759NRNG
759NRNG SuperDork
8/27/18 9:22 a.m.

yay that saw word.........So you have a vehicle that doesn't have a lot of lightweight  replacement body panels readily available..... I was referring to  'swiss' cheesing those interior panels not directly adjacent to heat sources. 

¯\_(ツ)_/¯
¯\_(ツ)_/¯ UltraDork
8/27/18 10:06 a.m.

In reply to 759NRNG :

Anything in the interior that doesn't serve a purpose has been removed, so there aren't really any panels worth doing that to- the easiest weight savings at this point are probably in the hatch and hood, but honestly I think if I can make the thing reliable and tough it's light enough to be perfectly competitive as-is.

759NRNG
759NRNG SuperDork
8/27/18 8:10 p.m.

duh I know nuttin' ' bout NASA rally regs....are you having to adhere to a lb/hp formula? that being said are you at the limits of a stout2.3L for stage rallying.....yay i know, all it takes is cubic$$$$'s. The hood and the hatch...have they been hole sawed?......or are you truly wanting to step back from all this and just focus on the H2 Kaw???? 

Pete Gossett
Pete Gossett MegaDork
8/27/18 8:42 p.m.

In reply to 759NRNG :

Weight isn’t nearly as important as durability & skill in rally. 

¯\_(ツ)_/¯
¯\_(ツ)_/¯ UltraDork
8/27/18 9:00 p.m.
Pete Gossett said:

In reply to 759NRNG :

Weight isn’t nearly as important as durability & skill in rally. 

This.  Especially here in the USA where nearly everybody is a pretty bad driver... maybe in Finland you need to chase every last gram wink

The regulations are extremely open, nothing keeping me from building an absolutely incredible car other than time and money... but if that's what I was chasing I sure wouldn't be wasting my time with this thing.  I just want it to run consistently and stop bending in half every time I jump it.

¯\_(ツ)_/¯
¯\_(ツ)_/¯ UltraDork
8/29/18 7:50 p.m.

OK.  Replaced TPS, replaced plugs and wires- car still has a miss at WOT, but at slightly less (we're talking 98%) throttle it runs quite well.

I think the throttle may actually be opening past 100% and berkeleying things up- it's a V6 Mustang throttle body and TPS, and although the TPS reads the same as the original, the butterfly is like 80% bigger than stock and I'm sure flows a lot more.  Anyone have any suggestions before I make a positive throttle stop and call it good?  It's certainly not short on power, so I won't miss that last 2% even if I am keeping myself from truly getting 100%.

mazdeuce - Seth
mazdeuce - Seth Mod Squad
8/29/18 7:55 p.m.

Throttle stop this weird Frankenstein car to keep it from terrorizing the villagers. Or to make it terrorize the villagers. That's probably more correct.

irish44j
irish44j UltimaDork
8/29/18 8:38 p.m.
¯\_(ツ)_/¯ said:

OK.  Replaced TPS, replaced plugs and wires- car still has a miss at WOT, but at slightly less (we're talking 98%) throttle it runs quite well.

I think the throttle may actually be opening past 100% and berkeleying things up- it's a V6 Mustang throttle body and TPS, and although the TPS reads the same as the original, the butterfly is like 80% bigger than stock and I'm sure flows a lot more.  Anyone have any suggestions before I make a positive throttle stop and call it good?  It's certainly not short on power, so I won't miss that last 2% even if I am keeping myself from truly getting 100%.

that actually makes a bit of sense there. If the butterfly is opening past vertical, could be causing some kind of airflow disturbance just momentarily enough to cause a miss? I would just make a stop for it and call it a day. Lack of power isn't your problem!

irish44j
irish44j UltimaDork
8/29/18 8:41 p.m.
759NRNG said:

duh I know nuttin' ' bout NASA rally regs....are you having to adhere to a lb/hp formula? that being said are you at the limits of a stout2.3L for stage rallying.....yay i know, all it takes is cubic$$$$'s. The hood and the hatch...have they been hole sawed?......or are you truly wanting to step back from all this and just focus on the H2 Kaw???? 

Basically most of the weight you could save with a hole saw, you could save by changing to lightweight aluminum jack ($$$), or going lighter materials with a lot of the gear we have to carry in rally (stuff that track cars don't have to carry). Most of that stuff has a bad cost-to-weight ratio though, its a diminishing return. 

¯\_(ツ)_/¯
¯\_(ツ)_/¯ UltraDork
9/3/18 12:37 p.m.

