no spark-need help
 

I have a 93 rx7 that turns over, but has no spark. Unfortunately I do not have a manual or the covers to any of the fuse or relay boxes to start tracking down the problem. Could anyone snap a picture of them or provide any help would greatly be appreciated. Could replacing the instrument cluster from another car cause this problem-the cluster is not lighting up either. Thanks in advance for your help.

Check the 40a (B1) and the 40a (B2) fuses under the hood on the battery positive connection.

I would use a test light on all the fuses under the hood. I also would assuming you have been cranking a bit take a smell of the exhaust. If you have been cranking the engine a lot trying to start if there should be a gas Oder. If there is not and no spark maybe the crank sensors need a look. IF the crank sensor is skewed in some way you wont have spark or injector pulse but you will have a fuel pump.

Good points.

is there a way to test the crank sensors and where are they located-

The crank angle sensors are a bitsh to get too, you'll have to remove a lot of parts just to even get a look, let alone removing them. There right behind the bottom pully on the drivers side. Start simple, check all your fuses, and test all the spark plug wires insure that they are plugged in correctly, and that the wires are actually in working order. If your instrument clusters aren't working it would either be a fuse or ignitor related, bad ignitor connection. The ignitor is near the drivers firewall, next to where the master cylinder is at. Hope that helps.

Thanks for all suggestions-I will start the investigation this weekend and let you know.

I had this same problem once, and it turned out to be that the crank angle sensor plug wire had come out it's socket, I had to repair it with solder. Remember, the coils will not fire if they cannot see any rpm signal from the crank angle sensor.

I haven't checked the crank angle sensor yet, thanks for the suggestion. Over the weekend- checked all fuses and relays. Cleaned battery posts and connections to the positive side fuse box. Dash lights are on again. Turns over, but won't start. Not getting a spark, but one of the coils tested did indicate it was getting power.

After cranking over the engine, I pulled a plug and smelled no sign of fuel at all. Nor do I hear a fuel pump. Soooo-what controls both SPARK and Fuel! ! !

Upon testing the relay and fuses-I was not able to get a reading of continuity from the EGI Relay. Is there a way to test the EGI relay and what readings am I looking to obtain. Of course- I have a spare EGI relay that does not produce a reading as well! This may be the route of all evil for me-please help! ! !

Egi and fuel pump relay both click upon turning the key on. I will assume they are not the problem. Still no signs of fuel once the spark plug has been removed and/or spark.
After reading multiple posts-I decided to see what codes might be present after jumping the diagnosis box--my check engine light never even comes on once the key is turned and obviously does not emit a flashing code. WHAT would this be indicative of and does anyone have any other suggestions on how to start my RX7!

have you checked the EGI relay(yellow) and curcit opening relay(green) in the main fuse box? those will both effect spark and fuel.

You should probably give us a little more history about the car. Like, was it running fine previously to this problem. Or is this how you bought the car? THere are several components that controll spark, the ignition, wiring harness, ecu, ignitors, relays, fuses, coilpacks, crank angle sensors, spark plug wires, spark plugs, and in my case a kill switch. I may have left somthing out but I think that purty much covers it.

I have tested both the green and yellow relays on the positive ground strap-I hear them click upon turniung the key. The yellow EGI relay gave a continuity test of @ 11.
History--Drove the car for about a year, then had a front end collission. Sat for about a year. Started right up and drove through the parking lot of the body shop to the frame rack-only ran for about 1 minute due to the fact that everything was not connected and/or missing from the front of the engine. Put a new core support on, but the body shop felt that the car would be safer in the long run to put a front clip on starting from the shock towers forward. Upon doing this, they naturally removed everything from the front of the engine, including the wiring harness, fuse boxes, grounds etc. I feel that I'm on the right track to putting everything back in place. I have left off the radiator, condensor, fans, intercooler, and air box. So far , I've been researching where the wires that were disconnected go and what they are for-which is why I originally asked for pics of the fuse boxes. I have checked all fuses and relays-they're fine. NO spark and no fuel. I have also noticed that when I turn the key on, the check engine light does not come on at all-not even to cycle through the normal test. Still looking at her clueless! !

ecu fuse

I am not a Mazda expert but normally the ecu grounds the check engine light. I agree with mad 7tist, and think you should look into the ecu power supply. That would be first on my list knowing the check engine light is in-op. Normally that means the ecu is off-line. Some cars will still have spark with out the ecu but as for Mazda I can't say. I also would look close at the area where the work was preformed. I see a lot of harness trouble where it is placed in an area where it rubs the frame etc and in time the insulation fails and a short or open circuit appears. This normally takes some time and driving normally it happens with in the first 6 months or so. Look at any harness area which is close to the frame/body/steel areas and maybe at a angle or binding. You also could after not finding anything, pull on the harness in one place and crank the engine. Keep picking a different part of the harness. Some times this will right the problem. Just try to keep the area last moved in mind so you can then if it starts take a good look at the wiring there. I have had problems where my helper moves the harness just poking around and the car starts but he didn't isolate the area moved, so you then may not be able to find it having to check each circuit one by one. You also might have someone sit in the driver seat. Pull/push etc on the engine harness and see if the check engine light flickers. Again keep a mental note of where and what you did to get this to happen.

Great ideas! I'll give it a try! Is there a way to test the ecu. I did notice that by the passenger headlight side of the harness; the outer covering was damaged by the wreck and has exposed the wires-they do not appear to be damaged though. I have not checked it out though-assuming that since it was on the other side of the car, it was not causing my spark or fuel problem. I'll say it first--maybe I should not be assuming...

Not to sound repetitive, BUT spark and fuel are BOTH controlled by the crank angle sensors, check there please, that's probably your problem somewhere inbetween the harness plugs or harness itself.

if the cel is not coming on the light is bunt out or the ecu is not getting power. i would start there. jsj has a good plan

www.iluvmyrx7.com for factory service manuals, im in the same boat as you, but my fuel pump is now working, but it wont start, fuel air mixture slowly pours out my exhaust, i believe its my spark plugs, my brand new sparkplugs have a weaker spark than my old cruded dirty plugs.

ill try to get some pictures up to help you get your fuelpump working. ive done all the tests for no spark conditions also. if you spark plugs still reek of gas then theyre shot after you clean them.

well looks like i have ignition, picked up new plugs yesterday, and i saw flames with the two trailing plugs in but no leading plugs, flames shot out the leading plug holes, but the car still wont start, i believe its an apex seal shot on rotor number 2, compression tests revealed 120-120-120 across rotor 1, and 90-60-60 across rotor 2. ;[

have you checked to make sure the leadings are firing? it will run with no trailing but not without the leading

yea, the leading were firing fine when fire was shooting from the leading holes, the leading plugs where grounded, spark was strong.

ok so do you have fuel press?

I'm having a similar problem, I still have to investigate more, but I went to start my car yesterday and It cranked and fired maybe on one rotor then shut off. I cranked it again and it just turned but didn't fire. Any ideas? I'm gonna try jumping it and cranking it over again and see if it works. The PFC works b/c the commander turns on, I get fuel pressure...but im not too sure about spark. I'll have to check the crank angle sensor if it doesn't turn over when I jump it. It was running so good too. I don't get it.