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Thread: Cranks fine, won't start, fuel injectors not firing (?)

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    Default Cranks fine, won't start, fuel injectors not firing (?)

    The car is an '87 Supra Turbo auto with minimal mods (3" exhaust and K&N air filter, both done by the p.o.).

    Background:
    Car ran fine til I broke a spark plug off in the head. Decided to take it apart, basically do a HG job on it. Got it apart, cleaned and decked the head and removed the broken plug. Put everything back together (man those vacuum lines and crap are complicated). Now it won't start.
    * At first I wasn't sure about the firing order, I mean which wires go to which coil plugs since my numbers on the three coils are worn off, but I found a picture in Haynes Repair Manual (section 5 page 7) and hooked the wires up like that (left to right: 1-6-3-4-2-5). I assume that is correct!?
    * I also wasn't sure about the instruction on installing the CPS (Cam Position Sensor), following the instructions at the Cygnus X1 MK3 TSRM and using my PDF 1990 TSRM I think I got it right. I tried using a timing light to confirm that the timing was good, but couldn't get a consistent signal from the spark plug wires as if it weren't firing. After checking that it was firing with a screw driver near a ground (it seemed to be firing sometimes but not other times) it still would not start. It would stumble a bit but never get over 300-400rpms and would never stay running/puffing/stumbling for more than 5 secs.

    Current Problem: Won't Start
    * I have checked everything I can think of now and it has a new battery with a full charge and cranks great. Using the screw driver method on spark plug wire #1, it is sparking, all the coils pass the TSRM tests and so does the igniter and CPS. The TSRM didn't say anything about there being voltage to the CPS and of the 4 wires non of them had 12V with the key ON, but the CPS passed the Ohm tests which were the only ones I found in the TSRM.
    Question 1: Is there supposed to be 12 Volts to any of the 4 wires going to the CPS?

    I can't find any grounds that I have forgotten to hook up, but that is a possibility.
    The fuel pump is working, and after loosening one of the banjo bolts and turning the key, fuel sprayed out. I don't know what my fuel pressure is, but I do have some fuel pressure in the rail.
    I rented a noid lite set to test the signal at the injectors and I think this is where my problem is. I checked the voltage at each injector connector first, and at every connector BOTH wires have 12 Volts with the key ON. I thought only one would have 12 Volts and the other would go to the ECU which grounds that wire and causes the injector to fire.
    Question 2: Is there supposed to be power at the injector connectors with the key ON, at one wire or both?

    The noid lites don't light up and I am pretty sure I am using the right one (it was a set of 6 and I am using the one labeled Bosch EFI). From what I understand if the wiring to the injectors is trying to fire the injector, the noid lite would be lighting up (either flashing or constantly lit up). It is not lit up at all, and I have tried 3 different injector connectors (#1, 5, 6).
    Question 3: What can cause everything except the injectors to work? Why would the injectors not fire?

    I have checked all the fuses I can find and they all seem good. Is there maybe a relay that could be out?
    When I first start to crank I hear one, or sometimes two pops like a fire/combustion, but then nothing else, just cranking. Is it possible that this is a tiny bit of fuel from the cold start injector that combusts, but then there is no more fuel?

    Thanks for any help you can give me, I am stumped.

    Additional Q's:
    *Is it possible the ECU got fried? Can I test the injector ground operation at the ECU? E10, E20 and E30 or something like that.
    * Why would there by 12 Volts at BOTH of the injector connector terminals?
    * Where does the ECU get its RPM signal from? The CPS?
    * If it is sparking, does that mean the CPS is working? Is that what tells the ECU to fire the injectors, or does it get that signal from somewhere else?
    * Could this still be a timing issue if the CPS is installed incorrectly (it seems like it would be backfiring or running rough if the timing was just off - I have moved the CPS without removing it to see if changing the timing had any effect and it did not have any effect).

    PS: I also thought about running the diagnostics, but since the battery has been disconnected it does not have any saved faults. When I put the wire in the diag plug and followed the instructions, the check engine light just stayed lit up, it did not flash constantly or with a code or anything. The diag did make the fuel pump come on though.
    1987 Supra Turbo white (stock with 3" exh and K&N)
    1978 Datsun 280Z (first turbo'd, now supercharged, MegaSquirt, etc.)

  2. #2
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    Default Re: Cranks fine, won't start, fuel injectors not firing (?)

    Your CEL should blink constistenly with E1+TE1 are jumped-weird; not sure why it would constantly stay lit- jetjock?

    does your cel come on key on, eng off? terminals not jumped.

    i would double check make sure you got all your grounds, vacum, isc hose hooked up properly. and everything is plugged in.

    i would also make sure your cps is properly install, #1 piston TDC Compression stroke.
    Getting old is mandatory, growing up isn't. --- Boostin Since 10/28/08
    13.4at105MPH/14PSI...The smell of cash is easily forgotten when all you smell is rubber.
    Be careful not to step in the bullshit.

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    Default Re: Cranks fine, won't start, fuel injectors not firing (?)

    have you reset the ecu by removing the efi fuse for like 30 sec? Fuel pump relay? injector resistor?


    What up dumbo!?

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    Default Re: Cranks fine, won't start, fuel injectors not firing (?)

    Quote Originally Posted by shiftysupra View Post
    have you reset the ecu by removing the efi fuse for like 30 sec? Fuel pump relay? injector resistor?


