can't figure out what is causeing this check engine light. please help.

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91EFHATCH

New Member
ok, first off i have a 1991 honda civic hatchback and we put a b18a1 block with a b17 vtec head in it. the ecu that came with the engine was already converted to a vtec ecu. but i now have hondata s100 on this ecu. my problem is that i will be driveing down the road and i will get up to about 50 mph and then slow back down and my check engine light comes on and throws a vss code. so i had jim at motorvations in trussvile to take a look at it when i got him to put hondata on it. he did some tests and thought it was the haylo in the guage cluster. my factory tach doesn't work but my speedometer and everything else does. it doesn't effect vtec from kicking in either. so i found another guage cluster and swithched it out. still same problem and the stock tach still doesn't work in this one either. and also jim noticed that there was a circuit that was suposed to have like 5 volts or amps going to the ecu and it was registering 11.5 or something like that. and we couldn't figure out why. does anyone know why this is and how to fix it? we have been working on this for a while now and it has stumped us. any help would be greatly appreciated. thanks.
 
2 posts only, and about the same thing. There's no help from seniors and search function for this is ass... what to do??

I can give you wiring diagrams for the USDM EF and maybe a flowchart for the code if you give me the code#

But my first instinct is to tell you to get the Tach to work. Again I have access to diagrams. PM me 'cause I'll forget this post.

The VSS is a pulse sensor off the cluster which works from your speedo cable. I know you have the cable since your speedo works....
I'm guessing the VSS is a square wave which will average voltage (5V) between BATT and zero. I suppose it could give BATT volts while not moving (and check your 11.5 batt).

I don't have access to the flow chart or all the diagams right now, but both the speed pulse and tach reference the ECU.

Make your tach work first. It's possible the VSS needs a tach signal at the ECU.

-3 sheets to the wind
scott
 
scott how would i go about getting the tach to work? i swaped the guage cluster with another one i got out of another car and it still doesn't work. so i don't know where to go from there. and if you could get me those wireing diagrams and charts you were talking about that would be great. i'm sure they can help some. but we are totally stumped. the guy that installed hondata on this car and tuned it is stumped too. do you think that there is something wrong with my ecu? could that be causeing the problem?
 
why would your guage cluster have anything to do with your vtec? Who did your wiring?

Because on an EF, the speedometer on the gauge cluster is cable driven directly from the transmission. The cluster then sends the speed signal to the ECU. Do your reasearch before you open your mouth, you fucking retard.

Anyways, to the OP, when you swapped out clusters, since the tach still didn't work I would guess that it's something in your wiring. Get a multimeter and start doing pin tests from the connectors on the cluster to your ECU.

It's also possible something is corrupt/malfunctioning in the ECU or the Hondata. You might try swapping that out with a known good unit as well.
 
the guy that put in the hondata did some pin tests. he also said that we would try swaping out the ecu with another one and put my hondata in it and see if that works. but if it was in my wireing would i just have to follow each wire or something? and what makes the tach work? what would cause that to not work?
 
its some wire off the distributor I do not remember which one off hand. If you have a manual, you should be able to trace it out easily.
 
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