Very slugish, wont accelerate

Fozbo

7M Love
Apr 4, 2005
290
0
16
Norman, Oklahoma
Cliffs: replaced shims, now car wont accelerate or even rev fast; no boost leak, no clogged IC/intake pipes, all wiring connected, no codes.

Edit: mods include built engine, turbonetics 62-1, hard pipes, upgraded IC, BOV ... nothing else really pertinent.


I just replaced some shims in the supra over about a month (school, getting shims, etc. compounded). I got it back together and now it's acting like I have a huge ass boost leak in the intercooler pipe; it won't accelerate at all when I give it gas. Naturally I idled it right back to my garage to check for an IC pipe that was open or something. I triple checked all the connections (i have hard pipes), so I am certain it is not a boost leak from the IC piping. I triple checked all the hoses and vacuum lines (although if it were a leak, it would have to be pretty big since it bogs worse than when my IC pipe blew apart). I also checked over all the connectors (especially the maf sensor) and everything was fine. I also made sure the BOV was working fine.

The car is not throwing any new codes.

My next idea was that the IC pipe was somehow clogged. I made this assumption because the wastegate was opening like normal when I was flooring it, yet the car wasn't going anywhere fast. The wastegate pulls its signal right off the turbo, so I thought there is an issue between the turbo and the engine.

In order for me to change the shims I had to remove the upper IC pipe. I had blocked off the open pipe with a plastic sack. I also had taken off my K&N to clean it and put it back on during the down time. So naturally I had two more areas to check: clogged IC pipe, or clogged/open intake. I just now got done taking apart my whole upper IC piping from the TB down to the IC, and everything was clear. I also took off my intake and made sure there was a clear path from the filter to the turbo fins. I even stuck a mirror down into the intake manifold and checked each runner.

The only thing that is saying it is not a boost leak is the fact that when I give it gas, it doesn't hesitate or shudder at all; it's completely smooth. Also, when I free rev it, it revs slowly.

My only other guesses are timing and/or fuel delivery. I have not messed with the timing (it was set fine before I replaced the shims). The car idles fine (had it idling and revving for a good 10 minutes) so I don't think I have a fuel supply issue. I am all out of ideas and thus I am posting :p.

If anyone can help out, that would be awesome.
 

Fozbo

7M Love
Apr 4, 2005
290
0
16
Norman, Oklahoma
I decided to test it out again after I got all the IC pipes back together. It still has the same sluggish behavior and it also can't rev past 4000 rpm.
 

zachm611

Beauty In Disguise
Apr 15, 2006
543
0
16
37
new mexico
have you checked for codes even though the CEL isnt on? just a thought but i honestly dont know... also what kind of shims are we talking about?
 

Fozbo

7M Love
Apr 4, 2005
290
0
16
Norman, Oklahoma
Nope, I'm talking valve shims. It was 4k rpms free revving and it doesn't matter whether it's in boost or not; it feels like it's not getting any power. No smoke at all.

Also, when I say "sluggish" I mean that it is not drivable (full throttle in first gets me going to about 15 mph in a few seconds).


Mods:
wiseco pistons / eagle rods / all ARP hardware + cometic MHG
5-angle valve job on the head
turbonetics 62-1 w/ hks style wastegate set at 10 psi
tubular exhaust manifold and 3" exhaust all the way back
3" IC piping + larger IC
GReddy type s BOV
K&N FIPK
SPEC stage 3
... probably forgetting something

I have a wideband controller installed, but it's all disconnected (none of the wires are intercepted, just tapped into). Also the controller had been installed and was driving fine before I replaced the valve shims.

Edit: yes, I have two preexisting codes, the throttle position sensor code and O2 sensor code. Both of which I have always had (I need to adjust the idle screw, and the only O2 sensor that I could get ahold of was a non-heater type, so it throws the code every time it starts cold). I have started it a few different times and have cleared and checked the codes throughout the whole ordeal.
 
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Fozbo

7M Love
Apr 4, 2005
290
0
16
Norman, Oklahoma
Yeah, I'm getting the timing gun from the parents' place tomorrow.

Also to boot: the spark plugs and wires (all NGK) are all about 3000 miles old.
 

7MGTEsup

Formerly 'Down but not out'
Jun 14, 2005
614
0
0
England
I had an issue like this when I first put my car back together. I put in the CPS as per TSRM but must have skipped a tooth. Car was flat as a fart, would boost but not pull. Turned out my base timing was set at 10* after TDC.
 

Datsrboi

Loud pipes Save Lives
Jul 31, 2007
797
0
0
Haltom Texas
www.cardomain.com
Down but not out said:
I had an issue like this when I first put my car back together. I put in the CPS as per TSRM but must have skipped a tooth. Car was flat as a fart, would boost but not pull. Turned out my base timing was set at 10* after TDC.


Lucky for you... I was 15 degrees off.
 

Suprizm2

Boost'n
Oct 19, 2007
39
0
0
Los Angeles
Yup check your timing, or while the car is on unplug the air flow meter sensor, rev it and if there is no change to the idle while its disconected that might be it. This happened to me!
 

Fozbo

7M Love
Apr 4, 2005
290
0
16
Norman, Oklahoma
Thanks for the support guys, turned out to be the timing after all (around what would be -5 or -10 degrees BTDC - or rather 5 or 10 degrees ATDC).