clarify; low idle hard cold starts

[Guest765]

I've searched and searched, found a lot about high idle but nothing about low idle when cold.

Starting the car cold it idles low around like 400-450 rpm, stalls when you let off the gas until warm. Once warm it idles at about 700 and runs fine. I think the temp sensor ii is probably bad, could that be causing most of this? I know I need a new iacv but I don't have the money right now and it idled fine cold in the warm Florida weather while I was down there. I rebuilt the iacv and verified it works by bench test, I do plan to post a guide on rebuilding the commutator inside since it ends up with holes in it from arcing once it sticks over time.

Its not a huge deal but its aggravating as all hell. All help appreciated.

[Danglerb]

Best to do one thread per car, put all the model info in your sig or profile.

What works well on the IACV is to replace brushes (find a match, file to fit or whatever) and just rotate the armature to a portion with less wear.

[Guest765]

wasnt possible on mine, the commutator was blasted 1-1.5MM deep and completely across all the contacts. also, one of the brushes was nearly gone. the other thread i posted had a completely unrelated question, dont see the issue posting a new thread for an unrelated issue. havent had a chance to change my sig since ive been posting from my phone.


anyone info on the posted issue is appreciated, thanks again

[Guest765]

So no one has any idea? I went through the common fixes thread and even resorted to searching rennlist. Not much there.

[Mrmerlin]

for low idle or rough idle try easy,
add a bottle of techron, do lots of short drives so the cleaner has time to work.

Next replace the temp 2 sensor and inspect the reading at the computer connectors.

Other fixes include have the MAF rebuilt install a new factory O2 sensor, replace the IAC valve,
I have repaired a few of these with silver solder used to fill in the armatures,
a new part is the best bet here and it is a wear item.
NOTE use the Porken blinker to adjust the idle.

make sure the Idle circuit can be shut off via the diagnostic plug at the engine,
if not then the computer needs to be replaced.
Porken has a few threads on RL search "adjusting the MAF" and other bits of info in those threads

[Guest765]

Thanks merlin. Looking like its the temp ii sensor, if I unplug it while the cars running the idle instantly smooths out. Plug it back in and it goes rough again. Auto zone just sold me the wrong sensor so as much as I don't want to wait for shipping I'm going to just return that one and order the cheap one available here.

[Guest765]

Funny thing is the resistance is pretty close to the test values but it does read a little high on my meter.

[Mrmerlin]

after swapping in the temp 2,
you might consider adding the other things i listed to keep the car running perfectly

[Guest765]

Trying to adjust the maf, o2 sensor is reading .1 to .2 volts at full warm idle which from what I read signals a lean condition? I can't get the plug out of the maf adjustment hole, its plugged with an aluminium plug. Conflicting info online is telling me that since I have an o2 sensor I can't adjust the maf? But then other postings say to use the o2 sensor as a guide to adjust the maf. I'm at a loss here, plugging the p/o's ridiculous vacuum leaks and fixing the completely WRONG vacuum routing the p/o had going on as we speak.

Anyone know what the deal with the maf adjustment is?

[Guest765]

Also, I'm already on my second or third bottle of techron I don't remember but its probably the second bottle.

[Mrmerlin]

the MAF should have the plug removed then it can be adjusted set it for a nominal setting of 380 OHMS .

NOTE you can check this prior to touching anything via the Computer connectors,
just use the Porken diagram to find the correct pins to check.

[Guest765]

I already pulled the maf and checked resistance, its reading like 290 between pins 3 and 6 where it should be reading 390ish according to those. Plugged the vacuum leaks and rerouted what was wrong, no change in o2 sensor reading. Reading on the other pins that's supposed to be four ohms is reading five ohms so that's damn near spec.

So I guess I'm going to have to drill that plug because I can't get it out at all. Maybe notch the side with the dremel and try to get down underneath it to pry it out without destroying the pot underneath.

[Guest765]

Got the plug out. Had to drill behind it, the steel snap ring was galded into place. Thankfully that's out, and the Macwas reading in at 240 ohms exactly, i bumped it up to 380 exactly and I'm going to test it now.

Any trick or clue how to get to the windshield wiper fluid pump? Got the reservoir out, cleaned it of all the rust and literal sludge, but I can't get to the windshield pump it looks like without ripping apart half the passenger side worth of hoses valves and hard lines. I don't want to do that obviously.

