Well, at 7psi. The car runs great no misfire very smooth acceleration at every gear and rpm. When I increase the boost to about 9psi or more, I get this misfire in 3rd gear mostly. I am using emanage blue, 1st time i noticed this misfire was as soon as i hooked up the emanage ignition harness. I am retarding -3 degree's from 3800RPM and above.

I changed my plugs from 2step colder to 1step colder, gapped them at .035
the misfire is less noticible and less often but still there. It usually happens at higher RPM's. Can it be that im doing something wrong when retarding the timing with the emanage?

 

do you have enough fuel? sounds like the problem I had at higher boost levels.. bigger injectors, z32 maf and emanage tuning fixed that...

 

Not retarding enough?

 

Well, the thing is, i dont have fuel problem at all. i have z32 injectors, emanage blue, and a VG maf(from a 3rd gen). Might think that the VG maf might be maxing out but its not, i have fuel at all rpm's. And injector duty cycle is at about 73%. I believe if maf was maxing out then i would lean out right away which is not the case.

Kevlo: i dont see how not retarding enough timing can cause this? any ideas on that?

 

When I would advance the timing alot I could feel and hear the misfires. Maybe you have too much timing still. Do around -6 degrees and see if the misfires stop.

 

Interesting, Well when i logged timing. It was at basically stock timing. 16*-24*. Thats excluding the retard, so get that and subtract 3. I'll still try to retard more and see how it feel.

 

idk but 370cc injectors werent enough for me.. even with the 555's I had to tune and add fuel using emnanage blue... might not really be quite enough imo?

 

I doubt it's a timing retard issue but that's easy to check, retard another couple degrees and see if anything changes. That's more timing retard than most guys have run at your power level (boost pressure means nothing, airflow is everything).

When you say higher RPMs what are you talking about 4000, 5000, 6000?

Have you done any datalogging of things like TPS, IDC, MAF V, boost pressure, AFR, etc.

 

I just changed the timing retard from -2 to -5 from 4000 to redline. I felt no misfire or hesitation at all, matter of fact I actually felt alot more power and very smooth. I have to drive it more for a couple days to make sure it was just not a lucky nite. But i really think problem is solved.

yea i logged TPS, IDC, and AFR. IDC is at around 75%, afr is at low 10's across the board. Maybe tomorow ill try and log MAFv, im curious about that now.

btw the misfire was about 4,000 or 4,500 with in those, which is where peak tq is usually at and timing starts to climb up. Im goign to try and log a few things tomorow.

 

Low 10's is a bit too low, you'll pretty much be washing down your cylinder walls with fuel. you should be aiming for 11.5-12. I've had an AFR of 9-10 before and it cause a lot of problems. After I replaced a bad WO2 sensor, I found how rich it was running, corrected it to 11.5 and it ran unbelievable.
Most people pull between 2-4 degrees of timing around 8psi depending on AFR. I run 4 degrees retarded @ 8psi and 11.5AFR. Seems to run great for me.

 

Yeah sounds right. Peak TQ is where you want the least amount of timing.

 

Well the thing is, I have the water/methanol spraying with a big shot 760cc since I am not intercooled. Without the meth my AFR should be close to 12's right now. Should i still try and bring the AFR close to 11.5-12 with the meth spraying?

 

Well I've never tuned with water/meth before, but I assume where your AFR is still just reading from your exhaust side, you still want to be around 11.5-12.

[edit]
Just some quick searching online found that water/meth will make your AFR seem a bit leaner than it actually is. But only by like .5-.6, so if you're showing 10, you're actually at 9.5ish, so you would want to be closer to 12 which would mean it's actually around 11.5

If someone has more experience, please chime in as I'm just going by some posts I found on the net.
[/edit]

 

well guys. I put up the boost. to finally test out 10psi since i got rid of the hesitation/misfires. went to 9psi, car pulls extremely smooth, no misfires no hesitation, turbo sounds crazy at higher boost.. I tried 10psi, but my MAF is maxed out at 10psi, although I dont lean out because of my correctoins, the maf still maxes out (maf input), so that could explain misfires i had before when trying 10psi. I guess 9psi is the max i'll go for now.

btw, i almost blew something. While tuning, I guess i was pushing the car too hard, ended up with no coolant/water in my radiator, temp went to 110C. I shut off, put new water in. Car runs fine for now. I am already considering it gone though. DE-K it is. for now ill just enjoy 9psi, then when it finally gives up on me. drop in DE-K and hopefully have Z32 maf by then to increase boost a bit more. Also i am retarding -7 above 4800, below is -6. And I also tuned it for mid 11's.


sorry I was trying to quote your post but I edited it on accident - Nealoc187

 

You're doing the timing backwards. You want to pull the most timing at torque peak - wherever that is on your dyno, probably around 4500 or so - and then start adding back a bit as you go towards redline.

