90 Fox-Megasquirt Difficult start (stock engine)

[LX2C]

Hi everyone. I am new to the forum and happy to be here. My 90 foxbody, which I bought new in May of 1990, is still in good shape and still has the stock motor with no modifications. Just about a daily driver. That said, a few weeks ago I purchased a megsquirt PNP-2 (MS) and decided to give it a try. I down loaded the starter tune from MS and was able to get it stated using the vaccum line and deleting the MAF and just using SD. (MS suggested) I did manage to get the extreem rich idle under control, with a few table idle fuel adjustments but have not mastered the difficult start.
The timing on the motor is at 14 degrees and the MS is at 14 degrees. When the motor does start, it reves good and holds an idle but does not go through a typical warm up process like the factory A9L.(1200 rpm and levels off at 800). The MS just starts idling at 800 rpm. There may be something incorreclty set here...
I am not looking for a crazy performace tune, just a good start at this point so I can drive the car a little with the MS.
Can anyone offer some suggestions? I can post my tune if that will help.
Thank you.
Wes

 

[nickyb]

I'm sure if you post your tune someone here (with m.s. experience) can look it over.

 

[LX2C]

Here is the tune. Thank you in advance anyone...

 

[LX2C]

I'm sure if you post your tune someone here (with m.s. experience) can look it over.

Thank you. I am new here and did not want to impose. Thank you for that suggestion. I just posted it.

 

[Blown88GT]

If it idles when cold & holds idle & doesn't stall, does it matter that it doesn't hold 1200rpm when cold, like the A9L?
The tune looks OK for an unmodified 5.0.
Remember, the A9L uses a MAF & the MS uses SD.

 

[Glliw]

While I'm not an expert in MS, I recently got one as well (going in the car next week) and am starting to get into the details myself so I took a look at your calibration and have a few thoughts.

• Injector size is 213cc / 10.5 = 20.2 lb/hr. Stock are 19lb/hr. Have you adjusted fuel pressure or injector size from stock to require the increased base injector size?
• The 1200 RPM cold idle during start up serves a few functions but primarily catalyst warm up. Does your car still have the catalyst? Like Blown88GT said, if it idles fine without stalling at 800 RPM, you're probably OK.
• If you still desire to have the increased cold idle speed, then I believe you need to use Closed Loop Idle in the "Algorithm" box of "Idle Control" under the "Startup/Idle" menu. You'll then need to adjust the "Closed-Loop Idle Target RPMs" table and probably the PID settings in "Closed-Loop Idle Settings" which will take some work to get correct I'm sure.

 

[LX2C]

If it idles when cold & holds idle & doesn't stall, does it matter that it doesn't hold 1200rpm when cold, like the A9L?
The tune looks OK for an unmodified 5.0.
Remember, the A9L uses a MAF & the MS uses SD.

Thank you. No, it does not matter. The real problem is the starting...(cold or hot) It seems to start better after I let go of the key, not during the actual cranking phase. This is very odd... The motor spins really fast and healthy. Marjor starting issues.

 

[LX2C]

While I'm not an expert in MS, I recently got one as well (going in the car next week) and am starting to get into the details myself so I took a look at your calibration and have a few thoughts.

• Injector size is 213cc / 10.5 = 20.2 lb/hr. Stock are 19lb/hr. Have you adjusted fuel pressure or injector size from stock to require the increased base injector size?
• The 1200 RPM cold idle during start up serves a few functions but primarily catalyst warm up. Does your car still have the catalyst? Like Blown88GT said, if it idles fine without stalling at 800 RPM, you're probably OK.
• If you still desire to have the increased cold idle speed, then I believe you need to use Closed Loop Idle in the "Algorithm" box of "Idle Control" under the "Startup/Idle" menu. You'll then need to adjust the "Closed-Loop Idle Target RPMs" table and probably the PID settings in "Closed-Loop Idle Settings" which will take some work to get correct I'm sure.

ok, Thank you . I will try anythig at this point. Much appricated. No Cats.

 

[86HO5.0]

Thank you. No, it does not matter. The real problem is the starting...(cold or hot) It seems to start better after I let go of the key, not during the actual cranking phase. This is very odd... The motor spins really fast and healthy. Marjor starting issues.

Have you verified voltage at the coil when cranking? Your description sounds similar to a bad/failing ignition switch.

 

[LX2C]

Hi. I am back on this project. I have not tried the coil voltage test. When I plug the A9L back in, the car fires right up and runs perfect. I have suspected it was not switch related, but will give it a shot. I will try a new base tune EEC4A8 again. The trigger wizzard did confuse me from the start, but I have a better understanding of it now. Point to note, when the car did fire up and run, which was not often, it seem to run ok, but did backfire during a WOT snap. That sounds like a timing issue to me. I will revisit the timing and do the voltage check. Thank you all.