random lt1 issue help!

[townsend]

hey guys so the mods are now on hold. i need to figure out what is going on with this thing.

it seems as though its randomly running out of fuel/retarding spark. right off idle pulling away from a light and when cruising barely touching the pedal then pushing it down to accelerate 5-10 mph, the motor "chugs" for a second. it only does it when the motor is warm. if i let off then push back down it smooths right out. im kinda at a loss right now considering it has good gas in it and a relatively new msd billet opti. any suggestions will be appreciated.

i have been reading about the ignition module going because of its placement on the drivers side head. anyone else had this start to go and act up?

[sweetbmxrider]

That will usually give you extended cranks, you should space the coil off the head now anyways. I would take some carb cleaner and clean the throttle body blades and opening some. Maybe reset the computer after and see how she runs after it relearns idle etc.

[townsend]

FIXED!! for now...unbelievable how a msd billet opti comes with vacuum hoses that are cheaper than the air hoses for my fishtank. 2nd broken one in a week...time to replace all vacuum hoses since p.o. said they are all original. plus the maf is oily from the air filter.

[LTb1ow]

MSD units do not come with hoses. So, odds are,their stock.

[greenformula92]

yes sir those would be stock hoses. and just as a FYI the ICM usually doesn't give you any warning, you will be driving down the road and all the sudden it will just die. then when the engine cools and the ism cools it will start and you can try to get it home.

[townsend]

yeah just got home with new hoses...they must all be original hoses because they are all cracked..

[townsend]

Well now I have an issue. It's still acting up. Put all new vacuum hoses on and cleaned maf, but it still randomly chugs off idle. I also have a nasty smell coming from underhood almost like really hot metal mixed with rotten eggs. The car has a new highflow cat so I doubt that its burning out already. I'm going to try to get a video so everyone can atleast try to see it when it acts up looking at the tach.

[greenformula92]

any codes?

[townsend]

nope no check engine light nothing....jumped out aldl and got nothing.

[townsend]

uploading video now i apologize for my complaining and your probably going to have to turn up your volume.

[greenformula92]

hmm. the rotten egg thing begs clogged cat but you said it was recently replaced. not saying that cant be it but chances are it isn't. does this only happen when warm, or is it all the time?

[townsend]

now its starting to become all the time cold or hot...it seems to be getting worse. you will see and hear when the video finally uploads to my photobucket. its like its either cutting most spark and missing all over or losing all fuel and missing all over.

[townsend]

here it is listen from 14 seconds on and ignore my talking...if you turn it up you can hear it go "pop pop pop pop" then it smooths out all of a sudden

[zraffz]

How long does it take to start when you crank it? What do your plugs look like?

Check your fuel pressure, bust out a can of ether and spray all the vacuum hoses.

[greenformula92]

check you fuel presure, check plugs and wires and look for any and all vac leaks. Whens the last time the fuel filter was changed?

[townsend]

fuel filter is questionable i asked previous owner and he said he didnt know a while maybe so im gonna change that today. also im gonna start checking every plug and wire. vacuum leaks should be nonexistent unless its a gasket mating surface

[townsend]

oh it starts right up when u crank it doesnt take more than 2 or 3 seconds cold

[JL8Jeff]

Does it still have the AIR stuff hooked up and the EVAP stuff? If the EVAP solenoid goes bad (it's on the side of the intake) it might allow air to be sucked into the intake all the time which will act like a vacuum leak. You might need someone to scan it to check the fuel trims.

[townsend]

yes all emissions are in place...i dont know anyone who could scan it..worst part about this is that there are no codes at all and its not everytime you hit the gas, although it is now doing it more and more

[zraffz]

Use a can of ether and get spraying. You'll quickly find out if you have vacuum leaks still.

Next do the fuel filter. Check fuel pressure. Check out your plugs and mist your wires when it's running (at night) to see if it arcs anywhere. Is your MAF damaged by any chance?

[townsend]

not sure if maf is damaged i was super gentle with it and i just cleaned it last night. after reassembly it got worse. your saying to spray the connections of the vacuum lines with ether? all i have is carb cleaner and starting fluid

[greenformula92]

unplug the MAF and see if that changes anything. it will give you a code but the ECM will just use the MAP for fuel trim

[townsend]

ok trying it right now

[zraffz]

Starting fluid = ether. Don't use carb cleaner, I think that would do more bad than good to your lines. Mist it over your vacuum lines and any place you have gaskets preventing vacuum leaks (ex: throttle body) while the vehicle is running. If their is a leak the idle will raise.
It's the fastest and easiest way to find vacuum leaks without owning any special tools.

[bigz28man]

Did you check the fuel pressure at the rails? Had a similar problem a few years ago, found out I had not enough pressure at the rails. Every time I would hit the gas it would fall on its face. Let of the gas and it ran at idle fine. Also check maf sensor as stated above, anyone you know that could swap theirs out to rule that out.