dustrider

2.7 stickshift 4x4 (197,000 got it used at 157)
it starts easy from stone cold but recently started stalling when cold when rolling down to a stop until the engine warms up and shows on the temp guage
it will sit there and idle fine and runs fine down the road but stalls when coming to a stop , which had me suspect EGR

it runs fine once the temp guage shows normal

no codes , plugs read nice chocolate brown

I checked the temp sensors under the hood for ohms according to the factory manual specs with a Fluke meter

Coolant temp sensor (not the sender) behind the head checked OK but I changed it anyway

temp guage sender reads OK

EGR gas temp sensor reads OL (open loop) when cold but manual says at 68f it should read 188.6-439.0 k ohms

can this egr gas temp sensor cause the cold stalling problem ? or maybe Im checking it wrong. I'm not eager to replace it because it is $200 ....200 %@#@#ing dollars !!!!

I removed the EGR and checked it against a new valve (it snaps shut when vacuum releases) and vacuum switching valves seem to operate normal
I clamped the vacuum line that operates the EGR and ran it stone cold but no change still stalled at stops

also had a rough idle and fixed it by removing the throttle body, removed the TPS and cleaned the Idle Air Control and throttle plate
replaced the plugs with Iridium and new plug wires
found oil on the rear plug wire in the plug tube so I replaced the plug tube seals and head cover gasket

double checked for vacuum leaks

one wierd thing is motor stalls if I remove the plenum with it running , I always thought it would run OK with it removed to spray carb cleaner in the throttle body but as soon as I remove the MAF from the stream it dies

idles smooth now warm or cold

Idle speed stays at 750 hot or cold start (?) is this OK should the idle speed be higher when cold starting ? ( bad ECU ? )
I checked the operation of the Idle Air Control valve by applied voltage as the manul says and it operates normal ( opens and closes)

any ideas what would cause it to stall at stops when cold ?

dustrider

could it be the Intake Air Temp Sensor (inside the MAF) telling the ECM that its hot out ?

corrosion at the ECM terminal ?

drkblu4runner

yes your idl should be above 1000 when cold. check to see if your Idle Air Control valve is getting any power when cold and hot

dustrider

Thank you for the helpful tips

will do

dustrider

the idle does go up momentarily after cold starting for about 5-10 seconds then drops off

I wonder if it could be the Intake Air Temp sensor incorrectly telling he ECM that it is hot out ?

shouldnt the idle stay up until the engine reaches operating temp ?

dustrider

I believe the cold stalling is solved . I changed the MAF sensor and after 3 stone cold test cycles it has not even stalled or stumbled , runs better all around too

the Intake Air Temp (IAT sensor) is integrated into the MAF sensor on this 98 2.7
I believe the IAT was sending a wrong or no signal to the ECM causing the cold start idle to drop off too soon after starting. After changing the MAF/IAT the idle stays up now until it warms up
before, it would stumble a little coming down to a stop even warmed up. Now it stays smooth
although I was not able to test the old IAT sensor, all the evidence points that way

dustrider

disregard the last post
the cold stalling is not resolved

if I let it sit 3-4 hours with a fan on it until it seems cold, it will not stall
but in the morning after sitting all night it will start right up but stalls when stopping until it warms up ( unless I keep it revved with the side of my foot as I come to a stop ) if I let it stall it takes a long time to restart (about a minute of cranking)

I would need to buy a guage so I had the local mechanic check the fuel pressure and it is perfect at 44psi with motor stopped and 39 at idle,
local mechanic suspected valves causing slightly rough idle and lack of power and suggested taking it to the Toyota dealer to get a diagnostic

I took iot to a dealer and the mech ran a $100 diagnostic,
all computer checks OK

says he is 95 % sure it is the IAC
said that even though it is cleaned and operates electrically it can have a weak spring
they did not have an IAC in stock ( $350 ? from Toyota) autozone $225, total IAC replacement at dealer $495 so I put it hold and drove off
dealer mech also found bad compression in # 1 cyl @ 140psi, #2 @ 150, #3 @ 180 and #4 at 190 psi
said it is the cause of the slightly rough idle and less power
dealer recommended a valve job . I asked about putting new valves on a 200.000 mile motor and the service writers said no problem,
local mechanic says from experience there is a high probability the bottom will blow and recommends just driving it

