ok so,most of you might remember the problems ive been having lately with my 85 z28,code 32s on cold mornings,no biggy,i know the cause,and am going to fix,codes 33 and 34 which pop up every once inawhile are leaving me kinda stumped.

anyways last saturday a bunch of guys went to the track since it was the last open day ,i ran some wierd *** times..

with the engine at about 200 degrees,and the SES light on,i ran 15.6@87

with the ses light off,and no codes present,it ran 17.7@74

with ses light on again and temp of about 190,it ran 15.6@90

with ses light on,it smokes like a ***** pure black,looked like a deisel

with ses light off,it runs hella rich at idle,but goes lean once your at WOT,cuts out,misses,pings,all sorts of lovely ****.


so ive pretty much come to this conclusion,unless some one shoots a CHEAP way to get this fixed,or at least attempted to fix,i dont want to start throwing money at the damn thing for no reason,anyways my plan is,to convert to the 730 speed density.

heres the thinking,get a 730 ecm off ebay,and get a painless harness,one i dont really want to rely on a used crappy old harness,there old and **** happens yunno...

or do yo uguys think i should just find a used harness and al that stuff on ebay?


or what would you do?


btw,the car is running no where NEAR its potential! id like to be running full tiem ALL the time,IM tmpeted to make my SES light say VTEC

 

I would say if you want to convert to speed density, then by all means do so. However, I would work on troubleshooting what you have first, fix those problems and then convert. Otherwise, you could just be digging an even deeper hole.

 

Do you have the "one of a kind" MAF in your '85? or the later, more common setup? I think it changed towards the end of the '85 run.


I'd only convert to SD if I had the earlier style 'one of a kind" since the MAF is so expensive, but if the latter style, then I'd fix what illed me...i/e most likely you can solve it (assuming no harness connection issues...which could be trouleshot with schematic and DMM) by replacing the relays and MAF...

But my gut tells me your problem is MAF, not relays...reason being is this...

Engine runs better with SES on...would indicate ECM senses MAF problem and runs to default MAF setting...

Engine runs worse with SES off...would indicate ECM is seeing parameters that are in it's usable range, but the info it'sgetting is whacked (from MAF) to operate correctly for given engine speed/load.

Another thing to note, even if you have an early styyle MAF...I think "JIM85 IROC" has used the Wells SU145 in place of his early '85, without issues. Cost of the SU145 is about $165.00, do a search and you'll find a few places posted here that you can order online.

Anyway, just my thoughts.

 

I was under the impression that the MAF itself was the same, but the ECM carries a much slower refresh rate which is not as good for monitoring values.

Good luck finding your problems,
Matt

 

MarkB:
(heres the thinking,get a 730 ecm off ebay,and get a painless harness,one i dont really want to rely on a used crappy old harness,there old and **** happens yunno...)


CaptPicardsZ28:
If you get the painless harness then I suggest you get the longer of the two for your year. I have an 85 as well and converted to SD and got the regular length harness. It wouldnt reach across the throttle body to connect the injectors on the drivers side. I re-ordered the one that is 4 feet longer. I routed it thru the same place the factory harness came out of because I couldnt find a spot in the firewall to drill a hole thru that I was comfortable with. Thats why it wouldnt reach. I bought mine from Summit. I got the ECM from Ebay. You will have to swap your ECM chip into the 730 ECM and.