What octane fuel are you using? I find it strange that you are having to pull so much timing ESPECIALLY with the water/meth. It makes no sense - guys have run as much boost as you are on stock timing with no meth and regular pump gas (not that I'd advocate that, but I've seen it done) yet you're apparently having to pull as much timing as I do at 15psi on pump gas - and you've got water/methanol injection on top of it which most people don't.

 

Well, remember I am not intercooled so its not like most guys that have IC. My cooling is just the meth/water. I use 93 octane. I think the reason I need to pull timing is because my MAF is from a 3rd gen which is calibrated for way smaller injectors, the most a/f correction i have on the emanage is -38, which might explain why I need to retard timing, because indirectly so much correction is advancing it. Its just what I think might be the problem. I might put in the 4th gen maf and see if i have to make so much corrections as well. eventually i will get z32, but not for now.

 

AHA! That explains it. Now it makes much more sense to me, I forgot you are non-intercooled and didn't realize you are using such large MAF conditioning values.

It sounds from your post that you are doing all your fuel tuning on the airflow map on the emanage (judging from where you said you have -38 values for maf conditioning.)

 

yea for fuel tuning i am only using the airflow map on the emanage. tuning using Throttle vs. RPM. Here is what gets me a bit confused. I have an OBD2 Scanner, and when I log my runs. my timing is basically the stock timing curve almost:

4100 RPM, 16*
4500 RPM, 17*
4700 RPM, 19*
5000 RPM, 23*
5100 RPM, 25*
and 25* to redline

If I have such large values for corrections, how come the timing is not being advanced drastically?

 

You really don't want to be tuning on the Airflow map - that's playing with fire. It doesn't take any atmospheric changes into account and it also doesn't give you any safety margin if you have a wastegate problem like a momentary boost spike. Tune on the additional injection map, you should only do part throttle and minor driveability fine tuning on the airflow map in my opinion.

I don't know how large of changes need to be made on the airflow map to start affecting your timing so maybe you are only seeing a degree or two of advance, but even so that's advance that you don't want.

 

Let me ask, if I tune using additional injector map, how would it know boost spikes, or atmospheric changes? Wouldnt I need to get MAP sensor, and boost sensor as well?

 

MAP sensor is a boost sensor but yes, you'd need that. You could use MAF voltage but your MAF is maxed out you said, so that won't do any good without getting a larger maf.

 

Yea its maxed out at 10psi. So i left it at 9psi. it shows 4.8v at most now. For now im going to stay as it is and enjoy it. Once i go into the higher boost 10+. I will take your advice for tuning. All I need is the larger MAF and MAP sensor. so it shouldnt be long before i do that. Thanx for all your advice.

btw, i changed my timing retard, most timing retard is at 4400rpm which is my peak tq, then i have less retard towards redline. car pulls very hard, thnx

 

no prob, glad i could help. you should dyno and get to the track on your new boost level. weren't you running like 6psi before?

 

Yea, my last dyno was at 6-7psi. did 258whp, and 263tq. 9psi feels really good compared to that, even with a closed 00vi. I gotta wire up the rpm switch to get my vias working. but even with it not working, wow im enjoying it. There is a possibility that I might be going to the track this friday, my last track visit was with the same 6-7psi. ran 14.1 at 102, 2.3 60'. theres ALOT of factors that will be different for this track visit on friday such as: going to be gutted (last time was full trim and full tank of gas), will be using slicks this time, 22" for shorter gearing, quicker rev/spool, also on the sawblades which is ALOT lighter than my titanium ed. rims (53lb each), also got header wrap on my entire catback (which made very noticeable difference with spool up and power), and ofcourse 9psi. in "theory" i should be mid 13's, low 13's. Last time i predicted pretty close. hopefully I am right again this time.

 

Your car is still an auto, right?

