cold start 4ltr 1999 explorer

[and11]

Hi back again i know this has a few posts on here about this problem but this as only become a problem for a short time when i start the engine from cold it starts 1st turn of the key revs to about 1200 rpm then drops to a good lumpy tick over then revs up then back to lumpy ' then if i drive away it revs and i don't have to touch the throttle for about 1 mile then all back to normal revs.
Jobs that have been done chains / guides full service AIR CON totally removed could this be related or is there a valve that could be the problem any answers would be great cheers

 

[J_C]

I'd check to see of the throttle body is sticking and hook up a scan tool to look at the throttle reading while it's happening... if not sticking, maybe the TB position sensor. I'd also check for a sticking throttle cable.

It would seem odd to me for the above to cause this only for the first startup and mile driven, but stranger still if it were happening (only) then from being off timing or a bad valve. Did the problem start happening immediately after the timing chains were done, or did some time pass?

Then there's the two bulk connectors: 2nd gen issues? Try this first!

 

[Fix4Dirt]

is it a vacuum leak? not too sure i 100% understand, but is it where it has erratic idle (ie. high, then low, then high again?) had a vacuum leak liek that that went away when hot (or at least it wasnt large enough that i would notice)

 

[and11]

I'd check to see of the throttle body is sticking and hook up a scan tool to look at the throttle reading while it's happening... if not sticking, maybe the TB position sensor. I'd also check for a sticking throttle cable.

It would seem odd to me for the above to cause this only for the first startup and mile driven, but stranger still if it were happening (only) then from being off timing or a bad valve. Did the problem start happening immediately after the timing chains were done, or did some time pass?

Then there's the two bulk connectors: 2nd gen issues? Try this first!

Thanks for replying it didn't happen strait away but it seemed to creep up on me if you know what i mean it only happens on 1st start up and runs perfect and well before one minute of driving or not moving . Throttle is free and cable not sticking , is there a cold start solenoid on these is it anything to do with the 2 solenoids in the middle of the inlet manifold , and were are the bulk connecters are they the square ones with the bolt in the middle thanks again

 

[donalds]

I vote intake gaskets
...aka vac leak...
I've been here with my 99
Before mods of course

 

[XLTrunner]

Intake gasket leak would certainly be a likely suspect...although, one would think it would set lean codes. At least that's what mine did under similar conditions. IAC?

 

[Fix4Dirt]

I vote intake gaskets
...aka vac leak...
I've been here with my 99
Before mods of course

yesyesyes! mine did that from there too! also the IAC Y piece did another leak at another time!

 

[donalds]

Can try to clean the iac
I'd try a DIY smoke test in the morning when it will happen before starting it

 

[J_C]

Thanks for replying it didn't happen strait away but it seemed to creep up on me if you know what i mean it only happens on 1st start up and runs perfect and well before one minute of driving or not moving .

Your wording is confusing, this above seems to contradict what you wrote previously. Like others I would wonder about a vac leak and check the long term fuel trims with a scan tool.

 

[and11]

Hi what i was trying to say is it did not have this cold start problem after doing the timing chains but a few weeks after it started to have a slight misfire after start up then idle fine now it seems to misfire for longer before it settles down basically getting worse

Your wording is confusing, this above seems to contradict what you wrote previously. Like others I would wonder about a vac leak and check the long term fuel trims with a scan tool.

Sorry what i mean is it plays up on cold start but runs fine after about 1 minute
. I did remove the upper intake manifold when i did my timing chains so i now suspect as you have all said it is more than likely the gaskets so i will check today thanks all

 

[J_C]

Did you try to reuse the 23 year old, old gaskets? Those, fuel injectors, just about anything (maybe not the IAC valve gasket) that old will need replaced if disturbed. If you did replace them, on some engines it is recommended to re-torque the bolts after ~ 100 miles as the gasket can compress some.

 

[Fix4Dirt]

also not sure if 99 still had this, but the Y by the IAC, later revised as an elbow was leaking on mine, it would get disturbed every oil change, as I had to change air filter so that joint flexed, as the tubing is quite rigid imo, so no wonder ig ripped over time!

 

[and11]

also not sure if 99 still had this, but the Y by the IAC, later revised as an elbow was leaking on mine, it would get disturbed every oil change, as I had to change air filter so that joint flexed, as the tubing is quite rigid imo, so no wonder ig ripped over time!

 

[and11]

I have looked today and re torqued the inlet manifold gasket and cleaned the iac lubricated the throttle linkage started up and it was a lot better not so much erratic revs so i might be looking for some new gaskets but over here in uk i prob have more luck finding rocking horse !crap! . Also as a experiment i have blanked my EGR and i must admit runs smoother when at norm running temp that it ever as done no light on dash but my EGR has no electrtial connections so i do not expect any problems but we will see cheers guys

 

[Fix4Dirt]

doesnt egr reduce temps? im not too versed on this, but iirc it reduces temps. imo, i would reconnect the EGR, but maybe im wrong

 

[donalds]

doesnt egr reduce temps? im not too versed on this, but iirc it reduces temps. imo, i would reconnect the EGR, but maybe im wrong

You are absolutely correct
Also to add
The burnt exhaust gas takes up space in the Combustion chamber
So helps on gas mileage to

 

[and11]

Hi i haven't been out for a drive yet but i will see how it goes with EGR deleted if it is no good or if i notice any fuel consumption difference or temp changes i will remove it. Also i have found some intake gaskets of ebay from a place called Gill in colorado £40 delivered cheers again