Sclippy96

Everything points to either a bad starter or bad battery especially from the low voltage I see in the logs, but both have been checked and swapped out for different ones with the same problem persisting.

I have a 1995 miata, MSPNP2 with EV14 650cc injectors and a BEGi Gt2554 turbo kit installed. Over the past few weeks my cold starts have gotten progressively more difficult. I had to use a jumpbox to be able to get the starter to spin enough to get it to catch on the first start of the day, but it will take 10-15 start attempts to even get it to start thinking about catching. Hot starts it will fire right up.

Now I can't even get it to start when I have it hooked up through jumper cables to another car. I switched the battery out with a know good one from my dads miata thinking that was the issue, but the starter is still very sluggish. It constantly acts like the battery is really low, even on jumper cables to another car, the extra juice doesn't change the results. I have double checked the wires at the starter and I get 12v there when I turn the key.

It'll crank for about 1.5 seconds at most before it stops and just clicks the solenoid. Bad starter right? I replaced the starter today with a refurb from napa auto parts. Went to start the car and nothing has changed. It still spins very sluggishly and wont start. I double checked for spark and I have it, I did hear it explode a single cylinder thru the exhaust once or twice, so I think if I can get the starter to spin up normally it will catch eventually.

Bad ground maybe? I used a thick jumper cable directly from the negative battery terminal to the block... no difference.

Bad hot lead from battery to starter? It gives 12v when checked with a meter, we did attempt to jump the starter on the car directly from a battery, got it to spin but the solenoid wouldn't extend out into the fly wheel.

Correct me if I'm wrong, I don't believe the ignition switch or the clutch switch wouldn't be the culprit in this case as I do have 12v at the starter when the key is turned.

I will pull the starter back out tomorrow to return it for another and run some tests on it before we try to re install it.

Anecdotally, when I was farting around with my ECU in between start attempts I did manage to corrupt the firmware and brick my megasqurt temporarily. While the ECU was bricked without a tune I was able to spin the starter much faster and longer than when a tune is loaded into it. In my mind with the tune it's as if the cylinders are getting loaded up with unburnt fuel somehow and the starter is having a hard time pushing through the extra compression.

I had to update the firmware into the MSPNP2 to bring it back to life. I reloaded my old known working tune back onto the new firmware. I have also tried different .msq files provided by diyautotune with no difference in the starter dragging.

I noticed when I look at the logs of my start attempts that the voltage will drop significantly during the start attempts, 6.4 volts at it's lowest and the engine makes it up to a peak of only 242rpm now. The logs of start attempts before the ECU firmware corruption had the rpm going as high as 689rpm.

Start attempt a few days ago:


Today:

Sclippy96

Bad ground maybe? i will use this procedure to test it: Flyin' Miata : Tech : Grounds

I am going to clean the chassis ground wires, the 4 places i know of:
1. front of engine near throttle body
2. shelf under the brake booster
3. PPF strap
4. battery to chassis in trunk

Also going to inspect and clean the clutch ignition switch at the key and bench the next starter before it goes in. Looks like an NB starter might also be a good idea too with it's reduction gear and higher torque.

sixshooter

iTrader: (12)

Pull the fuel pump fuse. Take all four spark plugs out and spin the engine. If it spins freely then your starter is good and something in the tune/timing or injectors is borked. Spinning it will also help to get any fuel or water out of the cylinder bores. If you have had a fuel or hydro locked incident then you will DEFINITELY need to change the oil before running the engine.

Pull the dipstick and smell the oil for the presence of fuel. And view it for the presence of water.

Sclippy96

I pulled the fuel injector relay and the engine will crank freely with good voltage. I also cleaned all the grounds up. I tried a different know good fuel injector relay in the fuse box and the moment I crank the engine with the relay in place the voltage will instantly drop to 8 volts or lower when cranking with a very sluggish starter still.

I believe I can rule out bad grounds or bad battery or bad starter. I suppose I have narrowed the problem down to the fuel injectors or fuel injector harness. Not sure how to proceed next with troubleshooting with the voltage drop I get when the fuel injector relay is in place tho.

Sclippy96

I switched the injectors out for the stock 265cc injectors thinking one of the ev14 650cc injectors might have gone bad and changed the req_fuel to match the old injectors, but that solved nothing.

Finally I checked the plugs again for spark, last time I only checked plug number one nearest front of the car and got a blue spark, but didn't check the rest. Today I checked them all and found that plug 1 still fires but plugs 2 & 3 show no spark and #4 is a weak orange spark. I am focusing on the coil pack now as the source of my non-start. I also switched the CAS on the head for another from my old engine and that didn't change anything about the spark.

Next step tomorrow will be removing the coil pack and testing the wire loom connector that plugs into them to check to see if I get both a constant 12v and if the firing signal is coming from the ECU to the coils when cranking.

Sclippy96

I made a rookie mistake of checking for spark on cylinder number 1 only and seeing spark and assuming the other 3 cylinders were good, they weren't. I then spent countless hours chasing everything under the sun, a new starter to redoing all the grounds to cleaning the ignition switch, changing fuel injectors, new battery. Finally went back to square one to retest for spark and found the problem as soon I tested cylinder 2.

I benchtested the coilpack using the method found here: Mazda Coilpack Benchtest Procedure

Turns out my problem was the coilpack had went bad, could only give spark to a single plug.

Spent another ~$80 for ebay Toyota COP's, COP pigtails, 10,000uf capacitor, and a few brackets to hold it down. Took a few hours to setup the new COP harness but it fired right up after I reset the MSPNP2 to 3.5ms cranking dwell and 2.5ms running dwell. P
Phew!

Learn from my noobish behavior, ALWAYS CHECK ALL SPARKPLUGS FOR SPARK!!!!

My Toyota COP install:

Dlaitini

That hold down method might bring you a bit of headache later.

If you have ever seen what a steel braided line will do to something it rubs against, the metal bar and the plastic of the COPs will vibrate and wear right through that plastic. Plus the more it rubs the bigger gap it will make and the more vibration it will have.