OK, I need help with a fuel problem...

[rakkasan]

I had my car tuned a few weeks ago, but I think the guy screwed it up after it came off the dyno. Follow along.....

When I started to drive the car away from the shop, it bogged a little, so I took it back. He hooked the laptop back up, made an adjustment & the car ran good enough for me to be happy. Near the end of the 80 mile trip home, it developed a miss.

Also, I cut the boost back from 18.7 psi to 15 psi. I felt as though the tuner got too much out of the 450cc injectors (467 whp), so I didn't want to push it.

I changed the plugs the next day & the car ran great. The old plugs were completely black & covered with soot & the bumper above the exhaust was covered with soot too (not oil though). It continued to great for about 70 miles or so, & then it developed the same miss again. I changed the plugs & the routine started over again.

Last night, when driving home, I hit 10 psi or so & the car started running like crap again. There is a lot of smoke pouring out of the exhaust & one, maybe two cylinders, aren't firing or are missing badly. The turbo would spool insanely fast from 6.0 vacuum to 3.5psi, but that's as high as it would go. It would start to stall the motor too, not letting it climb above 3.5k rpm. I changed the plugs again, drove it for 5 miles, same problem. When I pulled the plugs tonight, all six looked as though they hadn't been changed in 1000's of miles, not just 5. :nono:

I checked all of the I/C couplers & couldn't find any leaks. Not that it would matter because it's MAP, so unless I'm missing something, that wouldn't be the source. I also ran a compression check & all cylinders logged between 145-155 psi after 5-7 compression strokes. This is good, I thought that I thought I had burned a hole in one of the pistons.

So that's the symptoms, but I'm trying to figure out the cause. It's running rich as hell, but why? My first thought is one of the injectors, maybe two, are stuck open. But if this was the case, wouldn't only one or two plugs be shot & not all six?

Any advice?

 

[The Reaper]

damn man that sucks....

hows the AFPR? where's your base FP set at?

do you have a laptop??? if so hook it up and check it? maybe something got changed or he for got to save the map? im not too sure man. i haven't dove into the tuning world too much yet......sorry i can't help you more

 

[jza71]

It might be a symtom of running 100% duty cycle too much that the injectors always run @100% when ever it sees a signal.

If you have a laptop, you could load the ignition and fuel map on here and we might be able to figure out what is going on with your car.

You can try and drop the fuel pressure to about 28psi with vac line connected if it is running too rich.

One last thing, where/what are you Ignition Dwell set at?

 

[Rich]

What are you using for fuel/ignition management?
It sounds like you're running too rich; your plugs foul up and don't ignite good enough anymore and I guess the smoke is dark brown? And the goo on the back would be unburned fuel.
Be carefull with that, you can get bore wash when plugs are not igniting for too long a time.

What type of plugs are you using? If you run them too cold, they lose the self cleaning ability and they foul up. Maybe because you powered the boost down you need 1 step hotter plugs.

I know some tuners like to set it nice and rich to be on the safe side, for liability reasons. So like already said, try to hook up a laptop and see if you can log/view the I/J dutycycles.

 

[tissimo]

whats the a/f like? im sure mega rich.. take it back to your tuner

 

[T34418L3ONE]

Id check the injectors. Running them at 100% could have effected the spray pattern. Also check your FPR and its vacumm source.

 

[rakkasan]

I'm not really certain what the AFR is, I can't rely on my LC-1. It's never given me a reading that I trust due to it bouncing all over the place. I just bought a Bosch sensor from Aaron & will have it soon, so once it's installed, I'll datalog & figure it out.

The first thing I need to do though is figure out how to get it back to fouling out the plugs. Sounds stupid, right? I'm going to swap the coils around to try to figure out if one of them is bad.

I still think I have a wiring issue under the hood. I think it's existed since the swap, I just really suck at electrical stuff so I haven't been able to identify it. Voltage spikes high enough to pop the headlights can surely fry a coil or two too.

I wish that I lived closer to someone that could look at the wiring, because in case you haven't heard, I suck at wiring....

 

[rakkasan]

OK, replaced the ignitor, same deal. I bought a Bosch WB sensor from Aaron, so I'll get that hooked up & datalog to see what shows up.

I also want to check the timing. I'm running the old school, blue/purple HKS timing gears, so I think that it's possible that the timing belt jumped a notch or the timing teeth ring itself slipped.

Anyone have a pic of the crank angle sensors?

I haven't had time to check anything lately because I'm in the middle of another move, but fortunately, the place we're moving to has an oversized two car garage.:naughty: I'll have the chance to look it over closely now....

 

[soapra]

How is the Vac line that goes to the stinger? Did you use a good line? Check if the line is kinked or pinched. When we were developing the stinger on my car, I had an issue like that.

 

[RacerXJ220]

What's your fuel pressure set to vac line attached?

 

[rakkasan]

How is the Vac line that goes to the stinger? Did you use a good line? Check if the line is kinked or pinched. When we were developing the stinger on my car, I had an issue like that.

Ding, ding, ding! We have a winner...sort of. :icon_bigg

5/32" vacuum line was installed instead of 1/8", so every time I hit boost, the line would expand enough to allow a leak at the manifold. I replaced the line & spark plugs & it fired right up & idled smoothly. I still need to have the car tuned again, but that's small potatoes now that I have a good WB sensor.

89

 

[Nopaint]

Thats good to hear! Where you getting it tunned at?

 

[soapra]

Ding, ding, ding! We have a winner...sort of. :icon_bigg

5/32" vacuum line was installed instead of 1/8", so every time I hit boost, the line would expand enough to allow a leak at the manifold. I replaced the line & spark plugs & it fired right up & idled smoothly. I still need to have the car tuned again, but that's small potatoes now that I have a good WB sensor.

89

Yea man! :biglaugh: I did spend some time messing with that stinger on two cars once Aaron made that first jumper harness. It's Good to know that my mistakes helped you. Now retune again and let up know how it goes.