Chugging Idle/almost dies

[EclipticalGS]

Im at a loss with this idel problem in my 420a. An explanation of the noise is it idles at 750 rpm and it chugs up and down about 2 times /second. Anyway Today i tore the IAC out and it turn out that the middle two prongs were torched and had no resistance. So i replaced that. Then i went about replacing my TPS sensor cause that looked a little banged up. Nothing changed. Then i checked over my egr valve and that recirc tube that goes into the intake manifold. All those connections were tight and sealed. Then i checked and replaced every single fricken vacuum line going out on a hunch that that was it. btw my vacuum gauge is at 15??out of 30 at idle. So then again nothing changed. I guess what i can ask is that could my "Boop boop boop boop" idle be from a MAP sensor?????could it be from 2 02 sensors??? Should i check my cylinders for compression??? check fuel injectors also maybe.

Also my spark plugs, wires, etc are brand new. How can i check my ignition coil??

 

[cougarelimin8or]

If I were you I'd check your EGR again, remove the valve and make sure the plunger is fully closed. Carbon deposites can build up inside it and keep it open. If the valve checks out ok than get something that blows air and blow out the passage that leads to the exhaust and make sure it's free from blockage and likewise to the passage that leads to the intake. That will eliminate the EGR from your list.

 

[EclipticalGS]

ok to check the intake gasket should i like spray some type of combustable crap around it to see if idel changes?? and to Cougar..are you talking about taking off the EGR valve part that goes into the front right of the block??? where that egr solenoid/ vacuum lines are?? ### i have not done that yet. What do i do when i open that?? thanks!!

 

[SpyderDSM]

also double check that the ignition wires are all connected properly and to the correct cylinders, it sounds like you're misfiring

 

[EclipticalGS]

it does sound like a chugging misfire but there in the right spots 1 4 on the box and 1234 across the valve cover. 2 3

 

[SpyderDSM]

and spark plugs are gapped at .028 and you used dielectric grease for the wires? thats rough

 

[markdr7]

I had a similar problem to that a little while back. Mine ended up being a bad MAF sensor. Luckily it's a cheap fix at around $30 if thats your problem. Good Luck

 

[EclipticalGS]

yeah the plugs and wires have been swapd out many timez so there not the problem...how can i check the ignit coil??? can i test with my voltmeter somehow??? my car has no maf sens. it has a map tho

 

[toxicity883]

the stock coil is pretty bad about going out on the 420a, autozone can check sensors just hope you get a competent employee

 

[cougarelimin8or]

ok to check the intake gasket should i like spray some type of combustable crap around it to see if idel changes?? and to Cougar..are you talking about taking off the EGR valve part that goes into the front right of the block??? where that egr solenoid/ vacuum lines are?? ### i have not done that yet. What do i do when i open that?? thanks!!

You'll take those two bolts off that go to the side of the head to remove the EGR. Than look at the part that bolts to the side of the head, that's where the plunger is.

 

[EclipticalGS]

Ok. ill do that cougar after work tomorrow.. and about the ignition coil..can i check that myself?? what do you mean about going to autozone to check sensors??

 

[EclipticalGS]

so when i take off that EGR valve can i see if its stuck open a little?? and can i try to suck through a vacuum line to see if it opens up the right way???

Its sounds like a mechanism that if i started my car up immediately and sucked through that egr vac line while the car was running, it would shut the car off bcuz of the added carbon in the intake mani. maybe im wrong. ill just take her apartttt

 

[cougarelimin8or]

The plunger will be under spring pressure, I doubt you'll be able to open it by sucking. Just take a small pocket screw driver and push it down and make sure it opens and closes and seals shut when it does. The carbon deposits are what would keep it from closing properly.

 

[EclipticalGS]

ok im at work but a mechanic said that if the vlave is open a tiny bit it can make rough and crappy idle after warm-up..i think i found the problem. ill tell ya if its fixed in a few hours

 

[EclipticalGS]

ok so i had the egr valve out and in my hand, i wire brushed it and blew it out. The pintle part was able to move up and down with me sucking on the top vacuum line. So its not defective right?? I reinstalled it and everytime i would move the pintle and open up the valve when it wa idling, it would choke and sput and almost die. So maybe the egr valve can open really good but maybe it cant close all the way?? but i know it works..but may be stuck open still. I even sprayed some carb/choke cleaner in there and shook it up and blew it out so i think the egr is fine..idk.. what you guys think??

 

[VZRacing]

It could be the Idle Speed Control Motor, I had that die on me recently. A Haynes manual should tell you how to check to make sure it's good. I forget how off the top of my head it's pretty easy though just need a volt/ohm meter.

 

[EclipticalGS]

Ive done everything so far except for map sensor, ignition coil, 02 sensors, compression, fuel injectors and timing.. How can i check timing and how will i know if its a little retarded or advanced??? the guy before me did a new head gasket and timing belt and i doubt he did it right he was a great wire twister/taper.

PS..ive noticed something different about the noise...the car will start up and idle at like 1100 rpm for about 20 seconds until it warms up and the idle is perfect...but when it drops below 1000 rpms, its starts to get its "boop boop boop" like 2 times a second.

and to VZ..my car doesnt have an idle speed controller. It has an Idle air control valve which was already replaced...