Toyota Supra Forums! Join the Supra forum!

Toyota Supra Forums! Join the Supra forum! (http://www.toyota-supra.info/forums/)
-   MKIII Supra (http://www.toyota-supra.info/forums/mkiii-supra/)
-   -   big problem (http://www.toyota-supra.info/forums/mkiii-supra/6282-big-problem.html)

gomezmk 10-04-2006 05:49 AM

big problem
 
I have a 1987 supra turbo, mods are 2.5 inch inner cooler pipe, mbc 10psi, 3 inch full exhaust, adustable fuel regulator, no boost leaks for sure, foam air filter. Engine runs perfect, pulls ok under boost up untill I hit 5,000 rpm then the motor just starts back firing like crazy. I have a super monitor on the dash to check codes by pressing the buttons it will tell me the codes and the dash says, eng- ok. I don't know what to do. Am I crazy to think my foam filter is restricting air. Help me!!!!!!1

suprra_girl 10-04-2006 08:42 AM

sure you're not hitting rev limiter (oddly enough) early?

is it fast backfiring or consistent or just all over the place?
what codes did you pull, in your post do you mean the codes were clear?

gomezmk 10-04-2006 06:14 PM

The wierd thing is that when my engine was all stock at 6 psi of boost, it never did it that bad from 5,000 rpm to six, it use to just pull very slowlly from 5 to 6 so thats why I think my foam filter might be the problem because since I'm running more psi now more air has to flow through my filter which is probably now restricting the air even more. I have completelly no codes existing in my diagnostics check.

gomezmk 10-05-2006 10:31 PM

I ran the car without the filter and I noticed a torque increase but still would cutout at 5,000 rpm. I remembered that I installed bosch platium spark plug and I did researh and learned that they are no good for turbos so I installed ngk plugs, i'll see what happens now.

gomezmk 10-05-2006 11:40 PM

well i ran it with new plugs and it still does it wtf!!!!!!!!!!!!

gomezmk 10-06-2006 06:37 PM

Next is to try to readjust the tps, thats all I can think of.

suprra_girl 10-06-2006 08:25 PM

i think if it was the tps it would throw a code of some sort

can you describe the noise any better?

is it a slowish type cut or is it really fast?
is it the same cut as with the old plugs? or has the sound changed

nelly26 10-06-2006 09:42 PM

have you had fuel cut off bypassed if not, if you exceed the psi on turbo more than 10 psi it will cut out so will have to get the ecu chipped to bypass

suprra_girl 10-06-2006 09:49 PM

^ i'm confused

what has that got to do with his misfiring?

and just for future reference you can't "chip our ecu's" as such

fuel cut is not boost/psi referenced it is by hz which is what our afm measures and the hz frequency of fuel cut can vary it is generally between 11-13 for stockish vehicles and can be very low for high air flow vehicles

nelly26 10-06-2006 10:03 PM

when i had my boost put to 15 psi i found when it got above 10 psi she would cut out and miss fire i had her chipped and has been runing sweet

suprra_girl 10-06-2006 10:05 PM

as i said, it depends on your mods
most hit it between 11 and 13
i myself hit it at 8

and you cannot chip the ecu's but you can buy hks fcd's to wire in to move fuel cut

what did you buy to move fuel cut?

nelly26 10-06-2006 10:06 PM

i guess the chip in my ecu does not do anything then

suprra_girl 10-06-2006 10:08 PM

there is only one type of chip that is available for the 7mgte ecu and that is the (can't remember the damn name) but is made by reg reimer i believe

it's extremely costly to get done and not many do it... it's far easier to do the lexus 550's or hks fcd

so your chip not doing anything... more than likely ;)
you probly had a boost leak and repaired it without even realising

nelly26 10-06-2006 10:08 PM

sorry ill have to find out what chip they used on ecu im not to sure i let jap speciast deal with it has that sort of work i dont touch sorry

suprra_girl 10-06-2006 10:10 PM

all you need to do is drop your ecu down, undo the 4 screws in the top and take a good pic of them

then we'll compare to stock ecu's and see what is different if anything

what mods have you done to your car?
also what year so i can compare to the correct ecu

nelly26 10-06-2006 10:15 PM

not much had head gasket done with stainless steel one and had hybrid turbo fitted . i am still looking for the right body kit having problems finding the right kit . i have bbs wheels and straight throught exhaust. im steel looking the right stuff in uk its hard to get right stuff

suprra_girl 10-06-2006 10:15 PM

one more thing

could you describe what fuel cut felt like to you?
did it ever throw a check engine light or just misfire?

curious :)

suprra_girl 10-06-2006 10:20 PM

gomez: are you 5sp or auto?
does it do in a specific gear?
how much traction loss is there
only in wet? or both?

nelly26 10-06-2006 10:21 PM

i would accelerate to 125 mph and it would cut out after a few seconds it would start running with a bit of missing for a few seconds and then no problems i was told by mechanic it was fuel cut off he then chipped it that is what told me it cost me about 200 pound it could hks i have had a look invoice sorry he told me it was chipped git

nelly26 10-06-2006 10:24 PM

ecu did flash but i left to mechanic to sort out

suprra_girl 10-06-2006 10:27 PM

ah hah

what you encountered was speed cut
you'll find when you drop the ecu that there is a pink wire and you have a little black box intercepting it :)


get that lead out of your foot :p

edit: any ideas what git stands for? just curious

but also odd... is yours an import? rhd or lhd?
uk cars i believe don't have speed cut but i guess maybe your ecu has been changed as some stage

if you do get the chance to drop your ecu would you be able to write down the part number on the ecu for me... i have a friend with a complete parts list so i can determine the originality of your ecu in particular

the speed cut is usually about 120mph

nelly26 10-06-2006 10:41 PM

mine is uk spec rhd 5sdm 1992 i also have a 1990 aswell auto i have been told gear box has gone i dont have kick down any more and when put into drive it stalls and ecu light comes on

suprra_girl 10-06-2006 10:54 PM

ahh i would say being rhd that you will have speed cut then

to save you some money... do your own diagnostic ;) come back and post your codes and we'll see whats up with ya check engine light

maybe post a new thread saves hijacking gomez's lol

gomezmk 10-07-2006 03:01 AM

My car is a 5 speed. The cutout is a fast cut something like a rev limiter. I 'm leaning towards buying a hks fuel cut denfencer.

gomezmk 10-07-2006 03:04 AM

my car is a 5 speed and it does it in all gears. it's a fast cut out.

gomezmk 10-14-2006 04:22 AM

Hello everybody, I think I might know what the problem is. My bov is leaking big time. I have a cheap bov that is very similar to the turbo xs bov. I changed the position of the bov so the boost from the 3000 pipe is pushing on the side of the piston instead up on the piston thus compressing the spring. It still leaks but not nearly as much as it did the other I had it routed. When I test drove it , it pulled amazing at high rpm but now it cut out 5,500 rpm instead of the usual 5,000 rpm. I'm hoping if I get a really good bov, it might fix it.

gomezmk 10-20-2006 12:12 AM

I installed the new bov, it helped out but still didn't fix it, it still cuts out at 5,500 rpm. I rev the engine up in neutral and it cutouts at 5,500 rpm so I have no clue why it would do that! I did do a na to turbo swap on this car.

gomezmk 10-22-2006 10:37 PM

ok I finally found the problem with the cuttout at 5,500rpm. I took out the air flow sensor and it was covered in junk, I cleaned it really good and now I can rev it to 6,000rpm. The think is from 5,500 rpm to 6,000 it pulls really slow.


All times are GMT. The time now is 01:04 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87