engine continues to idle ok when warm in diag mode, then your looking at a sensor giving false information to the ecu. Obviously the opposite applies, if it does die in diag mode the same as normal, then you can rule out electronics and look at the basics.. air, fuel, spark.
 

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Discussion Starter · #14 ·
Makes sense .. I never really left it in Diag mode .. Just long enough to get it at the right RPM then pulled it to see how long the RPMs would stay there .. THat could an easy test to do today
 

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Discussion Starter · #15 ·
Well I have both CTS and tried it plugged in and unplugged ... in and Out of Diagnostic mode and it still dies every time .. :(
 

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Whenthe revs start to drop past 650, does the engine buck, or is it just a case of a slow smooth death until it cannot idle anymore and just stop ?
I would start at the basics now. Mechanical timing, crank at tdc and ensure the cam pully's align.

Crankcase breather system. Check the rubber pipe coming from the front of the front cam cover, clip it or tie wrap it in pace for testing to ensure no leak and follow it around until it meets the rubber pipe again and ensure this connection is sound, follow it to the metal pipe running under the TB and ensure this is ok, the metal pipe splits into two at the corner of the rear cam cover, ensure the connection to the rubber pipe going to the intake elbow is good, and the connection of the small rubber 90 deg bend at the other end to the rear cam cover is good too. Can you hear the PCV valve clicking when the engine is running ? does it rattle when shaken ? Is the collar it sits in tight and secure ? and the pipe to the inlet neck is connected ok. Ensure the oil dipstick seats ok too. Thats the crankcase breather system checked.

Now its vacuum pipes. Use the diagrams found on here to ensure the pipes are all routed correctly, it can get confusing, especially the connections to the metal pipes under the throttle body, as they overlap out of site and do not come out in the same sequence the other end. As you are running a ZE you have no EGR pipework to check which means everything should be accessible.
Then its ignition timing. If you have to start with the idle screw virtually fully open then do so, and slowly work your way down, get to 10 deg btdc, and bring the revs to 650, the timing will move, so get it back to 10 deg again and adjust the idle speed again.. keep going until the point it just sits at 10 and no longer needs the idle adjusting. Its now set.
If you are using a ZE inlet and a DE IAC, where are you getting the VAC feed from for the DE IAC ? PCV pipe ? I would run the ZE throttle body and ZE IAC together for the time being to ensure maximum compatabiility. Remember, if you are using the DE TB to the ZE IAC, you need to drill out the chamber for the vacuum in the DE TB :tup:
The fan on and off method for the TPS adjustment will be just fine in diag mode.

have fun ..
 

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Discussion Starter · #17 ·
OK .. here we go !! :)

When it dies it just slowly idles down and just gets too low to keep running .. No jerking or anything like that ..

Now on to the testing .. front cam cover .. The hard line going into the rubber fitting on the front seem in good condition and to be sealing well .. the hard line runs back in to the rubber line that again runs into the large hard line under the TB that branches off to the CAI and the left rear of the rear cam cover .. all of those connections seem good. Also there are 3 small hard lines under the TB that run from the front to the back .. two of them are unused on my car .. The one I do use is connected on one end to a T line that connects both VRIS 1 & 2 .. the other end runs to the vac chambers under the IM and hits a main vac source on the left (passenger) side of the IM ... And thats it for vac lines .. As for the PCV I didnt like how it sounded so I put another one on there with still no change ..

Im currently running DE TB and IAC .. and since there is no place on a ZE to get the vacum for the IAC I just have it plugged so there is nothing going to it ..

I did some playing and adjusting today .. with no major changes .. it seems a little erratic now .. sometimes it will sit and idle just fine .. but if I tap the accelerator when the RPMs drop they may just keep dropping .. Ive seen that it happens mostly when I have the heater going .. I played with it a few times trying to keep it from dying and if I turned the heater off I had a good chance of it not dying .. It also seems the warmer the motor is the worse it does it .. I drove to pick up my friend from work and it wasnt bad going there but I had to sit and wait for about 15-20 mins and I had the car running the whole time (this is when I was playing trying to kill it and trying to keep it running when I thought it was going to die) when it was time to go we took off and its like i couldnt keep it running nearly every time I let off the gas to brake/clutch the RPMs dived .. It starts right back up every time with out hesitation ..

I also swapped out the disty .. just in case this was one of those weak spark issues .. and it didnt change anything either ..

I didnt get a chance to do anything the the actual timing though .. :(
 

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How much slack do you have on the accelerator cable between the TB linkage and the bracket ? and have you tried experimenting with the throttle stop screws ? i would look at opening this gap a little more to slightly crack the butterfly open more on idle and see what happens. There is a TPS checking procedure in the UK section you can follow for setting the gap.

Also with the DE IAC disconnected, you are going to get a bad idle anyways.
 

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Discussion Starter · #19 ·
The throttle cable is tight .. Ive changed the stop screw quite a few times now attempting to get the car to idle right .. I was adjusting it a lot when I had the IAC blocked off thinking I may have to compensate .. But yesterday I got it to where it was idling like 2.5k and the top adj screw was all the way in so the plate should have been closed .. I adjusted the linkage stop screw and made it so it would be in the right idle range and die when the top screw was all the way in .. and had to readjust the TPS again after that .. That was early yesterday too .. I thought maybe I Was making progress .. but after picking my friend up last night I realized I had done nothing ..

I was wondering though .. because of my Frankenstein TB/IAC's .. I have the DE version on my ZE now .. so it has the hose for the vac source .. the ZE TB has an internal vac source .. Im blocking the hose on the DE TB basically taking away that vac source .. if I undid that and T'd it into the large hard line under the TB would that make a diff ??

I figured since both ZE and DE have Vas sources that its needed .. and i dont have a ZE TB with me right now .. so if I wanted to add the vac line on the DE thatd be easier .. I can just splice and T into the line that runs to the CAI ..

DE IAC Disconnected .. were you referring to the plug, coolant lines .. or the vac line which I just typed a lot about ?? :)
 

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Most 'T' into the PCV line and use a vac source from within the actual inlet and after the throttle body. If you have the intention of permenently using the ZE IAC, then just drill out the chamber in the DE TB and fit that. If you need directions to the thread, just shout. I did this to mine as i had an enlarged 67 DE TB and did not want to loose that when i fitted the ZE inlet.

Fully tighten the idle screw on the top and then back it off 3 full turns, and adjust the throttle linkage screw until it idles at 650.

Remember to do all this in diag mode buddy, otherwise everything you do will just have the ECU trying to change it at the same time.
 
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