vacuum lock issue?

supraluver4life · 08-04-2010, 02:35 PM

so about two weeks ago my car has been acting up (what a supra lol). Im really confused about the issue. So i go to start it up in the morning and it starts up fine i drive into town (which takes about 30 min) with no issues. Then i go to start the car up after letting it sit for 10 minutes and it just turns over and nothing!!! but then if i leave it to cool down for say like an hour it turns over and starts right up. Funny thing is, i think it got worse yesterday. I drove into town, stopped at autozone, and then went to turn my car on and it didnt work. Same issue so i left it for an hour tried again... nothing! so four hours went by and i finally said screw it ill come back and get it tomorrow, so we were rolling my car back around to the employee parking lot and i just randomly tried to roll start it, even though i knew if the starter doesnt start it roll starting it wont do shit. Then bam it roll started and ran fine. So i drove it home and parked it for a while. So theres my problem, some people have said that it sounds like a vacuum lock issue. Anyone with any ideas on how to fix this please chime in... because for now its just another supra sitting in someones yard

MA70-3.0GT · 08-04-2010, 03:45 PM

Vapour lock in an EFI system???

~I severely doubt it as the fuel pump is more than powerful enough to force an airlock through the system and if it were sucking air (different to vapour lock but worth ruling out) you'd A) have problems when running not just starting & B) probably hear the pump going crazy on cranking. More likely a dodgy relay or less likely a fuel pump issue.

Have you ascertained that you have a spark when it's no-go? any codes when it's running? If you do have a spark next time it won't start then get a jumper wire & bridge the FP & B+ terminals in the diag box, the pump should then run permanently with ign. ON, if that is the case and the car then starts we know where to look next...

EDIT- Green's linked to a thread below my post now & at the bottom of that is the TSRM page I was thinking of to test fuel pump/pressure, provided your starter's fine of course...

Green7mgte · 08-04-2010, 04:05 PM

see this

http://www.toyota-supra.info/forums/mkiii-supra/17283-88-supra-problem-need-helpp.html

talks about starter getting hot.
take a spray bottle with something cold or rubbing alchole and spray it onto your starter. if it starts back up than once cooled off. than you find your problem

cre · 08-05-2010, 03:10 AM

My old N/A's VAFM died in such a way that when heat soaked there was NO signal from Vs... Searched for a long time to find the problem and finally resorted to testing parts and then heating them with a hair dryer and retesting... the AFM was the second thing I tested and sure enough...

Green7mgte · 08-05-2010, 03:21 AM

sure enough what? cre are you alive??? dont leave me in suspense! guys i think somethings wrong with him! im comming over.

cre · 08-05-2010, 03:56 AM

I swear.... that boy's just not right....

CanadianBak'inSupra · 08-05-2010, 06:20 AM

just to clarify i dont think you even need a starter installed to roll start your 5 speed...
at least on my samurai i dont.

supraluver4life · 08-07-2010, 08:53 PM

so it might be the afm but i doubt it. its turbo and the last time i had afm problems (the harness had a short in it that i fixed) it started fine but would not rev over 2500 rpms and shot out clouds of soot... kinda nasty haha

but anyway, today i went to try to diagnose the problem, i drove about 10 miles till it was warm. shut it off and waited ten minutes, the usual time it takes t to not work after shutting the car off. if i try to start it right after i turn the car off or even five minutes after it starts up. but i waited the went out and tried to start it and SURE ENOUGH (haha, green im leaving you in a state of suspense lol)... it started, so i waited another ten minutes tried again and god damn it!!!! it started. its pissing me off, my car is so temperamental haha. i try to figure out the problem and it wont do it for me. anyway all this help is wonderful and more would be greatly appreciated

Green7mgte · 08-07-2010, 10:54 PM

Quote:

Originally Posted by supraluver4life

but i waited the went out and tried to start it and SURE ENOUGH (haha, green im leaving you in a state of suspense lol)... it started,

LOL.

it knows your trying to figure out whats wrong with it.. next time blind fold it and jump on its back.

seriously tho that is crazy.
perhaps the ambient temperature under the hood didn't reach high enough levels.. take it for a quick hard drive and see what happens then

08-04-2010, 02:35 PM	#1
supraluver4life 3" Exhaust Join Date: Nov 2009 Location: Santa Fe, NM Posts: 135	vacuum lock issue? so about two weeks ago my car has been acting up (what a supra lol). Im really confused about the issue. So i go to start it up in the morning and it starts up fine i drive into town (which takes about 30 min) with no issues. Then i go to start the car up after letting it sit for 10 minutes and it just turns over and nothing!!! but then if i leave it to cool down for say like an hour it turns over and starts right up. Funny thing is, i think it got worse yesterday. I drove into town, stopped at autozone, and then went to turn my car on and it didnt work. Same issue so i left it for an hour tried again... nothing! so four hours went by and i finally said screw it ill come back and get it tomorrow, so we were rolling my car back around to the employee parking lot and i just randomly tried to roll start it, even though i knew if the starter doesnt start it roll starting it wont do shit. Then bam it roll started and ran fine. So i drove it home and parked it for a while. So theres my problem, some people have said that it sounds like a vacuum lock issue. Anyone with any ideas on how to fix this please chime in... because for now its just another supra sitting in someones yard __________________ Cusco front, Tein Rear coilovers Massive DDP, 3'' custom catless exhaust, Tsudo muffler 4.5'' outlet, Apexi cold air intake, Act stage 3 clutch, ct26 turbo (stock)- 10psi +300rwhp "Not driving a car because its too nice, is like not fucking your gf so shes still tight for the next guy"

