MattODoom

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Car is a 1946 Ford Coupe

355 with a mild flat tappet cam, turbo 350 trans.

Heads are off of an 85 5.0L IROC - they have been port worked pretty well and possibly had a valve job.

TPI intake is stock, stock runners, plenum has egr walls knocked out.

The first major hurdle I had with the car was that it kept throwing code 43 - which is an ESC system error. This was causing it to consistently pull tons of timing out. I disabled the code 43 and zero'd out the max knock timing retard fields so I could get it running right. After that it seemed to run OK. I believe the problem is that my dad has a '165 knock sensor in it, and thus the ecm is seeing the wrong resistance from it.

Now that I got that out of the way ive been working more cruise tuning. The car has a slight burble when youre cruising 55mph like a miss. I think this is timing related.

Also, the car seems to be really rich even though its on stock AUJP VE tables. I would have figured that if anything it would need more VE, but I have pulled a lot of VE out of it to get it where it's at. Im guessing that the VE will increase once I fix the timing.

What im really asking for here is a rough starting point for a timing map for the car... it doesnt seem to run too hot on the stock AUJP spark advance table. Since the heads are off of a 305 motor id imagine it needs less timing to avoid knock.

91L98Z28

regarding being rich:

what's your fuel pressure?
with your air filter situated so close to the radioar, you're going to be sucking lots of hot air into the engine, hot air is less dense and requires less fuel.

regarding timing:

AUJP isn't exactly an agressive timing curve compared to something like ARAP. But at the same time, it IS set up for EGR, which I'm guessing you may not be running.

If you're running 87 octane + high compression (due to 305 heads) + preheated intake air (due to proximity of radiator) + iron heads + really small cam that spikes chamber pressure + no EGR to keep chamber temps in check, well, you certainly could be getting some pinging or detonation going on.

To get a rough idea if timing is your problem, just yank out 5-10* across the board and see what happens. It's a crude adjustment but can quickly tell you if you're just flat out over-timed or not.

I'd get a knock sensor in there so you can have more info about what's going on.

pull the plugs and check for signs of detonation too.

MattODoom

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The fuel regulator is stock so it should be OK, however I have not checked it to verify that.

The compression shouldnt be that high because it has dished pistons, im thinking somewhere around 9.3-9.5 to 1.

Im looking for just a good shape to use, then I can adjust the distributors base timing to offset the entire timing map to get close. The stock map makes no sense to me, for any given KPA reading the timing will advance a bunch, then retard quite a bit around 2600, then advance again. Seems to me like it should be a smooth ramp up and level out around 3000 or so.

91L98Z28

Part of what you're seeing in the stock timing map is due to the fact that PE has a timing adder of it's own. The timing falloff you see is complemented by timing coming in from the PE routines.

There has been discussion in the past about disabling the timing add in PE and having the timing table control everything. I don't have an opinion on this because I have not messed with it. Perhaps others can jump in, in this area.

You'll still need to be careful with the timing. The old iron TPI heads do not tolerate much total timing, and if you're running a full dish piston, then you have no quench (quench reduces tendency to ping/detonate). TPI F-bodies have a sort-of cold air intake which also gives them an advantage. A stock AUJP has a max total timing (at 100kpa) of 29.9* (26.0 from the timing table + 3.9 of PE timing adv) and are known to ping a bit even at those values with todays' fuels. You definitely can't just throw 36-38* of timing at it like you can with some of the (even older) SBC heads.

MattODoom

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I saw a timing map on here from a previous search that a guy was using on his vortec headed motor. Supposedly those vortec heads dont like much timing up top either, so I think I'm going to mimic that map and try zeroing out the PE adder and run all my timing in the table.

Also, I would like to double check on the correct way to disable to knock sensor and make sure Ive got that correct until we can replace it. I unchecked the flag for code 43, zero'd out the max knock retard and attack rate and change all of the activation parameters for the knock sensor to their highest.

Here is the vortec timing map I was referencing:
https://www.thirdgen.org/forums/atta...aph-timing.gif

MattODoom

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I implimented that new timing map and re-set my base timing for 6* btdc. I also did a little idle tuning in the garage... ive got it idling at about 125/128 int/blm and the inj PW seems to be about 2.4ms w/ stock 22lb injectors at 750rpm.. that sound about right?.

