DanM

I just tested the injectors and although the harness passed the NOID test and the rail is full of fuel (Ask me how I know) they are not firing. I'm so confused right now, I feel like my head will explode! 😣

So I bought some starter fluid spray today and gave that a squirt into the throttle body. The engine responded briefly! yay! before a big cloud of spoke started spewing from the exhaust filling my garage. I still have the rising MAP issue so reaching out to megasquirt direct on that one. Next step for me is to remove the fuel rail and injectors to see if they are actually spraying.

Thanks everyone for your input. I have the MSPNP2 (Plug and Play) MS, so in theory other than configuring the IAT and Wideband (from Drop down) I have nothing to do to get the engine firing (albeit un-tuned). I have checked that I am using the correct firmware and the Miata 9093 base map for start up. I am now at the point where I have had to recharge the battery 'cos of all the cranking and tests since last thursday........so who knows what the state of other components are now. I will definitely reach out to MS and see if it might be the unit.

Timing also seems to be good!

So, here is the latest: Fuel Pump - Working Intake - Clear Battery - Delivering Power Starter - Working Spark - Present Injectors - working I am currently trying to understand the Megasquirt data logs. My Manifold Absolute Pressure (MAP) is way off the chart like some crazy boosted engine without even cranking it over. I loaded new firmware on the controller but still the same. I'm reading all the megasquirt forums to see if I can get some kind of lead to follow....very frustrating.

Yeah, sorry Graham, I was very tired when I wrote that. It is 10 degrees btdc. I've updated it now. I'm taking input from multiple forums right now, just trying to gather as much data as I can to narrow down the problem.

I cranked it over and checked the timing last night and the timing is exactly where it should be, 10 degrees retarded Advanced.

So I'm moving this discussion from my build thread to tech talk to help anyone who may experience similar issues in the future. Background I am using Megasquirt MSPNP2 as my chosen ECU for my 1990/93 1.6 MX-5 engine. The engine is basically stock, but I have removed the Air Flow Meter and replaced with an Intake Air Temperature Sensor (IAT) and installed an Innovate MTX-L O2 sensor (wideband). I have loaded the base ECU map for 9093 mx-5 and adjusted the configuration for the IAT and O2 (basic drop down settings). Problem The engine will crank over but will not fire up on the base map (and it should). Checks I have the following data from the checks that I have performed. Fuel Pump - Working Intake - Clear Spark - Confirmed Battery - Delivering >12V Starter - Working Injector harness - Noid light test fail (12V Confirmed but no signal ground) ECU tuner shows RPM ECU tuner shows AFR (O2 sensor) ECU tuner not showing Throttle position (not sure if it supposed to) Engine light remains on when keyed to "On" position Why is the ECU is not sending signal ground to the injector? Any ideas for the pot?

So, at the end of another head scratching evening (again between kids activities, etc.). Here's what I think the status is: Fuel Pump - Working Intake - Clear Battery - Delivering Power Starter - Working Spark - Present Injectors - Have voltage, but need to test further. Cam Angle Sensor - Not tested yet. Enough for tonight. Next, I will either buy a Noid light for the injector harness or perhaps remove the fuel rail and test the spray on some cardboard. More learning tomorrow.

So I started going through the list: Fuel Pump - Disconnected (and got blasted in the face with pressurized fuel- yuck!) and tested. All good. Intake - Disconnected and checked for blockage. All good Battery - Checked with multimeter - All Good Starter - Engine turns over - Assume good. Injectors - Disconnected injectors and connected a light bulb to the harness. First I tested the against engine ground and the light came on. Then, I connected the signal ground from the harness and cranked over the engine....No light. Looks like I have no signal ground from the ECU. Time to retrace my engine harness to see where the issue may be.

Checklist for this afternoon. Not necessarily in this order!

I installed a fuel pump toggle switch so I could isolate the fuel pump if needed and I'm sure the pump was switched off. I'll check it out just in case...

