Re: [T3] FI woes - help!

[jadney@vwtype3.org]

On 20 May 2007 at 10:29, Chris Slaymaker wrote:

> I just got this car last weekend and so this weekend I thought I would
> do a tune-up and familiarize myself with it. 

> I drove fine from Denver to Knoxville.
> 
> This is what I did:
> 
> Adjusted valves - several were tight

> Tried to adjust points, but could not get dwell above 42 degrees, so I
> put in a Pertronix unit I had for my bus (but hadn't installed yet. 
> Now the dwell is at 52 degrees, and I'm OK with that. 

I'd be curious as to what was wrong that didn't let the points adjust any closer than 42 
degrees, but you've proven that this is not your problem.

> Changed the oil and cleaned the air cleaner.  While it was out, I
> cleaned things up in the engine compartment.  This may have been my
> downfall. 

> Compression is 125# on all but #3 which is 130#

Sounds fine.

> Spark plugs were whitish on the electrode ground (lean?), but the tip
> was OK and the threaded portion was black (not the threads) 

Sounds fine.

> Now at idle, the RPMs fluctuate about 50 to 100 or so.  When I
> accelerate, it stumbles and backfires, then catches. 

Some idle fluctuation is normal. The stumbling on acceleration is not.

> This morning, I found that one of the crimp on connectors for the #4
> injector was loose. (This FI system has been kludged together more than
> once.)  So this time I soldered and shrink wrapped it. 

Sounds good. Note that it doesn't matter which injector wire connects to which side of the 
injector; they are not polarized. One other thing to check is that the female connector pins 
are actually snug on the male injector pins. They often get loose, and this causes running 
problems.

> Pulling the wires off the distributor kills the engine on #2, slows it
> on #1 and #3, but doesn't seem to have any effect on #4.  This is
> probably part of the culprit (still).  I checked all the grounds. 

Check each SP connector to verify that it shows about 1000 Ohms. If they are open, replace 
them. The SP connectors are separately replaceable. If you still have the original right angle 
dist cap connectors, keep them and covet them.

Check the charging system voltage: It should be above 13.5 V at medium rpms after a nice 
warmup drive.

Check the hose to the manifold pressure sensor. Make sure that it's connected on both 
ends. If this is a 70-1, suck on the pressure sensor (thru a clean hose) and verify that it 
holds a vacuum, at least for a few seconds.
-- 
Jim Adney
Madison, Wisconsin, USA


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