I will get a new IAC and report back

dustrider

changed the $300 IAC and gaskets per the Toyota dealers diagnosis

absolutly no change

wasted $400

so much for the "professional" diagnosis

now what ?

dustrider

well aparrently this forum is as worthless as Toyota of Riverside,
No help here , Im just talking to myself

Toyota of riverside wasted my $400 on an IAC and now says the engine needs tore down to find it

booger eatin' morons

Toyota SUCKS the big one

wish I could strafe the stealership

thedrewski86

Dude that sucks!! I feel your pain but I got a 22RE so I'ma as worthless to you as Riverside Toyota and this site Just letting you know somebody read this, where are the experts here? If it makes you feel any better I just put $1000 into my Impala and still have the same effing problem!

dustrider

thank you Drewski
I feel like a homeless derelict mumbling to myself here while everyone just walks as far away as possible to get around me,

evidence to wit ;

Yes I see very little advantage in the new technology over the decades. More complexity to fail In the old days we just had to deal with burned points and dirty plug wires IMO the environmental crap is just a load of bullhooey , the motor is caused to loose efficency in order to gain envornmental advantage resulting in net neutrality
But we feel better about doing something to save the earth,
then some Volcano blows and cancells out the entire load of carbon and gasses saved in the entire 50 years of smog technology worldwide by pumping 8 times more into the atmosphere in just 3 hours than has been saved over the course of automotive history
and meanwhile China pumps out more crud every day than we do in a year
and we continue to secretly dump trillions of gallons of sewage into the oceans [/rant]

but I digress

I still cant figure out why the computer will not kick the idle up at cold start
maybe I could just run a choke cable up to the injectors and save having to buy a new motor like the dealer suggests

dustrider

Can someone please tell me
what does your non-stalling 2.7 or 2.4 do when you first start it in the morning
does the idle go above the warm idle spec of 750 ?
what RPM does the idle go to and how long does it stay at the raised RPM ?

kball

Don't know how much this will help you since my 04 has an automatic trans but when I first start it up the idle jumps to 1500 then comes down quickly to 1250. I put it in gear and it drops to 1000 and stays there as it warms up. Finally settling around 700-750.. whatever that mark is, it's not marked.

dustrider

thanx for the info

mine seens to go to 1000 then drops within 5 seconds to 750 and stays there , usually before I can put it in gear

ricky

Mine fires up and goes straight to about 1400RPM until the oil makes it up top, then it will sit normal at about 1500RPM until warm, and slowly taper off to normal ~750RPM idle.

dustrider

thats how I thought it should be but mine wont idle high before warm up

I think my valve/compression issue is a separate deal but I have 2 opinions now that compression is the cause

I am trying to decide if I should to just do the head myself or get a complete motor rebuild

I can just continue to keep it goosed till it warms up until I find a motor or roll the dice and do a valve job

I am afraid I will do a valve job and it will still have the same problem but will idle smoother but it might blow out the bottom end

or I might rebuild the motor and have the problem still there but at least I'll have a fresh motor

need a clutch too

James Woods

iTrader: (1)

So when you had the "worthless toyota of riverside" diagnose your truck, when did you drop it off to them? Was it that night and let them keep it overnight to cold soak to be able to duplicate the scenerio that you are having, or did you just stop by and hang around while they looked at it pressured by the fact that you needed it back right away?

I also don't think that giving the forum a little over 2 hours to wave a magic wand and find all your problems before casting us all off as worthless also is a great way to get people to help you out.

The reason I ask about the first question is because if your ECU is bad and never leaves closed loop, then that could be a problem. The best way for a mechanic to diagnose a problem is to be able to recreate it, also did you stick a OEM Toyota IAC on there or did you go get the one from Autozone? Although it is uncommon to get a new non working part, it does happen and when using auto part store stuff over the factory stuff your chances of getting a bad part goes up.

