Intermittent Starting Issue

[SGFMORover]

95 D1 196k auto; Every spring and fall in that 50-70 degree big temperature swing time of year my rover has intermittent starting issues, twice a year I think I've fixed it and it comes back 6 mo.s to a year later.
Engine will crank fine but never start, usually happens when its been used in the last 2-6 hours but has cooled all the way down. always when I'm away from home (been in walmart too long or at the end of a short work day)... in the last 4 years its had every temp sensor atleast 1x, ignition module, coil, fuel pump, fuel filter has been a year now, on and on.
One thing I've figured out, a tiny shot of starting fluid and she fires right up - every time. so she gets this once or twice a week for a month in the spring and fall. and once every 1-2 months the rest of the year. not good for her but no other choice. anyone have good ideas???
oh and she always hesitates and lags the first time I hit the gas in the morning when I leave unless she's warmed up.

[rdsrover]

Sounds like a water / condensation issue.
Do you always buy your fuel at the same place? Try Supreme at a high volume location.
Have you tried gas line antifreeze in the fuel tank?
It's a D1 - so it has a distributor cap? The tiniest bit of water inside from a near-invisible crack will weaken the spark enough to prevent starting.
Have you changed the spark plugs and checked the gap?
Starting fluid is extremely flamable and ignites with a weak spark, so I would say your spark is too weak for what may be a poor fuel because of reasons above, or the spark is at the wrong time - a timing issue might be the problem. Hope you figure it out.

[SGFMORover]

always run 90 octane or higher have used additives - no change. this has now happened in 4 states - dozens of stations. plugs and wires and cap multiple times. oh and it has literally never caused a check engine light - naturally. no idea how to check/adjust timing accurately... but you could be on to something....

[wrighthm]

Hey man, I've got a series rover so take this for what it's worth. I have the exact same problem the same time every year. Yesterday in fact on my way home, I had jusqt entered my neighborhood and the truck dies. I promptly walked home and grabbed an old coil I had lying around after checking all visible electrical connections and finding nothing wrong. The truck started up and got me home. When I bought my truck and immediately changed everything critical out for new and then I started having problems. Every year on the first day that the temperature significantly changes I have had this problem since upgrading to new goodies. Last year I ruled out the coil since it was new, so then I changed everything else out for a second time which led me back to the coil. After all this I ended up grabbing the old coil that came in my truck and putting it back on. I've had no problems in the 8k miles I put on the truck since then, until yesterday on the very first day the temperature here in Lexington KY hit close to 80. I couldn't get it going again until I swapped in one of my old faulty coils.

I've talked to a lot of people who say that some newly manufactured coils will fail when they get up to temperature and that has been my experience exactly. The coil that failed yesterday and that is the same one that fixed my issue about a year ago looks like it came over on the mayflower.

I have also had trouble with other parts for my rover that were newly manufactured, Particularly master cylinders. Oh and one more thing I have had aftermarket and genuine parts fail on me. All the coils were genuine and about half of the cylinders.

My 2

[SGFMORover]

went through a similar coil diagnosis a couple years ago.... WEIRD thing here is aside from an occasional miss if it reallllly gets hot it performs runs great when its 80+..... had a lightbulb moment - i think. pulled the cap today to see if there were any signs of issues..... hint of dust-water spots on inside of cap..... cap isn't cracked but there's no seal between the cap and the distributor??? I'm assuming SOMETHING sits between the metal and plastic to seal out moisture? anyone know a part number?

[dandruka]

leaky/faulty fuel injectors.

My 99 D1 had this for the longest time. It would start great in the morning but if I went to start it after being off for several minutes, no dice.

I tuned it up, mists of water to look for arching, battery, etc etc etc. But then Someone suggested I clean my fuel injectors. instead of buying new, I removed them and had them serviced. I haven had the problem since.

I was told that if they get gummed up or clogged, they will leak a bit of petrol in the cylinder causing a rich start. However, if allowed to cool, the effects are reduced thus easier starting. Makes sense.

Good luck

[1996trek4]

what did it cost you to get the injectors rebuilt?

I have a similar problem every once in awhile if shut off warm for 15 minutes or so, never at a gas stop for 5 minutes. Once a month or so it will do it on a cold start too. I ran injector cleaner through it, didn't change anything. Always run premium in it... I also heard it's a sign of the fuel pump going out, the valve will intermittently fail allowing fuel to drain back into the tank... It's so intermittent it is hard to figure out...

[dandruka]

It was some time ago but I believe it was somewhere in the ballpark of $25 per injector. It was a place in warren ave in Portland Maine. The name escapes me at the moment. It did seen to work for me.

[phoenix]

compare resistance of your coolant temp sensor and the thermostat, to the factory specs, mine ran quite well except a little hot when pushed hard, ,my engine is a 4.6 modified and restroked using gm internals, the factory thermy was too restrictive, I located a high flow unit and as the weather is changing the temp sensor seems confused and sets a code and goes into limp rich mode.. basically as the coolant temp lowers, resistance in the sensor rises to a peak of 9700 ohms thus widening the injector pulse, as it warms it drops resistance to a low of 150 ohms at 220 degrees thus shortening injector pulse... if pulse widens when cold it dumps lots of fuel (same basic as a chocked carb) as it warms and the 02 sensors begin doing their job and checking with the temp thus correlating and working together to achieve stochiometric mix of 14 to 1.... bottom line, your temp sensor may not sense it is cold and thus it takes a little while to saturate the chamber to make it run when cold....

[1996trek4]

update, i replaced the fuel pump and filter....has not done it since. it took awhile before it was often enough to properly diagnose...the valve in the pump was allowing fuel to back drain.... no idea why it started out doing it between 15-30 minutes of shut down every once in a great while fine cold...got to the point it was doing it cold too, checked pressure at the rail, little fuel....left key on for awhile and it fired right up. did this a few times to verify... i got replies about injectors, crank sensor, temp senders, everything short of a low tire lol...oh well, figured when it got bad it would be obvious what was going on....thanks all