EFIDynoTuning Forum

The test is null and void if the air filter and tail pipes weren't blocked. The smoke will take the easy way out, meaning the air filter or tail pipes. Half of the valves are open at any given time. There could be a few other hoses that need to be pinched shut as well.

red5.0fogger wrote: ↑2021 Jul 19, 12:46 The test is null and void if the air filter and tail pipes weren't blocked. The smoke will take the easy way out, meaning the air filter or tail pipes. Half of the valves are open at any given time. There could be a few other hoses that need to be pinched shut as well.

I tested the maf tube and everything separate from the intake manifold.

When testing the intake manifold yes some of the intake valves are open. BUT the exhaust valves are closed, so all it does is fill the cylinder with smoke until pressure backs up. It can't go nowhere else. Once in a while one cylinder might be on overlap when the inlet and exhaust are open at the same time but all it takes is a little bump of the crankshaft to cure that problem. When I did the smoke test on this one I didn't get any smoke out of the exhaust. Zero. Not until I smoke tested the exhaust system itself and found a couple leaks, and still has a flange leak at bank 1 that I don't know what to do with.

y'all take a look at this, sitting in the shop doing a quick log. You can see what I am dealing with. The past 2 months were spent fiddling with this and that. I actually removed all vacuum hoses save for the FPR. Re-routed the fuel lines. Played with PCV. Ain't much I haven't thought of, only thing I cant do is scope the injectors. But if it were an injector or harness or ecu problem, it'd show up under a load too would it not?. If it were an ignition misfire, it too would show up more under load would it not? Tonight I drove over to the local DG and back, with the cooler and dryer air, a full throttle snap is useless-indicating to me, that either there is no misfire detectable, or I can't notice it. Zero traction in 1st and 2nd, 3rd breaks loose too up to about 75mph and 4th is just dangerous speed with all the bears and deer running around so I didn't even attempt. Idled back home. Has a dead spot off idle as you're getting into the throttle, when you whack it, it falls on it's face for a split second and then finally picks up--but only under a load. Sorta like a misadjusted Holley accel pump. Anyway, have a look and you'll see what I'm dealing with. Maybe useless datalog just sitting there in the shop but you get the idea what it does as far as differences between the banks.

There is something funky going on with that data log...
I don't know if it has anything to do with the difference in bank fueling, but it could.

The log starts off strange to me. Fully warm, ATMR1 at 255 and no O2 sensor switching, LAMBSE at 1.000 and not trying, Kams at 1. Like fueling reset, but its already running and been running... Ultimately, they do start switching.

At the 2:00 minute mark in the log, both LAMBSE jump to 1.000. LAMBSE 1 is is most noticeable thought because its further off.

LAMBSE1 drops from 1.13 to 1.00 instantly... Kinda strange. Then it starts slowly creeping back up adjusting itself to where it was...

At 2:04, 4 seconds later, BAM... Both LAMBSE appear to instantly reset again to 1.000 again... This time its more obvious because they say at 1.000 for a few data points and then the ECU starts adjusting both of them in sync until HEGO2 starts switching.

It looks to me like something keeps partially resetting the ECU.

Could something in the tune be corrupt and causing this?
A bad capacitor or a bad ECU?

I sent the ECU off a couple months ago. They put new caps in, and supposedly replaced (or repaired?) the "power supply". It changed nothing but hey at least it's new.

It goes into OL at idle. That may have been one reason LAMBSE went to 1.00 instantly, and then as I get back on the throttle it came back so suddenly. Mike has it set up that way in the tune. The reasoning it was done, was because with a CL idle, the LAMBSEs are way off, just like you are seeing in the log. It is also OL for I think 2 min or so after start. I had TP running for a little bit while doing the log; even before, perhaps why you're seeing ATMR1 at 255.

I tried moving delta back a little to see what happens, especially considering 90mm throttle body and as the throttle is opened, even a tiny bit, RPM comes up quickly--it's still in OL, then once it gets to a certain point, usually around 1400 RPM or so, it goes in to CL, timing jumps up, and it gets honestly uncontrollable to the point where you can't "feather" the throttle to just cruise. Gotta keep the RPM up. I don't know if it has anything to do with this issue, or the issue has anything to do with that but I felt it worth mentioning. I reduced DELTA a little to attempt to solve that but it then causes issues with dashpot which needs to be adjusted anyway, however with the issue I'm having, dashpot and delta are at this point the lesser of the many issues. Need to get fuel lined out first and I can't do that with how it acts. I cannot get a good datalog (step 1b I think) from 175-200 imaf. About 250 is minimum that I can control the vehicle. It bucks so hard below that, it's impossible to hold the throttle.

Looks like you have a leaking fpr diaphragm. Yank the vac line off and take a look otherwise you have a leaking injector on bank 1 as its yanking 27% fuel while the other side is adding 5%.

viewtopic.php?f=22&t=253&p=3504#p3504

I found at least part of it, although I know it won't solve all of it.

#4 spark plug, Autolite 3924 (the new style), insulator was falling off of the electrode. It was just flopping around between the insulator and the ground strap. Glad I thought to check that and for once I'm happy that it wasn't worse. Especially today. 9/11 is a somber day anyway, and my 20 year old cousin passed away this morning in a car wreck.

Took FPR hose off, it's nice and dry. I actually took the FPR apart a few months ago when I got back into town because the little check ball was stuck. No other problem encountered while taking care of that.

I'll check injectors the best I can. I am pretty sure I can power the pump and with the throttle body and elbow removed look down it's throat with a nice bright flashlight. If anything's leaking I should see it right? Maybe a dribble?

no change.

running compression test ok nothing obvious. #4 gets blacked quickly. Swapped injectors between #3 and #4 no change. Tried spark test, tried different distributor, plug wire swap, and of course smoke tests. This morning I removed the engine/injector harness and inspected it with a fine tooth comb, aside from being an old original 1992 harness nothing stands out. Put it back on, no change. Removed the EFI harness from the car and looked at that too, nothing obvious and I looked hard. Just reinstalled, no change other than a half day of working on it.

Process of elimination, has to be an ecu issue, elbow issue, or header issue although I can't see the latter two being viable. I wish I had another A9P to try but I don't so I guess I'll have to send this one off for testing. Anyone have any suggestions where to send it to?

Probably be cheaper to just buy a 94/95 stang automatic ecu from your local auto parts store.

I picked up a reman (blue streak) computer. 95 Mustang automatic. There are no markings on it as to it's catch code. Anyway, I'm going to try to repin this weekend and hopefully get a good start on it.

Do I need to download a different def?