Hot Start and Restart Problems

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67StangWy
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Hot Start and Restart Problems

Post by 67StangWy » Tue Jun 02, 2020 8:17 pm

Couple trips down to Colorado for a tune, and the mustang is running great, dyno numbers were awesome, AFR looking sweet....but when I shut it off I can not get it restarted until is has cooled down. I hate to run it back down there for that, didn't miss a beat on the Dyno for restarts..but was also consistenly having a fan on it between tunes and fixing a few things.

Anything specific I should look at before hauling it back down and leaving it for a few days for them to replicate the problem?

Thanks
67 Mustang, 351W, T5, Lightning injectors, Lightning MAF, Twisted Wedge Heads, Custom Cut Cam, TanksInc Tank and Fuel Pump, 328hp to the wheels at mile high altitude.

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cgrey8
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Re: Hot Start and Restart Problems

Post by cgrey8 » Tue Jun 02, 2020 8:29 pm

Injector Cranking PW vs ECTn (FN348 in GUFx defs)

The pulses are evidently sufficient for cold conditions, but may need to be fattened up at higher temps. If fattening the values doesn't do it, then it's POSSIBLE the values are too large and it's flooding it. But my guess is it's not rich enough to crank the engine. Engines are usually quite tolerant of rich AFRs on crank...so close enough is good enough. But they are not tolerant of cranking lean. A tad lean and they are temperamental.
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA

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67StangWy
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Re: Hot Start and Restart Problems

Post by 67StangWy » Wed Jun 03, 2020 7:43 pm

65534 1.00
180 1.00
150 1.10
70 2.50
40 5.00
20 6.50
0 21.89
-20 38.76
-65536 38.76
67 Mustang, 351W, T5, Lightning injectors, Lightning MAF, Twisted Wedge Heads, Custom Cut Cam, TanksInc Tank and Fuel Pump, 328hp to the wheels at mile high altitude.

67StangWy
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Re: Hot Start and Restart Problems

Post by 67StangWy » Wed Jun 03, 2020 8:04 pm

From what I have read on the forum I believe they should read more like this?



65534 2.32
180 2.32
150 2.67
70 6.61
40 12.18
20 16.41
0 25.39
-20 44.96
-65536 44.96
67 Mustang, 351W, T5, Lightning injectors, Lightning MAF, Twisted Wedge Heads, Custom Cut Cam, TanksInc Tank and Fuel Pump, 328hp to the wheels at mile high altitude.

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cgrey8
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Re: Hot Start and Restart Problems

Post by cgrey8 » Wed Jun 03, 2020 9:12 pm

I'd say if it cranks fine at lower temps, leave them alone and up the PWs at higher temps. Those 1.x values, for sure, need to be doubled...if not set equal to the example function you posted. My gut feeling is setting them to something around 2.2 will have the problem fixed.
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA

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Re: Hot Start and Restart Problems

Post by cgrey8 » Wed Jun 24, 2020 5:55 am

This past weekend, I drove the truck down to South Ga (from Atlanta area) and while the truck cranks fine hot when it's only run for 20-30 minutes, if it runs for longer than an hour, it does seem to have trouble re-cranking. It does crank, but it has trouble cranking. This obviously isn't an issue with ECT or ACT. But what else is there? It occurred to me...fuel temp. I have a return-style fuel system and a high-flow fuel pump. So it's quite likely that after long running times, the return fuel is heating up the fuel in the tank making the supply fuel temp higher.

But what I don't know is why this has anything to do with cranking quality. It seems like it is cranking lean, but enriching the cranking and starting stuff in the tune made the problem worse...to the point the engine wouldn't crank at all. So I'm wondering if at higher supply fuel temps, if it's cranking too rich and struggling to crank? I tried smelling the exhaust, but with CATs installed, that was useless. It had no smell even when it was obvious I was cranking REALLY rich.

Returning to the original tune that would at least crank the truck also restored my ability to at least crank, even if a little rough for the first few seconds. So now I'm thinking at really high engine temps with high supply fuel temps, it might be possible to overdo the enrichment on both crank and startup. Engines may not be as tolerant as I originally indicated under high engine and fuel temps on crank.