[Mrmerlin]

push the rubber tabs into the engine bay,
outside to inside this will free the pump

[Guest765]

I kind of can't reach the stupid thing though with my hand, is it better to try and come at it from underneath? Didn't feel like crawling under the car to find out, gravel driveway.

[Guest765]

Hey what's the green plug coming out of my computer box in the foot well? Two green wires, with a plug end on each. It was disconnected when I bought it and I just plugged it together today for ****s and giggles. Can't notice it doing anything at all, connected or not. Saw some mention of it being for fuel mix or something?

[Guest765]

Sorry, figured it out. Retards timing 3 degrees. Strange thing is I can't tell any difference at all connected or not.

I also checked the idle disable on the test plug, it does work it starts stumbling when I short the pins.

I guess the bad temp2 sensor and badly adjusted maf would explain why I've been able to run on 87 octane with no issues so far, probably so rich that there's no chance of detonation happening.

Guess I'll unplug the green wire again, unless I hear any knock or ping no point in having it connected.

[Mrmerlin]

if the idle is stumbling then you need to adjust the idle, then MAF , then the idle,
a blinkr is helpful here Porken makes them.
BUT before you go adjusting the idle you need to make sure that all of these parts are good or your wasting your time,
MAF recently rebuilt they go bad,

temp 2 , yes they fail test via removing the plug and one side of OHM meter to ground the other to one of the pins test both pins as each one sends a signal to the LH and EZK computer.

ISV its a wear item they do get holes in the armature and then stick in a certain position

ignition wires make sure they are fresh , arcing wires seen at night can spell trouble,

vacuum lines work best with fresh lines,

O 2 sensor yes they do wear out replace with a factory part not a cheapo cut to fit unit.

TPS short connector wire, the connector breaks at the connection next to the water bridge

[Guest765]

I broke the tps connector already, rebuilt it with epoxy thankfully it was the male end, still works.

Temp2 is on the way, ordered here.

Can't afford a maf anytime in the forseeable future and cannot send it out for rebuild this is my DD. Unfortunate for sure.

I rebuilt the iacv with hard silver solder, and bent the arms inside to get better contact since the carbon brushes were toast. Can't afford that for a long time either but the rebuild is holding for now, knock on wood.

I'll have to buy a diy cut and crimp kit for the spark plug wires, I just know those are going to be expensive if I buy a set made OEM.

Can't afford the o2 sensor either, going to have to wait on that or sadly go cheap and replace with OEM when I find work.

What happens with the car is it idles great warm, sometimes hunts for idle but I'm positive that's the rebuilt iacv acting up. What happens is if its cold it idles LOW and will start hunting then die. Very hard to restart if you let it die in the first 30 seconds of running. I've killed the battery twice letting it die on a real cold morning. It also will die before and sometime after warmup if you dump the throttle while the rpm is high, like shifting to neutral at a stop. It actually idles at a higher rpm after playing with the maf.

So based off your advice and what I can afford right now, I'm going to wait for the temp2 sensor to get here and throw that in then try a rough and quick idle, maf adjust, then idle adjust again as you posted. I'll do it again right when I get everything replaced totally.

The reason I have to be a dick and jury rig things here is because 1.) I'm unemployed, I do contract based IT/networking work and I don't have any work right now

And 2.) I have to replace every ball joint, bottom passenger has noticeable play, do the TB and check the water pump, which i have receipts saying it was done, and I need two front tires baaaaaad. I don't want to get tires until I get the ball joints done for obvious reasons. The car also needs brake pads all around, all the above parts listed for the engine, plus plenty of interior cosmetic work. So I'm spending money on safety to get the ball joints done ASAPand then iI'll move to the other stuff in order of damage possible if it breaks.

Appreciate the help merlin, ive torn down my old 944 inside and out but the 928 is seriously hard to find information on and I don't even know 100% if I have the right WSM, and they're impossible to read on the screen so I need to get them printed, which is something else I can't afford right this second. Sucks.

[Guest765]

Looks like the blinker is just a 12v led light from positive battery jumper to terminal A. Then he has a switch to turn the idle control on and off as needed, I'll just use a paperclip for that since the blinkers seem to be NLA from porkens site.