[KlrStng]

Well, I am glad I didn't celebrate prematurely, because running the BAP wide open only made the cold run problems worse.

I am convinced that it is some sort of fuel issue now. When the problem happens it is as if I am starving it for fuel. However, as I get into boost, the problem pretty much goes away, with a few hiccups. After 5 mins of driving, the engine warms up and the problem goes away.

I can watch the AF gauge and when I hit about half throttle at around 2k-2500 rpm, it goes full lean and the car feels like I just turned off the key. If I get into more throttle, it will all of a sudden surge and take off, with a couple hiccups that read as a quick jolt to AF on the gauge. If I back down, the AF goes normal and the engine runs normal.

I wonder if the factory Fuel Rail Pressure sensor is inaccurately reading the pressure as too high, which would tell the computer to cut fuel pressure, effectively killing my injectors? I am pissing in the wind, because I don't know exactly how the computer controls stuff like this.

I almost got into an accident this morning because I basically had idle or full throttle. I was spinning and turning sideways trying to pull into traffic and avoid gettin hit when the engine bogged. Very frustrating.

The tuner at KB is not being much help.. His point of view is that the same tune is in thousands of identical cars and works perfect. I agree, but I can't seem to get the point across that I can't find a mechanic doesn't suspect the tune right away. If I can't get help from KB and can't get help from the limited local techs, I am up the creek..

Bottom line is something is not functioning right, but what it is I don't know. If it was an injector, then the car would run, just seem to misfire a lot. If it was the plugs, the AF would go rich when it happens, and it doesn't, it goes full lean. If it was a vacuum leak or a boost issue, it would idle wrong and not run right at any temp, and it runs perfect once warm.

The hard part is nailing it down.. what is left? BAP reads perfectly, and I double and triple checked the wiring. Fuel pump seems fine once the engine is warm, plenty of WOT fuel when it's warm, and the car has to sit for more than 4 hours before it does this, so any component not in or on the engine is totally cold after a couple hours, and I can pretty much rule it out. Injectors would all have to be bad at the same time to lose all power like that, so I doubt an injector is bad, and having more than one run improperly when cold but run fine when warm is unlikely.

It keeps pointing to fuel pressure (the one gauge I don't have yet), but I keep thinking if the FRP sensor is reading wrong, the computer will open the injectors for a shorter time or something and starve the engine of fuel. It is all I can think of.

[stlwagon]

Hate to say it but it might be time to deep-six the BAP and get a set of GT500 pumps.

[travelers]

Originally Posted by stlwagon

Hate to say it but it might be time to deep-six the BAP and get a set of GT500 pumps.

I would feel safer with the GT500 pumps also.

[frarmar]

My car does the same thing when it's not warmed up, although I'm not sure mine is as bad as yours. It sounds to me like your car is barely driveable when cold.

My car hesitates and AFR gauge goes sky high like you stated, and it only does this when I semi-aggressively give the car throttle from a dead stop with the engine not warm. My solution thus far is to just wait until it's warm to get into the throttle too much. I'm not too worried, because it never does it if I wait until it's warm. For the record, my car did this before I had a BAP and after...

[stlwagon]

Any updates????

[sqidd]

Originally Posted by stlwagon

This is just the reason I've never been much of a fan of boost-a-pumps!

What do you mean? You have an incredibly complex fuel system that if it screws up even just a little on an FI car it will do damage quick. And then you want to add another electrical unit to the system that from time to time runs the pumps way outside of their designed range.

What could go wrong?

[travelers]

Originally Posted by sqidd

What do you mean? You have an incredibly complex fuel system that if it screws up even just a little on an FI car it will do damage quick. And then you want to add another electrical unit to the system that from time to time runs the pumps way outside of their designed range.

What could go wrong?

That is very true the more stuff and I mean electronics you put in there the more things that can go wrong.

Like the old saying goes Keep it simple stupid....

[KlrStng]

Originally Posted by stlwagon

Any updates????

I am sending the programmer in to Ken and he is going to try 2 new tunes, one slightly richer on the cold run and one much richer on the cold run. He doesn't think it will solve the problem, and I am still looking for a solution.

