Little Duke Coupe

[Fierofool]

Took the car in to get an alignment.  They set the rear to specs and the front, except camber.  Greg did a great job without an alignment machine.  Camber was something like 9 degrees.  Way out, but equal on both sides.  They said that it would take about 3 hours to bring the camber into specification at $70 per hour.  No thanks.  It will go to Roger's alignment guys up in Gainesville where they do what they need, at the standard alignment price. 

The car drives great as it is, but too much mileage will take a toll on the tires.

I replaced the injector last Friday and drove it about 30 miles over to meet ScottB.  Then back.  Today, I drove it to Church then to Cleveland, Ga.  A round trip distance of about 150 miles without any stalling issues.  Maybe the injector will be the answer.

Pat, when can it come to visit you for a while?  I have my 86 parked in the grass.

[TopNotch]

Pat, when can it come to visit you for a while?  I have my 86 parked in the grass.

Bring it on over. It will have company. Our grandkid's mother just bought an 85 GT that has been re-bodied to look like an 86 GT, and it has a 3.4 in it. It's for one of the grandkids in the future. The wiring is a complete mess, so it will need some work.

[Fierofool]

The coupe is back at Pat's.  Mechanically solid and running good.  If you need temp transportation, call or email TopNotch.

[Fierofool]

Yesterday at the car show someone asked about the stalling issue of the Duke Coupe.  I came to believe that it was the throttle body injector breaking down and I replaced it.  It's been running well during the times TopNotch drove it. 

Yesterday as Roger and I were returning from the Boy Scout car show, I made it from Villa Rica  to the Ashford-Dunwoody area of I-285 an while we were running along in the center lane at about 70 mph, it shut down.  I threw it out of gear and began coasting, trying to move toward the shoulder.

I made it and while still coasting, turned the ignition to the OFF (not LOCK) position for a moment then tried to restart.  It fired up, I shoved it into 3rd and merged back into traffic.  On the remainder of the trip home, it shut down another 5 times.  Using the same solution, while coasting I restarted the engine and kept moving. 

I guess the throttle body injector isn't the problem after all.  Anyone have any other possibilities?

[TopNotch]

What is the condition of the fuel pump? Has the pressure ever been measured?

[Fierofool]

When I first got it, the fuel pump didn't work.  I had Ashby install another pump.  It was a used pump.  I don't know if the pressure has ever been tested, but even after cycling the pump several times, it has some long cranking times.  Each time when I was coasting, it would start immediately after turning off the ignition. 

[TopNotch]

My 88 had a starting and stalling problem during warm weather a few years ago. It turned out to be the hose between the fuel pump and steel line. It wasn't submersible, and it wasn't clamped, and in warmer temperatures, it got softer, causing more leakage. I think the fuel pump warrants examination.

[Fierofool]

I think at the time the tank is down it might be best to just install a new pump, too and eliminate any possibilities of problems down there. 

I'm now kind of glad that Ray's friend who was supposed to drive the Coupe didn't show up.  I thought the stalling problem was cured.  It could have been bad news if that had happened to him while on the interstate, not knowing to turn it off and restart. 

I need to find the fuel pressure gauge and check for pressure and bleed down. 

[Raydar]

Interesting that it would restart right away.
I'm guessing that this system works similar to the V6 in that the ECM turns on the relay, which runs the pump.
I'm also guessing that the oil pressure sender supplies a backup to the ecm/relay circuit.

Based upon those suppositions, I would disconnect the oil sender, and see if it starts and runs at all.
If it does, I would reconnect the oil sender and unplug the fuel pump relay and see if it still cranks and runs.

You might be able to draw conclusions from the results.

The fact that it restarted after turning the key off and then on (and start) also leads me to believe that if it died again, you might be able to leave it in gear and just cycle the key. The forward momentum would serve to start the engine.
If it requires an actual switch to the start position, it might indicate a failure in one of the ignition circuits. (Again, based upon the premise that the V6 ICM has different start and run circuits. I'm guessing that the Duke ICM is similar.)

Of course, it's not a bad idea to check the fuel pump and hose. But stuff is always easier to fix if it will stay "broke".

Working in telecommunications, I always hated those mysterious "miracle fixes". They always seemed to "unfix" themselves at an inopportune time. Usually at 3:00 AM, on a week when I was on call. 

[Fierofool]

I guess the reason I used the starter to restart was because it died with the clutch engaged and disengaging and engaging the clutch wouldn't start it.  Of course, I hadn't turned the ignition off and on, yet. 

I guess I could try the relay and pressure sender disconnect tests even without it stalling.  Just by disconnecting them should have the same effect?  I think Pat has already replaced the ICM and the crankshaft sensor. 

[Raydar]

...
I guess I could try the relay and pressure sender disconnect tests even without it stalling.  Just by disconnecting them should have the same effect?  I think Pat has already replaced the ICM and the crankshaft sensor.

Since there are two separate circuits that can power the fuel pump, I was just wondering if one of them might be failed outright, and then the other one is "breaking down" and causing the stall. If it runs on both circuits, then the problem could be something else.

If you got an inductive timing light with enough cable to reach into the cabin, it might be worthwhile to connect it and leave it connected while driving around. If the engine stalls, pull the trigger and see if you still have spark. Probably would be better if you have a passenger. Could get distracting.

[TopNotch]

Keep in mind, as you consider all these possibilities, that the problem only seems to happen in warm weather.

[Fierofool]

Hooking up my big pistol grip timing light like that gives me some great ideas.  Sit in a business driveway, point and pull the trigger at speeders, ricers, and any variety of others. 

Problem is, that you might have to drive around for months before it happens.  I suppose that should it happen, just stop with the ignition on and if you have a passenger, have them try starting it without turning off the ignition first.  If no spark, then we know it isn't fuel.  I do believe it's fuel related though because there's no raw fuel or flooding when it stalls, even if you leave the clutch engaged so whatever it is, it cuts off the fuel supply. 

Does the 88 Duke need spark signal for the FP or injector to operate?  Our previous solution was to tap on the injector while cranking. 

[GTRS Fiero]

Was this ever fixed?  I'm curious what caused the problem.

[Fierofool]

It hasn't been fixed.  The car isn't driven enough to really get a handle on it.  I recently drove it on the 150 mile Polar Bear Run without any problems.  I have another ECU for it, but have never installed it to see if that's the problem. 

It actually seems to be electric related because when running 70 down the interstate and it shuts down, restarting it doesn't throw a big cloud of raw exhaust.  If using the starter to restart, it fires right up, normally after the ignition has been turned off for 5 seconds or so.  When it shuts down, it doesn't sputter or backfire.  It just acts as if the ignition switch was turned off.