No start on a Sc'd Mk1

dsr30 · 03-13-2006, 01:04 AM

i recently got a sc'd mk1 with 104xxx miles but am unable to get it to start. when i crank it runs for 1 sec and then dies. i'm getting spark and fuel seems to be intermitent. using a noid light on the injectors, the light comes on sometimes, but when it does it's dim and then it goes out after a sec. i was told that a bad vaf could cause this starting and then dying problem. can some one please give me some advice? btw. the sc belt is broken, could this cause any problems?

MR-Fixer · 03-13-2006, 01:57 AM

The SC belt also runs your water pump. If you run the car w/ no SC belt for more than a few minutes, I garantee you will blow a head gasket. Very expensive to have that fixed at a shop. The SC is totally sensored, and wired into the running of your engine.

Its possible that your only problem is the belt being broken. One other thing you should check is: turn the pulley on the SC by hand while there is no belt on it. It should spin freely. If it is stuck hard, then that's why your belt broke. If its frozen, you need to probably replace your supercharger, or buy some spendy new SC components from the Yota Dealer.

MR-Fixer · 03-13-2006, 02:05 AM

Oh one other thing, don't hook up your injectors to a test lamp. They run at 5 volts (hence the dim light). Injectors have a special ground wire running back into the ECU, and can't be grounded elsewhere. I don't know if you damaged your ECU doing that or not. If I were you, I'd buy a CD on SC repairs off EBay (maybe $10. for almost 1000 page manual). And then look up troubleshooting, and diagnostic code checks.

TheAmazingDave · 03-13-2006, 10:36 AM

The car will start and run fine without the SC belt intact, but as pointed out the waterpump is also driven on the same belt and the engine may quickly overheat.

The symptoms described point to a bad air flow meter, aka AFM. It could also be a loose plug on the AFM if the metal clip is missing which is pretty common. However if you or another person tried to unplug the AFM by unscrewing the plug instead of removing the clip- to separate the plug the AFM is now toast. Never unscrew the plug on the AFM! There is a switch that turns on the fuel pump inside the AFM when enough air flowsthrough it that the ECU knows the engine is running. The engine start sequence only runs the fuel pump for a few seconds, long enough to start the car. If the ECU doesn't get an air flow reading from the AFM the fuel pump is immediately shut back off.

CpuZapper · 03-13-2006, 12:46 PM

Along with what 86mister2 said, if you have any major vacuum leaks that can also create the same symptoms. If there is not enough air flow to open the AFM (IE its breathing through a big hole somewhere instead), the fuel pump contact won't open, and the pump will never kick on except in the few seconds of initial priming. My '86 was doing the exact same thing when my fuel pump wouldn't come on - bad AFM in my case.

EHolmes744 · 08-16-2006, 11:46 AM

ok
before you go through alot of unnessary test check your ignitor.i bought my SC that wasnt running but would start up an run for about 2 seconds.i did all the test on the ecu and everything else. if you have a BGB there is a test that you can do to the ignitor to check the voltage its putting out. mine was way below spec.got a new ignitor an it started right up. if you cant do the tests see if you can borrow one from somebody in your area to try an see if thats the problem.
Ernie

03-13-2006, 01:04 AM	#1 (permalink)
dsr30 No Skills Join Date: Mar 2006 Posts: 4 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	No start on a Sc'd Mk1 i recently got a sc'd mk1 with 104xxx miles but am unable to get it to start. when i crank it runs for 1 sec and then dies. i'm getting spark and fuel seems to be intermitent. using a noid light on the injectors, the light comes on sometimes, but when it does it's dim and then it goes out after a sec. i was told that a bad vaf could cause this starting and then dying problem. can some one please give me some advice? btw. the sc belt is broken, could this cause any problems?

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03-13-2006, 01:57 AM	#2 (permalink)
MR-Fixer Censored *** censors Join Date: Feb 2006 Location: Censored Posts: 95 Thanks: 0 Thanked 1 Time in 1 Post iTrader Rating: (0/0%** )	The SC belt also runs your water pump. If you run the car w/ no SC belt for more than a few minutes, I garantee you will blow a head gasket. Very expensive to have that fixed at a shop. The SC is totally sensored, and wired into the running of your engine. Its possible that your only problem is the belt being broken. One other thing you should check is: turn the pulley on the SC by hand while there is no belt on it. It should spin freely. If it is stuck hard, then that's why your belt broke. If its frozen, you need to probably replace your supercharger, or buy some spendy new SC components from the Yota Dealer.

03-13-2006, 02:05 AM	#3 (permalink)
MR-Fixer Censored *** censors Join Date: Feb 2006 Location: Censored Posts: 95 Thanks: 0 Thanked 1 Time in 1 Post iTrader Rating: (0/0%** )	Oh one other thing, don't hook up your injectors to a test lamp. They run at 5 volts (hence the dim light). Injectors have a special ground wire running back into the ECU, and can't be grounded elsewhere. I don't know if you damaged your ECU doing that or not. If I were you, I'd buy a CD on SC repairs off EBay (maybe $10. for almost 1000 page manual). And then look up troubleshooting, and diagnostic code checks.

03-13-2006, 10:36 AM	#4 (permalink)
TheAmazingDave Cage Fighter Join Date: Mar 2005 Location: San Jose, CA Posts: 1,112 Thanks: 13 Thanked 7 Times in 7 Posts My Google Map iTrader Rating: (0/0% )	The car will start and run fine without the SC belt intact, but as pointed out the waterpump is also driven on the same belt and the engine may quickly overheat. The symptoms described point to a bad air flow meter, aka AFM. It could also be a loose plug on the AFM if the metal clip is missing which is pretty common. However if you or another person tried to unplug the AFM by unscrewing the plug instead of removing the clip- to separate the plug the AFM is now toast. Never unscrew the plug on the AFM! There is a switch that turns on the fuel pump inside the AFM when enough air flowsthrough it that the ECU knows the engine is running. The engine start sequence only runs the fuel pump for a few seconds, long enough to start the car. If the ECU doesn't get an air flow reading from the AFM the fuel pump is immediately shut back off.

03-13-2006, 12:46 PM	#5 (permalink)
CpuZapper RallyRacer Join Date: Mar 2005 Location: Portland, OR Posts: 482 Thanks: 7 Thanked 25 Times in 22 Posts My Google Map iTrader Rating: (1/100% )	Along with what 86mister2 said, if you have any major vacuum leaks that can also create the same symptoms. If there is not enough air flow to open the AFM (IE its breathing through a big hole somewhere instead), the fuel pump contact won't open, and the pump will never kick on except in the few seconds of initial priming. My '86 was doing the exact same thing when my fuel pump wouldn't come on - bad AFM in my case.

08-16-2006, 11:46 AM	#6 (permalink)
EHolmes744 No Skills Join Date: Dec 2005 Location: Ft Lauderdale Posts: 5 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	ok before you go through alot of unnessary test check your ignitor.i bought my SC that wasnt running but would start up an run for about 2 seconds.i did all the test on the ecu and everything else. if you have a BGB there is a test that you can do to the ignitor to check the voltage its putting out. mine was way below spec.got a new ignitor an it started right up. if you cant do the tests see if you can borrow one from somebody in your area to try an see if thats the problem. Ernie