North American Turbocoupe Organization



First Test Drive!!!
Tedybear315 Offline
Junior Member
#1
Well,

Finally pulled the ol' bird out of the 'barn' and drove it down the hill.

Found a major cooling leak, and resolved that.  (coolant feed line to turbo, needed re-clamping)

Went a bit sneaky and the wife took it down the road and back.  Turbo managed only 5lbs of boost.  But all things considered?  Not to bad.

Transmission was very slow and sluggish to go into gear.  Found it was almost a quart low on Merc.  Added and it goes right into gear now.

Hopefully fixed the dead AM/FM cass. radio.  (blown light bulb and a dead push/click on/off volume switch.)  I'll find out Monday if that works.

Three issues still remain.  And sense I've been laid off while this 'virus' has NYS (and many other communities shut down)  I have plenty of time.

Issue #1:   Fans do come on when the car is first started, or when it stalls out.  We had it doing idle and it still seems to have issues with it going into high idle, and the temp creeps up a lot higher then I would like-Almost into the overheat zone.  When we first tried to pull the EEC codes, the engine almost overheated-  During the KOER test it didn't kick the fans on.  Radiator seems to be okay, as we took it down the road for a test drive and the temp gauge dropped back to midrange. 

Issue #2:   When the engine is cool or cold:  The engine seems to have a very high frequency vibration.  Doesn't seem to be miss-firing.  Just vibrates the whole car rapidly.  Goes away when things are warm.

Issue #3:   Idle seems to have a mind of it's own.  We where outside the car with it idling and it started to kick up to about 1500-1800 for several minutes and then settled back down.  We've cleaned the throttle body, and discovered the cruse cable was to short pulling the throttle plates open slightly. (corrected)   Now given the issue with #1 with the engine seeming to run "Hot" and the fans not seeming to come on-  I think the engine might be kicking the idle up to increase coolant circulation.   Or we could have a vacuum leak I've not tracked down yet.  I'll be tinkering with it and seeing what's up.

Any clues would be helpful.  It took off pretty smooth and ran decent.  Just concerned about these last 3 issues.

Thanks!
S-
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Jeff K Offline
Administrator
#2
When the temp gauge goes hot do the oil pressure and fuel gauges also go up? If so, the problem is a failing IVR. The IVR is a mechanical / thermal throwback to the 1960s and failure prone. I think you can buy solid state replacements available on Ebay or build your own for $8 or so worth of parts.

Check TPS closed throttle voltage. If over 1.0 Volt you will get high idle. Best to set it around .85 to .90 V. Be sure it returns to the same volts every time throttle is closed and volts increases smoothly as throttle is opened. Failure to return to the same closed throttle volts or volts dont increase smoothly as throttle opened = failing TPS.

Have you removed, cleaned and lubed the IAC? Vac leaks can also lead to high idle.

Vibration could be a missfire. Use ONLY the stock copper spark plugs or their NGK 2238 equivalent and Motorcraft plug wires (WR4011C). Never use Platinum plugs in a TC.

Both fans should momentarily kick on during KOEO test. Do they?
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Tedybear315 Offline
Junior Member
#3
(03-23-2020, 02:06 PM)Jeff K Wrote: When the temp gauge goes hot do the oil pressure and fuel gauges also go up? If so, the problem is a failing IVR.  The IVR is a mechanical / thermal throwback to the 1960s and failure prone. I think you can buy solid state replacements available on Ebay or build your own for $8 or so worth of parts.

Check TPS closed throttle voltage. If over 1.0 Volt you will get high idle. Best to set it around .85 to .90 V. Be sure it returns to the same volts every time throttle is closed and volts increases smoothly as throttle is opened. Failure to return to the same closed throttle volts or volts dont increase smoothly as throttle opened = failing TPS.

Have you removed, cleaned and lubed the IAC?  Vac leaks can also lead to high idle.

Vibration could be a missfire.  Use ONLY the stock copper spark plugs or their NGK 2238 equivalent and Motorcraft plug wires (WR4011C).  Never use Platinum plugs in a TC.

Both fans should momentarily kick on during KOEO test. Do they?

Temp gauge goes "hot" and the oil pressure gauge goes up with the increased RPM.  Didn't see the other gauges go up.  Now it's interesting that you mention the voltage regulator for the cluster.  The one on the current cluster had a minor case of the crusties.  So I swapped it out with the donor car cluster regulator that was in much better condition. (Looked new actually)

IAC was also swapped out with the donor.  It was clearly sticking badly and the idle was all over the map.  So the IAC replacement helped quite a bit.

