Welcome to the club 91CRXisGo. You experiences sound very similar to mine issues. So I'll chime in.

For the Limp/misfire CEL issue. After I did the CKP relearn this issue seemed to stop for me. You will need access to a HDS to do the CKP reset though.

For the pinging I also noticed this when the weather warmed up. Gary mentioned it (page 32) too with details how he modified the analog 1 map. I ended up adding a column to the analog 1 map and added a bit of fuel on the supplemental injecton map around 2000-3000 rpm @ 20-30%.

Also from a longevity standpoint, I would highly recommend using dialectic grease in all the connectors in the SMT8L. They are not robust connectors and can use all the help they can get.

Hope this helps. Good luck finding time to work on your car with the new one!

 

You can do the CKP relearn without the HDS, it's just a bit annoying. The repair manual says the HDS can selectively clear the CKP pattern and that "generic" scan tools will clear ALL commands in the ECM/PCM (idle pattern, ckp pattern, freeze data, snapshot, DTCs). That if you use a generic scan tool, you'll have to do the idle relearn, the ckp relearn, THEN drive, drive, drive to set the readiness codes. This is also mentioned in the install instructions.

I've used the UG to clear DTCs so many times, I've lost count... but I know that I've only attempted the idle and ckp pattern relearns a few times. So, either it's not "generic" enough to clear the idle/ckp pattern, or it is and it sets on its own. Going back to the install instructions, it says it only really affects lean running fuel economy.

I'm not saying it won't/didn't help, it's just for me... its affects aren't very clear.

91CRXisGo, sorry, I meant there's an even more conservative tune than the one that came with the piggyback. Didn't mean to imply it was aggressive or anything.

BTW, do you have an automatic or a manual transmission?

 

You can do (supposedly) a CKP relearn without a HDS, but I have not found another tool that can do the actual reset. There really is no confirmation that the CKP has been relearned.

I don't believe the UG can do a ECU reset (I do actually have one). I don't believe clearing DTCs with the UG resets idle/ckp either.

One of the factors that confirmed my theory on CKP relearn is that one time when I was relearning the CKP I messed up the procedure and actually got the misfire DTCs. Also in the FSM one of the first steps to troubleshooting the misfire codes is actually relearning the CKP.

 

I can't recall getting hit with limp mode or getting the misfires, while driving around 2k-3k RPM. Nor was I hit with either on the few times I attempted to do the CKP relearn.

I also find it very strange, that I was the only one able to reproduce the "hold at high RPM" limp/misfire.

However, I did have the "rough" idle that a few others had, where it would attempt to idle at even lower RPM and flat out stop sometimes, yet without trouble codes too.

The repair manual I have only tells you to do the troubleshoot CKP before diagnosing the misfires, IF you have those codes (p0335 and p0339 which are no and intermittent signal). Otherwise, for the random misfire (P0300), it tells you to start with clearing the ECM and ckp pattern, then do idle and ckp relearn at steps 25-28 of 31. For the P0301 to P0304 codes, its at steps 43 to 46 out of 54.

Honestly, I think the idle and ckp relearn procedures are like the readiness codes, in that, assuming the car isn't throwing TCs left and right, it will eventually set/learn and doing it only makes it learn/set "right now."

In any case... it is all a bit strange.

 

I have a suspicion that my car sudden drop and bounce back in rpm might be temperature/hot weather related. It is hot and humid here in Tampa FL with daytime 90°F heat until the sun retreats. Yesterday early evening on my way to martial art class while sitting idle waiting for the green light, the rpm dropped suddenly from ~850 rpm to ~500 rpm and immediately bounced back to ~800 rpm. I noticed that the MAF intake air temperature on my UG was 125°F, timing was at 0 and the air fuel ratio went from ~14.5 to ~12 then back to ~14 on my AEM Uego gauge. The A/C was at full blast. This occurs very infrequently and this it the first time it happened while I was watching the gauges. I have not noticed any engine pinging. But I might adjust/retard timing at high intake temperature even though I run 93 octane fuel.

 

Well must have jinxed myself talking about how I fixed my misfire/limp issue. Because I just got limp mode twice on a hour long highway drive. WTF!

 

did you check the UG for the cause of the limp? Misfires?

 

The first limp the CEL flashed but did not stay on. The second limp kept the CEL on and threw the misfire codes cylinders 1-4 and random. If I can get this to happen consistently I will try to get a snapshot with the HDS during the limp.

 

Do you recall roughly what you were doing? Going WOT, holding RPM for cruise, etc?

