Car does not start when hot

[zachmac]

If I crank the starter the engine will not start when hot even though the starter will be rotating the engine very well. At the same time, if I push the car and engage a gear, then the engine comes to life almost immediately. I have no idea how to explain this. What does (or does not) get engaged differently when the engine is cranked by the starter or rotated by the motion of the wheel? quote]

The only difference in what you describe is the path for current through the ignition switch. You are getting current to the coil and plugs when in the running position but not in the start position. When I get home tonight I'll research this and remember what is different but I am pretty sure you are looking at an electrical issue, most likely in the ignition switch and starting circuit. It could be the air flow switch as I think that plays a role in starting versus running but it's weird that you have the opposite problem most people have, no fire when starting versus in run. That tends to support a worn air meter surface.

This isn't a fuel delivery problem or the car wouldn't start and run so well on the pop the clutch start. Been I while since I messed with the fuel injection (sold my 80 years ago) but I kept all my files from then so I'll dig in tonight.

[CajunMike]

Check the control module as mentioned. It's a $25 part. Spent a week trying to figure this out, replaced several things before I got to it. I would drive to a store and get back in to leave no start.. Had to wait till engine cooled to start again. This happened several frustrating times. Would crank cold no problem. Good luck.

[zachmac]

I have an excell table I put together years ago on the combi relay. You'll see power is routed differently when cranking versus when in run. Perhaps something temperature related is causing your relay to work initially but not when hot? Send me an off forum email and I'll send you the file. It may help diagnosis?

[zachmac]

Couldn't get it to format so here is a photo of my relay table.


If you notice, the power to the fuel pump and FIs is different in the "run" key position versus "cranking". Seems like you are getting it both positions when cold but for some reason only in "run" when hot. I'd warm it up and check for FI firing *(you'll need a node light and a friend) while cranking. I suspect you'll find there are not firing when hot an cranking but have power in run which is why it will start with a rolling clutch pop.

[md88plt]

Check distributer cap. I installed a new distributer cap (made in China via World Auto Parts brand) that ended up being defective. The defect showed up when the engine temperature rose to normal temps. The heat from the engine/exhaust manifold was heating the distributer cap and changing the internal resistance of the cap so that the car would not start and or lacked power. I finally figured this out with my ohm meter. Hope this helps. BTW I always make sure that my parts are not Chinese made.

[PAV1980Spider]

Thanks a lot for your help! I think that next to check will be all related to the ignition key, which has been giving me troubles for awhile. I know there is something loose in it since every now and then I need to wiggle it a bit to turn the engine off.
Need to find a node light and a friend now though.
Sorry for not responding on time.

[PAV1980Spider]

Finally the problem with the hot start is resolved. It was related to the vapor lock, which was suggested earlier in this postings by another member, although it was not the fuel injectors going bad but the pressure regulator.
The pressure regulator had gone bad; I did not even think of looking at it until I found a discussion about similar hot start issue on a blog site for Mazda.
The check was very simple - run the engine, pull the vacuum line and see if there is gas. If there is, then the regulator is bad. In my case ,there was gas in the line, lots of it.
So, got the part for $35 from E bay and just put it in. Run the car, got the temperature to 190 and then left it for 30 minutes. The car started instantly. Did it a few more times with the same result. I do not know if she will change her mind tomorrow but for now she is officially cured.
Cannot express how relieved I am and little upset with my self - after 5 1/2 months of tinkering, putting tons of new parts, etc, it took me 15 minutes to resolve the issue once I knew what to look for.
Well, at least this may help next guy when their Spider inevitably develops similar problems.

Thank you all for your helpful posts.