L jet issue? or maybe ignition... runs for 2 minutes

vwfye · Post by **vwfye** » Thu Apr 28, 2005 11:53 am

then it shuts down, restart and after 30 seconds, shuts down again and so on. let it sit awhile, then the routine starts over. bad coil? valves tight? this is a car i am just picking up and would like to drive home. i have the FI tester, and troubleshooting guides, but i was hoping someone might have a "been there, done that" short cut. 74 with L jet on it. thanks!

DeathBus · Post by **DeathBus** » Thu Apr 28, 2005 2:14 pm

Go through and do a whole tune up, points plugs, wires, adjust your valves. After if it keeps doing it check fuel pressure. You might even have a clogged filter, pump or tank.

Guest · Post by **Guest** » Thu Apr 28, 2005 2:17 pm

i have been reading the posts in the 412 forum and the bosch manuals... wow, that is alot to digest. the manual suggests the CHT sensor/Air Flow Meter and the post suggest fuel pressure/regulator or a clogged sock... so, at least i have a few directions to look at 1st!

vwfye · Post by **vwfye** » Thu Apr 28, 2005 2:18 pm

ooops, that was me

DeathBus · Post by **DeathBus** » Thu Apr 28, 2005 2:20 pm

Anonymous wrote:i have been reading the posts in the 412 forum and the bosch manuals... wow, that is alot to digest. the manual suggests the CHT sensor/Air Flow Meter and the post suggest fuel pressure/regulator or a clogged sock... so, at least i have a few directions to look at 1st!

Always start with the easiest 1st, a tune up, then look at the harder stuff. if you are leaking ANY gas, the fuel pressure will not be right and the car wont run right. If you have a plug that is misfiring the car wont run right. Make sure you do these 1st!! Did I get my point across?

raygreenwood · Post by **raygreenwood** » Thu Apr 28, 2005 5:46 pm

If it was a CHT...and it was reading incorectly...and maxing out and shutting you down....it would not restart after 30 seconds easily. There would be little or no change to that sensor over quite a few minutes.

This sounds like the classic symptoms of a clogged sock filter in the tank. If it was the AFM....it wouldn't do this anyway. There is nothing time related in that unit. If it ran for two minutes...it should run.

This is a fuel issue. You either have a clog...or a weak pump...or a clog causing the pump to overheat quickly.

Also check for vacuum leaks. If the auxiliary air reg is not closing...and the fuel mixture is a bit off in baseline...it could cause this.

Yes...a simple tune-up is recommended just to cancel out a lot of potential variables. Ray

vwbill · Post by **vwbill** » Thu Apr 28, 2005 6:22 pm

I would read Longbeach's post about something alot like the problem you are having! Ray will always send you in the right direction! I think Longbeach's issue ended up being the fuel pressure regulator but it doesnt hurt to check out the components and fuel system along the way.
I would get a fuel pressure gauge and test the pressure at the left fuel rail test screw! If you read the Longbeach post Ray describes a way to bypass the fuel pump relay system to run the pump on its own so you eliminate that stuff and its a good thing to carry with you in the glove box.
I would get a multimeter if you dont have one to test the components.
Good luck! Bill

Guest · Post by **Guest** » Fri Apr 29, 2005 8:06 am

i read longbeach's troubles yesterday. interesting stuff. the 1st thing i will do with the system is check fuel delivery.

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L jet issue? or maybe ignition... runs for 2 minutes

L jet issue? or maybe ignition... runs for 2 minutes

check out LongBeach's post about his Ljet problem!!!