Todays attempt to start the engine was full of thrills, disappointments and a lot of frustration... My RS232/USB adapter arrived last night so the first thing I did this afternoon was connect the Tuner studio software to the ECU and load the base map for the 1990/93 Mx5. The FDTI adapter Tuner studio connected to the ECU While I plan to use the base map until I get a proper tune, I did have to make some minor configuration changes to account for the AFM delete (replaced by a GM IAT) and Wideband O2. Once loaded my daughter helped me push the car outside to see its first bit of sunlight in nearly 2 years. What then followed was approx. 2 hours of pure frustration while my laptop died, and I somehow lost connection to the ECU. By the time I eventually got everything back to where it was, it was time to collect my son from his summer activities and make dinner. Back in the garage it went. 😑 Keen to make progress after dinner, the kids helped me push the car back out this evening and I got straight on to seeing if I could turn the car over without any fuel in it......Click! ****!!!! Nothing! After what seemed like a few minutes of scratching my head, I remembered that I had installed a clutch safety switch. Well, good news Mr Safety Inspector, it works!! I engaged the clutch, turned the key and the engine turned over. Yay!! Happy Days!! With that major milestone achieved (for me at least), I added some fuel to the tank. Thankfully, the first hose clamp was a little loose and started to leak after a a few drops of fuel were poured. This was enough of a reminder to go around all the hose clamps and give them a bit of a tighten before putting anymore fuel in. Finally at 21:30, I was ready to go. I hopped in the car and turned the key a couple of times to allow the fuel pump to push fuel into the system. Then I cranked it over. No change. It sounded exactly the same as it did without fuel. After doing some basic checks I tried two or three more times, without any change. Too exhausted to do anymore problem solving this evening, I pushed the car back in and packed up for the night. Tomorrow is another day of learning!

While waiting for my ECU cable adapter, I decided to continue with other stuff. Next on my list was to position my windscreen. I still have to figure out how I'm going to get them more "chromey" but in the mean time I wanted to get everything test fitted and the holes drilled. First, I secured the scuttle and made myself a windscreen support out of an old pallet I had laying around. I noticed that I had a bit of difficulty getting the 6mm bolts through the layers of fiberglass (Scuttle and tub) so I think I'll get some longer ones for the final fit. Once everything was secured I positioned the windscreen and side pillars. Looking closely I noticed that although the windscreen positioned itself in the channel, only the edges were actually touching. Has anyone else experienced this? Is this a problem? Next, I assembled the side screens so I could adjust the windscreen rake. There are no obvious marks identifying where to position the hinges so I carefully put pressure on the frame with my fingertips and once I felt something that seemed like a hole I gently marked it with the end of a pen (Nib in). Then I punched the bolts through the holes and secured the hinges. For me the set up position (1007mm - screen to back chassis rail) was a little too long and the doors did not sit on the side of the tub. After tilting the screen back a little on both sides the sidescreens lined up pretty well. Once I was happy, I removed everything, drilled the holes and then test fit everything again. Finally, in preparation for receiving my ECU cable adapter (hopefully) tomorrow I put the wheels back on, lowered the car and then rotated it so I could easily push it out of the garage for my second attempts at a first start.

With a couple more garage hours allocated today I decided to press on with some other tasks. One of which was filling up the brake system. I made myself a rudimentary break bleeder just to make sure the pipes were filled. I'll bleed them properly when I have someone here to help. Now time for a shower, dinner and beer! 🍺

Thanks Graham, So things have sadly ground to a halt today....... To get things start off I took out the plugs and poured some oil into the cylinder, left it a short while and then cranked over the engine by hand. I'm very glad I did, because a lot of burr and chaff came out from my accessory belts and pulleys. Must have got stuck in there after I drilled some holes for the loom or body work. After blowing it out with compressed air and gently brushing the belt with a nylon brush all was cleaned up. The engine cranked over well. 😀 Next, I got my Wideband sensor set (I took it out of the dash panel and held it in place with a cardboard box) up by heating it up and calibrating it to the atmosphere. Good to see my wiring was working so far!! Finally, I loaded up the Megasquirt Tuner Studio to my laptop. This is where things ground to a halt..... Unfortunately, the cable provided does not fit my laptop and so I'm not able to download the base tune to the ECU until I get one ordered. Close but no cigar!!! Now I have to wait for the new cable to be delivered before I can continue.

So yesterday I spent the afternoon and evening filling the car up with fluids. Engine, Transmission, Differential and Coolant. Due to the lack of access to the transmission and differential filler holes I bought some 1/2inch vinyl tube and drip fed the fluid from above. Made a mess at first but slow got into it. Differential (Much easier than the transmission) I filled the coolant in steps while it slowly seeped into the system. I left it overnight and then topped it up again this morning. I also installed new spark plugs, HT leads and finally the air filter. Today I will focus on the megasquirt set up and hopefully turn over the engine to get the fluids pumped around. Does anyone have any start up tips for me? I'm feeling quite nervous, considering I assembled the engine myself!