Reinstalled skid plate, repacked wheel bearings, cleaned the engine bay, sealed crack around roof scoop, and made a throttle stop.  This fixed the misfire for roughly 5 minutes of drive time, then it started appearing at random throttle positions and rpms...

Thinking back, these symptoms are similar to the time I had an intermittent fuel injector failure; which, thinking it was a fluke, I corrected by swapping that one injector for another from my spares collection.  Now I'm thinking maybe there's no such thing as a reliable 3 decade old fuel injector, so I ordered new ones.

The good side of all of this is that I drove the car for 45 minutes and, apart from the mysterious misfire, it ran great the entire time!

¯\_(ツ)_/¯
¯\_(ツ)_/¯ UltraDork
9/9/18 10:13 a.m.

OK.  E36 M3.  This berkeleying car.  

I swapped injectors for new ones:  

This did nothing to improve the problem.  I checked ignition timing, spark, and fuel pressure, then took it out for a drive.  After all of about 3 minutes, the car began misfiring and losing power.  About 1 minute into my attempt to limp it home, the catalytic converter caught fire.  I briefly considered the merits of letting it burn to the ground before extinguishing it.

Flat towed the car home and set about replacing or checking literally berkeleying everything.

So far I have swapped or checked all of the following with little or no change:

  • Distributor
  • Ignition module
  • Coil
  • Plugs
  • Wires
  • Cap
  • Rotor
  • Cam timing (+1 and -1 tooth both run worse)
  • Ignition timing
  • Fuel pressure
  • Fuel injector spray (removed from car and observed while cranking)
  • Compression test
  • Visually inspected valvetrain
  • O2 sensor
  • VAM
  • TPS
  • Stuck wastegate open
  • Removed exhaust at turbo
  • ECU

That last one is the only one that produces a real change, but it's the wrong ECU for the VAM and injectors I have so it shouldn't run right anyway.  Here are the plugs:  

It seems like it's running extremely rich, retarding the timing a lot, or some combination thereof.  I think my list has it narrowed down to either bad wiring or a bad ECU, although I haven't completely ruled out all of the new injectors being garbage.  I'm going to work on something else while I let it (and myself) cool down.  As I said to Sara yesterday: "this car is going to make a great first rollover for us."

¯\_(ツ)_/¯
¯\_(ツ)_/¯ UltraDork
9/9/18 12:38 p.m.

I swapped injectors back to my crusty old stock ones, and it was like getting into a time machine- drove the car and we're right back to a small occasional miss.  The new fuel injectors were bad the whole time.  THE NEW FUEL INJECTORS WERE BAD THE WHOLE TIME crying

Bad picture, too mad.  Whatever asshat at Standard Motor Products is responsible for approving these things for production should be fed their own fuel injectors until THEIR personal gastrointestinal exhaust is on fire just like my car's was.

I'm back to not really knowing where to go with this- I doubt it's an ignition problem since I'm now running a completely different ignition system in pretty much every way.  Fuel pressure checks out just fine, scales with boost and everything.  Maybe I'll just run a bottle of fuel system cleaner through it and see what happens.

de80q
de80q Reader
9/9/18 1:18 p.m.

Unfortunately SMP injectors are known to be garbage.  If you have a spare set of injectors, I would consider sending them out to have them cleaned and balanced.  This way you have know good name brand injectors, and can rule that out too.

 

The injector cleaner isn't a bad idea though.  If you run that through, and it seems to help, then a good freshly cleaned set should solve the issue.

¯\_(ツ)_/¯
¯\_(ツ)_/¯ UltraDork
9/9/18 1:42 p.m.

In reply to de80q :

I knew they were cheap and crappy, but not "function for 3 minutes before burning your car to the ground" crappy.  Lesson learned!

Rotaryracer
Rotaryracer Reader
9/10/18 11:28 a.m.

Probably already been done, but I didn't see it in your list a couple posts back....fuel filter and/or strainer?  I had a Ford 5.4L that was eating gas (more so than usual) and the exhaust would burn your eyes.  I didn't think it was the filter as it had been changed within the last 5-10,000 miles...but evidently there was enough crud in the tank to pack it full of sludge, making the ECU try to force feed gas to overcome it.  It also did a great job of superheating both cats and probably busted up some of the cat material in there, based on the rattling sound in exhaust.  frown

Good fuel pressure makes me think this might not be the case, but should be a cheap part to rule out? 

¯\_(ツ)_/¯
¯\_(ツ)_/¯ UltraDork
9/10/18 11:30 a.m.

