I have an issue with a 1993 Ford Tempo. It is owned by a auto parts store and is used for deliveries so it gets a lot of use from day to day. Several different mechanics have looked at it and no one can figure out exactly whats wrong.
The issue is this - The car stalls out at about 2 or 3 oclock everyday after being used for deliveries starting at 9 oclock. It will stall while idling in park, while stopped in drive, while coasting/accelerating in drive. The temperature is normal. Is will start to idle and run very rough and the car is less responsive to the gas pedal about 10 minutes before it stalls. Once it stalls, if it is allowed to sit for about half an hour it will start and run fine for a little longer but eventually stall again. After it sits for a few hours it is fine to run for a few hours again. If you try to start it right after it stalls the first time the engine will turn over but stall out again in a few seconds, if you keep trying to restart it it will eventually not even crank. Also it will occasionally stall like this/run rough in the first 10-20 minutes of driving.
I suspect a fuel issue but i dont know any help would be appreciated.
Are you a mechanic? If this is a delivery vehicle for a parts supplier I’m suprised they haven’t just had one of the repair shops they use fix it. Anyway, if you suspect a fuel issue check the fuel pump operation both during normal operation and the stall/no start condition. You’ll need a labscope and a low amp probe, should be easy to do on this car as you can access the fuel pump wiring at the inertia switch. Look at the waveform to determine amp draw and rpm of the pump. You may want to check the pressure manually with a gauge but that’s less informative.
im not a mechanic. we have had a few of our mechanics look at it to try to figure out what the problem is. A few have had some theories but no one is sure. i dont know if anyone ever hooked it to that equipment. ill find out and if not ill give it a try. If it is the fuel pump, does it make sense that it runs okay for a few hours first? does the fuel pump get “tired” for lack of a better term?
This car should be one of the infamous TFI equipped models; meaning a Thick Film Integrated ignition module.
These are prone to heat related failures and symptoms can vary from bucking and lunging at times to flat out stalling and dying. It can mimic running out of gas.
Testing the module often means nothing as it may test fine and still be faulty.
Do a net search for “TFI Settlement” and you will find the sordid details behind this problem. And it’s too late to gain any reimbursement…
My assumption was heat-related ignition failure too. @mikeo, the next time you’re going out grab a spark tester and a can of starting fluid off the shelf. (Perhaps notify “the boss” first).
The next time it stalls out and won’t start, first floor the accelerator firmly while turning the key. If that helps assume that the engine is being flooded out, probably by fuel injectors on the fritz.
If that doesn’t work, then move on. For the next two you’ll probably need an assistant. Use the spark tester to check for spark. If you don’t have any, assume the TFI problem. If you have spark, blow some starter fluid into the intake and see if that gets it to fire a bit. If it does, then assume something like heat related fuel pump failure.
It’s entirely possible that the car has the original TFI module. I replaced the TFI module on my old Mercury 3 times; the original and 2 aftermarket Wells modules.
After the 2nd Wells failure I rounded up a piece of finned aluminum heat sink from the aircraft salvage and mounted the module to that. The revamped part was then mounted inside the air cleaner housing and the wiring pigtail was extended to fit.
This meant that every second the engine was running cool intake air was flowing over the heat sink/module. No more TFI hiccups after that and I think that some aftermarket companies offer a relocation kit for those modules which basically does the same thing I did although I think they relocate them to the fender instead of the air cleaner housing.
The TFI module base gets almost red hot with the key on and engine cold. Ford had the wisdom to then mount it to the distributor located near the thermostat water outlet so not a lot of heat was ever going to be eliminated.
Thanks for all the responses everybody! Im about 99% sure that one of the things our in shop expert tried was replacing the ignition module, but i don’t think he was aware of the module being prone to heat related failure due to its location. Based on all the stuff i read above it sounds like that could very well be the problem.
So what yous are basically saying is, we need to relocate the TFI module and rig it in a way that protects it from overheating, correct?
If so, even though there is a new one in there, would it have been damaged from getting hot over the last few weeks to the point that we should get another new one before rigging it?
1993, eh? Actually, the first thing you need to do from here is get the engine evaluated on an analyzer.
If they did, in fact, already try changing the TFI module, my next guess would be the coil pack.
But why guess when an analyzer would give you real, hard data to work with?
