Engine idling problems.

[xpeed]

I know some people here had similar problems but I can't figure out the problem still. Whenever I turn the engine over, the rpm drops to 800 and then 500 and then dead unless I give it some gas above 1000 rpm and keep it there for a minute and then it's fine again. It doesn't happen all the time but only certain times and it only happens right after I fill up with different octane from 89 to 91 and vice versa.

So I narrowed it down to several things:

Fuel filter: I know I need to replace it but maybe it's one of the main problem why it dies on me.

Fuel pump: Maybe I need to replace the fuel lines/pump?

Spark Plugs: I replaced them with iridiums and I know it's not one of the source of the problem because it still does dies on me at random moments after I replaced them.

Pistons? Loss of pressure inside the cylinders? Can't figure out why other than not enough fuel getting inside the cylinders.

[tony4ta]

hey x,

I have the same problem with my 95 camry. Replaced fuel filter...still rough idle, and hard start in the cold. Replaced all plugs....still rough....cleaned throttle body, and hole to idle air control valve....nothing.

Now I am focusing on the mass air flow sensor, and the egr valve. I will let you know how that turns out. If you hear anything, post it. I cant stand the rough and low idle at stops.

-Tony

[xpeed]

^ i will. I think I get it seafoamed and see if that solves the problem before I start spending $$$ on parts and find out they're not the problem. =|

[fenixus]

clean the Idle Air Control Valve. this thing is supposed to keep engine speed over 1k rpm after initial cold start and then gradually drop it down to normal level (700+/-50) once Engine Coolant reaches normal operating temperature (usually when thermostat starts opening).

dirty/sticky/faulty IAC valve will cause your symptoms. check FAQ section for rough cleaning (Throttle Body & IAC) or look for Mr. Perkins DIY on IACV removal and thorough cleaning.

another thing worth checking (resistance check between terminals) is Engine Coolant Temperature sensor for E.F.I., it may be reporting wrong temperature (resistance) to computer at cold start, so it "thinks" the engine is warmed up already while it's cold and delivering wrong fuel/air mixture.

[xpeed]

^ Yup, checked all that. I cleaned the throttle body while I was installing my SRI. No problems with them whatsoever. Like I said, I can't pin point the problem. The engine starts up fine at cold start ups. It's only when the engine is all warmed up it happens. It only happened five times since I got the car in October.

The only problem I can think of is probably the fuel isn't being delivered properly at random. I'll check my IACV if it keeps stalling after seafoam and replace the fuel filter. Thanks fenixus for your input though.

[fenixus]

intermittent problems are hardest to pinpoint ... good luck!

if you suspect fuel delivery then have an OBD2 scanner handy and scan live data when problem happens. fuel trims and oxygen sensor (or AFR) readings should get out of whack if fuel delivery fails.

also on a side note. running out of fuel (until engine quits) sets a code.

[tony4ta]

Hey Fenixus,

I checked my coolant temp sensor today, and it seems that the wires and connector to it are badly corroded and open. you can actually see the wires to the connector have oil residue and green corrosion on them. Can i somehow splice the two leads and reattach to connector? I ask because I see you have some expertise with connectors and such....

-Tony

[fenixus]

ouch. that's bad. I would try cutting the connector off and cleaning it as best as possible (re-using) with alcohol or electrical parts cleaner spray (from auto parts store). see if wires right by connector are good and can be re-used for splicing (best if you can use crimp connectors instead of 3-way splices). make sure the terminals in socket and on the sensor are in good clean rust-free shape.

then track down the corrosion on original wires and see how deep the damage goes into the harness. hopefully it's just a short section.
cut off damaged wires and get a replacement wire length of same gauge (AWG) as the original one, and re-connect things.

good luck!

ECT for EFI connector is part of engine wire harness, so if you cannot fix it, that would mean you may need to replace the whole engine harness. lucklily this is the most populat car wiring harness on junk yards and ebay, so finding a cheap replacement should not be a problem if things go this way.

Originally Posted by tony4ta

Hey Fenixus,

I checked my coolant temp sensor today, and it seems that the wires and connector to it are badly corroded and open. you can actually see the wires to the connector have oil residue and green corrosion on them. Can i somehow splice the two leads and reattach to connector? I ask because I see you have some expertise with connectors and such....

-Tony

[tony4ta]

its the wires connected.....to the....connector. i will try to take a pic and upload it

[xpeed]

Fenixus: I found out that the problem to my idling problem is the IAC. My mechanic will try and see if he can clean it for me, but he said if it can't, might as well replace it for new. I trust my mechanic and he's really good and gives good prices so yeah. Thanks for the help though.

[fenixus]

sure thing, try cleaning first, replace only if necessary.

you could try cleaning it yourself if you have time
5sfe IAC Removal (lots of pictures)

just get new gaskets (Throttle Body and IAC for your model) from dealer before tackling this.

Originally Posted by xpeed

Fenixus: I found out that the problem to my idling problem is the IAC. My mechanic will try and see if he can clean it for me, but he said if it can't, might as well replace it for new. I trust my mechanic and he's really good and gives good prices so yeah. Thanks for the help though.

[ajkalian]

Originally Posted by xpeed

Fenixus: I found out that the problem to my idling problem is the IAC. My mechanic will try and see if he can clean it for me, but he said if it can't, might as well replace it for new. I trust my mechanic and he's really good and gives good prices so yeah. Thanks for the help though.

If you want to attempt to clean the IAC yourself follow this search thread. There are many discussions on how to clean and adjust the IAC.

http://www.toyotanation.com/forum/gt...3Ff%3D103#1163


.

[xpeed]

Yeah, I've read the seen the DIY on cleaning them. I just don't have the time to do it though that's the thing. I also need to get my car seafoamed.

[fenixus]

the simplified version of IAC cleaning is here:
How to: Cleaning Throttle Body -4 Cylinder Engines- With Pictures