Thanks Graham, I hadn't even thought of that!!!

Productivity seems to be high at the moment and so I'm trying to maximize my time in the garage. Yesterday I attached the exhaust pipe to the chassis. First I located the mounting point on the chassis and drilled a pilot hole from the inside-out through the fiberglass. Then I masked off the area, inserted the bolt and sleeve and marked around them as a template. Slowly I worked from the outside-in filing out the hole until the sleeve passed through. I wasn't sure how the rest of the mounting brackets were oriented, so with some help from members of the UK forum I was able to assemble the other parts. To ensure I was able to get my spanners in there, I first attached the mounting bracket. Then I assembled the rubber mount and exhaust cradle to the silencer using loctite on the cradle bolts. Again thanks for the advice! Doing it in this order made it easy for me to offer up and secure the exhaust to the chassis will minimal fuss. With the exhaust now in place, its time to prepare the Megasquirt and begin planning for a first start!

More bodywork tasks this weekend. Rear lights. As you can see I still love the blue painters tape. Unfortunately the nuts and bolts needed for the indicator units were missing from my stash, so I will need to buy them tomorrow when the stores open after the long weekend. I think I will also take the time to spray some rubberized protection in the wheel arches before I finally attach them. I also positioned the nose cone, drilled through the fiberglass and installed the top bolts to secure it. Unfortunately I was missing the bolts for the lower mount so I used my workshop chair to hold it in place temporarily. With the nose cone lined up I positioned and drilled the underside of the body to the chassis, using Clecos to keep it all in place while I rivetted. I dabbed a bit of silicone sealant on each rivet before squeezing them in.

More little tasks yesterday. First I attached the rear body work, trying to keep the wheels hub. centralized in the rear arches. The RHS was spot on so could be rivetted immediately, however the LHS needed a bit more fettling. I think I managed to get it within about 5-10mm of the target. Then I installed the fuel filler neck and cap assembly. First I masked the inside, temporarily attached the hose and used it to identify the centre of the 65mm circle cutout. After drilling a pilot hole from the inside I then moved outside used a hole cutter to do finish the job. Finally I marked and drilled the gas cap screw holes before fitting the cap and clamping everything secure.

I managed to complete a few smaller jobs in the last few days. All progress is good progress. First I fitted my Revotec self sealing hose connector to the air intake for the crank case ventilation. This was the second one I had to order as I messed up the part number on my first try. Anyway its now fitted so the intake is now buttoned up. Then I moved on to the fog light switch, the only stand alone Miata switch that I decided to reuse. It took a few tries to get the position and orientation correct, but I think it came out ok. I then had to re-install the dash panel to see how everything would look when its done. Its not perfect, but its tidy and a bit more interesting to look at. Next I made up a new wideband O2 sensor input connect for the megasquirt. I decided to make a separate input instead of splicing into the existing harness just incase I have to put the stock ECU back in for safety inspection. The set up was very flimsy with just one pin being used in the connector so I ran the wire through a pvc cable jacket that I had laying around and wrapped it secure with cable tape. Lastly, I fitted the rear arches. I have used the M6 hardware provided for now, but plan to swap it out for plastic bolts (or it is Nylon I can never remember).

I have three buttons (Haz, Demist, Horn) and have managed to get the following functionality: Button on/off - Pass Button Illumination w/ sidelights on - Pass Button Illumination when button on - Fail I am now exploring an Arduino set up to get the illumination I need. Do you have experience with that?

I am about to start wiring my new Caterham (eao) switches and need help understanding the connections points (13, 14, X1, X2 etc.) at the back. Anyone able to help?

With my intake tube and exhaust back from the welder, I can start to assemble the Megasquirt infrastructure. I opted for the MSPNP2 with the 1990 miata map, so just need to install a Intake Air Temperature sensor in the intake and a run a hose from the intake manifold to ECU to measure the Mass Air Pressure. New IAT with K&N filter (RU-5174) To hold it all together I fabricated and painted a small hanger to secure the intake with a hose clamp.