civicex_88005

I installed a B16a Sir II into my 94 civic ex. About 3 weeks ago the tach started jumping but no performance change. I would iratically jump when accelerating but woulnt jump under no acceleration or at WOT. This was going on for about a week. Then the ECU started reading what the tach showed itstead what it was at in reality and i could feel little jumps. So when i would be at lets say 2500 and the tach was showing 6200, the ecu started thinking it was really at 6200 and changing the air/fuel ration for 6200 rmp (i think). That went on for a couple of days (i wasnt driving to much) and then one day it wouldnt start. I bought a new ignitor and coil and installed it but it still wouldnt start. I checked for spark and I would get a initial spark (when you turned the key) but none after when cranking the motor to start.

So I got another distributor (b18c1). I put the new ignitor and coil in that distributor and it started working again (saturday). Now it is tuesday and the tach started jumping again and the ecu is thinking it is the rpm that the tach shows. I can feel little jumps befcause the ecu is being tricked.

I dont know where to go from here. I have followed everyones advice so far. Does any one have any more suggestions? Is there some relation between the throttle and the distributor that could be getting voltage spike when I press the gas to accelerate? Or should I just take it into a car electronics shop?

I appreciate all of the prior help and for future help.

Leon

Bull_head360

i would have to say your ecu is fucked up. either borrow a tach and run it directly off your distributor (its the solid blue wire on the 2 wire plug next to your dizzy) and see if it does the same thing, or swap out your ecu with another from a friend and see if it still happens. let us know

civicex_88005

I dont think buying an after market Tach will fix the problem becuase the ECU is reading the false RPM from the distributor.

I would love to swap ecus with someone to try that but I dont know anyone here that has a B16a SIR II in their civic.

Thanks for suggestions

Bull_head360

k, well i've never heard of the ecu using the RPMs to distinguish how much fuel and air is going into the motor. thats why i think your whole ecu is fucked up.

civicex_88005

Im pretty sure the ECU use that and alot of things to distingush the air fuel ratio. Also I know the ecu uses the distributors RPM to tell when to engage vtec and I can feel vtec kick in when the tach jumps past 5800rpm even though I really at lik 2500rpm.

Bull_head360

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civicex_88005 &raquo;</TD></TR><TR><TD CLASS="quote">Also I know the ecu uses the distributors RPM to tell when to engage vtec and I can feel vtec kick in when the tach jumps past 5800rpm even though I really at lik 2500rpm.</TD></TR></TABLE>

The ECU tells the motor to engage vtec, the dizzy just sends the signals. When the ECU identifies that the signal is above vtec engagement, the ecu sends a signal to the vtec solenoid which engages vtec. Another reason why I think your ecu is fucked up...if you already replaced all the **** in the dizzy, then there's no reason why the sensors or anything else in there would be ******* up and telling the ecu wrong things...you did replace the sensors, correct? otherwise it could be the sensors inside, or your wiring might be fucked up to begin with...if you put a tach straight off the dizzy, you would know whether or not its the sensor. if you swap in another ecu, you would know if its the wiring or if its your ecu. hope this helps

civic_eg-o

I had this problem before, except for the no start condition, it might have been a coincidence but the problem went away when I changed my spark plug wires. try swapping wires with someone that has a B16a.

civicex_88005

Exactly what sensors are you talking about?

I replaced the ignitor, and coil (no go). Then I bought another complete distributor . The car ran but I thought it would be a good idea to put the new ignitor and coil from the 1st distributorin the second distributor(good to go for 4 days).

I really appreciate your help on this.

LEon

Bull_head360

if you replaced your whole distributor, then there isn't anything to worry about there. check that your plug wires are secure, cuz my MR2 did this once as my #1 wire came off (its worth a shot but i doubt thats it) but definatly try to get ur hands on another ecu to test it