91L98Z28

keep in mind that timing is related to more than just the heads. cylinder pressures (closely related to cam design), rear end gears, vehicle weight, etc., all play a factor. the same motor in a 3/4 ton pickup won't need (or tolerate) as much timing as the same motor in a 4.11 geared 2500 lb drag car.

a pair of vortec heads on flat top (or D-dish) pistons will tolerate a LOT more timing (without pinging or detonating) than a pair of old TPI heads on full dish pistons. They won't make any more power because of the additional timing, but they _tolerate_ it much better. a non-quench motor with old heads will just go into rampant pinging/detonation. one of the many reason that vortec/fastburn type heads and good quench are so nice to have.

2.4ms on stock 22lb's seems in the ballpark, perhaps a tad high; but if you're generating healthy crosscounts, and the timing is appropriate for that map/rpm (low-mid 20's at idle) then that's that, that's what the motor wants for that given map/rpm.

are you running headers? if so, are you using a heated o2 sensor?

MattODoom

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At idle shes running about 18* timing or so, ive got the max timing at around 29* (too conservative? too much?) in the 100 KPA column. The car id guess is pretty light... probably like 2700 lbs? if even that much. Has a 3.55 geared ford 9" rear.

The car has block hugger shorty headers with the O2 in the drivers side collector, single wire non heated o2.

I do have an AEM wideband setup in m 88GTA but it'd be kind of a PITA to get it into the '46.

Attached is a screenshot of my timing map up to 4800 rpm.

91L98Z28

your midrange 100kpa timing looks quite agressive. It's hard to tell for sure (the graphical charts are great eyecandy but hard to read data from) but it looks like you're at about 28* at 3200rpm. A stock AUJP (main timing + PE timing) is 21* at the same rpm/kpa. I'm assuming you've zero'd the PE timing add table.

TPI heads, in stock form, are known to not tolerate much timing. My personal work supports this, Glenn91L98GTA made some posts about this a while back, and here's another I found:

https://www.thirdgen.org/forums/diy-...etonation.html

In short, I think your WOT (100kpa) timing is probably more aggressive than it needs to be, and that if you had a knock sensor installed and working, and went datalogging, you'd probably start seeing knock counts accumulate starting around 2500-3000rpm and many degrees of pulled timing all the way up to redline, if not audible pinging. in otherwords, I think you're probably running too much timing for the combo especially through the mid-RPM 100kpa cells.

A stock AUJP car typically picks up knock at 3500+ even with 91 octane fuel, resulting in a degree or two being pulled out here and there.

Your timing map doesn't look anything like a typical stock timing map that I've seen, it looks like an emulation of what a mechanically advanced distributor with a vacuum advance pod might do. (??)

typically, the stock GM timing maps I've seen have peak timing in the mid-load cells (40, 50kpa) and trail off as you go higher or lower on the MAP axis.

With all that said, if it's working better than what you had before, that's fine; but still don't be opposed to tweaking on it further as needed, and definitely get a working knock sensor so you can have some more eyes in the engine and see whats going on in there.

Have you gone driving already with the new timing map?

My opinion on what I'd do if it was my car:

1) go back to AUJP timing map. if a particular area was noted to be much better with this timing map you tried, then you could incorporate that into the AUJP map. (let's say it idled smoother and the new map had 4* more timing at idle, then massage the AUJP map and get 4* more timing at idle into it).

2) get that knock sensor working ASAP

3) go for a drive and get familiar with the characteristics of the car in this config, datalog and see where you get knock, and pull timing in those areas

4) if there are any areas where you did not get knock that have drivability problems, try decreasing the timing a few degreses and go driving. If the problem worsens, then increase the timing a few degrees past where you started and see if it improves.

5) the WB would probably be helpful/useful. if you don't want to / aren't able to put another bung in the headers, you can always disable closed loop, yank the NB, and install the WB in it's place.