Why not return to the Toyota dealer and tell them your story and see if they can't look at it again for no charge and see what they might find?

dustrider

I did that
The Toyota service writer said all they could do was tear down the engine

I installed the totally overpriced precious $300 toyota OEM IAC
I had a feeling it was a retarded lame diagnosis but gave it a try anyway thinking the pros had some edge over lil 'ol hillbilly trailer park diagnostic me

I was hoping the toyota dealer had more experience and test equipment than I do

I dropped it at noon and waited till 4pm

if toyota cannot test an ECU after cooling for 4 hours then I render them worthless

I dont have an endless supply of money to sink into an old wore out truck and I live up on a mountain with nobody to give me a ride and I figured it would be worth a try

maybe I shold leave it overnite so they can misdiagnose it again , them let them tear down the old motor and maybe the bill will be who knows what @ $2,000, $5,000 ? maybe replace the motor and still not cure the idle speed at cold start ?

they didnt find it
it was worth a try for $100
taking their stupid advice and trusting them cost me another $300 on top of that

so I lost $400 on the deal
I should have trusted my intuition and cut my lossses right there
or maybe I should leave it overnite and throw down some more ?

thanks for the tip on the ECU

I am suspecting that , its worth an $1100 spin of the wheel I guess
I was hoping the "experts" and all their toyota diagnostic equipment could confirm it

in fact hot or cold a trace at the ECM would confirm no signal IN from the teperature sensors or OUT from the ECM to signal the IAC to switch

instead the toyota dealer dropped the ball and didnt even try they just wanted me to drop it off with a big blank check or not waste their time with small potatoes

however I suspect the tech never even plugged into the ECM because it was running OK and just made a wild guess at the typical IAC problem
Or I could just goose the gas so it doesnt stall and save all the money and time and aggravation of throwing grossly overpriced toyota OEM parts at it until something sticks, just like what the dealer does

my edjumacated guess is that I would have left it overnite and they would have just said the same thing "needs a valve job $1500 + parts to start and we go from there"
I know it needs valves, but I just want it to stop stalling at cold start right now not an overpriced valve job that might take out the bottom end

actually I know for a fact that I can do a better job and do the valve job myself send the head to a machine shop and do the total job for about $500 where it would be about $2500 at the stealership

scuba

How long have you owned the vehicle?
Have the valves ever been adjusted?

The 2.7 has a bad habit of the exhaust valves getting too tight and either burning a valve or cracking the head.
When they did a compression test did the do a leak down test as well to rule out the bottom end as the cause for low compression?
My guess is you have a cracked head or a burnt valve.
Do a clearance test of all the valves and post up the numbers. The sticker on the underside of the hood or the FSM will show you proper numbers.
If the valves are too tight, you could try shimming them first and go from there. DIY should only be about $150. If you still have the issue I'd pop the head off.

I can get a video tonight of my 2.7 at cold start and post it up to YouTube by 11 if you think it will help.
Fwiw, cold start idle is 1250-1500 and should settle down to 750 when warm.


Where is pismojoe when we need him?!? Lol.

dustrider

this is an extremly difficult diagnostic problem

I dont expect to get any love from a dealer (or an internet reputation defender) the dealers are in business to make money, not help out a broke hillbilly like me, they got people with real money in the customer waiting area in business suits working on their laptops, sipping on starbucks they don't need me

I ran through all the typical things that cause it

I was hoping someone had something that would help

I have tried everthing but a new $1100 ECM

and a $3,000 + engine rebuild

and the truck is mabe worth $4000 maybe get 5,000 if its all rebuilt

so that makes it a live with it or leave it situation and toyota is no help at all but thats OK because it is just another old clunker and 200,000 miles before it exceeded the cost effective repair level is OK

I bought it last july with 157,000 for $5500
and it now has 201,000
put on a 3" level lift bilsteins, BFG's, brakes and exhaust manifold ( another $1800)
the AC compressor clutch just went out and its due for a clutch

I could sell it for $3000 on craiglist and come out ahead instead of dumping $3000 + into repairs at a stealership .
or if I do the work myself the $3000 would go a long ways towards a motor rebuild, clutch and AC compressor