i have a 91 crx si i recently purchased
the tach is retarded, it reads either 0 or 500 at idle

its not actually that rpm because i hooked up to my smog analyzer and it was idling at 750

could someone tell me whats going on??


and the other thing

check engine like (MIL) comes on only at steady cruise between 1000 and 2000 rpm(at least thats what the tach reads)

no code was stored, tried driving it with another person in the car to see if there is a code when the light comes on, and nothing

led on ecu works, code gets stored when there is a fault (pulling off IAT)

any suggestions????????

if anyone went through this problem please let me know, its driving me crazy

 

What were the codes that were previously stored in the ECU?

 

no codes stored when light came on, pulled off iat and a code was stored, my problem is that the check engine light comes on between 1000-2000 rpm with no codes what so ever

 

some help please

 

Wow strange. Perhaps the wiring to the cluster is faulty or a bad connection somewhere. Can't really help you over the net sorry. Bump for someone that might be able to

 

if i was u i would check all the wireing behind the cluster to see wats goin on u can find the diagram on this web site as well to guide u..

 

For the bad RPM readings, check out your distributor coil and igniter to make sure they're within spec. Sometimes this is a sign of impending distributor failure.

For the CEL, have you tried resetting the ECU and seeing if it does it again?

 

it reads fine, i backprobed the coil wire to a separate tach and it read perfect, i guess there is something wrong with the my stock tach,

my real concern is the check engine light, i wanna know why is it turning on with no code set, and it only happens between 1000-2000 rpm at steady cruise

 

and ive resetted the ecu. pulled both the ecu and hazard fuze, still there, my only other option is to replace ecu??? but if no one ***** with them, they normally wouldnt go out

 

Yeah, my guess is that it's an O2 sensor. Try a different ECU just to be sure. I have also encountered a "ghost" VSS code before.

Try a different ECU and report back.

 

how did u even come to the conclusion that its an oxygen sensor, because i tested it, response time is fast (under 100ms) and it switches properly

but how did you even come to the conclusion that its the oxygen sensor?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by a2nchinaman &raquo;</TD></TR><TR><TD CLASS="quote">how did u even come to the conclusion that its an oxygen sensor, because i tested it, response time is fast (under 100ms) and it switches properly

but how did you even come to the conclusion that its the oxygen sensor?</TD></TR></TABLE>

Just a common occurrence in my experience from what you're describing. But if you've tested it and its OK, nevermind.

Have you tried a different ECU yet?

 

nope thats what im trying not to do, because i dont want to go out, buy a part, turn out its not the problem, and be stuck with that part

basically what im trying not to do is replace a part thats not broken, what did u do with you codeless MIL???

 

When my VSS was unplugged, it would code at low RPMs, and only after running to higher RPMs first. But it did store a code, so it may not be directly comparable to your case.

I guess that's another vote for "check the instrument cluster wiring"...

--DD

 

replaced cluster with one i had, worked fine, still the check engine light comes on with NO CODE