I give up...M50 swap rus like ass!

[e30s50dan]

ok..completed a NV M50 swap recently and having hesitation issues..

The car misses and backfires. when the car is cold,it starts and runs fine till its WOT then it misses..when its warmed up,it misses at low rpm's and high rpm's and of course WOT.

I first suspected bad gas, as the car has been sitting for over a year before the swap,so I completely drained the tank.I also installed a new fuel filter TWICE! still runs like ass!,but better

NO codes are found 1444..so i still thought i may have a fuel pressure issue,but it checks out fine.. 46psi @ idle and 53-56 @ all rpms and WOT.

If I am easy on the gas up to almost redline,it feels great,but if Im crusing and punch the gas it hesitates and misses till i back off.

I installed new plugs,2 fuel filters
I suspect MAF, Coil's,dirty injectors,but no codes and never once have i seen the CEL

...any thoughts R3V en's :???:

[lifeiskaos]

Check your plugs and coils and coil boots. If there is oil down there, replace your valve cover gasket and the two spark plug gaskets. If some coil boots are broken/falling apart/incorrect resistance, replace them. Either situation could cause the spark to jump elsewhere (ie valve cover) and cause a misfire

Probably wrong, but it's just an idea... It happened to my buddy

[e30s50dan]

no oil..new gaskets,and I did check the boots.didnt see any cracks.plugs have a nice color also,maybe a smitchet lean

[richardb]

My guess would be the maf, do you have a buddy close by you can swap maf's with for a few min to see if it runs better? Don't give up yet!

[e30s50dan]

My guess would be the maf, do you have a buddy close by you can swap maf's with for a few min to see if it runs better? Don't give up yet!

I will have a maf Saturday
thanks I won't give up

[nrubenstein]

Vacuum leak? Get out the carb cleaner.

[MIKe30]

these swaps will drive you crazy. I know mine is.

[e30s50dan]

Vacuum leak? Get out the carb cleaner.

I coudn't find one.it starts and idles fine.nice and smooth.new intake gaskets,hoses,etc

[slo325i]

maybe the coolant temp sensor to the ecu?

[White325is]

unplug the maf and try and drive it. see what happens. If it fixes it then its your maf. you can drive it like that for a little bit untill the ECU learns the maf isnt there then you will have to plug it back in.

[HellzMindPlaya]

have you messed with your maf at all? When I was just helping a buddyget his swap together we somehow got the maf in the wrong direction (the arrow is supposed to point towards the intake) the car started ok, but ran like shit off idle. I tried swapping ecus, and then was going to swap mafs, and that iss when I noticed it was backwards. Car ran loads better with the maf in the correct direction! Just something to check.

[e30s50dan]

maybe the coolant temp sensor to the ecu?

will try this evening..I thought about that today,since it run pretty good COLD

[e30s50dan]

unplug the maf and try and drive it. see what happens. If it fixes it then its your maf. you can drive it like that for a little bit untill the ECU learns the maf isnt there then you will have to plug it back in.

I tryed unpluging MAF and it ran like shit! runs alott better plugged in

[White325is]

Then it sounds like you have other issues and the problem isnt the MAF..
maybe Vac leak? While the car is running spray a starting fluid over the intake where it would seal against the head, around all vac lines, etc..
If it revs up then you know you got a leak and it needs fixed.

[e30s50dan]

Then it sounds like you have other issues and the problem isnt the MAF..
maybe Vac leak? While the car is running spray a starting fluid over the intake where it would seal against the head, around all vac lines, etc..
If it revs up then you know you got a leak and it needs fixed.

cant find any vac leaks,sprayed intake,hoses,etc...I have a semi loud exhaust,so i should be able to hear if any change....NOTHING..runs smooth at idle.

Tryed unpluging temp sensor,with NO change,but CEL came on so I know it working

whats next??!..the damn thing has good mid-rpm range power,so I dont think its low compression