FI vs. Carbs

effvee · Post by **effvee** » Wed Jul 26, 2006 11:28 pm

Here in So Cal, there is triple digit numbers and then it rains. Now the heat is to much

richcarl32 · Post by **richcarl32** » Sat Jul 29, 2006 9:10 am

i had a clyde from the vw club of athens visit me today, fuel pressure is good, liter per minute with no regulator, 42 lbs at .9 liter perminute with regulator. also ihave a new situation here. the engine will crank fine but will only run for 2 or three seconds. then it quits. this sis the first time i have ever heard her run at all. i am soooo excited about it. okay, she is timed good enough, and now what guys.

krems · Post by **krems** » Fri Aug 11, 2006 7:06 pm

MASSIVE TYPE IV wrote:The progressive sucks. Period.

I never had any luck with them on TIV engines, all they do is cause rich running, tuning problems and ice up in the winter...

hmm, the 1.8 im looking to buy is noted by the owner to be sluggish, thing is it has the silly progressive carb on.

i should probably look to test it with some 44 IDFs before tearing it down to inspect it eh? (although i'll probably do that anyway)

dr. no · Post by **dr. no** » Sat Aug 12, 2006 9:41 pm

Temp II sensor (CHI on #3)

richcarl32 · Post by **richcarl32** » Sun Aug 13, 2006 7:07 am

the temp sensor II is fine. i tested it yesterday and it was at 1826 ohms @ 90 degrees. i checked the scale and it is in the ballpark of 2500 ohms @ 68 degrees.

raygreenwood · Post by **raygreenwood** » Mon Aug 14, 2006 10:02 am

How is the boot between the AFM and the throttle body? It sounds like the afm switch that is suposed to keep teh fuel pump running after you start cranking...is not working.

Try this. Wire teh fuel pump direct to the battery to run constant. Now crank it. Ray

richcarl32 · Post by **richcarl32** » Mon Aug 14, 2006 4:05 pm

boot is in great shape. no cracks at all. the elbow at the aux air reg is toast though. i also had a leak at he tee onb the brake booster. i hope this is it.

raygreenwood · Post by **raygreenwood** » Mon Aug 14, 2006 4:52 pm

The quick way to test an handfull of things is just to temporarily wire the pump direct to the battery. This iwll tell you that the engine runs aand allow you to tune it.

Its quite possible that the flap in the AFM is stuck and not properly moving. The way this thing works...is that when the flap is closed...ie....engine off....the fuel pump goes through its two second "buzz" cycle when you turn the key....pressurizing the injection system. Once you start cranking...the airflow pulls the flap off of its stop....allowing a switch to close...which allows the fuel pump to run constant when the key is released.

If you have huge vacuum leaks...and the elbow on the AAR....and the brake booster port...might together just qualify when the engine is cold......they may be allowing enough air to bypass that flap that the switch does not get closed to allow teh fuel pump to run constant.

Or you could have a bad connector or a sticky switch inside teh black box on teh AFM. Ray

Post by **Piledriver** » Mon Aug 14, 2006 9:15 pm

Ray Sed: "90% of all FI problems are wiring harness related."

...But 95% of all "FI" problems are really ignition issues.

There's a big line that goes to the charcoal canister, too...

Time to hotwire the pump temporarily and break out the unlit propane torch.

raygreenwood · Post by **raygreenwood** » Tue Aug 15, 2006 7:06 am

Yup....thats pretty much correct. About 90% of all EFI problems.....not immediately traceable to the ignition...are wiring or connectivity related. It really is true. Most of the last 10% are vacuum leaks and fuel pressure related. Ray

Clatter · Post by **Clatter** » Tue Aug 15, 2006 4:33 pm

Check the hose that goes to the charcoal purge dealie on the back of the airbox.
A leak on that sucker is at the throttle plate...
Check, or better yet plug up, your EGR...
They erode, and leak all the time, too.

What was that guy's name who rebuilds EFI harnesses again??
he still doing that?

Those '79-Only, Cali-Only wiring harnesses are worth saving!

richcarl32 · Post by **richcarl32** » Tue Aug 15, 2006 7:07 pm

how do you plug up an egr? what does the charcoal dealie do?

raygreenwood · Post by **raygreenwood** » Wed Aug 16, 2006 10:41 am

The charcoal cannister captures all of that expensive fuel that is evaporating in your fuel tank as it sloshes around....and allows you to at least burn it in your engine....instead of venting it to air. Its not entirely great for efficiency...but at least you are not venting to the air and losing it altogether and creating smog. It has a vacuum line that goes to it. It must not leask. In general you are allowed "0" vacuum leaks of any kind in the system. Ray

richcarl32 · Post by **richcarl32** » Thu Aug 17, 2006 12:42 pm

how do you plug up an egr?

Clatter · Post by **Clatter** » Thu Aug 17, 2006 1:58 pm

EGR stands for "Exhaust Gas Return" and it was a dumb idea they had to try and reduce emissions.
There is a tube about 1/2" that goes from the exhaust on the left side of the engine, through a little metal box (that always rusts away) and into the plenum, or intake manifold.
Take the thing off, and note the pattern where it bolts up.
Make a metal plate with the holes in the right place to block it off.
Some people just blob it shut with silicone, but it might get sucked into the engine.

Air leaks are a progressive type of disease.
A really big hole, like one of the hoses being gone altogether will give the symptoms you describe.
Smaller ones will cause your engine to run lean and die early, but seem to run fine (until it dies).
Go over every hose. Double-check with a known good van to verify all is right.
What you describe sounds to me like a big fat hole somewhere.

Oh, yeah, and thank Jake for hosting this thread.
This is really the "Jake Forum", and most all of your questions have been answered somewhere before on the FI forum.

http://www.shoptalkforums.com/viewforum ... e88de962f4

Shoptalkforums.com

FI vs. Carbs

In SoCal

fuel pressure good