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-   -   First drive issues after rebuild T2 '88 (https://www.rx7club.com/new-member-rx-7-technical-256/first-drive-issues-after-rebuild-t2-88-a-1100525/)

kutteke 05-18-16 10:52 AM

First drive issues after rebuild T2 '88
 
Hello,

I've been rebuilding my car for the past 1,5 years and I thought I was finally ready.
I had the car on jack stands and i was able to start it and let it warm up for a few times while i was checking and fixing leaks. After this i took it of its jack stands and was ready to set the timing using the timing light,but it won't run anymore ... i'm not getting a spark it seems. (checked with a spark plug taken out on leading side and not seeing spark when I crank it)

I have checked and cleaned all the connections and grounds i can access, checked the ecu connection in the foot well and all seems ok.
All the fuses are ok too. (engine fuse inside car on passenger side and fuses under hood)
tried the unflood trick but that doesn't seem to be the issue as the spark plugs seem dry when i take em out. Fuel pump is confirmed working. (not sure if injectors are doing anything, but they should be fine since it ran for a few times before.

Could it be the CAS that's set wrong? the set idle screw that's not right? I don't know i'm out of ideas and out of my league at this point. Was really glad i got so far as to start it and make it run again but i'm desperate at this point.

Engine is rebuild using goopy apex seals for the rest it's bone stock.
Anyone have an idea where to check or what I can do to diagnose the problem?
Problem is time, in 2 weeks I'm moving and I need to get it running to drive her to my new place.

Any help will be greatly appreciated.

If any pics are needed or things need to be checked let me know i will get back at you asap.

Thanks in advance guys/gals.

satch 05-18-16 12:57 PM

Each of the coils has a Black/Yellow wire (trailing has 2 of them) and w/key to on they should have 12 volts. Does it

kutteke 05-18-16 01:15 PM


Originally Posted by satch (Post 12065017)
Each of the coils has a Black/Yellow wire (trailing has 2 of them) and w/key to on they should have 12 volts. Does it

the connector going to the coil (black and green wire) does give 12v but i can't find a black-yellow wire on the leading side, on the trailing side yellow-black wire does give 12 but i can only find one.

satch 05-18-16 02:02 PM

Perhaps the colors are different but the lead coil would have but two wires and one would have 12 volts w/key to on. The trailing coil should have two plugs. One has but two wires and both should be the same color. On a USDM vehicle the color would be B/Y.

With respect to the lead coil the second wire is usually coded Green/Yellow. This wire is the trigger wire from the ECU. W/the main pulley spun by hand and w/key to on the voltage changes from 5 volts to 0 volts (pulley can be spun by turning the alternator pulley).

Also, the easiest way to check spark is by pulling the plug wire from the coil bore and resting the plug wire against the coil bore and w/key to start there should be evidence of spark(s).

And you can check if there is a short in the system by checking the Brown/White wire at the boost sensor w/key to on as it should read 5 volts. If it does not then that would prevent there from being spark etc and the car will not start.

And your plugs might be wet or damaged thus creating a no spark situation.

kutteke 05-18-16 02:24 PM


Originally Posted by satch (Post 12065042)
Perhaps the colors are different but the lead coil would have but two wires and one would have 12 volts w/key to on. The trailing coil should have two plugs. One has but two wires and both should be the same color. On a USDM vehicle the color would be B/Y.

With respect to the lead coil the second wire is usually coded Green/Yellow. This wire is the trigger wire from the ECU. W/the main pulley spun by hand and w/key to on the voltage changes from 5 volts to 0 volts (pulley can be spun by turning the alternator pulley).

Also, the easiest way to check spark is by pulling the plug wire from the coil bore and resting the plug wire against the coil bore and w/key to start there should be evidence of spark(s).

And you can check if there is a short in the system by checking the Brown/White wire at the boost sensor w/key to on as it should read 5 volts. If it does not then that would prevent there from being spark etc and the car will not start.

And your plugs might be wet or damaged thus creating a no spark situation.

Ok great i'm going to check all this. i'm also going to get new plugs (altough these are new since rebuild) just to be sure. I have tried the atf trick because i thought it had low compression, it didn't start but it couldn't have been good for the plugs.

My buddy has an imported usdm fc from 87, i'll ask if he can come over to compare the colors so i'm measuring correctly.

