yllager2013

Finally got around to doing head gasket / timing belt on my 03 d17a1. Got everything back together and running and I'm having idle issues now. Car idles at 2k in park and neutral on a hot engine (cold idle starts slower but gradually goes up as engines warms up). With trans in gear it drops right down, but still seems high (~1k). Went back and pulled the airboxes off to make sure I had all connections and hoses right. Ran some carb cleaner through iac port in tb and put everything back together. Seafoamed it also after which seemed to smooth out the idle a little except for the high rpm issue. Intermittently get p1129, 1505 and 505 codes (all idle related dtcs). Finally completely pulled off iac valve and cleaned it more thoroughly tonight (haven't tried to put it back in yet). Any ideas? Could a vacuum leak cause the high variance in idle between drive and park? My intake gasket was pretty shot, but i couldnt find one locally so I figured on getting everything back together and changing it out later.
Thanks for help

ezone

Reassemble.
Plug off that IAC port with your finger see what the idle does. Might have the IAC stuck wide open.

P1129 is MAP voltage high, not idle.
Triple check the cam timing. Off time by a tooth or two is apparently a common cause of the P1129 and could also be the cause of the high idle rpm.

yllager2013

Pulled the crank pulley and timing covers and timing is dead on. When I plug the iac port engine stalls. I didn't try it for long (it was cold engine). It should close once engine warms up correct?

ezone

No it should not close completely because that IAC is what controls the idle speed. The IAC should be in control of the idle speed.


I would have done that check with the engine fully warmed up.
If it doesn't die when you cover the hole, then you probably have vacuum leaks or the throttle might be held open a bit, or something like that.
If it does die, then the IAC system is probably the cause of the high idle, and you then need to investigate WHY it is wide open.

yllager2013

Ok, plugging iac port kills engine when warm. After seafoaming engine and cleaning the iacv as best i can, its stabilized a little, but idle rpms are still high (900-1000). Rpms still jump by 100 or so when in park or n only. Turning a/c on drops the idle rpm by 100 or so. Only dtc i have left now is p0505. It almost seems like an electrical or ecm issue. Idle roughens noticeably when I unplug my obd reader (even while driving it will act like its going to stall right after I unplug the reader) Its like more load on the a/c and alt smooths it out.

ezone

P0505 only means the PCM can't control the idle speed. Does not define why.

Still sounds like the IAC is sticking. Beat on it with a screwdriver handle and see if the idle speed drops. Use common sense, don't beat the snot out of it and break it.

If it is sticking, tapping can jar it loose or let it move and change the idle speed. If it chganges, you should then know it is stuck.


I would want to see a real scanner that would show what the PCM sees in a data list.





That's a strange one to me. My HDS scanner shouldn't do that, but I can't speak for anyone elses.

yllager2013

Idle has settled somewhat and no codes have come up since the last time I cleared it (after ~30 miles). Maybe the seafoam cleaned it out good enough finally. I did check the codes again with my more detailed bluetooth obd reader and did get a body code (p1298), which is the eld, so that may be the source of the electronic issues. Not sure why it just came up after reassembling everything from the head gasket, but anyway, I'm mostly up and running (and able to go over 65 without blowing the coolant out of the rad!). Thanks for the help

yllager2013

double post

ezone

P1298 is not a body code, it's technically a powertrain code.
Just replace the ELD in the fusebox, it's a known problem. That code normally does not turn on the CEL so many people never know it is there.

PDF link to the bulletin: http://www.crvownersclub.com/TSBs/2005/05-006.pdf

HTH

yllager2013

Finally got around to replacing the eld.. no more codes, everything runs fine.. except I can't figure out this stupid electric issue. If I try to start the car without my odb dongle plugged up, its difficult, turns over multiple times before I get crank. Once it cranks, it will sometimes stall just a few seconds after driving it, sometimes 10 or 15 minutes later. Battery light will flash and I get a clicking sound like a loose battery terminal wire or something. However, I plug in the odb reader before starting, and cranks up perfectly, runs perfect, zero issues as long as the reader is plugged up. I did a 4 hour drive with it plugged in and zero problems. Very annoying. Tempted just to leave the $12 thing plugged in permanently. Maybe there is a faulty ground somewhere and the odb reader is providing enough of a ground in its circuitry to let the electric system run fine. Any ideas?

ezone

Never had to chase that, but this is what I would start with:


Grab a voltmeter. Measure between a "known good" ground, and terminal #4 and then #5 in the DLC connector. Drive long enough to have it act up and see what the voltmeter is reading when it does.

Both of those terminals are generally considered grounds but come from different locations....
#4 is a grounded directly to the steel dash frame.

#5 is a sensor ground from the PCM. If the PCM has lost any of its grounds, then your OBD dongle might be supplying the missing ground by bridging from pin #4.

You just had a bunch of stuff apart. You could have left ground wires off/loose/corroded etc. The small grounds G101 (above the thermostat housing/next to radiator hose) are extremely important for the computer. Clean and shiny metal is needed for good contact.
Actually, now that I looked at a wiring diagram, I'd say to recheck this first.