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90 Maita will crank but won't start

'90 Miata w/ 60M. Problem: eng cranks but will not start. Car ran great prior to problem and passed smog test. Problem started to surface as the car became harder and harder to start due to "no spark" each time. NO "CHECK ENGINE" light ever came on when the car ran. Items already replaced: Battery, spark plugs & wires,coil, cam pos sensor, ignitor, main ign relay. Areas ck'd: "Check eng" dash light, all body grounds,all ECM grounds, power from ign switch to ignitor, airflow meter ground. ** No power to injectors or airflow meter when key is hot or when cranked. "Check Eng" light does not come on prior to cranking or when key is initially turned to accessory. Can anyone help with suggestions or info on what additional electrical test to run or how to find a more comprehensive electrical manual. Anything at all would be greatly appreciated.

Reply to
darylDJ
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Sounds like your initial statement of "no spark" is no longer true. If you are sure there is no power to the injectors... have a look at the 'fuel injector' fuse(30A) in the main fuse box, the 'engine' fuse(15A) and the 'main relay'. From what I see in the schematics in the Haynes manual, the 'engine' fuse is hot in run or start, this picks the 'engine' relay, which passes power from the always hot 'fuel injector' fuse to the injectors.

Pete

Reply to
Simply Pete

Might be the ignition switch. It has a lot of contacts, among the ones that are still working are those that enable the starter. The ones that enable the ignition, however, may be kaput.

Ken

Reply to
KWS

No, if there is no spark, it will not start. How did you check for spark? Are you aware that the timing belt also controls the spark? I'd take a look and see if my valves are opening and closing to see if the belt is still functional. Granted, 60K miles is replacement time and they will generally go well over that, age does have an impact. It may have been starting to fray, allowed the timing to jump and then quit altogether. It's a simple look see inside the oil filler hole to see if the cams are turning. If not, needs nothing more than a timing belt. Electronics are not an issue on the Miata (it's not Lucas electrics after all and you've already replaced the whole system (with the exception of the fuel pump which is where I would look after checking the timing belt).

Tom

92 Red (gone but not forgotten) 05 Vette (red, but of course)

Reply to
Tom Howlin

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