90c350

Your timing graph looks almost identical to mine!!! But i am running old style heads-non-vortec with low compresion 8.5.1. My 350 likes to have that kind of timing. So I would think that you may have a little to much for your combo?? Just my thoughts. Although your car is light with a fairly denent gear the computer may be pulling out a little timing under hard throttle.

91L98Z28

In this case it can't, because he isn't running a functional knock sensor.

MattODoom

iTrader: (1)

I haven't had the car out on the road since I put this new timing map in. I like the overall shape of this map a lot better then the AUJP one because it makes sense, yes it is modeled after a traditional mech/vac advance but that's what works. I'm going to pull out some timing in the 100KPA column and reshape it a little.

The problem we had before with a bone stock AUJP map with 6* dist timing was that the car ran like total ****, it was an absolute dog and couldnt get out of its own way. I retarded the dist a little, still with the AUJP map and it was like I added 7 cylinders to the motor, it was beautiful but kept burbling at 55mph cruise.

MattODoom

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This looking any better?

91L98Z28

The engine really doesn't care what "shape" the graph is, it wants what it wants. It's easier for our minds to grasp a nice smooth timing chart that emulates a 1970's distributor, and sure it will work, but it won't be optimum for the engine. that's why they went to computer controlled timing...to gain more control over the timing than an old school distributor could provide. the results may not be pleasingly shaped timing charts, but they work. I'm not knocking the distributor (my 71 with it's 406 still runs a highly modified HEI because I haven't taken the plunge to EFI yet on it); but to emulate the limitations of a mechanical timing device is to throw away the advantage of computer controlled timing, in my opinion.

With that said, I think it would be "easier" to start with the stock AUJP timing map and modify it till it fits your needs, but if you've already started with a different timing map, well, it's not the end of the world. In the end, the final timing map will be the same: it will be whatever the engine needs and wants. bear in mind that the end result will likely will not be a symmetrical, logical, smooth graph that you're starting with, so don't try to force it to be; or you'll just end up fighting with it in the long run. For example - once a motor gets "on the cam" and starts running clean, you're going to see rapid changes in cylinder pressure, burn rate/time/pattern, VE, etc., which will not be smooth gradual curves in the VE or timing tables, but perhaps abrupt changes over short ranges of RPM. That's ok - that's what the engine needs and wants.

The way to fix the burble at your 55mph cruise is to observe what RPM and kpa you're pulling at the 55mph cruise. then, take a few degrees out of that spot in the timing map only (and a few surrounding cells, don't make a spike) and then go for a drive. If it gets better, then you're going in the right direction (try a bit more); if it gets worse then you're going in the wrong direction.

MattODoom

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Waiting to get a brake line fixed before we can hit the road again.. but thanks for all the help thus far 91L98Z28! I've returned it back to AUJP timing with the PE adder enabled again.

MattODoom

iTrader: (1)

OK 91L98 heres an update:

Were running the car on the AUJP timing table again. I had to make one smoothing swipe somewhere around 2800RPMs there was a cliff that was causing the timing to bounce up and down at cruise - hence the burble. Now we've got a low speed 20-25mph burble that im working on.

When we go into AE mode (not full blast but accelerating) we get a lot of "bang bang.. bang" out the tailpipes, however BLMs are right at 130. My first thought was a lean misfire or pop or something but I believe its timing related. Think I need more timing in these areas?

I have a log file of the drive for TunerPro RT if you'd like to look it over.

91L98Z28

someone else will probably need to jump in here. it could be backfiring through the exhaust, it could be oxygen getting into the exhaust (are you running the AIR pump?). A stock calibration runs the AFR rather rich to save the catalytic converter in PE mode, but you probably don't have a cat, so you could have good conditions for combustion in the exhaust. What are you running for an exhaust system?

BLM is (almost) meaningless anytime you're in PE because you're open loop at that point and by definition richer than stoich.

Get any black smoke out the exhaust?

MattODoom

iTrader: (1)

Hahaha AIR pump... are you kidding me? It's a 1946 we dont even have side mirrors or seat belts!

Well like I said this was just tipping into throttle to accelerate and not hitting PE mode.

No cats, the exhaust is true duals with straight thru magnaflows.

No black smoke, car just seems really lethargic, even for a TPI.