Gotta go to sleep now. Thanks already!

kutteke 05-19-16 01:28 PM

Ok so here are the results:

current battery voltage: Imgur: The most awesome images on the Internet (i know on the low side right now)
brown white wire at boost sensor with key on: Imgur: The most awesome images on the Internet
the 2 wires at the connector going to lead coil: Imgur: The most awesome images on the Internet
tested the green-yellow wire with + side of multimeter and - side at ground and only getting 0.06v
this doesnt change when i turn the main pully.

going to check resistance on the coils themselves too now.

any idea where to start looking or does this just mean my wiring loom is fubar?
Everything else is acting normal (dummy lights and i hear the fuse clicking when i turn the key to on)

satch 05-19-16 02:26 PM

So you took the voltage of the Brown/White wire at the boost sensor w/key to on and it registered only .19 volts? (should read 5 volts) Just enlighten me and tell me what the other wire colors are at the boost sensor. There should be 3 other wires and they are colored; Brown/Red, Black/White and a Black wire (the Black wire is the ground wire but on some models it is Brown/Black). Some people who have a Brown/Black wire for a ground often confuse it w/the Brown/White wire and am making sure you are not making this very mistake.

kutteke 05-19-16 03:14 PM

yes that is correct, if i measure the ground on the black cable i get 0.14 if i measure on the body i get 0.20

satch 05-19-16 03:20 PM

Unplug the AFM and recheck the voltage on the Brown/White wire at the boost sensor to see if the voltage indicates the proper 5 volts. W/the reading of .19 volts the car cannot possibly start.

kutteke 05-19-16 03:25 PM

OK so the MAF sensor wire was loose, i'm getting 5v now. checking the coil voltage now (battery is too low to get it going

kutteke 05-19-16 03:29 PM

The yellow green wire at the coil still gives me 0.05v though but i'm happy at least one reading is making sense now :).

kutteke 05-19-16 03:43 PM

Ok just got it running! forgot to plugin the CAS after checking it earlier today. stupid me... but together with the MAF sensor wire it fixed the issue it seems :). I owe you a burger. do you have paypal?

satch 05-19-16 03:48 PM

Needn't worry about a burger for that's what this forum is for (lucky you!).

kutteke 05-19-16 03:55 PM


Originally Posted by satch (Post 12065562)
Needn't worry about a burger for that's what this forum is for (lucky you!).

In any case i'm very thankfull for the help :). Going to bed again. got a day off tomorrow going to drive it from day till night! (stupid break in period though)

kutteke 05-21-16 06:29 PM

ok it seems i'm not out of the woods just yet... i'm wondering how to boost the idle speed a little so it doesn't die everytime i let my foot of the throttle.

Also i'm having an issue with my brakes. Everytime i pump the brakes the pedal becomes stiff with an acceptable amount of pedal travel. but if i let it be for about 5 seconds and press again my foot goes 3/4th of the way before it brakes slightly. It's making it very hard to be safe when always blipping the throttle.

I've bled the brakes starting from the furthest point of the brake cilinder and working my way to it. Both bottom and top bleeding nipples on the backside brakes. Both nipples on the abs as last point. no bubbles to be found. I'm wondering since the brake fluid was completely drained if i have to bleed the brake cilinder as well (somehow?). Vacuum line to intake is connected and isn't leaking as far as i can see. But i don't think the vacuum is leaking since the pedal is lighter than its supposed to, not heavier. or am i looking at this wrong?

Any tips are welcome :)

satch 05-21-16 07:32 PM

The BAC has an adjustment screw on turbos. Does it die just at very low speeds such as at a full stop. Does it die w/the clutch pedal depressed or not?

kutteke 05-21-16 10:26 PM

ok so I tried adjusting that screw but it doesn't seem to affect anything.
The engine dies the moment i don't touch the throttle, it doesnt die when driving in gear. it tries hard to stay running under 1000rpm but it just barely dies. it hasn't been run more than 5 miles yet. this is without pressing the clutch. if i press the clutch there is no difference.

satch 05-21-16 10:40 PM


Originally Posted by kutteke (Post 12066384)
ok so I tried adjusting that screw but it doesn't seem to affect anything.
The engine dies the moment i don't touch the throttle, it doesnt die when driving in gear. it tries hard to stay running under 1000rpm but it just barely dies. it hasn't been run more than 5 miles yet. this is without pressing the clutch. if i press the clutch there is no difference.

There's a check connector near the lead coil which has two wires (Black wire and an Orange wire). These wires need to be jumpered together first before adjusting the BAC.

kutteke 05-28-16 07:46 AM

sorry for the late post. I've been busy lately :)
I've jumpered said wires but adjusting the bac screw doesn't really affect anything it seems. the bac connector does look a little past its prime, could that be the issue?

satch 05-28-16 10:48 AM

you cold play w/the throttle stop screw to help increase the idle a bit. Look in the FSM for its location or use the advanced search function (I know there's pics in the thread created by njgreenbud).


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