ok, there are many many bugs with my DOHC ZC swap. I figured most of them out, but this other problem recently came about. when I first started driving it, it had CEL code 4 and 8. I was taking it to work once and It backfired real bad and wouldn't start for like 15 minutes. I thought it was my timing, so I retimed it. now the timing is dead on. I reset the ECU and there was no codes for a few days. It still drove a little rough at low RPM's. It to it to this guy I know and he plugged up a open vacuum line that was from my charcoal canister. I drove It and it was amazing how well it worked. so I came home I let it sit over night.

Now the new problem, I went to start it up in the morning to take it to school and it took a few more cranks than usual to start up. Then the car was idling a like 100 RPM's literally I drove it out and man that thing was ***** slow, I couldn't keep up with traffic. and I couldn't rev past 3k. Im getting code 4 so far but thats it. It sounds like I have a 2step rev limiter at 3k. Help me out here guys. My Auto teacher says its probably the fuel filter. personally I think he full of ****.

The motor is an obd0 DOHC ZC running a PM6 ECU. I also did the mpfi swap. also I heard obd0 cars don't go into limp mode?

 

You need to fix all the codes or when your ecu cant detect a vital sensor it will throw a check engine light, retarding the timing and dumping excess fuel...this is known as "limp mode"...to make it go away, find out what code its throwing and fix it. Check your ECU. You said you had a code 4 and 8, Do you know what those are on the ZC?

Limp mode means ECU cann't read input from a serious sensor or multipe codes like you case with code 4 and 8. Limp mode will be fixed when other problems are fixed!

Is the ecu chipped or stock??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by alscrx &raquo;</TD></TR><TR><TD CLASS="quote">You need to fix all the codes or when your ecu cant detect a vital sensor it will throw a check engine light, retarding the timing and dumping excess fuel...this is known as "limp mode"...to make it go away, find out what code its throwing and fix it. Check your ECU. You said you had a code 4 and 8, Do you know what those are on the ZC?</TD></TR></TABLE>

4 Is crank angle and 8 is TDC sensor. I dont know where the Crank Angle sensor is but I know the TDC sensor is bult in the dizzy. Im not 100% sure how the fix these problems, I though it was timing

 

Crank angle sensor is in the dizzy, Check your dizzy plugs or wiring since you did the Dual point to Multi point. Bet you the wiring is wrong. If You double check it and its wired correct, replace your dizzy. Easy fix. Both codes having to do with dizzy. you not reving up past 3k is from limp mode. OBD0 does throw limp mode man

 

Well I think I fixed the problem. I dunno for how long though haha. well One of the connections I soldered was loose or broken, so I put a crimp on it reconnected the ECU and It seems to run fine now. Hopefully it doesnt come back like it usually does. *crosses fingers*

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by low91rex &raquo;</TD></TR><TR><TD CLASS="quote">Well I think I fixed the problem. I dunno for how long though haha. well One of the connections I soldered was loose or broken, so I put a crimp on it reconnected the ECU and It seems to run fine now. Hopefully it doesnt come back like it usually does. *crosses fingers*</TD></TR></TABLE>


Well I guess I spoke too soon because I was driving to work and bam the CEL pops on and now Im getting code 8, TDC sensor again. There are no other symptoms it backfires real bad but it always does that.

This car is really starting to bug me
Any suggestions?

 

Maybe take it to a real mechanic or some place that deals with mostly imports. Are you sure your plugs are in the right place? I mean, some places if they cant find out whats wrong and fix it then they wont charge you even if there was labor involved. Anyway, thats just what I would do.

 

who the expletive told u OBD 0 cars cannot go into limp mode who ever misguided u should get shot in the face for this misinformation , also what dizzy r u using? you know to make it run @ peak u need a Si dizzy right?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jdm_titan &raquo;</TD></TR><TR><TD CLASS="quote">who the expletive told u OBD 0 cars cannot go into limp mode who ever misguided u should get shot in the face for this misinformation , also what dizzy r u using? you know to make it run @ peak u need a Si dizzy right?</TD></TR></TABLE>

All the searching I did there was a few threads that said it didn't. Its was cutting fuel at 3k. I fixed that by reconnecting the Crank Angle Sensor.

Im using The original DOHC ZC dist. The damn TDC code is killing me!!!


Also when I accelerate at lower RPM's it will speed up in like steps or increments, it not smooth. Up top its okay I guess. I know its faster than the D15 DX motor, even if it aint runnin right.

 

no one else?

 

Code 4 - Crank Angle Sensor.

On the DOHC ZC, it's on the exhaust cam inside that special sensor. If you are using the DOHC ZC dizzy (only one that bolts up) then you must also wire that sensor in.

 

omg, when will people STOP calling the cps (cylinder position sensor) the crank sensor????? if the cps on the end of the exhaust cam is bad, you'll get a code 9...code 4 is CRANK POSITION SENSOR which is located in the DISTRIBUTOR which has been said in this thread alone like 5 times...jesus....just go find a known good si dizzy and slap that on there and see if it fixes your problem...but more than likely you've got wiring issues...i just did my dohc zc swap and i had the same code 4 problem, i put on a new dizzy and bam....no more codes, no cel, no nada...she runs GREAT! also ludesrv, a dohc zc dizzy IS NOT the ONLY one that bolts up...an Si will work just fine with a little convincing

 

Sorry, some of us don't rig our cars. And also the 88-89 Teg dizzy fits fine.

 

rig? i didnt rig my car...i am currently running an 88-89 teg dizzy myself, but in all actuality the si dizzy will work, you just have to make it bolt up...i wouldnt call that rigging, i'd call that doing what needs to be done..but thats just me

 

Well I fixed the code 4 problem because a connection came undone so thats what happened.

Now its the code 8 that keeps popping up after a while. The symptoms are backfiring (Might be an exhaust leak..) and stumbling upon acceleration. say if I take off in first and start to accelerate and hold it at about half throttle, then give it more gas i like cuts off misses a little bit and then gets back up at higher RPM's. I checked all my vacuum lines and theres no leaks, timing is DEAD on. so i dunno, I do have an exhaust leak where the manifold meets the downpipe.

 

Have you checked inside the dizzy? There could be "crap" inside screwing with the sensors. It happened to me.