1993 Fleetwood hot start problem

John D. Hague · #1 (**permalink**) 10-28-07, 09:15 PM

My 1993 Fleetwood Brougham starts fine when the engine is cold but after being driven in weather with temperatures above 80 degrees and parked for about 20 minutes, the car will start, then sputter and die and then crank and crank before it will restart. When it restarts, it will splutter for about 5 - 10 seconds, then run fine. During cool weather, It doesn't have a problem.

If the car sits for about an hour, it will start fine. I have replaced the fuel pump, the fuel pump relay, the oil pressure relay with no effect. The car sets no codes when this happens.

Could this be a vapor lock or a fuel pressure regulator problem? Isn't the fuel pressure regulator hard to change on this car because it is built into the throttle body assembly?

One clue is, if I force a fuel pump run when the car is hot, the car starts fine. I do that by applying 12 volts to the fuel pump test connector.

96Fleetwood · #2 (**permalink**) 10-29-07, 09:12 AM

How about the EGR valve?

John D. Hague · #3 (**permalink**) 10-29-07, 05:34 PM

The EGR Valve was also replaced without any effect on this problem.

delzy · #4 (**permalink**) 10-29-07, 05:37 PM

It sounds like you are boiling fuel in the line somewhere. Perhaps the fuel line or exhaust has been routed poorly?

John D. Hague · #5 (**permalink**) 10-29-07, 06:54 PM

I agree that it sounds like I am boiling fuel somehow. I have followed the fuel lines from the tank to the throttle body and it isn't obvious to me that they are routed near anything that should heat them up. Is there a likely spot for this to happen?

I have even considered trying to insulate them some way but I don't know exactly how I would do that.

z06bigbird · #6 (**permalink**) 10-29-07, 11:38 PM

Quote:

Originally Posted by John D. Hague

I agree that it sounds like I am boiling fuel somehow. I have followed the fuel lines from the tank to the throttle body and it isn't obvious to me that they are routed near anything that should heat them up. Is there a likely spot for this to happen?

I have even considered trying to insulate them some way but I don't know exactly how I would do that.

Put several old clothes pins along the fuel line. They will dissipate the heat.

John D. Hague · #7 (**permalink**) 11-03-07, 11:49 AM

I have just ordered 6 magnesium clip-type clothespins to attach to the fuel line to see if they would serve as a heat sink to keep the fuel line temperature below the boiling point of the fuel after the engine is shut off. Does that sound reasonable to anyone else?

N0DIH · #8 (**permalink**) 11-03-07, 06:24 PM

Check the evaporative emissions too.

Try removing the gas cap before you start and see if that fixes the problem. If there a misrouted or broken line in the evaporative emissions can cause strange issues.

Check fuel pressure when you know the condition will happen. I would have checked fuel pressure first before throwing the pump and relay into it. You can toss a lot of money away throwing parts at a problem. Almost everything is troubleshootable, don't guess. Make sure if you take it to a mechanic that they don't do the same thing (all too many do the same blowing hundreds if not thousands of your money just troubleshooting because they don't have a clue). Find a GOOD mech that you can trust if you are taking it to one. Dealers aren't perfect either.

John D. Hague · #9 (**permalink**) 11-04-07, 07:47 PM

That sounds like excellent advice. So far, all of the fuel pressure readings have been well within spec.

I'll check out the evaporative system tomorrow.

Regarding the dealers, our Cadillac Dealer had the car for a week and the service manager drove the car home every night and they couldn't figure it out.

I am determined to get this fixed. The car is pristine and a great car to drive with this one exception.

Thanks for your guidance . . . .

N0DIH · #10 (**permalink**) 11-05-07, 01:38 AM

Where are you located?

GM had some issues with the B/D Bodies and getting one of the evaporative emissions hoses pinched from the factory. Take a look at the canister and all hoses in/out of it. You will probably have to climb under the car to see the canister in the front pass side.

John D. Hague · #11 (**permalink**) 11-07-07, 02:21 PM

Thanks for the advice.
I am located in Indianapolis, Indiana.

I just looked at the cannister, which is located on the left front side, and all of the hoses that I can see look fine. The electrical connections look solid and clean.

I'll check the evap tubes under the car as soon as I can get the car on a lift where I can really take a close look at them.

I just installed 6 magnesium clip-type clothes-pins along the fuel line on top of the engine, hoping that they might serve as a better heat sink for the fuel line. However, the temperature in Indianapolis today is 45 degrees so I can't duplicate the failure mode. The temperature needs to be in the 80s or so and then, after a 30 minute or more drive and a 20 to 30 minute park, the car will start immediately, then die. It will then crank for about 5 seconds and start again, flutter for about 5 seconds, and then run fine.

I could live with that situation if I had to, if I believed that it would not worsen when I was on a trip and get me stranded. On that basis, the situation is very frustrating. I have this beautiful car that I am afraid to drive on any extended trip in warm weather.

I deeply appreciate your advice.

John

John D. Hague · #12 (**permalink**) 11-12-07, 04:51 PM

I just checked the evaporative system per the Factory Manual. The only problem that I discovered is a 30 ohm resistance to ground in the ECM connection that is supposed to supply a ground to the solenoid on the top of the cannister.

I have a good 12 volt signal on one end of that solenoid but when the solenoid is loaded onto the circuit, the voltage across the solenoid is too low to pull in the solenoid. This is due to the 30 ohm reistance in the ground circuit.

Is this likely to cause my hot start problem? If so, do I need a replacement ECM? Or, is this likely to be a connector problem in that ground line?

N0DIH · #13 (**permalink**) 11-13-07, 01:12 AM

There should be a common ground point for the PCM, to the engine to the body, etc. I would look for them, they cause all sorts of headaches.

Try to disconnect the vapor canister purge line from the throttle body to the engine. See if that fixes the hot start problem....

Check the grounds all over, look for good engine to batt, batt to body, PCM to batt, etc. Make sure nothing is rusty or corroded over the years.

John D. Hague · #14 (**permalink**) 11-15-07, 01:03 PM

I just checked the grounds and, especially the ground for the ECM and all seem fine.

I am now planning to take the car to the Cadillac dealer and ask them to duplicate my tests on the purge valve circuit and then change out the ECM if that is the problem.

Do you believe that this purge solenoid problem could contribute to my hot start problem or is this just another problem?

John

N0DIH · #15 (**permalink**) 11-15-07, 06:39 PM

I would disconnect the line first, eliminate the purge canister from the equation.

Do you have a leaking fuel pressure regulator? How long does it hold pressure after you shut the car off? It should for quite a while. If raw fuel is leaking in the TB, could be a problem.

Question. In the hot start mode will it start on carb cleaner spray?? DO NOT spray the electrical part of the injectors. this could spark a fire. Have someone crank it and have you handy to spray down below the injectors.