    What up dumbo!?
    hey hey, hows the car runnin

    EDIT: Sorry not really relevant to post; MOD please delete.
    Getting old is mandatory, growing up isn't. --- Boostin Since 10/28/08
    13.4at105MPH/14PSI...The smell of cash is easily forgotten when all you smell is rubber.
    Be careful not to step in the bullshit.

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    Default Re: Cranks fine, won't start, fuel injectors not firing (?)

    fired her up last night drove down the street.. got to the end and got thrown back into the seat and my brother was like "god damn!" haha, then it ended 20 sec later when the intercooler hose popped off as well as i now have a leak in my radiator... haha oh well, but she runs good minus some small kinks.

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    Default Re: Cranks fine, won't start, fuel injectors not firing (?)

    Quote Originally Posted by shiftysupra View Post
    have you reset the ecu by removing the efi fuse for like 30 sec? Fuel pump relay? injector resistor?


    What up dumbo!?
    The ECU gets reset everytime I leave the car because I disconnect the battery.
    My fuel pump is working, so I think the fuel pump relay is fine.
    I don't think the injector resistor is a problem, because I do have power at the injectors. The problem is the injectors aren't firing. But strangely they have 12V at both terminals, is that normal?
    1987 Supra Turbo white (stock with 3" exh and K&N)
    1978 Datsun 280Z (first turbo'd, now supercharged, MegaSquirt, etc.)

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    Default Re: Cranks fine, won't start, fuel injectors not firing (?)

    Quote Originally Posted by dumbo View Post
    Your CEL should blink constistenly with E1+TE1 are jumped-weird; not sure why it would constantly stay lit- jetjock?

    does your cel come on key on, eng off? terminals not jumped.

    i would double check make sure you got all your grounds, vacum, isc hose hooked up properly. and everything is plugged in.

    i would also make sure your cps is properly install, #1 piston TDC Compression stroke.
    Yes, the CEL comes on when I turn on the key, and then it just stays on when I jump the diag terminals.
    I will check those other things, including the CPS, but it seems the problem is with the injectors not firing.
    1987 Supra Turbo white (stock with 3" exh and K&N)
    1978 Datsun 280Z (first turbo'd, now supercharged, MegaSquirt, etc.)

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    Default Re: Cranks fine, won't start, fuel injectors not firing (?)

    you will get 12volts on both sides of the plug, but ONLY if the engine isn't running and the plug IS plugged in and KEY ON. but if its not i dont think you should, if i'm reading the schematic right.

    i'm thinking your constant CEL when terminals jumped is an issue- again i tihnk jetjock has the knowledge if he wants to share.
    Getting old is mandatory, growing up isn't. --- Boostin Since 10/28/08
    13.4at105MPH/14PSI...The smell of cash is easily forgotten when all you smell is rubber.
    Be careful not to step in the bullshit.

  9. #9
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    Default Re: Cranks fine, won't start, fuel injectors not firing (?)

    Quote Originally Posted by dumbo View Post
    you will get 12volts on both sides of the plug, but ONLY if the engine isn't running and the plug IS plugged in and KEY ON. but if its not i dont think you should, if i'm reading the schematic right.

    i'm thinking your constant CEL when terminals jumped is an issue- again i tihnk jetjock has the knowledge if he wants to share.
    OK, good. And do you know if the noid light should flash while I am cranking, or will it stay lit up? I guess it doesn't matter, cuz it's not doing anything, and I know that's not right.
    I will re-try the diag procedure. One question I had about that was: it says to put the tranny in neutral, is that for both auto and manual trannies, or just manual. I have an auto, and I put it in Neutral with the E-brake on for the diag procedure. I did not try it with the shifter in Park. Maybe it doesn't work for autos in Neutral. I will try it again, this time in Park.
    1987 Supra Turbo white (stock with 3" exh and K&N)
    1978 Datsun 280Z (first turbo'd, now supercharged, MegaSquirt, etc.)

  10. #10
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    Default Re: Cranks fine, won't start, fuel injectors not firing (?)

    Quote Originally Posted by Brazle View Post
    OK, good. And do you know if the noid light should flash while I am cranking, or will it stay lit up? I guess it doesn't matter, cuz it's not doing anything, and I know that's not right.
    I will re-try the diag procedure. One question I had about that was: it says to put the tranny in neutral, is that for both auto and manual trannies, or just manual. I have an auto, and I put it in Neutral with the E-brake on for the diag procedure. I did not try it with the shifter in Park. Maybe it doesn't work for autos in Neutral. I will try it again, this time in Park.
    yah I am not sure about that, i would try both; cant hurt. also i would try holding the gas down once you jump them, cause that should throw code 51(i think) for sure. i would also pull your efi fuse for a min to try and reset that damn CEL, i know when you disconect the bat it resets it too but...

    did you disconect your bat first thing when you started pullling your head, dont think i've heard of the cel staying on solid when checking codes.

    EDIT:http://cygnusx1.net/supra/Library/TS...aspx?S=FI&P=59

    thats the schematic i was reading, remember you cant have voltage drops if current isn't flowing, thats why you see 12volts in, 12volts out, ONLY if it was plugged into the injector.

    never used nor learned about those 'noid' lights.
    Getting old is mandatory, growing up isn't. --- Boostin Since 10/28/08
    13.4at105MPH/14PSI...The smell of cash is easily forgotten when all you smell is rubber.
    Be careful not to step in the bullshit.

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