HELP !!! RMW won't start after sitting for a couple days

Dear fellow longroofers,

I recently developed a starting issue with my '95 RMW.

After sitting for a few days, I can't get her started without spraying starting fluid in the intake.

This isn't a battery problem - it'll crank all day..... it just isn't getting gas, no matter what I do with the pedal.

I might mention that this car sits at the airport for a few days at a time, in Iowa, in the elements - which have been around freezing lately.

This problem doesn't occur when it's warm outside.

I recently replaced the Optispark (with a good one, not a cheap one), as well as the plugs & wires, and she's always started fine.... until now.

Please help ! Thank You in advance.

Andy  

Sounds like you already know it's not getting fuel.   Once you spray starting fluid and it fires....does it keep running?  Or does it die as soon as you stop spraying?

 If so, first thing I'd do is jump the fuel pump connector (little connector hanging around the outside of the  underhood fuse box) to the positive battery terminal and listen for the pump to activate.  Could be a bad pump or one about to go.  

You can also see if you have any pressure at the schroeder valve on the fuel rail (release it...crank the car a few seconds...then release it again to see if it built up pressure)  If not, then most likely pump.

If it keeps running after you spray start, then it could be something else. Id have to think about that one. Might be PCM or sensor related in this case...

Starting spray has a wider explosive range than gasoline -- so it can still ignite even if the gasoline mixture is too rich. That said, too lean is more likely, especially after sitting for a few days.

The answers to brokecello's questions will be useful here. While the pump is a possibility, so is the relay. Applying power to the fuel pump test connector bypasses the relay. If the car currently keeps running after a spray start AND you find it will start without complaint when applying power to the connector then I would strongly suspect the relay is at fault (once the car builds oil pressure, a second set of contacts in the oil pressure switch keeps the pump running).

Another possibility is that the pump, relay, wiring, etc. are all just fine. You mention it has been cold of late. Did this problem crop up after the weather turned cold? If the coolant temperature switch is out of whack, the PCM might think it's a lot warmer than it really is and will command a lean mixture instead of the enriched mixture required for a cold start. I had this happen once on my 92 -- it was -20°C outside, but the temperature sensor was reading +20°C. As +20° is a perfectly valid reading, it didn't throw a code. The only way to reliably diagnose this sort of problem is by using a scan tool to read and evaluate the raw data stream. You can use a multi-meter to read the resistance of the sensor, but that will not help if the problem is in the wiring instead of in the sensor.

Could you just be out of GAS?

In answer to these questions, the problem started after it got cold, and it does keep going after it starts with the starter fluid.... although I have to 'feather' the accelerator to keep her running.

(And, no, it's not out of gas, Mr. Flasheroo  )

I will try the suggestions of jumping the fuel pump connector, and I might just swap out the coolant temp. switch, as I have a sneaky suspicion that is the culprit.

Can I run diagnosis on the coolant temp through my climate control on the dashboard ?

This is good s**t, boys.... and why I bought the RMW !!

Thank You all in advance !

No, unfortunately it appears the coolant temperature is not accessible through the climate control. If you have a FSM, there is a listing of the sensor resistance to temperature conversions. It goes something like this:

With an engine temperature of 68°F, the sensor resistance should be 3520 ohms (3.52 Kilo ohms).

59°F is 4.45 Kohms

50°F is 5.67 Kohms

...

-15° is 21.45 Kohms

-40°F is 100.7 Kohms

So if you know the outside temperature, you can measure the resistance of the sensor and see if it's close.

If the resistance at the sensor seems OK, then check the resistance at the PCM between C25 and B16. It should be the same. Higher means resistance in a wire or connection, lower means something is shorted.

BTW: there's two temperature sensors. The one that goes to the gauge is above the starter. The one you want (that connects to the PCM) is next to the water pump.

(there's technically a third temp sensor, but it's in the transmission)

Everything mentioned here is a viable issue. But let's not forget about a faulty ignition coil. High resistance in the coil will cause these symptoms too, and as mentioned by BuickWagon the starting fluid has a greater potential to ignite than a rich mixture and has a smaller energy requirement from the coil. As the coil warms the resistance values "self-correct" until the next cool down. This use to be a big problem with the Magnavox coils on the 3.8L waste spark ignition systems. I know this is not the system we are dealing with here, but a coil is a coil.

Try this experiment, the next time this happens remove the coil, measure coil resistance on both primary and secondary sides. Bring coil into the house and warm for about an hour or so, at room temperature, re-measure resistances and compare to previous readings. If the coil is good the readings should be relatively close. If the values changed dramatically you need a new coil. Now regardless of the value, reinstall coil and see of the engine now starts. If it does, replace the coil. If you don't have an ohmmeter to measure resistances, skip that part of the experiment and continue the process.

This is a no cost way of testing without guessing with minimal labor. Coils breakdown in many different ways, high heat and frigid temperatures seem to affect them most for starting issues associated to a faulty coil. An FYI, for every .001" increase in the plug gap the demand on the coil increases by 1000 volts.

Buickwagon wrote:

If the coolant temperature switch is out of whack, the PCM might think it's a lot warmer than it really is and will command a lean mixture instead of the enriched mixture required for a cold start. I had this happen once on my 92 -- it was -20°C outside, but the temperature sensor was reading +20°C.

I think Buickwagon might have hit the nail on the head with this observation, and this is why:

Ever since I put on a new Optispark, water pump & thermostat (plus all new hoses), my coolant temp gauge in the dash has been pegged to "HOT", although the car isn't running hot. As a matter of fact, it shows "HOT" when I start the car even after it's been sitting outside for three days.

I think the PCM thinks the car is hot, and is leaning out the mixture. This may also explain why she's so difficult to start after she trucly is hot - the PCM thinks it's cooler than it actually is.

The first thing I did when I got the car (besides clean it) was put on a new starter, so I'm going to change both the coolant temperature sensors, as I might have disrupted/broken them both at one time or another.

I'll report back after I replace them both. Thank You all !!