MaroonLynx

Hey guys,

I own an 87 base model and last week I was taking a friend for a rip and on the way home a coolant hose that went from the block to the heater core tore on me. My car has never had issues with temps so I wasn't looking at the temp gauge very closely for most of the night, until I was at a light and suddenly a bunch of steam was coming out from under my hood, I look down and the gauge was pinned at max. I know earlier that night the temps were fine and there wasn't any major coolant leak at the light 50 yards back, so I think it was only overheating for a minute or two. The hose that burst is known to quickly spew out almost all the fluid so I would imagine it could overheat that fast. Anyways I replaced the hose and temps are fine now, but my idle is f***ed up. When I would cold start it, it will start, rev up to around 2-2.5k then just drop and stall out, unless I hold the gas for around 5 seconds continually. I know something is up with my water thermosensor (won’t give car enough gas to start below 55* and needs me to blip throttle on cold start), but this is different. After it will idle on its own the idle will fluctuate usually from 800-400ish OR it will seem fine but still fluctuate +-100. This pretty much stays the same until its at running temp. When ive taken it out for a drive all seems well. There is no breaking up at high rpms, and the car feels mostly fine except 2nd gear which kinda maybe feels slower. I can't tell. Regardless it doesn't smell especially gassy and I can't tell if it is running rich or lean... or normal. The plugs have 4k miles, the wires have 2k on them and I've only driven maybe 10 miles since the initial incident. I had my gf rev up to 1.5k and sprayed starter fluid around the driver side of the BAC(where the spider nest of vacuum lines is) and it will go up to 2k when I do that. Between the fact that it does that and will bog down and stall I guess it is lean, but... yeah. Anyways the last thing I will add is that a couple times it has revved between 1000k and 200rpms when I was waiting to make a turn while driving. It is even stalled once. I think all the information should be here. Sorry its a book. I will add a link to the videos I have in a second post.

Thanks
Stephen

MaroonLynx

Interior at a spot sign

Exterior video

Oh and I have had no issues with hot starts, so Im assuming its not compression, nor do I have access to checking the compression.

WondrousBread

Before worrying about compression (although testing it is always a good idea before putting any money into the engine) I'd worry about the connectors under the hood. Mazda didn't use well sealed connectors for the underhood electronics. So if it was spewing steam and coolant/water into your bay, it would be a good idea to check the connectors for your coolant temp sensor, Throttle Position Sensor, Air Flow Meter, etc. Really, any connection should be checked on a car this old, but those are the easiest to access. Start checking nearest where the hose burst. I wouldn't be surprised if some of the connectors are green inside because they were covered in coolant mixture or sprayed with steam. Clean anything that is corroded and see if that improves the situation.

Also there are two connectors directly below the TPS connector for the Air Control Valve, one is black and one is white. Don't forget them.

lduley

iTrader: (1)

sorry to say it, but it sounds like a dead rotor to me by the tone of the exhaust. Start with a compression test first and foremost

MaroonLynx

Took it up to Wisconsin this week, about 700 miles... and now it idles almost 100%. Would a dead rotor be able to do that? it still surges between 1000-1500 while warming up, but other than that it seems to be driving a lot better.

SirCygnus

iTrader: (1)

no. an electrical connector may have just been wet.

psyaddict

yup, if it works fairly well now it's probably a wet connector, some more driving and it should vaporize

MaroonLynx

Alright, that's what I was thinking too. Thanks guys