I still need to back probe the TPS.  I did test it for dead spots and carbon tracking internally.  Smooth as butter with no jumps.  But that doesn't mean it's set correctly.  I'm leaning towards vacuum leaks.  The ol' girl sat for a number of years and it's a safe bet I'll need to replace all the vacuum lines with new.

Think I'm going to see about hooking up an old school temp gauge on the car and watch what happens in 'real time'.  It's circulating coolant decent,  we have a new thermostat installed.  It might just be a bad gauge or IVR.  Need to get a good baseline.  Maybe dig out my old IR temp gun..

Plugs are all 'new' and we went with autolites.  I usually love working with NGK (we run most with NGK and never had a complaint)  Autolites claim to be "OEM style".  Then again I can claim to be heir to the crown!  Doesn't make it true.

Getting snowed on again, so for the time being the car's going to sit outside.  Supposed to get rain as well.  We're hopeful that natures car wash can work some magic before the wife scrubs it down with the sponges and such.

And on the lighter side?  I've got no clue where Ford hid the low pressure port for the A/C.  I know it was converted-  And I've got all the tools except the recovery machine.  It's still got a small charge left in it.  We've had the whole thing apart and no signs of the low pressure port!  I know it's there somewhere LOL!

Ah well.  I'll pull the vacuum 'tree' off the donor car and run it down to the parts house.  Oddly enough they are still open!  Probably get a few boxes and just replace 'em all for a fresh start.  All it takes is one flexing just right and that will create a headache.


S-
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Jeff K Offline
Administrator
#4
Stock, the low pressure AC port is on the top of the accumulator at the firewall. Semi PITA to get a gauge on it. When I completely rebuilt my AC system back in 2011 or so, the replacement accumulator / dryer (4 Seasons I think) was an exact fit replacement with the low side port it.

Failing IVR will result in the temp, fuel and oil pressure gauges all climbing to max at the same time and staying at max for a few seconds to a few minutes until they return to normal.

We had some snow over night, but the sun came out and it was all melted by noon, thank goodness.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Tedybear315 Offline
Junior Member
#5
Snow's been here most of the day.  About 3-4 inches.  Took some time to clean out the tool room up in the 'barn' and tomorrow I'm going to see how many 10mm sockets turn up now that I'm not needing them.   And then it's the trash.  1 bin of scrap metal for the pile.  And 4 bags of trash so far. 

I'm a bit of a parts hog--  But most of the stuff I'm tossing out?  My step father loves to put all of his  "Don't throw that out...I'm gonna fix it and use it on a different project".  He had a fit when I tossed out a roached set of jumper cables.  Rusted and caked with yuck.  He actually dug them out of the trash bag and hung it up proclaiming how "You need to consult with me before throwing anything else away...I've got a use for these!".  (So far it's a toaster, heater, dehumidifier, couple of sink faucets (the kind you can replace for under ten bucks))...  

That was 3 years ago, and I just tossed 'em out again and buried them in the bag.  They where still hanging like a trophy where he put it.

Once it dries out I'll put the car back into the work bay and do some additional testing on everything.  Due to this 'china virus' it looks like I'll be unemployed for about a month or so.

S-
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Mikey97D Offline
Member
#6
Maybe a bad thermostat? I read on one forum a bunch of problems with thermostats and finding the right brand.

Edit: Found the thread. Most of them were having problems with it running too cool.(opening too early)
1988 TC, 5 spd, Stinger 3" Exhaust, Schneider Roller Cam, -4° Cam Pulley, Cone Filter, Gilles Boost Control Valve set at 17 psi, CHE Rear Lower and Upper Control Arms, Braided Brake Lines, Hawk HPS 5.0 Front and HPS (F) Rear, CRES Inserts in front calipers, and '93 Cobra Wheels with General 235/50R17 Tires.   
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Tedybear315 Offline
Junior Member
#7
Special thanks to Jeff for giving me the virtual 'kick in the rear end'.

The low pressure port is indeed on the accumulator on the firewall.  The PO has several of the wiring harnesses zip tied directly over it, and it was fully buried.  I stumbled upon it when I had to remove (yet again...) the inter-cooler and started feeling up parts.  It's rusted up.  So I'm on the fence.  I think what's the best option would be to replace it.  It's extremely low on charge, and considering how rusty it is-  I'd rather not throw a full charge into it just to have it blow out.  Yeah, that's in a PITA spot!  Just glad to have found it!  I have full gauges and a vacuum pump for hvac work.  It'd be a nice diversion.


