newbie needs some help. Cannot keep car running

[SpeedFrK]

Hello,

Recently got my 944 turbo wired up with MS3. I cannot keep the car running. I got my base tune from another 944 turbo guy running larger injectors. I scaled my required fuel based on my injector sizing but am using his fuel map for the most part. I have posted a datalog and my tune. Any help would be appreciated.

Symptoms experienced during starting:
-Have to hold down throttle to 10% and car will stutter and eventually start.
-Car did start up 2 times and I could give it a bit of gas to get it up to 2000+ RPM but it would always die.
-Now the car will not start and stay running very well, it also backfires pretty bad. Its running very rough.
-I tried starting it for a good while today with very mixed results...only 1 in 5 times would it turn over the engine to try and start, the rest of the time it would just spin and spin with nothing.

This is my first MS install, I built this myself using the DIY kit. Any help would be greatly appreciated...just not really sure where to start. All of my settings seem reasonable and I got it to start once already...but now nothing. I await your responses. Thanks.

[Paul_VR6]

What is the ignition setup? Sounds like its either still really lean or ignition timing is off. If it doesn't have a fixed toothed wheel with a known angle, you will need to sync the timing.

[SpeedFrK]

Ignition set up is wasted spark with LS coils wired using the FET driver method. I am using spark A and B off of top of R26 and R29 respectively. Tested spark in test mode...confirmed Spark A is firing Cylinders 1 and 4 and Spark B is firing Cylinders 2 and 3.

Timing is set by a trigger wheel (60/2) and a VR sensor from a 4.0L ford. Tooth count past TDC is 11(i started counting as the last missing tooth passed the VR sensor) and I have my Base timing set to 66 Deg BTDC (360/60 = 6 deg/tooth * 11 Teeth = 66 Deg BTDC) I think I have this right...

The odd par is the car started up and ran for a min or two..then died, it always died. But now its back firing and if I can get it to run, it idles very rough. I did try scaling my fuel table by 5% then 10% then 15% and it seemed to get worse....hard to tell though. I probably need to take a more systematic approach to testing this.

My only question to you guys is, is there a chance I could damage the motor trying to start it without the correct timing??? Did I already do some damage? Thanks guys.

[billr]

Have you checked ignition timing with a simple (non dial-back) strobe light? Is this a 944 with two VR sensors back at the flywheel? I think the connectors to those are identical, and can be inadvertently swapped by mistake. Post a tooth-log. Damage the engine? Probably not, but you could start a fire or maybe damage the starter/gears if it kicks back against the starter repeatedly. Check the ignition timing, set cranking advance to zero, and it won't kick back.

Your "req_fuel" is set correctly for your injector flow and engine size, but do you know that it was set correctly for the engine/tune you took it from? (What was the injector flow and fuel stoic for the tune you started with.)

[turbo conversion]

You may also pull your plugs and see if the are wet or dry, this will tell you what is happening with your fuel.

David

[SpeedFrK]

So thanks to a super smart guy on the Rennlist forums I think I may have found the issue....for some reason I was only running 1 squirt per engine cycle and my injector staging was set to simultaneous...So this explains the lean condition....I dont have a cam signal and should not be running that injector staging. Ill try to start the car again tomorrow with the altered settings and we will see.

BillR - I have a timing light in waiting for when I can get the car to stay running without me holding the throttle down. Ill dial the base timing in hopefully tomorrow.

David - I did pull all four plugs and none of them were soaked in fuel so too rich is definately not my problem, but thanks for the advice.

[billr]

It's a bit harder to check timing when the engine is only cranking, but it is certainly possible to do; and that is the time to do a first check, before trying to run.

[SpeedFrK]

The car started and got warmed up ...I was not in fixed advance mode so it was running pretty crummy...My ignorance didnt realize this so I started advancing timing via the Tooth #1 angle and noticed that when I advanced it a bit it ran better, that is because it was using the table. I actually got the timing mark on the TDC indicator with my timing light by changing my tooth #1 angle from 66 to 78. The car warmed up fully and then died. I struggled to get her to start again, tried changing cranking pulses and probably changed a bit too much stuff. Saved all my tunes so its not hard to go back. After struggling to get her running for a bit, I realized my error and changed the timing to fixed advance at 10 deg per the manuals instructions ...oops. Now I can get the car to run and stay running but it will not idle when hot. I have posted two logs of me starting with about 40-50% throttle holding the gas and gradually letting off the throttle until she dies. Not sure what is killing the car. The car does have a throttle body set screw as well as a Idle adjustment screw that I played with a bit...thinking if I could get the car to hold the idle itself I could put the timing light back on it with the fixed advance setting and try to dial my base timing in the right way...... Any help you guys can give on why its cutting out when I let off the throttle would be helpful. The odd part is that it idled, abiet very rough due to the 18 deg advance it was getting from the table without me setting my base timing but it idled up and out of WUE, and now it wont.

[billr]

Want a guess? It is too lean while idling, try fattening the VE table.