problems, problems, boosting problems.... how bout some help?

[gixxer750]

Come on guys!!! need help!

Ok, as some of you know, I just pulled my engine and trans for a clutch replacement. I replaced 90% of the engine's gaskets and seals while I was in there.(oil pan, rear main seal, crankshaft front seal, cam seals, oil pump drive seal, valve cover gaskets, turbo return line gasket, intake mani gasket, and exhaust manifold gasket. )

I got the car all back together, and it is driving. It runs flawless off boost, but when the boost hits, everything goes to shit I ran it hard a few times, and it pulled great. Then a few more times running it, and it ran like absolute ass. When the boost hits, it feels like timing is pulled( a LOT!) and the car ceases to pull. As the RPM's climb, the engine starts to misfire. When it gets to about 4k rpm, I get small fireballs out my open downpipe as the turbo STRUGLES to hit 4-5 psi no matter what the boost controller is set at. I set my greddy profec b spec 2 at 100% boost, and got 7.8 psi, and hit fuel cut. I have a lex afm, and I was running up to 19 psi of boost before hand. The car will not go past 5000 rpm with the accelerator floored. My SAFC2 has recorded a max frequency of 1422 hz from the AFM. The knock readings read 0 throughout the RPM range on the SAFC. I unpluged the TPS, and it seemed to help for about 3-4 seconds, then it went back to the way it was running.

I have hardpipes, and I have checked all the couplers and replaced some even. All my clamps are so tight they are about to break. I am pulling 20 inches of vaccum at idle. I know this sounds a LOT like a boost leak. I tried pulling fuel with the SAFC ( -3%) and it didn't help at all. I cranked the fuel up to +10% and it made the problem worse. Timing is set at 10 degrees BTDC....

SO.....WTF?

Any ideas?

 

[gixxer750]

oh, forgot to mention...only code is a fuel cut code....

 

[shaeff]

sounds like your timing belt is off a tooth, or that you have a CODE 52 that isnt registering somehow...

check your Knock Sensor connections, and re-check your base timing. make sure you have the diagnostics jumped when you set the IGN timing.

-shaeff

 

[gixxer750]

I had the diagnostic connector jumped... I am thinking the timing belt could be off a notch. I also thought of the code 52, but my SAFC is reading the knock sensors.

One other detail I left out.... The car pops on decel, instead of coming down smooth. It didn't do that before the engine pull. Would a tooth off on the timing belt really do all this? I mean....the thing may have 110 hp right now

You don't think its a boost leak?

 

[shaeff]

could be a boost leak... but it really sounds like your T belt is off a tooth...

-shaeff

 

[gixxer750]

I'll pull the timing cover off in the morning and see. I hope thats what it is....I'm tired of chasing boost leaks that I can't find.

 

[CPT Furious]

I think the same thing, either timing belt or knock sensor...I had your EXACT issue and one of my knock sensors was jacked up. However, the S-AFC wasn't really showing a problem, but I also got a code 52.

 

[bwest]

i had a very similar issue, but it was a boost leak. i hade a loose coupler that would allow a pipe to separate under boost, but it would run ok in vaccum (the fit was tight enough to keep the pipe semi-seated). just a thought...

 

[gixxer750]

ok, update

I've double checked every freaking coupler on the car. They are all tight, I don't physically see any cracks in my couplers. So, I don't THINK its a boost leak, but I am not ruling it out. I am still only getting about 4-5 psi.

At part throttle, the car seems to have better throttle response, and pulls good up until 4k rpm, where it hits a spot where the engine just all at once seems to quit firing. This is all 50% throttle or less. If I floor it, I get misfires and pops starting at 3k rpm up until the car hits a dead spot at 3.5 k rpm up to 4krpm....where it doesn't pull anymore, and seems as if ignition is cut until I remove my foot from the throttle. The car seems to run only slightly better cold. Seems as if it is very rich. I checked my cam timing, and it is spot on, with the crank pulley at 0 and both cam gears lined exactly up.

However, this new description is slightly improved from before, when I had the timing at 10 degrees BTDC. I have advanced the timing slightly, to 15 degrees BTDC, as that is where it was upon reinstalling the engine and checking it with a timing light. It now has off boost throttle response and power much like it did before pulling the engine, but it is only slightly lacking from before. It seems to hit positive manifold pressure early than it used to(about 1 psi), but it doesn't really climb after hitting the positive side. The boost only goes to 4 by about 3k, and I'm getting the 1 psi at about 1300 rpm under part or full throttle.

Any ideas guys? I miss my power!!!!

 

[gixxer750]

you know, now that I think back, I remember the crank pulley being at 5 degrees when I timed the engine when building it....does this sound right? I guess I need to go dig through the TRSM

 

[aye mate]

I say knock sensors or timing belt off a tooth. In that order.

 

[shaeff]

you know, now that I think back, I remember the crank pulley being at 5 degrees when I timed the engine when building it....does this sound right? I guess I need to go dig through the TRSM

to set base timing, you must set the crank pulley to zero, and line up the cam notches with the markings on the back cam cover. put the belt on, turn it 720* and re-check that the crank is still at 0* and that the cam notches are alligned with the matchmarks on the back cover.

if so, your base timing is perfect. then jump TE1 and E1 in the diagnostic block, (sets timing mode) loosen the CPS bolt a little bit, and set the ignition timing to 10* BTDC, then tighten the CPS bolt again. your timing should be dead on.

if that timing belt is even 1 tooth off, it'll throw off the whole thing.

another point of interest. i had a problem like this when i first put my motor back together. it turned out that the timing belt tensioner mounting bracket was bent, and that when i started the car, the T belt would skip a tooth. i straightened out that bracket, and havent had a problem since.

-shaeff

 

[gixxer750]

problem found......the only coupler I really couldn't check....other than looking at it. I built a boost leak tester.....and found a bent hose clamp on one coupler that was leaking a little... And that the turbo outlet coupler had cracked all the way around the back side.... It was not pretty. That explains why I was running pig rich and not making any boost. Now....after putting the engine back in, the car pulls harder at 10 psi than it did at 15 before....and 15 scares me in the lower gears, because the car is sideways.

 

[GrimJack]

I love it when I'm right. Seriously, it's good to hear that you are back in business!

 

[gixxer750]

don't forget....thats what I thought from the begining too... thanks for the help guys.

 

[aye mate]

Boost leaks are GHEY

 

[gixxer750]

defective couplers are ghey

 

[gixxer750]

oh yes.....could someone please explain to my car now that by the time it gets into third gear the tires should have stopped spinning. I tried to tell it, but it doesn't seem to understand.

 

[MDCmotorsports]

Gixxer. 315s will solve your car's non-listening issues.

Also, how did you make the boost leak tester? I have a mild version of EXACTLY what your car was doing.

 

[gixxer750]

went to home depot....bought 2 2.5 inch rubber caps for pipe. pulled the 3000 pipe off the throttle body, put a cap over the end of the 3000 pipe. I put another cap over the turbo inlet. I then cut a hole in one of the caps, and stuck in my blow gun nozzle for my air comp... Made sure its a super tight fit. I pressurized the system up to 25 psi(I have been known to run 22 lbs of boost or so on occasion), sprayed all the couplers with soapy water and watched for bubbles.