FD won't start...go figure lol
 

Hey guys, this is one of my first of many issues I have tackled on this car but I will give you a little background first to try to help you help me haha.

Bought this car about 2 months ago, nothing has worked correctly since the first day I bought it, which I figured was pretty standard on these cars since the guy who did all the work did a CRAPPY job with the wiring and installation of various other things as well. I'm talking about wires and loose connections ALL over this car. He also removed the starter assist apparently so the car starts like an old classic, needs to be started about 3-6 times before the car actually turns over. For what it's worth, the motor was just rebuilt a few months ago and have had about 700 miles put on it, 250 of those miles were from me. It has APex 3mm seals, street port, and a few minor things, also has stock fuel system installed as of now. I do have the fuel system and pumps ready to be put in and then tuned but I want to knock out this problem first and get it to start. With that in mind, here's what happened:

About 5 weeks ago (I have two cars I'm working on and I didn't have time for the RX7 until now) I was driving to work before I realized it the car was overheating. There are two reasons the car was overheating that day, one was because the guy who had the car before me wired up the cooling fans to a toggle switch and I actually forgot to manually turn it on (10-15 min of driving in the cool AZ desert). So, obviously that part is my fault! Next, I have a single turbo and my A/C and another tensioner pulley have been removed so my belt that wraps around the alternator and the crank pulley, is "tensioned" with the water pump pulley and nothing else. What's wrong with that is that the belt slips and doesn't get a good grip on the water pump pulley. So when I noticed that the car was overheating I bailed into a parking lot and walked to work. I left the car there all day and let it chill out, then after working for 10 hours I decided to give it a try and added some fluid to it to compensate for what was lost.

So, here I am 5-6 weeks later and the car won't start. I just bought a new starter and installed it so I know that's not what the problem is as of now. Could it be spark plugs? I feel weird trying to start the car 20 times in one sitting, the starter is working but nothing will give the slightest indication that it will actually turn over. What do y'all think? Sorry for the long story but I'm hoping that it will help diagnose the problem...

Cody

do you have an aftermarket temp gauge? how hot did it get if so? It's very easy to blow a coolant seal if you overheat it. I'm currently trying to fix a coolant issue myself as you can see in this thread https://www.rx7club.com/3rd-generation-specific-1993-2002-16/why-am-i-dropping-coolant-982348/

there is a lot of info in there about the coolant system, but one thing you should check is your plugs to see if they are getting wet. good luck with everything.

Take out the spark plus and make sure all 6 faces make compression since this is free and simple.

Starting problem....
 

pulled out everything to get the plugs installed and I had a couple of questions....

1. Do I need one step colder plugs since I'm running the GT-40 single turbo or do these RX-7s even use those?

2. The wires were loose and pretty crappy as far as quality goes, I am looking into aftermarket plug wires, does the size matter, AKA I think stock is 7mm or 8mm...

3. Everything seems to be fairly easy to change once I take off the air intake parts and the oil filler neck...once I change the plugs and gap them correctly, what if the car doesn't start after that? What are my options then if the spark plugs do NOT fix the problem?

Thanks for all your help guys but I am waiting until I get newer plug wires and I already have the OEM NGK spark plugs to replace the crappy ones that are in there now haha. Thanks again!

Cody

How much boost are you running. If you are at stock. Boost levels run 7&9's. If not you can run all 9's and if you still have break up run 10's.

Stock Ngk plugs hold pretty good. If u ever want to upgrade u can run 10mm wires but I have run 20 psi w stock Ngk wires.

If car doesn't start after that check normal things like map sensor hose disconnected, check tps settings, fuel spark and as someone else mentioned check to see that u have compression on all 6 faces while the plugs are out. Good luck

what do you mean its not turning over?
or do you mean the car won't fire up?
if you have a brand new starter and power from the battery and it is not turning when you crank you have other issues not related to the sparkplug.

The boost I'm running is impossible for me to determine at the moment, he had the stock fuel system, injectors, rails, etc. in the car, as well as rebuilt the motor within 700 miles on the car so I have been breaking in the motor and haven't been over 3000rpms. I have barely heard the BOV because I'm frightened to blow the motor with that huge GT-40 and no fuel...once I get the car up and running I will install all the fuel upgrades, gauges, turbo timer, and everything else he gave me with the car and will have a local shop tune the car.

I bought some NGK blue wires that say 5 on them, I'm assuming they're 5mm since they're smaller than my 8mm ones that are in there at the moment. The spark plugs he gave me are NGK BUR7EQ and model 6917. I'm assuming these are all correct parts for me at the moment and I'm going to proceed and install them all right now.

Please let me know if all of my info is correct since I'm super new to this car...also, does anyone the NGK SPark Plug Gap by chance? I'm only finding the 1st and 2nd gen answers but need the 3rd gen specific gap please.

Sorry, I meant the car is not actually starting/firing up...everything cranks and blah blah blah, power is fine from the battery and all that but it won't fire up so I can drive it.

you should have bur7eq in the leading plug holes (lower holes)
and bur9eq in the trailing plug holes (the upper or top holes)

Ok, thank you for clearing that up because I've seen a ton of differences in opinions all over many different threads and forums. I will buy those tomorrow locally at Napa or Pep Boys (they have them on their site so I will see if they're in stock).

By the way, I did check to see if the spark plugs work and there is NO spark whatsoever when attempting to start the car...we tried a couple different plugs, different coils, and different wires. Does anyone have any idea where to go to next? My buddy said I should get a meter to read the power to see if the coil packs are getting power. I checked the fuses to make sure they're ok but I'm going to try to find the ignition fuse next...

If you read this please help! Haha, aside from checking compression, what would also be on your to do list for this problem? Thank you in advance!

Cody

If you have replaced all of those things, and the coils have 12v power, it may be the crank angle sensor(s) It wont fire unless it know when to spark. They are situated where they cannot be adjusted, so they could be outright dead.

And ive owned an FD for 12yrs and never had to gap a rotary spark plug. The many options on the heat range depends on your build. i use all 9s but im single...

Let us know if there is power on the coil.

Sorry for the late reply, basically there is no power to the coils...so you're thinking crank angle sensor perhaps? I'm trying to get Glen from AZ rotary rockets to come help me since he is super knowledgeable but he is definitely a busy man so the car is still sitting. If anybody has any input on dead coil packs then that would be great :-)

There is no gap on the spark plugs. Performer a deflooding procedure, new plugs, check spark on all 3 coils, check map sensor vacuum line. Fire her up

Replace your coil pack wiring harness. Mazda has an updated harnesses to make them more reliable since this is a pretty common failure. Call Ray at Malloy Mazda and he'll hook you up with a new one.

Also, at this point, if you've been cranking and cranking with little to no spark, the engine is probably flooded. Get the new coil harness, hook it up and try to start. If it doesn't fire after a couple seconds, check your plugs to see if they're wet and smell like fuel. If so, follow deflooding procedure and give it hell.

Finally found the problem, well not me but a local rotary wiz found it quickly :) The previous owner who wrecked my electronics and wiring, cut the wire and spliced it off the crank sensor so the car wouldn't turn completely over.

Regardless, I found out that my fans in the front (behind the radiator) weren't on high enough power to effectively cool, the spark plugs were for a different car, ignition was messed up...all in short, the car was screwed up before I even bought it lol.

I'm having this guy fix all these things and I will be driving my car by Friday and I will be updating the mods I do as I keep them coming. Thanks for all the support guys and I am happy to be in the FD again! I will be installing the fuel system and trying to get the car ready for a tune so I can FINALLY drive it wide open throttle instead of under 4,000 RPMs.