Has anybody else ever had this experience?
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA

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EDS50
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Re: Hot Start and Restart Problems

Post by EDS50 » Wed Jun 24, 2020 7:54 am

I NEVER increase fn348, always DECREASE the msec values. Always decrease it when a larger than stock injector is used. This is what mine looks like with 80's compared to stock a9p:

Code: Select all

 65534   0.25     65534   2.00
   180   0.25       180   2.00
   150   0.50        50   2.30
    70   1.50        70   5.70
    40   3.43        40  10.50
    20   4.42        20  14.15
     0   7.15         0  21.89
    -2  12.66       -20  38.76
-65536  12.66    -65536  38.76
1992 Mustang LX - 25.1c Chassis, Vortech Blown Dart 332, Lentech Trans, TRZ Backhalf, A9L using A9P Tune, Moates QH/SL v1.9, BE, EA, TunerView

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Re: Hot Start and Restart Problems

Post by EDS50 » Wed Jun 24, 2020 8:02 am

cgrey8 wrote:
Wed Jun 24, 2020 5:55 am
This past weekend, I drove the truck down to South Ga (from Atlanta area) and while the truck cranks fine hot when it's only run for 20-30 minutes, if it runs for longer than an hour, it does seem to have trouble re-cranking. It does crank, but it has trouble cranking. This obviously isn't an issue with ECT or ACT. But what else is there? It occurred to me...fuel temp. I have a return-style fuel system and a high-flow fuel pump. So it's quite likely that after long running times, the return fuel is heating up the fuel in the tank making the supply fuel temp higher.

But what I don't know is why this has anything to do with cranking quality. It seems like it is cranking lean, but enriching the cranking and starting stuff in the tune made the problem worse...to the point the engine wouldn't crank at all. So I'm wondering if at higher supply fuel temps, if it's cranking too rich and struggling to crank? I tried smelling the exhaust, but with CATs installed, that was useless. It had no smell even when it was obvious I was cranking REALLY rich.

Returning to the original tune that would at least crank the truck also restored my ability to at least crank, even if a little rough for the first few seconds. So now I'm thinking at really high engine temps with high supply fuel temps, it might be possible to overdo the enrichment on both crank and startup. Engines may not be as tolerant as I originally indicated under high engine and fuel temps on crank.

Has anybody else ever had this experience?
Have you tried opening the gas cap to see if there is any built up pressure when you experience this issue? Could be vapor lock. Is your fuel pump hanger the same as a stock fox body Mustang hanger?
1992 Mustang LX - 25.1c Chassis, Vortech Blown Dart 332, Lentech Trans, TRZ Backhalf, A9L using A9P Tune, Moates QH/SL v1.9, BE, EA, TunerView

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Re: Hot Start and Restart Problems

Post by cgrey8 » Wed Jun 24, 2020 8:21 am

EDS50 wrote:
Wed Jun 24, 2020 8:02 am
Have you tried opening the gas cap to see if there is any built up pressure when you experience this issue? Could be vapor lock. Is your fuel pump hanger the same as a stock fox body Mustang hanger?
The tank vents into the stock carbon canister. I guess it's possible the tube is blocked. Although I've never noticed a buildup of pressure in the tank when pulling the gas cap.

As for vapor lock, I tried priming the pump multiple times when it wasn't cranking. That wasn't the problem. Once I loaded the original tune back in, it did crank, just not as lively as I'm used to.

I am going to increase the prime-time of the fuel pump just in case bubbles are forming in the line. The longer prime time should give the fuel pump a better chance to clear them and thus build pressure. Although I doubt this is the issue since I have the stock pressure regulator back on the truck.

As for my cranking PWs, I have 36lb injectors, and my PWs are higher than stock values for some reason. I'll drop those below stock values and see if that fixes my issue. I'm dumbfounded I've had them set that high for this many years and never noticed a problem.

