high idle and dies after 95 m42 into e30 swap

[n2motorsports]

Quick background - car is a 91 m42.  It blew a headgasket and a 95 m42 was swapped over.  Only block was used, we retained all the accessories from e30's m42 (maf, TB, belts, harness, etc). The only thing that was added to the swap was a new clutch and mustang injectors.
Now car idles around 2k, check engine light doesn't turn on (during startup as well), stumbles and dies.  Can it be that the old Maf is trying to relearn these new injectors?  I should add that the car sat for almost a year (bad fuel?) .  

We checked all vacuum lines, cas, icv, plugs, fuel lines crossing, maf ... with zero luck.  Any ideas?  Can't do WOT because the check engine light doesn't work.  Do I have to use the e36 accessories?  
Thanks for any help.

[n2motorsports]

still stumped.  swaped back to old injectors and the car idles for a bit longer til it eventually dies if foot is off the gas.

pulled the injectors and they were wet with fuel and black.  after swapping out the mustang injectors and going back to stock, our new injectors aren't wet but blackish.  maybe the COP conversion?  should i go back to stock setup?

were we suppose to use the ecu from the e36 or any other part?

[DesktopDave]

Have you swapped any of the sensors off the old block?  Did you use the e30 TPS or the e36 one?  My first guess is that the TPS isn't working - stomp test isn't working, you're not getting a CEL and the car won't run unless you have a foot on the pedal.  IIRC the early unit is closed at idle & WOT...the later one is a variable-resistance unit.

The later M42 should be a drop in replacement...there were no significant changes to the later M42, just small improvements like knock sensors, the DISA manifold, a serpentine belt setup, the timing case and EWS.

[n2motorsports]

we swapped all sensors over.  pulled the tps, cas, ivc, from a junker and no difference.

ill probably swap back the coils from the COP to stock, at this point im just gonna throw parts at it til it works

[DesktopDave]

Yeah, that's what I was worried about.  I kinda figured you'd done that but it never hurts to ask.  I'd get the old multimeter out instead of tossing parts at it.  It's more frustrating to do it that way but it might be something simple.

BTW, did you check the static timing on the motor?  Old motors have a bad habit of eating the timing rails & jumping a tooth or two on the cams.  That'd cause a high idle in some cases.

[n2motorsports]

BTW, did you check the static timing on the motor?  Old motors have a bad habit of eating the timing rails & jumping a tooth or two on the cams.  That'd cause a high idle in some cases.

How do we do that?

Did a comp test 160 across the board.  Sounds like timing or possible ecu?

[91 e30m42]

so any year M42 would be drop in replacement in the e30 because before i was gonna get my MM motor i wanted a 94-95 M42 and my mechanic said it couldnt be done because we our e30's dont support the knock sensors???

[n2motorsports]

so any year M42 would be drop in replacement in the e30 because before i was gonna get my MM motor i wanted a 94-95 M42 and my mechanic said it couldnt be done because we our e30's dont support the knock sensors???

ran the VIN on my engine block.  1995.  just use the block, and swap everything else over including the valve cover.

finally the weather cooperated and I'm back at it (80 degress :cool:)

after reading a few threads, sounded like a major vacuum leak.  so I pulled the the tb and upper intake.  nothing was out of place but like an act of God, i dropped a nut into the lower intake runners so I had to fish that out.  good thing i did because guess what?  see below:



darn dowels...turns out when we swapped over the old intake to the new block, there was a set of dowels that stayed on the engine side and another set on the intake side.  so the dowels smashed against one another to create a huge vacuum leak.  

then I believe with all the bucking of the engine this happened:



can, i just unbolt the 2 bolts and replace that top rail guide?  now im worried that other plastic rails may be damaged...oh why do we love these troublesome engines!!!

[d.hitchcock]

The upper rail can be removed without any additional disassembly.

d.hitchcock

[n2motorsports]

The upper rail can be removed without any additional disassembly.

d.hitchcock

Thank you.