I wonder if the first time was setting pending code and the second was the full DTC.

~~~~~

One of these days, I'm gonna have to either reconnect the SMT8-L or swap the OE fuel pump back in (would also need fuel pressure gauge).... I haven't conclusively determined if either or both changes eliminated my misfires. But honestly, my laziness is beating out that "need" to find out... It works and I'm happy.

 

These episodes happened while going about 75mph and slightly accelerating to maintain speed. They happened about 5 min apart. Then no issues for the rest of the trip home. I even tried to get it to happen.

 

At that speed with throttle, i'm thinking the sc was boosting (bypass closed). But thats about all i can extrapolate from that...

I've cruised (without cruise control) at higher speeds for longer, so i'm not inclined to think it was the same issue i had, unless you were using 4th or lower gear. Another reason is that i was able to replicate the issue fairly often.

Did you re-pin the harness?

 

Its very intermittent. I have driven 5 months with no issues. I did not re-pin yet, as I had no reason to.

 

While accelerating aggressively from 2rd to 3rd gear I have gotten random engine misfire on all cylinders twice. Once in May and once in June under 90°F heat in the mid afternoon with the A/C on full blast. On both occasions I had to pull over to the side on the road and clear the DTC with UltraGauge. Immediately after clearing the DTC, I would attempt unsuccessfully to reproduce the problem. This small irritant and the sudden drop in rpm at idle are the two issues that occur infrequently. If I am able to consistently reproduced these problems and establish a pattern, narrowing down the culprit would be easier. I will stabbed at the valves adjustment as a start. The valves was adjusted at 50K miles and good likelihood needs to be adjusted at 107k miles.

 

Don't ya just love intermittent problems?

Either of you guys willing to unhook the piggyback? The shortcut method is just revert the MAF and CKP wires back and then unplug the unit from the harness (that's what I did with crimp on bullet/flat connectors).

Steven, I take it you still haven't gotten the AEM fic6? Although I have it, I'm not actually doing anything with it aside from logging on occasion. Once I get a better understanding of tuning, I'll change the zero maps into something (btw, anyone know the injection response time on stock... or how to find out?).

 

I'm guessing that if one were to briefly disconnect the CKP signal while the car is accelerating it would go onto limp and DTCs for misfires would appear.
Anybody want to try that?

In our setup the SMT8L intercepts the CKP signal. So I see two possible scenarios:
1. The CKP wires have a intermittent failure (maybe a bad connector)
2. The SMT8L is f**king up. (yes that is a technical term)

Now lets think about how many of us have experienced limp mode/misfire DTC......all of us? I believe some that have re-pinned still have seen this issue, correct (Fuzzy, Steven)? So the chances that we all have the same random bad connection in the connector is slim.

What is the SMT8L doing? brown out, timing issues, lockup?
If a had a spare laying around I would bench test the CKP output under voltage fluctuations, and electromagnetic interference in an attempt to recreate. But I just happen to have this type of test equipment at work.

I wonder if anyone at Perfect Power would be willing to talk to us about this issue a bit?

 

Edit: had a long post but decided to shorten it because i forgot something.

If the Fit's ECU doesn't get a CKP signal, it will throw the P0335 DTC. If its intermittent, it'll be a P0339 code. And in the times i got that P0335 code while driving, it was never accompanied by misfires.

However, i won't say it CAN'T trigger misfires, since i don't know if there's a situation where it might prolonged enough to affect ignition spark, and yet not enough to throw a code... Though i have my doubts.

What i forgot was how the SMT8-L would react to a loss or intermittent ckp signal. Would it throw out a signal that could be completely off time? Or would it simply send no signal? Or in the case of intermittent input, pass an intermittent signal output. I'm leaning towards passing no/intermittent signal.

 

Just doing a quick post, Haven't had any time to look into any of this yet. But hopefully will soon. Couple new points

New baby was delivered 9 minutes after reaching the hospital, and yeah the Fit was the taxi for that drive, maybe unsupercharged it would have been 7 minutes

Also, I have had at least two more CEL Limps happen. One at high rpm for 15-20sec and one just driving normal.

Trying to download tuning software but the links arn't working. And Ive got like 20 min free time...... UGH ><

 

Update:
30 mile trip
4 limp modes
And several instances in 5th gear car stared bucking and tossed a p0339 with a VSC light.

Took several scanguage code clears to get rid of it.

 

did you use this one: https://dl.dropboxusercontent.com/u/...loy_Public.msi?

With that DTC, I'm thinking maybe your wire harness has a loose connection... either at the install part or on the plug connector to the unit. Start your car, let it idle and once it seems stable, wiggle the unit/wire harness and see what happens. You might benefit from doing a re-pin.

What other DTCs did you get besides the P0339? And were they separate or with the P0339.

~~~~~

Congrats on the baby.

 

Gonna dabble with this hopefully at the end of this year. I have a '10 Fit Sport AT.