New 5ktq, new problems...

[Doyt W. Echelberger]

Hello John....I'll just tell you what I had to do at times with my 87 5ktq.
Maybe some of the same will help you.

First thing, I'd replace the entire throttle switch, since all the
originals failed at the internal solder joints and people drove them that
way for years.....microfractures develop, resistance goes up. This switch
is also the WOT switch, and may be the source of your failure to deliver
extra fuel for the boost phase. Even the electrical connectors to this
switch are suspect.

Second, I'd pull out the washer fluid reservoir, being careful not to
fracture the supply hose to the wipers. Disconnect the electricals of the
washer pump first. Now FEEL all along the heavy rubber hose between the
lower wastegate chamber and the intake manifold. That hose tales a lot of
heat, and ages fast, and hardens up, and then crumbles into dust which gets
pulled into the intake, leaving nothing but a fabric shell that covered the
hose. But it looks like a good hose to casual inspection. Replace that hose
if you find it to be faulty.

Third, I'd FEEL all around the base and lower half of the crankcase
breather hose, checking for soft spots and actual faults in the hose.
Replace it if you find it defective. Follow this hose on up to where it
attaches to a metal tube, and continue to examine all the connections to
the several other vacuum hoses in that area, especially the ISV. There is a
small vacuum hose in that area that attaches to a tiny opening in the
intake manifold, and mine was out at one time.

Fourthly, I'd look at the attachment of the vacuum hose that fits on a
nipple UNDER and to the engine block-side of the throttle switch. Very hard
to see or even get at. May be disconnected or hardened up and fractured.

That should keep you busy for a few minutes.

Doyt Echelberger
87 5ktq in Ohio   USA



 >>>>>>>>>>>>>>>>>>
At 05:29 PM 7/12/2003 -0400, you wrote:
>Well I finally got the new 5k. The car looks great, but unfortunately
>doesn't run as good as it looks. What I got is a misfire that only occurs
>at the verge of boost, basically every time you give enough throttle to
>bring the boost to the .9bar area the engine starts missing. No codes
>showing, and no visible problems (ie. all intake boots apear to be
>healthly enough, no cracks, micheling man is a bit on the soft side but
>not broken). I've already replaced the plugs and fuel filter with new, and
>the plug wires and cap with good used spares. Also tried a second ECU, but
>I kinda knew that wouldn't help. Fuel pressure is fine, just shy of 3.5bar
>when running, a tad over 4bar dead head pressure.
>
>Stale gas was suspect, so I pumped out the tank and gave it 5 gallons of
>fresh 93. The old gas was a bit on the nasty side, but nothing bad enough
>to gum up anything.
>
>Any ideas?
>
>-Cody Forbes
>'87 5ktq - Black beauty
>'91 80 - still debating on turbo