But what's so confusing is how the engine cranks just fine when it's completely up to temp, but just not run for hours prior to being turned off. Again, the only thing I can figure is the fuel is heating up so the fuel atomizes quicker when it's hot vs when it's cooler. I just would've assumed the heat of the engine would make the fuel line temp irrelevant particularly with the small amounts of fuel injected at crank. But apparently not!
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA

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Re: Hot Start and Restart Problems

Post by EDS50 » Wed Jun 24, 2020 8:54 am

cgrey8 wrote:
Wed Jun 24, 2020 8:21 am
EDS50 wrote:
Wed Jun 24, 2020 8:02 am
Have you tried opening the gas cap to see if there is any built up pressure when you experience this issue? Could be vapor lock. Is your fuel pump hanger the same as a stock fox body Mustang hanger?
The tank vents into the stock carbon canister. I guess it's possible the tube is blocked. Although I've never noticed a buildup of pressure in the tank when pulling the gas cap.

As for vapor lock, I tried priming the pump multiple times when it wasn't cranking. That wasn't the problem. Once I loaded the original tune back in, it did crank, just not as lively as I'm used to.

I am going to increase the prime-time of the fuel pump just in case bubbles are forming in the line. The longer prime time should give the fuel pump a better chance to clear them and thus build pressure. Although I doubt this is the issue since I have the stock pressure regulator back on the truck.

As for my cranking PWs, I have 36lb injectors, and my PWs are higher than stock values for some reason. I'll drop those below stock values and see if that fixes my issue. I'm dumbfounded I've had them set that high for this many years and never noticed a problem.

But what's so confusing is how the engine cranks just fine when it's completely up to temp, but just not run for hours prior to being turned off. Again, the only thing I can figure is the fuel is heating up so the fuel atomizes quicker when it's hot vs when it's cooler. I just would've assumed the heat of the engine would make the fuel line temp irrelevant particularly with the small amounts of fuel injected at crank. But apparently not!
I asked about the stock fuel pump hanger because they are known to severely aerate the fuel the way the return line is configured with high volume after market in tank pumps. I am going to post a link for you to check out. Let me know what you think.

http://www.promracing.com/high-flow-fue ... tangs.html

Just for reference if anyone cares, I use this hanger (modified) with a Dodge Hellcat 525 pump in the stock unmodified fox body tank with full fuel system -8an feed, -6an return. I got tired of the constant whine and fuel slosh of the Weldon 2025 pump and sumped tank on the street.
1992 Mustang LX - 25.1c Chassis, Vortech Blown Dart 332, Lentech Trans, TRZ Backhalf, A9L using A9P Tune, Moates QH/SL v1.9, BE, EA, TunerView

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Re: Hot Start and Restart Problems

Post by cgrey8 » Wed Jun 24, 2020 8:55 am

It's the stock Ranger sending unit. I don't know how similar they are to Mustang's sending unit. I do know I cannot let the fuel level get below 1/4. The 255lph pump will pull air if I take a tight turn or slam on brakes and the fuel level is low. So I've just learned to refuel when the needle gets between 1/2 and 1/4. I never recall this being a problem when it was the stock fuel pump. It looks like this:
Image
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA

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Re: Hot Start and Restart Problems

Post by EDS50 » Wed Jun 24, 2020 8:58 am

cgrey8 wrote:
Wed Jun 24, 2020 8:55 am
It's the stock Ranger sending unit. I don't know how similar they are to Mustang's sending unit. I do know I cannot let the fuel level get below 1/4. The 255lph pump will pull air if I take a tight turn or slam on brakes and the fuel level is low. So I've just learned to refuel when the needle gets between 1/2 and 1/4. I never recall this being a problem when it was the stock fuel pump.
Fuel pump hanger, not sender. (maybe yours is a basket design) I edited my reply , watch the video. It will explain everything.
1992 Mustang LX - 25.1c Chassis, Vortech Blown Dart 332, Lentech Trans, TRZ Backhalf, A9L using A9P Tune, Moates QH/SL v1.9, BE, EA, TunerView

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Re: Hot Start and Restart Problems