 

I agree with Neal, I used to tune on the Airflow map until I realized how much correction to my timing it was doing. I bought the Greddy pressure sensor and started tuning off the additional injection and it was much easier. the AFR didn't jump around as much and I could fine tune it for boost rather than just for MAF voltages.
Glad to hear how good the car is running for you now. I still have lots more tuning to do before I see results like yours, so it makes me anxious to see how mine will work

 

2 heat ranges colder than stock is fine.. I would say to drop the gap down a little further.. maybe .030" or so, and see if that helps.

 

^^ yes it is. That tranny is pretty ubber. So far its taking the power with no problem

 

Nealoc: Yea i am still auto. That is my favorite part. You step on it from the line and you only feel the initial lag at low rpm then once that boost kicks in, you dont loose any boost through the gears, the auto+00vi is very nice. you have a constant pull with no drop in power when it shifts, judging by my dyno graph and where my 00vi switches, i am at peak hp all the way down the track in every gear.

Zero-K: I will really consider the tuning via additional injector with the pressure switch. Ill purchase it soon. thnx

TurboS13: Is it safe to be running such a low gap? i wanted to go as small gap as possible but didnt think .030 was ok. i am at .034 right now.

 

I love my automatic, too.. I had my plugs set at .030 last season, until I worked out my $50 "Voltage Boosta", which raises the output from the coils. I gapped to .035 and picked up 2 MPH immediately. I could probably gap wider if needed - I'm sending 16 volts to the coils, and it goes to 20+ volts if needed. Cheap, simple, and very effective.

 

I guess when I increase the boost more, ill go ahead and change the gap to .030 or steal the voltage boosta from eddy (95blkmax) lol since he has been getting some of ur advice but hasnt installed it yet.

 

It's an easy install, even on a temporary basis, and you can create a lot more spark at the plug. A LOT more spark.

Since you are getting your beast under control now, why have ignition misfires? BOOSTA it.... Eddy made up that phrase, didn't he?
.

 

Why wouldn't it be safe to gap them to .030"? I've gapped plugs down as far as .026" to avoid misfire.. If you can ramp up the juice to the coils, then, you could probably run a bigger gap, and make a little more power, but, sometimes, closing the gap is the only way to avoid misfire.

 

Ok i will def. do the booster then. for now, i have a new little problem to solve. Possible blown head gasket.

 

Agreed, but if you could increase the coil voltage and increase the spark gap voltage so you can run a bigger gap, wouldn't you?

It's a $50 power supply that runs off the battery and has an adjustable output voltage. You can power it from the harness connector that goes to the coils (red wire) and feed the output to the coils. Cut one wire, battery voltage from the harness, higher voltage back into the other side of the wire, to the coils. Instant higher coil voltage. Lots more if you turn it up.

Considering what you do with engines, seems like that would be "useful" on occasions........
.

 

I have my plugs gapped at 30 too. I had them gapped for 34-35 but I was hearing the occasional misfire, gapped them for 30 and didn't have a problem after that. The only thing about gapping them closer is that they get hotter which causes them to burn out faster. No different than upping the spark though.

Oh no! What problems are you having that make you think it's the head gasket?

 

Everytime i floor it a few times, the level on the overfill tank keeps going up pretty high, then i check the radiator and its low. The more i push it the higher the level goes, eventually it spills out. Basically telling me that there is pressure building up in the cooling system. No sign of oil in the coolant though, but i think its enough evidence to tell me that its blown headgasket or on its way out. correct me if im wrong.

 

^^ same thing I had going on with my 3.5, only that normal driving would also cause it. Changed head gaskets to triple layer Z33s and new OEM headbolts and that problem is gone.

If anyone has any other ideas on this please jump in. As of right now we're looking at an engine swap coming up in a few weeks. Motor has not been purchased yet, so any ideas now are welcomed

 

The number 1 and most obvious option would be to have a leakdown test done on the current motor. You don't want to be guessing with this type of deal.

 

Honestly.. I don't usually mess around with factory engine management when I build something that's making big power. I opt for Electromotive's TEC3-R, which comes with GM coil packs. So, I don't really have a lot of experience with rigging up voltage amplifiers on stock coil packs. On a 250-350whp car, we might stick with a stock ECU/piggyback, in which case, reasonable plug gap is possible without a failed spark event, but, above that, I push for my customers to go standalone. With the TEC3, I've run as much as .036-.037" plug gap, on a cold plug, at the 600-700whp level.

Sounds like a good buy for 50 bucks though..