Okay,  some updates.

We intentionally put a lower temp thermostat on the car.  Nothing to drastic, just a notch down from stock temp.

I swapped out the temp sensor (the one at the intake) with the donor car's one.  Fan(s) come on and work once the gauge hits about 75% of the sweep.  So that's good.  It's functional!

I've set the base idle using the listed procedure on the radiator shroud to about 750RPM.  Also adjusted the TPS so it's about 0.96ish.  I didn't find any dead spots during the sweep. 

Wife ran it around the yard and parked it.  Once in park the car decided to jump back up to about 2000 RPM and sat there.  Engine temps climbed slowly up until it hit the "L" on "normal" and the fan kicked on.    We threw on the old IAC just for snits and giggles...  Restarted it and the RPM seemed to be stable this time.  It's a bit of a mystery.  At times it just jumps up to 2k...and other times it's okay.  Both IAC's appear to be normal.  And when it spiked to 2000RPM I unplugged the IAC and the idle dropped to base.  So I'm confident the IAC's are both working and not sticking.  The ECU is commanding the IAC's to be that high.  Trying to figure out why?

All things considered I might swap out the TPS completely.  We've looked into possibility of a vacuum leak.  Even though the hoses are old, nothing leaky.  Might just be simpler to just remove the TPS from the equation completely.  Maybe once it's 'hot' it's starting to get a bit dodgy...  

Quite the interesting puzzle.  However we are making solid progress!  Looking forward to actually being able to get the car street legal and tooting around with it!

S-
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anasazi4st Offline
Senior Member
#8
(03-27-2020, 10:12 PM)Tedybear315 Wrote: Special thanks to Jeff for giving me the virtual 'kick in the rear end'.

The low pressure port is indeed on the accumulator on the firewall.  The PO has several of the wiring harnesses zip tied directly over it, and it was fully buried.  I stumbled upon it when I had to remove (yet again...) the inter-cooler and started feeling up parts.  It's rusted up.  So I'm on the fence.  I think what's the best option would be to replace it.  It's extremely low on charge, and considering how rusty it is-  I'd rather not throw a full charge into it just to have it blow out.  Yeah, that's in a PITA spot!  Just glad to have found it!  I have full gauges and a vacuum pump for hvac work.  It'd be a nice diversion.


Okay,  some updates.

We intentionally put a lower temp thermostat on the car.  Nothing to drastic, just a notch down from stock temp.

I swapped out the temp sensor (the one at the intake) with the donor car's one.  Fan(s) come on and work once the gauge hits about 75% of the sweep.  So that's good.  It's functional!

I've set the base idle using the listed procedure on the radiator shroud to about 750RPM.  Also adjusted the TPS so it's about 0.96ish.  I didn't find any dead spots during the sweep. 

Wife ran it around the yard and parked it.  Once in park the car decided to jump back up to about 2000 RPM and sat there.  Engine temps climbed slowly up until it hit the "L" on "normal" and the fan kicked on.    We threw on the old IAC just for snits and giggles...  Restarted it and the RPM seemed to be stable this time.  It's a bit of a mystery.  At times it just jumps up to 2k...and other times it's okay.  Both IAC's appear to be normal.  And when it spiked to 2000RPM I unplugged the IAC and the idle dropped to base.  So I'm confident the IAC's are both working and not sticking.  The ECU is commanding the IAC's to be that high.  Trying to figure out why?

All things considered I might swap out the TPS completely.  We've looked into possibility of a vacuum leak.  Even though the hoses are old, nothing leaky.  Might just be simpler to just remove the TPS from the equation completely.  Maybe once it's 'hot' it's starting to get a bit dodgy...  

Quite the interesting puzzle.  However we are making solid progress!  Looking forward to actually being able to get the car street legal and tooting around with it!

S-

You might well find that the best fix is simply a new TPS. Upon starting it immediately would jump to WOT (wide open throttle). I messed around with mine for what seemed like far too long and gave up, installed a new one, set it for .94. Problem solved.
Another proud dues-paying member.

1987 Turbo Coupe w/T5OD, 8.8 axle, grey smoke; most options. Got it in 1991 with 41K miles: 3 turbos, 2 heater cores, 1 T5OD full rebuild, 5 clutches, 1 head gasket, 2 Teves II ABS units, etc. later....
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