When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hello everybody before I start describing my issues I'll first list the mods that I've done.
1992 motor
Built bottom end with Manley rods and Supertech pistons 8.5:1 compression with Weisco rings
Brand new head (stock just new hla lifters)
DW 340 L/HR pump
DW 1000cc injectors with stock rail (could be the issue)
Garrett gt2252 Turbskie with stock wastegate (7lbs)
UPP custom manifold and exhaust
Megasquirt ms3pro
Brand new stock ignition
ATI superdamper
I am running AC and Power steering, the manifold allows me to
Fidanza lightweight flywheel
ACT fullface sprung clutch
GM AIT sensor
Koyorad Radiator
Flyin miata variable tps upgrade
So, I started the car for the first time in mid december of last year. The car did not want to stay running for more than 5-10 seconds and when it did run, it was lean, REALLY REALLY LEAN. 22ish afr. I didn't start the car for another 2 months due to work reasons. So then I try starting the car now and nothing happens at all. So I check the base timing, good, check ignition timing, good as it is locked at 10 degrees adv, take the spark plugs out to see if they fire, obviously while grounding them, and they check good. Then I go to check if there is fuel and there is a little in the cylinder but I don't think it's enough. Also I don't know what this could be, but it looks like there is little black specs on top of the piston. Could just be carbon buildup from when it did run briefly. So I check the fuel lines and it shoots out fuel so I'm not worried about that. then I check the rail and there is fuel there as well. Therefore my hypothesis is that the injectors are not spraying enough fuel and Im pretty sure I proved this because I put a little bit of fuel into cylinder #1 by removing the spark plug. Then when I tuned it over the motor caught for a brief second then died, which makes sense. I then received a dead time sheet for my injectors since they are 1000cc and punched that in. No change, still not catching. I then sprayed starting fluid in the turbo and it ran for about 2 seconds. I am now convinced that my injectors are not working. Problem is, I don't know why, and it's really getting frustrating. I have the Req fuel correct in megasquirt, which is 2.7 for 1595 cc engine with 14.7 afr and 1000cc injectors. In megasquirt it reads that there is a pw and I tested the injectors with the can test mode in megasquirt and they were firing. I'm running out of options folks.
So I guess I have a few questions
#1: Even though the injectors are brand new, could starting the car that lean make them dirty or clogged up? I wouldn't think so since they're brand new injectors but I guess it's just an option.
#2: Is something not calibrated that should be, maybe I missed something while installing them?
#3: Could the new compression ratio come to effect since stock it is 9.5:1 and mine is now 8.5:1
#4 Could it be that I'm running the stock fuel rail with huge injectors?
#5 Could it be that the stock fuel pressure regulator is faulty, I've read that they are good for a decent amount of HP, which I am only shooting for around 200-225 whp
#6 I the Req fuel wrong in megasquirt? I will list my current tune and a datalog from the starter fluid start below. Again my req fuel is 2.7 which is really low but it's what it calculates to.
Any Help would be Very appreciative since I am out of ideas and my field of "expertise". Thank you all if you read this and again any ideas or advise would be a true blessing.
*UPDATE*
I took the injectors and rail off and cleaned them both. I had good fuel flow spraying out of the injectors so that would lead me to believe that I have poor fuel pressure. Although on megasquirt is states that the engine is receiving 101 kpa of fuel pressure but I will check the fuel pressure with an actual test set.
101 kpa is the "fuel load" which basically means map pressure, Miatas don't have fuel pressure sensors. Run the test with a fuel pressure sensor/test kit.
101 kpa is the "fuel load" which basically means map pressure, Miatas don't have fuel pressure sensors. Run the test with a fuel pressure sensor/test kit.
*UPDATE #2*
Megasquirt reads "RPM NOT SYNCED". I didn't think anything of it because the car is able to start with it but apparently its an issue. I'm still in the process on trying to figure out possible causes but if anybody has any ideas, that would be great.
*UPDATE*So turns out that the fuel pump wasn't installed properly, thanks to me, so after fixing that, fuel pressure was good and the car started. My issue now is that the car idles super lean. Around 18-22ish afr is where it wants to idle. The req fuel is correct, I played with the fuel ve table and that helped a little, I let autotuned do its thing and instead it brought the fuel up too much and the car started to vary in rpm WAYYYYY too much. It pulsed from 1900 rpm to 3100 rpm with the afr ranging from 15 to 22. NOTE*, that the car is now 8.5:1 but that doesn't explain why its still super lean because the base tune is for 9.5:1 which means "more fuel". Also, my rpm not synced issue went away when the car started.
You have 121.7 at 12v listed in the post I quoted but the sheet you provided says 1.217 at 12v. Either you mistyped in your post above or you are putting the wrong numbers in the MS by a large margin.
There's a big difference between 1 and 121 milliseconds.
Jgilby
You took the deadtimes for 2bar pressure, moved a decimal point on 2 digits to the right, and than entered it as %% (1.217ms -->121.7%)
You use a serious stuff
You have 121.7 at 12v listed in the post I quoted but the sheet you provided says 1.217 at 12v. Either you mistyped in your post above or you are putting the wrong numbers in the MS by a large margin.
There's a big difference between 1 and 121 milliseconds.
Ok, I guess I misunderstood how to enter it in megasquirt. I'll change that and post an update when I can. Thanks btw
Assuming your have stock NA manifold referenced 3bar FPR
and that FPR is still properly working with the oversized 340lph pump
you have to enter Deadtime@13.2V=1.187 and Deadtime Voltage % Curve = grey color highlighted numbers
*UPDATE*
After correcting the deadtime, my afr target is almost spot on! My only issue now is a high/creeping idle, but as far as the fuel issue, it seems to be fixed!
03-12-2020, 02:22 PM
No fuel on start
0