If the module was recently replaced then the odds of it failing again so soon are pretty slim with a few exceptions.
Those exceptions would be if the module was replaced without cleaning the pad on the distributor where it mounts and if the special grease that should be provided with a new module was not used.
If the module has been changed recently then random stalling could point in a number of other directions. It needs to be determined in a no-start situation if the spark is missing or if it’s a lack of fuel pressure. Those 2 things are actually tied together.
So a few more possibilities:
Intermittent fuel pump.
Inertia switch as asemaster mentioned.
CCRM module which is basically a big box o’relays. The internal relays may not be faulty but the wire connector that mounts to the module can get iffy over time; meaning a poor pin connection.
Failing ignition switch; the electrical part. What can happen over time is that the switch contacts will fail due to current load of accessories such as cabin blower motors. They pull a lot of current and aged accessories pull much more. This current passes through the switch instead of a relay and eventually the heat causes the switch to give up.
Now that you said ignition switch, it possible that was what was changed instead of the ignition module. I know whichever it was it was changed out front of the shop with minimal tools (socket wrenches and such)
Well, the ignition module is easy to change out and it’s under the hood. The ignition switch is more time consuming and near as I can remember the steering column has to be dropped and the anti-tamper screws on the switch have to be drilled out.
About all I can suggest is allow the car to run until it dies and won’t restart. Spray a shot of aerosol carb cleaner into the intake, see if it runs for a few seconds, and work from what happens there.
Diagnostic codes can be pulled although these are comparatively crude compared to more modern vehicles. There are some codes that can point to a stalling problem and may even be left in the ECM’s memory.
I won’t go through how to do that as it’s lengthy and the procedure can be found easily on the net or in a basic service manual.
Thanks for all your time and advice ok. Same to everyone else. The cause of the problem, while still up in the air, is way closer to being found now than it was before i started this thread this morning.
Im glad i came here. Thanks again everyone! Ill keep this updated as i (or the people i work with) go through the things suggested here.
It’s a 93 Tempo. If there is anything wrong with it, somebody should decide to get a real car. The liability here is tremendous. Whoever owns the business should tremble whenever an employee drives that thing. Safety should count for something.
I’m not sure what being an unlovely economy car with 21 years on it has to do with safety. If it is a rustbucket, yeah, but that’s facts not in evidence, Mr. Mason. If anything, the fact it can’t get out of its own way might make it safer in the hands of a (likely younger) parts runner.
You’d think a decent parts store could just keep throwing parts at it. Or they would have a good enough relationship at a shop to help them out. But if they are using a 20 yr old Tempo as a delivery vehicle, I would guess no one gets their parts on time.
Nice guys, real helpful responses in 2 out those last 3 (thanks meanjoefan). Im guessing pleasedodgevan and PvtPublic have no clue what its like to run a mom and pop business in this day in age.
The car handles fine, it stalls out once a day at about 3 o’clock and you can tell before its about to stall giving the driver plenty of time to get off the road. Just because its an old car does not mean its not a real car. however, you sound like a real…never mind.
Pvt Public, you want us to to throw parts at it, then put down the car for being 20 years old. contradict much? Just think about that. As far as parts on time, your dam right they are on time otherwise there is no way a mom and pop parts store is staying open these days, especially 5 minutes outside philly.
I came here trying to find a way to keep the store i work for from having to start looking to by another vehicle because one of the current ones is just barely not working , for the most part help with that is what i have gotten, and its been awesome, too bad i had to log on today and waste my time reading ignorant bs from pleasedodgevan and pvt public. Yous two can skip this and any other thread i may start in the future.
If this were my car and I wanted to diagnose the problem without using a pro mechanic I’d do what cigroller is saying, keep a spark tester and starter fluid with the car at all times. When it fails, install the spark tester and see if a good spark is being produced. Likewise with the starter fluid.
Reflect upon this from a scientific perspective. Car engines basically work now the same way as they worked in 1920. There’s only a few things that can cause the engine to fail to run.
No spark
Not enough or too much fuel
Not enough air or too much air
Spark ok, but spark timing is off
Valve timing is off
Low compression
Exhaust restriction
If you hired a mechanic, what he’d do is start down this list, one by one. Cigroller is addressing number 1 and 2, the two most likely culprits.