08-04-2010, 03:45 PM	#2
MA70-3.0GT 12psi boost Join Date: Oct 2009 Location: Crewe, England Posts: 356	Vapour lock in an EFI system??? ~I severely doubt it as the fuel pump is more than powerful enough to force an airlock through the system and if it were sucking air (different to vapour lock but worth ruling out) you'd A) have problems when running not just starting & B) probably hear the pump going crazy on cranking. More likely a dodgy relay or less likely a fuel pump issue. Have you ascertained that you have a spark when it's no-go? any codes when it's running? If you do have a spark next time it won't start then get a jumper wire & bridge the FP & B+ terminals in the diag box, the pump should then run permanently with ign. ON, if that is the case and the car then starts we know where to look next... EDIT- Green's linked to a thread below my post now & at the bottom of that is the TSRM page I was thinking of to test fuel pump/pressure, provided your starter's fine of course... __________________ '89 MA70 Supra GT aero 3.0turbo JDM, Rebuilt motor, K&N intake, 3" stainless turbo-back. New turbo and braided line kit... '89 Honda NC27 400, NC23 cams, open pipe, PC36a shock & possibly Showa USD forks... '83 Yamaha 29R XJ750E-II, number 69 off the line, only runner in the country? Original except Koni shocks '95 Honda PC26 CB500R, Winter hack, hateful, trying to sell it I'm not paranoid, they really ARE after me!!! Last edited by MA70-3.0GT; 08-04-2010 at 04:10 PM.

08-04-2010, 04:05 PM	#3
Green7mgte Supra Forum Moderator Join Date: Nov 2009 Location: Green-Ohio Posts: 1,297	see this http://www.toyota-supra.info/forums/mkiii-supra/17283-88-supra-problem-need-helpp.html talks about starter getting hot. take a spray bottle with something cold or rubbing alchole and spray it onto your starter. if it starts back up than once cooled off. than you find your problem __________________ 92 Ma71 7mGTE Auto. SafcII Supra FAQ Supra MKIII FAQ Classified Section guidelines : Last edited by Green7mgte; 08-04-2010 at 04:08 PM.

08-05-2010, 03:10 AM	#4
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	My old N/A's VAFM died in such a way that when heat soaked there was NO signal from Vs... Searched for a long time to find the problem and finally resorted to testing parts and then heating them with a hair dryer and retesting... the AFM was the second thing I tested and sure enough... __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

08-05-2010, 03:21 AM	#5
Green7mgte Supra Forum Moderator Join Date: Nov 2009 Location: Green-Ohio Posts: 1,297	sure enough what? cre are you alive??? dont leave me in suspense! guys i think somethings wrong with him! im comming over. __________________ 92 Ma71 7mGTE Auto. SafcII Supra FAQ Supra MKIII FAQ Classified Section guidelines :

08-05-2010, 03:56 AM	#6
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	I swear.... that boy's just not right.... __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

08-05-2010, 06:20 AM	#7
CanadianBak'inSupra Official hall monitor / search nazi - NO SOUP FOR YOU! Join Date: Oct 2009 Location: Canada, BC Posts: 837	just to clarify i dont think you even need a starter installed to roll start your 5 speed... at least on my samurai i dont. __________________ 1984 supra - 1uzfe - w58 - 4.10 - 1 piece aluminum shaft.

08-07-2010, 08:53 PM	#8
supraluver4life 3" Exhaust Join Date: Nov 2009 Location: Santa Fe, NM Posts: 135	so it might be the afm but i doubt it. its turbo and the last time i had afm problems (the harness had a short in it that i fixed) it started fine but would not rev over 2500 rpms and shot out clouds of soot... kinda nasty haha but anyway, today i went to try to diagnose the problem, i drove about 10 miles till it was warm. shut it off and waited ten minutes, the usual time it takes t to not work after shutting the car off. if i try to start it right after i turn the car off or even five minutes after it starts up. but i waited the went out and tried to start it and SURE ENOUGH (haha, green im leaving you in a state of suspense lol)... it started, so i waited another ten minutes tried again and god damn it!!!! it started. its pissing me off, my car is so temperamental haha. i try to figure out the problem and it wont do it for me. anyway all this help is wonderful and more would be greatly appreciated __________________ Cusco front, Tein Rear coilovers Massive DDP, 3'' custom catless exhaust, Tsudo muffler 4.5'' outlet, Apexi cold air intake, Act stage 3 clutch, ct26 turbo (stock)- 10psi +300rwhp "Not driving a car because its too nice, is like not fucking your gf so shes still tight for the next guy"

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