afro88

iTrader: (2)

I know this has been posted countless times but my problem seems very different than most people's.

When I originally got my 87 TII it had the normal hot start problems and wouldnt hold a consistant idle (it would bounce up and down, not too bad but noticeable). I replaced the old turbo intake boot because I thought it could be a minor vacuum leak and the boot was cracked at the turbo. That helped a bit but not too much.

Then one night I was driving along and when I depressed the clutch to come to a stop the rpm dropped all the way to zero and the car shut off. When I finally got the car to start again I realized it wouldnt hold idle. I inspected some of the vacuum hoses and found that half of the nipple on the bov was hanging out. So I got new hoses but havent replaced all of them yet just the one from the upper intake mani to the bov. The car still wont hold idle unless it's driven for a while at rpm over 5k and then it will hold for a little bit but eventually die again.

The car also hesitates pretty badly. It did before, but now it has gotten much worse. It will go all the way past red line but it stumbles around 3k-5k (didnt pay too much attention to rpm since other things were more important at the time). And also it backfires a hell of alot more than it used to. And a hell of alot louder. I mean I have no problem with that but I'm sure it's not a good thing when it gets worse than what it was and you havent done anything. The really loud backfiring only occurs when a load is put on the engine and you lift, otherwise there are just the normal flames.

I have no idea what this could be. I'm pretty damn close to just going for a full rebuild but if I dont have to I dont want to. Could it be the ground on the rear housing? Could it be injectors? Wiring harness? Plugs/wires? MAF? I'm really stumped right now. Thanks for any help that can be given.

EDIT: Oh yeah and the emissions are all eliminated.

well uhhh

alright, i had a very similar problem, car was cool, then had little idle problems, then wouldn't idle, then started overheating. i replaced every gasket, vac line and removed emissions. Still no idle. I forgot to replace LIM to block gasket and o-rings, turns out that was the problem. coolant was bypassing the o-rings and warping the gasket, not only loosing coolant but loosing it into the intake, causing all kinds of idle/stumble problems, plus the overheating. I dont know if this is your problem, but its worth looking at. while you are at it, it would be a great opportunity to reground your ecu, get injectors cleaned, replace plugs and wires etc... it will be worth it in the end.

Go48

iTrader: (7)

Check the compression first and if that is good, then look for un-metered air entering the intake or a vacuum leak. You can spend a lot of time tracking down phantom causes when the problem could be a failing engine.

afro88

iTrader: (2)

I may just say f-it and do a complete rebuild. Checking things and replacing little things one by one is a waste of time when I can just rebuild and not worry about anything any more. Meh... I'll think about it some more.

Also today the add coolant dumby light came on as well as the buzzer. It turned off by itself but I shut the car off and checked the coolant. There was plenty of coolant in the resovoir and the upper and lower openings, so I dont know what that was all about because the car wasnt even fully warmed up yet.

SkyWalker

i got the same problem now. . .mechanic says I blew my engine. coolant seal and summin else, I can't recall right now.

well uhhh

its a pretty simple process, compression test and then pressure test cooling system. Go from there. It makes no sense to do a complete rebuild if you dont need to, plus you would probably need to replace the gaskets anyway. suggesting a rebuild because you dont know whats wrong seems pretty ignorant. Lets NOT just throw money at a problem to make it go away, but instead take the time, do it right, and learn something in the process. if you plan to stay with the FC its worth it to learn everything you can. you won't be disappointed.

well uhhh

This sounds EXACTLY like my problem! same timeline and everything.

arghx

iTrader: (3)

^ you need to make sure there is no air in the cooling system. do a search on that.

To the OP, if compression is good you need to first check your TPS (do a search on that). Make sure that is set properly and the resistance is in spec, and if it isn't, replace it. Then you need to pressure test the intake for vacuum/boost leaks. You can build your own tester or use something like this: http://www.boostpro.net/prodtester.html (universal one at the bottom). Once you hook an air compressor up to it you will be able to hear, feel, and see (using soapy water) the air escaping. You can build a pipe to replace your TMIC out of home depot stuff, for purposes of the test.

afro88

iTrader: (2)

Fixed problem please erase thread.

ForsakenRX7

What was the problem? It could be useful information to the others here having similar problems.

afro88

iTrader: (2)

Well the dumby light and buzzer coming on was because a friend opened up the lower radiator cap instead of the upper one, so there was air in there I'm guessing, I just topped it off and it hasnt went off since.

The hesitation and no idle problem was rediculously simple and I feel stupid for not realizing this sooner , but the vacuum cap on the tmic came off some how. We found the problem by just moving our hands over the engine bay while someone held the gas pedal, when stepping on and letting off of the gas you can feel the air going in/out.