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[N1 Andy]

So, I'll try to make this as short as possible.

I was on my way to the track last weekend, did a 3&4 gear pull on the freeway then the car started missing, what seemed to be ignition breakup, I got it off the freeway and pulled into napa, opened the hood to find oil in the plug hole on #4, I figured "cool, theres the problem" fixed the plug wire hole gasket, put a new set of plugs in, still doing it. After messing with it for 2 hours in the parking lot I said screw it and jumped in my friends car and headed to the track. I come back 6 hours later and the car fires right up, runs perfect. It idled in the parking lot until it reached operating temperature, at 180f it started doing it again.

I towed the car most of the way home behind my buddies truck, got 5 min. away from my house and started it, runs fine. I ripped it home, runs amazing, spins 3rd, runs just as good as ever. Get it home let it idle in the garage for 15 min. It starts running like crap again. It runs perfect until it gets to operating temp. the only way I can explain it is it runs like a car does when its running out of gas.

I'll go over what I HAVE done.
swapped plug wires
new plugs brk7es-11 @ .020 gap
fuel pressure is fine 48psi consistant
new ignitor in the dizzy
swapped internal coil
new coolant temp sensor
swapped ecu and pumpgas/racegas maps
compression test = 215 over all 4 (perfect)
swapped main relays
checked resistor box wiring, replaced resistor box, resistance shows 2.7 ohms @ injector clip
swapped fuel pumps
cleaned IACV
New headgasket
swapped whole dizzy/plug wires
swapped fpr
It does NOT lose power to the coil or the fuel pump

The car is a stock bottom end ls/vtec right now on 110 octane @ 18psi
PTE 880cc injectors
Walboro 255
Extralargenog/Supergenius handmedown FPR
Resistor box
ITS GT61S turbo
Motorola 2.5bar
Stock Ignition system
Dyno tuned on chrome by D. Lee

Any ideas? I'm tearing my fucking hair out over this.  I can USUALLY figure this shit out but I've tried everything I can think.

heres a video of this bucket acting up.


Only thing left is swapping the MAP sensor, and the injectors, but I don't have any of that shit laying around so I'm kinda stuck.

[92CXyD]

I do not think it is your map sensor b/c on your tunerview it was not registering at a perfect vac.

760mm/29.9in of hg

[bigdaddyvtec]

my car acted like that when the hg wemt

[N1 Andy]

I do not think it is your map sensor b/c on your tunerview it was not registering at a perfect vac.

760mm/29.9in of hg

the tunerview has always been a couple psi behind actual, I don't have it calibrated for the 2.5 bar properly, if it is even a 2.5 bar...lol its a turbohf special, stock housing 2.5 I think?!

my car acted like that when the hg wemt

I think that may be it too. oh well, head needed to come off anyways, fix a little oil leak around the hg.   Strange that compression test shows perfect though, and its not pressurizing the coolant system.  I DID notice alot of moisture from the tailpipe though, enough to where it was pooling under the turndown on the garage floor. 

[turbohf]

i think thats a 3bar map Andy. you can double check. im pretty sure i wrote on the bottom of it what pressure it was.

i have a 2.5bar in my car currently.

[DmC]

Im leaning towards head Gasket on this one to. because it probably starts when the thermostat opens up and the water gets hot enough to get under pressure then gets sucked into a cylinder. Id get it doing that again shut it off and pull the plugs. Or leave the radiator cap loose and see if it still does it. Fuck it just pull the head.

[Joseph Davis]

When it's a headgasket, or multiple valves slightly warped, it "usually" only misfires under load.  Your mileage *will* vary.

I'm a fan of testing with a different known good distributor (coil/ignitor).  Stock ignition is strong, sure, but it's also prone to failure within the hot dist enclosure and the electrical loads it handles.

[HiProfile]

Pull out the t-stat, install a big washer. Problem solved.









Actually I'd check the IAT sensor, as well as the IAT correction tables. Who knows, maybe one is making it dump/pull fuel like crazy. I'd also leave the HG possibility open. I've seen some weird things, so I wouldn't leave out the possibility it will suck coolant in but seal outward pressure perfectly.

[superdaveosbourne]

Dave coleman had similar issues in his rally car and it turned out to be the headgasket.
http://www.motoiq.com/MagazineArticles/tabid/59/articleType/ArticleView/articleId/883/Technobabble-How-to-Fix-a-Headgasket-With-a-Garden-Sprayer.aspx

[N1 Andy]

shit, didn't even know there was more reply's.  RHMT only sends me one notification then its done.  so....update:

I ripped the head off, replaced with a new oem gasket, re-torqued the head...still fucking does it.

