backstory, used to have an 87, blew it up and got rid of it(big mistake), found another one and bought it immediately, however i need some advice, whenever i turn on the engine, 1: i need to be on the throttle to warm it up. 2: when it is warmed up the engine bounces between 1200 & 1500 rpm. any help supremely appreciated

 

does it have emissions removed?..any Mods at all.
If you can help by taking pics of the engine bay,or describing what has been done to the car,other than it is an 87 with erratic idle..heh..(need more info!!!!.) cheers Man.

 

what if any emissions does it still have? the thermowax and or the bacv should be able to maintain an idle id everything else is ok. check for mac leaks and set the tps first.

 

sorry it took so long, but i'm posting pics while the batt charges, so i can post a vid

 

electrical problem....from the picture you've posted this is the first thing I saw

 

Can you elaborate?

 

i would say coolant problem. missing rad cap and broken off return nipple

 

It could be a lot of things... We need more information.

The pictures just show missing parts, extra wires to the battery, etc...

 

my car does the same thing, 91 coupe na. lopping between the same rpm as you mentioned. but not every time about 75% of the time after the car has been warming up for a while. I don't need to get on the throttle to start it, it starts fine either way (in 1st gear or neutral). I have apexi intake and corksport cat back. i know for a fact all my flanges are tightened and the manifold is up to torque. the engine behaved the same way before the mods as well. the repair book says it's a vacuum leak if the engine lopes...

 

OP. check for and fix any vacuum leaks first. This means most likely taking off the intake manifold as the vac spider for the oil injection system is prone to breaking from age. Just a good time in general to replace all the very old vac lines, clean the egr valve, have injectors cleaned, clean carbon off 6pi sleeves so they rotate freely, ect.

After getting that in good order get it started and fully warmed up to set the TPS. Vac leaks and bad or incorrectly set tps are the leading causes of poor or no idling, doing those two is pretty much prerequisite for further diagnosis.

 

thanks for the input, keep it coming.

ok so i believe the random wires that are running from the battery are for the fuel pump cut-off switch, the guy who sold it to me was like blah, blah, blah...

The missing radiator cap, guy told me that they break a lot, so he just capped it off.

it does however have aftermarket exhaust on it, although i don't think it was put on that great, since when i wind it up there is a lot of smoke coming from the header, as well as the back.

im also concerned about the process of getting the engine warmed up, i have to manually keep rpm's on the engine ~3000 to keep the engine alive. otherwise it will die. could this fall under the bac and injectors?

i know it's a lot in his post but, my haynes manual can only get me so far

 

ok, here's a vid of the idling
http://www.youtube.com/watch?v=mj0DLuH_mKY

 

ok, so disconnecting the bac valve, dropped the idle speed, as well as the bouncing. so now i just have to get a replacement.

 

or is it something that can be cleaned/fixed? mazda said they have a new one for 6 hundo. not going to pay that

 

I saw a leak on your coolant hose going to your firewall. I had the same problem, you need to take it one at a time. I'll start with your TPS, Idle mixture on top of your Dynamic Chamber, make sure you put a jumper on your GND and TEN wire, and this is the one that worked for me you're not suppose to touch it because it's factory sealed play around with your variable resistor. Good luck!