In reply to Rotaryracer :

The inline filter (after pump) is brand new, strainer on the pump is very new as well.

crankwalk
crankwalk SuperDork
9/10/18 2:06 p.m.

Grounds? I had a 240SX with an SR swap that did this after I replaced some motor mounts. Turns out when I jacked the motor up, I broke a couple flimsy factory grounds. After I replaced it with a few large gauge wires, I was good again.

irish44j
irish44j UltimaDork
9/10/18 4:38 p.m.
¯\_(ツ)_/¯ said:

OK.  E36 M3.  This berkeleying car.  

About 1 minute into my attempt to limp it home, the catalytic converter caught fire.  I briefly considered the merits of letting it burn to the ground before extinguishing it.

 

trying to be like Dan Downey......

 

Saron81
Saron81 Reader
9/10/18 6:19 p.m.

Knock sensor still plugged in?

Unhook it and see if it goes away.

2.3s make all kinds of racket, and the knock sensor can be pretty sensitive. 

¯\_(ツ)_/¯
¯\_(ツ)_/¯ UltraDork
9/10/18 6:55 p.m.

No knock sensor, not sure it would even run with one!

Got injector cleaner, going to run that and see what happens.

logdog
logdog UltraDork
9/10/18 9:01 p.m.

Have you thought about fuel volume causing your drivability issue?

I have seen a few cases of a slightly kinked fuel line causing a high load loss of power/miss/hesitation.  These were all on bone stock direct injection turbo CUVs and the damage was so small you could feel it when you ran your finger along the line, but couldn't really see it.  But that's all it took to freak the ECU out at WOT.  Ive seen one extreme where it would act up every time you went WOT and the other extreme where it only did it when going up a steep hill and giving it full throttle.  The symptoms varied a bit car to car, but the root cause was the same.  I know we are dealing with 2 different types of fuel systems but I could see volume starvation causing your issues.

 

¯\_(ツ)_/¯
¯\_(ツ)_/¯ UltraDork
9/10/18 9:30 p.m.

How do I measure for that?  Figure out my fuel demand and measure the volume the pump moves?  My fuel pump and lines are oversized a bit, I wonder if the regulator might be going...

logdog
logdog UltraDork
9/10/18 10:07 p.m.

Ive never actually worked on a Merkur but I think its safe to assume it has a return line style fuel system.  Sometimes service info will include a volume test spec but its kinda rare.   Basically you remove the line from the fuel rail, stick the line in some sort of measuring device (large glass measuring cups work well), power the pump, and record the amount that comes out in a specified time.  Unless you have a known good car to get a value from it might be hard to know what is good and what is bad.  I would start with a very careful inspection of the lines, both feed and return.  Your fingers will feel things your eyes cant see.  You say the lines are a bit oversized.  Did you install them or did a previous owner?  If they were bent by hand you could have a small kink.

Are you measuring fuel pressure at the rail?  Did you check it under load or just at idle?  

¯\_(ツ)_/¯
¯\_(ツ)_/¯ UltraDork
9/11/18 6:13 a.m.

They're -6AN lines front to back, braided stainless so if I tried running my finger along them I'm not sure I'd have fingers anymore by the end!  I installed them, and as far as I can tell they're not kinked in any way.  I'm measuring fuel pressure at the rail, and have checked under load but could check again, maybe with a camera so I don't have to try to look at the gauge while my foot is to the floor.

EDIT: According to some fuel calculator things online, I should have plenty of headroom with somewhere between 90-120 liters/hr of fuel flow.  I know my pump technically has like twice that, and I've blocked the return line and seen over 90 psi, but this means for a volume test I should be able to collect somewhere between 1.5-2 liters of fuel in less than a minute.  I can definitely check that.

FIYAPOWA
FIYAPOWA Reader
9/11/18 7:26 a.m.

TL;DR: maybe the fuel filter is clogged?

 

Just a random input, and you may have already tried this, but I had a car that developed a miss that got worse until it would barely run above idle, changed a bunch of parts etc., but finally figured out that the brand new fuel filter had completely clogged in a couple weeks.  Apparently, the guy before me never kept more than 1/2 tank of fuel in the car, and the top of the tank was rusted.  Ergo, me filling it up loosened up the rust, which clogged the brand new filter.  Repeatedly.

 

Our Preferred Partners
0pipW4Xr5FHLIlAQ4wnIEbXlOY6Dsi6kJYnU1HA5IHIGWvZ6t9c6U5a71wvqzjR9