Thermo Time Switch for '87 5ktq? [was Fuel Pressure Testing - 5ktq - where to tap?]

[Ben Swann]

It looks like I have a faulty Control Pressure regulator, but I don't see
how that explains the system leakdown.

See comments below - total leakdown overnight both control and system
sides.  Stone cold control pressure was 45 PSI - Bad Control Pressure
regulator?

Has anyone been able to clean these.  I did one on a Dasher years ago.  Is
the one for the 5kq similar?

Ben

On Thursday, April 11, 2002 10:34 PM, Ben Swann
[SMTP:bswann at worldnet.att.net] wrote:
> Well something would seem to be.  Here are the results of the pressure
testing.
>
> Note: I used two guages and can shut off either side.  The system side
guage tended to read a little higher, so I give a range, or an average of
the two.
>
> Ambient temp = 67 degrees
> Engine cold, not started, warmup reg. connector unplugged:
> Cold Pressure(engine not running, fuel pump only): 15-18 PSI
> System Pressure 88-91 PSI
> Shutoff Pressure, engine not run - System side only: 50 PSI
> Shutoff Pressure with Control side open: 43-45
>
> Engine started,
> Control Pressure: 30 PSI upon startup
> System Pressure: 90 PSI upon startup
> Control Pressure 5min into warmup(fan not running) 35 PSI
> Control Pressure (Fan just coming on): 38 PSI
> Control Pressure ( Fan Cycling): 40-45 PSI
>
> Residual Pressure(s) -
> Hot just after shutoff: 47 PSI
> 5 min after shutoff: 45
> 10 min: 43
> 20 min: 42
> 1 hour: 40
>
> I checked about 4 hours after testing: 0 PSI - there was total leakdown
in the system!
<snip>
> Currently, I have both valves closed, to see if either or both sides have
leaked down after sitting.
>
Overnight - total leakdown on both system and control side.

Charged system with fuel pump running, and control pressure measured at
45PSI - so is control pressure regulator the culprit?


> Also, checked the thermo sensors - both were 0 ohm hot, 1.5k ohm cold.  I
would think since both had identical readings, they are both good, except
for the 0 resistance when hot.  Perhaps my meter is not reading right.
>
> Also, in addition to going over all potential vacuem leaks many times, I
did the propane test, which revealed nothing.
>
> Anyway, it would be nice to nail this problem.
>
> Thanks for the tips so far.
>
> Ben
>
> '87 5000 tqa Pearl - Engine rebuilt and running...Elgin 270i260e cam,
lifters & techtonics springs, new rings and bearings, seals.  T03/K26
hybrid turbo, 2-Piece Exhaust manifold, highflow cat and 2.5" Stebro
exhaust.  Bypass valve and supplimentary fuel injector installed(but not
connected to fuel yet) in intercooler. 200 Flywheel, Clutch and Pressure
plate.  Using existing QLCC chip & Schrapnel Knob for control - set for 1.7
bar max during break-in.
>
> On Thursday, April 11, 2002 5:08 PM, Huw Powell [SMTP:human747 at attbi.com]
wrote:
> >
> > > Yeah, I got the guages hooked up, and so far don't see anything out
of spec.
> > >
> > > I have not done warmup tests, only cold with fuel pump running,
engine off.
> > >
> > > System Pressure = 88-90 PSI
> > > Control Pressure = 30 PSI
> >
> > I *think* that control pressure should be lower when cold, more like 15
> > psi or so. (goes to 45-50 or so when warm)
> >
> > So your warm up reg might be at fault.]