Honda D Series Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
I bought a 1994 hatch with a SOHC VTEC ZC. It has a few bolt ons (i/h/e) but came with a P06 ecu. It ran a little rough when I bought it (and never engaged the VTEC), so I had it chipped and converted to a VTEC P28. Using Crome, I flashed a few base maps (started with a D16z6) and then tried the P29. It runs better, but still rough. Does anybody know what ECU the ZC is supposed to use? I read a few places it was a PM7, then P07...then someone said to run the stock z6 maps...but I think they run in limp mode. (The VTEC wiring is all there and the O2 sensor has been changed to a 4-wire) Can anyone tell me what might work...the engine is stock other than the header/intake/exhaust.
 

·
Registered
Joined
·
6,103 Posts
Do some basicas first. Load up a stock d16z6 fuel and ignition map.

Then get the engien warmed up, until the radiator fans kick on a few times.

Then shut it down, short the service connector in the passenger footwell near the ecu, and do a timing verification with a timing gun.

You will know it is shorted and in "service mode" when the check engine light stays on while idling.

This is wher ethe ecu is among otherthings, keeping ignition flat and un-changing, so you can see where base timing actually is.
Once you find out where base timing is, set it in your ecu tuning software, and go from there.


ALWAYS get the basics done. Without the basics known, you are looking for a needle in a haystack. Its definitely in there, but why sturggle?


Download some tech manuals, and run through a few of the basic diagnostics to figure out if all your sensors are operating properly, make sure ground wires are clean and tight, make sure there is NOT a ground from battery negative to thermostat housing, as it can sometimes cause sensor interference issues (Not me personally, but enough reports to consider sound advice at least).

Finally, look over the engine harness, all the way up to the ecu. Make sure the vtec wiring is proper, make sure the TPS and MAP wiring is good and plugged in to the correct spot (they share exact same plug, so check wire colors).

Finally, be sure the battery is charged up. A crappy battery can cause some finicky behavior when the ecu is trying to learn or make use of new maps in the tune.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
I have set the timing several times, but lately when I try to put the car into service mode, the check engine light doesn't stay on. It comes on for a few seconds and then goes out. Is this a bad ECU?
 

·
Registered
Joined
·
6,103 Posts
What are you using to put it into service mode?

It may be as simple as the pins in the service plug are getting beat up a bit, and losing connection
 

·
Registered
Joined
·
4 Posts
Discussion Starter #5
Im using a paperclip. Ill try again and check the connections...sometimes it does look like its not connecting, but I have the paperclip in it pretty good.

I did find out recently that the timing belt I put on was incorrect...Im sure that has some negative effects as well. (I have a gates t22rb on it now...and it should be the t14)
 

·
Registered
Joined
·
6,103 Posts
Might have to just cut the plug off, strip the wires, and use an actual switch, and have a nice firm on and off solution.

I usually use a paper clip as well. Just might be the plug is a bit tired with age or something.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #7
So I went out this afternoon and tried to use a paperclip to short it and it didn't work. The check engine light never came on, regardless of what I did...so Im going to put a switch on it like you suggested....Im hoping thats what it is.
 

·
Registered
Joined
·
6,103 Posts
Good point above Rob

OP, I think I might have some crome documentation somewhere in my computer backups. Ill see if I can find it. Checksum rings a bell of some sort, though I cannot place it. Rob probably knows if he mentioned it though.
 
1 - 9 of 9 Posts
Top