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i have a 93 with a 1.8L swap it has been running fine for over six months. last night i started to wire in a apexi neo and managed to install it wrong but the car ran....anyways i took the apexi neo out and returned the wires back to the correct spots and tried to crank the car and it would try to start then sputter and die. i gave up on the car for the night and started working on it this morning trying to find the problem. first i swapped out the MAF with another one to see if that could be the issue and it still would not run. next i pulled the plugs to see if i was getting spark and cyl 1,4 did not have spark but 2,3 did have spark. so my guess is that i messed up the CAS or the ecu...can anyone give me your thoughs on what could be the problem?
 

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once my engine(96) wasn't firing cyl 1/4 but was firing 2/3 like yours. signals all looked good out of the cas, so I figured the computer was kaput. changed it but no luck.
turned out, the problem was with the CAS -one of the metal arms that triggers one of the hall sensor had become dislodged somehow. -this caused the timing between the 2 cas signals to be wrong and the computer could not deal with it. -just pushed the arm back and all was well. (attached are the waveforms I was seeing)

imo
first switch coil connectors to make sure it is not the coil
then double check where you tapped in for the ign for the apexi neo to make sure everything is correctly hooked up .

not sure what tools you have, but next I would put a meter or scope on the 2 signal lines coming from the CAS. with motor cranking they should measure about 3-4.5v
With the ignition on, but engine not running, these signals will normally be either about .5v or very close to 5v

its strange that the error codes do not seem to correlate to your problem. this may point to an ecu problem.

do you have any spare parts to swap in?
 

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Kicked off the island..
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Had a spare ecu. Tried it, no luck. Pulled the CAS out and cleaned it. No luck. Didn't know what to look for such as damage to the arm like you mentioned. Just wondering, how could these get damaged? Will try switching the plugs on the coil and see what that does. But your description sounds very accurate. Thanks.
 

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hmm just remembered, I was assuming you have 94+coils

if you are using the original 93 coils, there is 1 connector for both coils. -its a little more difficult to test them

please advise.
 

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im having almost the same problem with my 1.6 all of a sudden my car just wont start. it just turns but doesnt fire up. so i check to see if i was getting any sparks, and i found out i was only getting sparks on cylinders 1 and 4... so i went and got another coilpack, put it on and the same thing happened. so i tried using the 2 functioning coils from each coilpack and put it together and i still got the same results.

to elimininate the sparkplug wires as the problem i tested all of them on coilpack no 1 and 4. and then on 2 and 3. they all only had fire in 1 and 4...

im pretty sure that the wiring harness is intact coz i drove the car the night before the day it wont start... i know im just missing something...

what do you mean by"metal arms that triggers one of the hall sensor had become dislodged somehow" coz i cant seem to find it?

any suggestions?

thanks!
 

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i checked my trouble codes its 02 and 03. do you guys know how to test the cas and pcm? thanks!
 

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ryster- the CAS is internally different on the pre-94 cars, employing LED's and phototransistors with a wheel with cutouts. 94-97 engines used the hall sensor type CAS.

according to my manual codes 2 and 3 are for the cas.

by popping off the top of the ecu, you can measure voltages from the cas and measure signals going to the ignitor/coils. (see doc enclosed for 91 ecu)
cas = 2E&2G ign=1G&1H

the 2 signals from the cas should not measure 0v or 5v when cranking. probably s.b. about 2-4v.
the 2 signals to the ignitors should not measure 0v. probably s.b. about 1v

good luck.

 

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oreo- thanks man! will do this tom. oh and i have a cas from a 94 and a 93. so you mean to say since the 94 up and 93 down cas are different... the 94 cas wont work on my 91 right?...
 

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to say since the 94 up and 93 down cas are different... the 94 cas wont work on my 91 right?...
I think it should work just fine unless there is something different in the camshaft attachment hardware but I doubt it. The NA6 and NA8 CAS generate the exact same signal. I am not sure about the electric connectors though. Check if the plugs are interchangeable
 

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sorry, I meant that the CAS was internally different. as such, yours could not have the same internal problem as mine had.

they hook up with the same connector, and are compatible with each other.

 
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