The other night I warmed the car up until the temp gauge was where it is when normal, and until I drove a little, it still did the same thing, although it only lasted about a minute. So it isn't just a warming issue, it's something about driving it.. perhaps some injectors just need to be worked over a little before they work 100%? I don't know. Short of replacing parts, I am at a loss.

What it acts like is a cold engine with no choke. I can reproduce the problem 100% of the time now, and with the weather in the 70s and 80s now, it only lasts a couple minutes.

The threshold seems to be about 4 hours.. if it sits longer than that after driving, the problem starts again, any less and no problem.

I have to wait 2 more weeks before I can start buying stuff again, or I will be carrying a credit card balance, something I havent done for 11 years, and don't intend to do. The fuel pressure gauge will be on the way starting July 1, followed by LCA's, reloc brackets, adj UCA, and some engine dress stuff.. Perhaps I can get to the point where I am not wanting to spend more money this summer.. .. Nevermind..

I would like to see if the fuel pressure is doing something odd, but I don't think so.. I checked the voltage going into the fuel pump driver and it reads a solid 17.22 volts cold or warm, and I just don't see that being the problem. I can see the fuel rail pressure sensor doing something odd if it's bad, but I won't be able to figure that one out until I get the gauge.

I knew I was going to be kicking myself when I sold my SCT X3, and now I want to datalog this problem and I don't have a way to do it.. I practically gave the thing away too.. gonna cost me like $150 more than I sold it for to get another one if I want to datalog. *sigh* hindsight...

[KlrStng]

Originally Posted by frarmar

My car does the same thing when it's not warmed up, although I'm not sure mine is as bad as yours. It sounds to me like your car is barely driveable when cold.

My car hesitates and AFR gauge goes sky high like you stated, and it only does this when I semi-aggressively give the car throttle from a dead stop with the engine not warm. My solution thus far is to just wait until it's warm to get into the throttle too much. I'm not too worried, because it never does it if I wait until it's warm. For the record, my car did this before I had a BAP and after...

Sounds identical to my problem.. the only time it was really an issue was last week when I drove the car to work in the morning and tried to pull into traffic with the engine stone cold. The hesitation kept me from getting out there so I put my foot to the floor, at which point I got into boost and took off with tires spinning and redlining in about a half second, then eased off which went back to the super lean sputtering, then got into it to go and started spinning, etc.. Very bad.

The BAP change only made my idle take longer to stabilize after being on the throttle.. Before I bypassed the vacuum switch, it was fine, and now (cold or warm) when I come off WOT the idle will bounce from 400 rpm to 1000 rpm and back 2 or 3 times before settling down.. I imagine it's because I have more fuel pressure than I should and the computer is trying to shorten the pulse of the injectors to get the right idle.. probably harder to do with more pressure. I will go back to the vacuum switch this weekend.

Just to eliminate it as a possibility, I am going to change the fuel filter this weekend too. I am considering getting a set of injectors, just to replace them all and see if it fixes the problem. That is what it really acts like.. is the injectors need to be "warmed up" before working right.. A mechanic suggested using a datalogger to check what the computer thought the engine temp was when it was cold, thinking perhaps it never senses the cold status of the engine and never goes to a cold run program. Since I equate the problem to running a cold engine with no choke, this is a possibility as well. Problem is I have no way to log the data.. haha. I am thinking about getting an aeroforce gauge in place of a fuel pressure gauge..

[Earl_the_Pearl]

Originally Posted by KlrStng

The hesitation kept me from getting out there so I put my foot to the floor, at which point I got into boost and took off with tires spinning and redlining in about a half second, then eased off which went back to the super lean sputtering, then got into it to go and started spinning

When you get it fixed you will look back on that a laugh. I wonder what the other drivers on the road thought.

[stlwagon]

Originally Posted by KlrStng

I am thinking about getting an aeroforce gauge in place of a fuel pressure gauge..

That'll give you a good reading of fuel pressure at the rails.

[KlrStng]

I swear I am cursed or something..

The car sat for 4 days because of crappy weather. Today is perfect out, so I pulled the car out of the garage this morning and let it run for about 5 minutes before driving. The same problem with it going lean and sputtering was happening all the way to work, getting a little better as I went, and finally going pretty much away when I arrived 15 minutes later.