I'm gonna try replacing the FPR first, then borrow my friends Dizzy.  If that shit don't work ill try stock injectors, map and remove j-1 jumper. 

good thing is, I had a oil leak around the head gasket,  so I needed to replace the h/g anyways.

Thanks for the replies

[N1 Andy]

Actually I'd check the IAT sensor, as well as the IAT correction tables.

but the tunerview shows iat's working properly!?

[N1 Andy]

Not the dizzy or the FPR, my checklist currently looks like this:

v - FPR
v - Dizzy
v - Injector wiring
v - Million fucking things I already listed earlier
   - Map
   - Injectors
   - Full coverage/strip it and shove it off a cliff

In THAT order.

[Joseph Davis]

I have one defective Motorola 4 bar on my bench, car runs great most the time with it and then the pedal goes dead for 0.25 to 1.5 seconds out of nowhere.  Datalogs show the MAP voltage drops to a fixed -15.3 in/Hg when this happens.

Good luck, shit like this can fucking plague you.

[chris]

Did you get the head decked while it was off?

[Joseph Davis]

Also, checked that the valves were seating/sealing?

[N1 Andy]

I have one defective Motorola 4 bar on my bench, car runs great most the time with it and then the pedal goes dead for 0.25 to 1.5 seconds out of nowhere.  Datalogs show the MAP voltage drops to a fixed -15.3 in/Hg when this happens.

Good luck, shit like this can fucking plague you.

the tunerview doesn't show anything out of the ordinary for map values though...leads me to believe that the other 3 bar (actually the one in my car is a 3 bar too, not 2.5) that I will be picking up from mr turbohf tomorrow is not going to fix my problem, but its worth a try.

Did you get the head decked while it was off?

no, but I DID before this build.  Maybe 5k miles ago?!  I dropped a valve on my last n/a build and I had 2 of the seats replaced, all seats cut, and head decked.  Lack of a precision straight edge is the reason for not checking if it was still flat.  The motor has never been above 208*f so I would hope the fucker isn't warped

Also, checked that the valves were seating/sealing?

Negative, I suppose just because the compression test came out spectacular really doesn't mean shit.  I need to do a leakdown test right?

[chris]

warped is a generic term anytime any head comes off regardless it should get decked especially one that gets the shit kicked out of it.



Just because people get away with it every so often doesn't make it right.

[Adam Hopkins]

So you did change the WHOLE distributor? Everyone get so hung up on coil, ignitor they forget that there are more sensors.

It sounds to be something ignition related from your video, almost sounds like ignition is very retarded .

[Joseph Davis]

Good point, Adam.  I've had CKP/TDC/CYP signals get fucked, you can look at the RPM plot in 2D logs and it's super spikey going up and down during a pull, causes cars to break up and sputter.

Bad alternators will also do something similar.  Log battery/alternator voltage during a pull.

[N1 Andy]

So you did change the WHOLE distributor? Everyone get so hung up on coil, ignitor they forget that there are more sensors.

It sounds to be something ignition related from your video, almost sounds like ignition is very retarded .

yes I did, first I changed icm and coil, then later I changed the whole dizzy and wires. 

[N1 Andy]

Fucking map sensor...Car's fixed.  Now its just a different map sensor then I tuned with, the one I got from dustin is mpx4250ap which tells me its a 2.5 bar, I'm pretty sure I tuned on a motorola 3 bar mini.  Anyone know where to get the mini 3bar besides xenocron? or have a part number I can search for?

boost guage is registering 14psi and tunerview shows 17.8psi, at least its rich not lean right? can't turn up the boost anymore because it hits boost cut at 19psi

Thanks for the map sensor Dustin I appreciate your help!

[92CXyD]

Try this thread for the part numbers.

http://www.realhomemadeturbo.com/forum/index.php?topic=249.0

[N1 Andy]

thanks, that helps alot! ill order one today

[turbohf]

no problem man. just glad you found the problem.


you try taking the 3bar apart yet? im sure its full of hondabond or something to keep the map from moving around, but maybe a wire broke off?

[Joseph Davis]

Feels like a load off your back, right?

[bigdaddyvtec]

Or a load on it... A hot runny one.

[widebody93]

Spiker I bet it is not covered in greasy food left overs as your seems to be/WAS  Jew