Thermo Time Switch for '87 5ktq? [was Fuel Pressure Testing - 5ktq - where to tap?]
rob3 at hod3.fsnet.co.uk
Fri Apr 12 19:30:36 EDT 2002
To me it sounds like your SP is high and your control pressure
consistently low. I'm no expert but IMHO 5bar is a good SP and 3.5 - 4 bar a
good warm CP. Easiest next move would prolly be a warm up regulator
substitution and re-check.
In general Low CP = Rich mixture.
Also when warm, try disconnecting the CSV wire to see if it starts better
In case it helps here's some readings I got recently
Cold, Jumpered FP - 1.2 Bar (~18psi?)
Warm 3.8 Bar
Hot(fan cut in) 4 bar (65 psi)
System 5.5 Bar (77psi)
residual t0 3.5Bar,
----- Original Message ----- >
> Message: 8
> From: Ben Swann <bswann at worldnet.att.net>
> Reply-To: "bswann at worldnet.att.net" <bswann at worldnet.att.net>
> To: 'Ben Swann' <bswann at worldnet.att.net>,
> "'one at humanspeakers.com'" <one at humanspeakers.com>
> Cc: 'Bernard Littau' <bernardl at acumenassociates.com>,
> "'quattro at audifans.com'" <quattro at audifans.com>,
> "'quattro at isham-research.com'" <quattro at isham-research.com>
> Subject: RE: Thermo Time Switch for '87 5ktq? [was Fuel Pressure Testing -
5ktq - where to tap?]
> Date: Fri, 12 Apr 2002 08:58:23 -0400
> Organization: Swann Family
> 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
> Has anyone been able to clean these. I did one on a Dasher years ago. Is
> the one for the 5kq similar?
> 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
> > 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!
> > Currently, I have both valves closed, to see if either or both sides
> 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.
> 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
> bar max during break-in.
> > On Thursday, April 11, 2002 5:08 PM, Huw Powell
[SMTP:human747 at attbi.com]
> > >
> > > > 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
> > > psi or so. (goes to 45-50 or so when warm)
> > >
> > > So your warm up reg might be at fault.]
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