NOT hitting boost car seems to bog out NEED HELP!!

[turbosupraIII]

I just put on a hks ssbov, k&n filter with maf adaptor, and a costum 2.5 inch turbo back exhaust, with a complete tune up on the car. now it idles perfect but when i went full throttle on 1st or 2nd gear it seems like its not hitting boost??? when i try to go full throttle it stops at like 2500 to 3000 rpm and the stock boost gauge jumps to like 4 pounds then back to negative vac? Seems like to me like there is no boost or fuel cut off or something. I need help plzzzz

[cre]

I hope you didn't try to clean the AFM with any cleaning problems... it's not what's generally referred to as a MAF and MAF safe cleaners are NOT save for use with a KV AFM which is what you've got.


Have you checked for error codes? http://www.cygnusx1.net/Supra/TechTi...ror_codes.aspx

Check for leaks in all of the piping after the AFM.

[turbosupraIII]

these are the codes im getting 24, 31, 52
intake air temp sensor signal, air flow meter signal, and knock sensor signal.

[cre]

Well, that explains a lot. The car is running in what's generally known as "limp mode"... it's a fail safe mode where the ECU, in response to certain diagnostic failures, imposes a low RPM rev limit, adds a lot of fuel and pulls spark advance.

Now, did you clear the codes after checking the first time, then take it for a drive and recheck?

You need to handle the error codes one at a time. The code 52 is rather common and is generally resolved by rewiring the sensors; see the MKIII FAQ section for a writeup on it.

24 and 31 are both AFM related codes. Inspect the harness and contacts for damage and signs of corrosion. Then reconnect and make sure the connection is solid.

After each of these you may reset the ECU and take the car for a medium distance drive and recheck for recurring codes when you get back home.

If the AFM related codes continue follow the instructions here:
http://www.cygnusx1.net/Supra/Librar...ection=FI&P=96

[turbosupraIII]

what if i just change the knock sensor instead of rewiring it will this help the issue?

[cre]

If the problem is the wiring... the problem is the wiring. That's the most common cause of an error 52 and it's the cheapest thing to do to try to fix it.

If you want to try swapping sensors, have at it (the one by the starter sucks and is very easy to break, so be careful). You can get used sensors, but then if the error continues you still don't know if it's wiring or another bad sensor... new sensors are VERY expensive.

[turbosupraIII]

so if i do the wiring the light will go off? and also i cleared the codes and now when i drive in any gear it goes to 2500 rpm all fine but then trying to go faster it bogs out and backfires??

then drove it back home checked the codes again and now its giving me a 42 and 52 code?

also on these cars does the knock sensor keep the car from driving like this?

btw thanks for all the help

[cre]

You need to work through and fix any and all existing problems which may be causing error codes. PERIOD. Just because they didn't recur this time around doesn't mean there's not a problem there too... but for now start on the problems which are recurring at a high rate: ie. the knock circuit.

I'm not promising that the wiring will solve the code 52... I've never seen your car. But the wiring is the more common point of failure and it's MUCH less expensive to replace than the two sensors.

Code 42? Speedometer also not working?

[turbosupraIII]

ok cool then i will frist do the knock sensor rewire.. now do I have to do both or just the one closet to the alternator?