Post by cgrey8 » Wed Jun 24, 2020 9:01 am

I updated my response above with an image of what my in-tank sending unit looks like. The TRE Performance 255lph pump just replaces the stock 88lph Walbro. Also my Advance Auto sending unit uses a round metal vessel for the level float instead of that black foam. The OEM stock sending unit used that foam and over time, the center of the foam wallowed out and came completely off the rod which kept my fuel indicator at empty all the time until I got the sending unit replaced. I was pleased to see the updated design used a metal vessel instead of that black foam.
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA

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Re: Hot Start and Restart Problems

Post by EDS50 » Wed Jun 24, 2020 9:04 am

cgrey8 wrote:
Wed Jun 24, 2020 9:01 am
I updated my response above with an image of what my in-tank sending unit looks like.
I see that now. Interesting design. I'm wondering if you could switch over to a Mustang tank. That would most likely fix your problem. I'm sure the Ranger engineers never anticipated a 255lph pump to be used in their stock configuration.

Looking at your hanger more carefully, I am almost willing to bet you can use the mustang hanger in your tank and modify your stock sender onto it to make it work.

Not sure on the length between the two if there is a difference to take into account for tank depth but would be a worthwhile project to delve into if you were interested.
1992 Mustang LX - 25.1c Chassis, Vortech Blown Dart 332, Lentech Trans, TRZ Backhalf, A9L using A9P Tune, Moates QH/SL v1.9, BE, EA, TunerView

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Re: Hot Start and Restart Problems

Post by EDS50 » Wed Jun 24, 2020 9:17 am

cgrey8 wrote:
Wed Jun 24, 2020 8:55 am
It's the stock Ranger sending unit. I don't know how similar they are to Mustang's sending unit. I do know I cannot let the fuel level get below 1/4. The 255lph pump will pull air if I take a tight turn or slam on brakes and the fuel level is low. So I've just learned to refuel when the needle gets between 1/2 and 1/4. I never recall this being a problem when it was the stock fuel pump. It looks like this:
Image
You shouldnt have to refill between 1/2 and 1/4 tank. I would drop your tank and see if the fuel baffle/shelf/tray the pump sits in broke away inside the tank.
1992 Mustang LX - 25.1c Chassis, Vortech Blown Dart 332, Lentech Trans, TRZ Backhalf, A9L using A9P Tune, Moates QH/SL v1.9, BE, EA, TunerView

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Re: Hot Start and Restart Problems

Post by cgrey8 » Wed Jun 24, 2020 10:27 am

The stock tank looks something like this although my tank is plastic, not metal:
Image

With the exception of some minor contours in the plastic on the very bottom of the tank right where the fuel pump sits, I don't believe there are any baffles in the tank. It looks similar to this:
bottom_of_fuel_tank.jpg
bottom_of_fuel_tank.jpg (48.8 KiB) Viewed 268 times
But because the tank is long, you couldn't adapt a Mustang tank into the space where a truck fuel tank goes.
...Always Somethin'

89 Ranger Supercab, 331 w/GT40p heads, ported Explorer lower, Crane Powermax 2020 cam, 1.6RRs, FMS Explorer (GT40p) headers, Slot Style MAF, aftermarket T5 'Z-Spec', 8.8" rear w/3.27s, Powertrax Locker, Innovate LC-1, GUFB, Moates QuarterHorse tuned using BE&EA

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Re: Hot Start and Restart Problems

Post by EDS50 » Wed Jun 24, 2020 11:32 am

Ah yes, I see the difference. There has to be a tray or pocket of somesort the fuel pump sits in. You should have no issue running the fuel level down past 1/8th tank without any sloshing issues. I expect that behavior with a sump tank or stock tank with a broken fuel tray/pocket. Maybe your fuel pump doesnt sit as low in the tank as the stock one did?
1992 Mustang LX - 25.1c Chassis, Vortech Blown Dart 332, Lentech Trans, TRZ Backhalf, A9L using A9P Tune, Moates QH/SL v1.9, BE, EA, TunerView

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Re: Hot Start and Restart Problems

Post by cgrey8 » Wed Jun 24, 2020 11:38 am

Now that's a possibility
...Always Somethin'

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