At lunch, 4 hours later, same thing. All the way home. When the engine was completely hot, I got on it and at about 1/3 throttle I was going lean again, but once I got into boost it went rich and finally went to 11.5 at WOT. Soon as I got off it sputtered and went rich for a second, then back to normal. When I got home I popped the hood and it was HOT under there, so I know this had nothing to do with the engine being cold. The oil separator was dripping worse than before, so I took it off and cleaned it and siliconed the heck out of it, then cleaned up the oil it dripped on the COP and the valve cover.

I went to eat lunch and came back out to put it all back together, and upon inspection, there was a small pool of oil on the passenger side where the supercharger bolts to the manifold. I dipped my finger in it and looked and sure enough, blue supercharger oil. Upon inspection, it has oil pooled up around the rear bolt, and around the seam where the supercharger meets the plate that bolts to the manifold, from about the halfway point back and around the underside of the supercharger, and a couple inches forward on the drivers side.

I just got off the phone with Kenne Bell tech support, and the guy didn't seem too concerned, just asked that I clean the oil and get some tracing powder to locate the leak. It has to be coming from the front of the supercharger because that is where the oil is, but so far I don't see where it would have dripped from.. I think I will pull the unit this weekend and look at the underside. I am getting sick of this and want to cover all my bases anyway.

The cold run issue is becoming an all temp issue, and the techs at KB think it's a vacuum leak that seals up when the engine warms, and the only place I can see that happening is where the supercharger meets the manifold. They think the bogging is actually the computer pulling timing when it starts to go lean and the knock sensors detect it, suggesting a major vacuum leak. Engine physically warms up and problem goes away.. I guess it makes sense, so I am going to look at it from that perspective, although I have inspected all the vacuum lines a dozen times.

What I haven't done yet is pull the compressor, and if the rubber o-ring got slightly dislodged when I placed the compressor on the manifold, there could be a leak there that seals up as the supercharger and manifold heat up and expand. I might just add some silicone to be safe as well when I put it back on, just so I know 100% that it isn't leaking there. When the compressor is off I should be able to find the oil leak easier (i hope) and get that taken care of as well.

I had 2 shows lined up this weekend, and I might just have to miss them both to do this.. Happy Father's day.. haha

[stlwagon]

Don't get too discouraged! I think you'll find something when you pull it off.

[jaja6009]

We are all pulling for you. I thought you were gonna have to pull of the blower at one point. Im hoping and thinking that by the time you bolt it back on all problems will be solved.
Good Luck!!!

[KlrStng]

A quick update:

I pulled the supercharger off the manifold. The first thing I saw was some oil (looked like engine oil, maybe from the pcv or passenger side breather?) on the two mating surfaces. Thing is, it was on BOTH sides of the o-ring.

When I first finished the install, I had a small coolant leak that sprayed a little coolant on the front of the supercharger and manifold. The surface of the manifold was machined smooth when I assembled the supercharger, but now it is all white, like coolant got on it and dried, only it didn't stop at the o-ring, it is all the way from the front of the manifold surface to the hole into the manifold.

Also, when I first installed the supercharger, it rocked ever so slightly on the mating surface, which I figured the o-ring would take care of. My gut feeling is that the O-ring was NOT sealing all the way.

Last week and the week before, it would go lean at throttle minus boost, ONLY when cold. This week it was doing it worse when cold, but even warm it was going to 15-17 AF ratio under part throttle, and back to 11.8 at WOT in boost. That screams vacuum leak to me, and since the surfaces were both metal, heating them would expand the metal and seal the leak, only it was getting worse..

The oil leak is in the snout of the supercharger, under the pulley.

For now I am going to reinstall the supercharger using silicone, the way it was done before they added the o-ring. Because I don't think that either the supercharger flange, or the manifold surface is flat (can't tell which), I think I will push for them to just send me a new supercharger and manifold, that way I don't have to deal with the oil leak OR the poorly mated surface.

Using silicone to seal the two pieces should tell me this weekend if this solves the problem, and I can take it from there.. It only took me 20 minutes to remove the supercharger, and 10 of those were draining the fuel pressure and detaching the fuel line to get access to one of the bolts.

I am going to go clean the surfaces once more and bust out the silicone and re-seat the supercharger.. God I hope this is it.. I am running out of places to look..