Lately I've been working on this '87 TII, and it's been giving me some pretty big challenges.... Anyways, a little back-story:

I bought this car in running condition about 4 months ago, after it had been sitting for about 2 years. The engine bay was virtually stock--although the previous owner had installed a new engine several years prior to it being parked. Either way, when I drove away with it that day I knew it was going to need work, because there were some pretty serious hesitations throughout the power-band, and the car was virtually unable to produce any boost-pressure without severe bucking--which in my simple mind meant an "engine-bay clean-up" in conjunction with a full tune-up...

Well, of course it's never that easy, and if any of you has ever spent a good deal on time trying to restore these cars, SOMETHING new and unexpected always comes up. The RULE is; something is never as it seems, nothing is ever easy, expect the unexpected and ANY short-cut will always come back to bite you in the ***... You can count on these rules.

After finally getting a chance to work on the car, I wheeled it into my garage--stripped the engine bay and began the process of putting it back together, minus the emissions-control stuff and other "extras". Block-off plates were installed, as were new gaskets, o-rings, filters, hoses etc.

Well, upon finishing I fired her up and backed the TII out of the garage... Everything seemed fine until I noticed smoke... Lots of smoke. Cursing the sky, I got out and smelled the smoke which had that wonderful "oily" smell and look to it. Gritting my teeth I ripped off another turbo from a different TII and did the swap.

As I backed the TII out a second time I noticed more smoke... I decided to let the TII idle and just hope that it was burning off oil-residue left over from the "old" turbo. Not so much... Within ten minutes, our alley outside my garage was full of a billowing cloud of white-ish grey smoke. I shut the TII off dejected, got out and slammed the door. Lesson: Nothing is ever easy.

The next time I tried to start the car (to move it out of the way of a visiting FD), something let go internally and the engine began "running on one rotor"... I checked the compression and sure enough, a low 75 on one of the front pulses and everything else was 100psi.

I pulled the engine, tore it down and discovered one of the side-steals had decided to get carbon-locked all of a sudden. Thanks side-seal! Whatever, I suppose, since I discovered soon after that the reason for the smoking was due to the flattened oil-control ring inserts and flattened springs. It needed a rebuild either way.

I rebuilt the engine and got it running and driving OK, aside for a few sketchy hours when I was first attempting to start it... It smoked for an HOUR straight. All of my other rebuilds have been pretty much smoke-free after 20-30 minutes.

Either way, even after the fresh rebuild and engine-bay cleanup/tune-up the TII was still bucking and hesitating like it was when I first bought it. I replaced all the sensors in the engine-bay and was still left with the pathetically un-fun TII.

That is until I decided to replace and redo my engine-bay and ECU grounds. I noticed during the engine install that the battery-ground on the starter through-bolt was pretty haggard and chewed up--so I cut off the chewed up end and attached a new heavy-gauge wire and 'ring'. After that, I redid the ground on the top of the engine block (ECU/sensor ground) and added another ground at the pressure-sensor because this is an early-87 TII with only the single-wire at the pressure-sensor plug. I also redid the tranny bell-housing ground with a thicker gauge wire and cleaned up it's grounding points. Afterwards, just to put the icing on the cake, I pulled up the passenger carpeting and put a nice ground right at the ECU as suggested by HAILERS (search for ECU grounding) if you want to know more about this.

Either way, I started the TII up about 30 minutes ago and began driving it around... I can't be happier or more impressed. I have no hesitations and this TII feels like an ANIMAL. It wants to spool the turbo and just GO like it hadn't done before. To say night and day would be a petty cliche', this feels like a different car.

Either way, thank you HAILERS, NZ and A-Cake for various informational tid-bits through-out my searching...

Good grounds FTW.

 

Excellent post - but did this cure the smoking issues? So the fuel mixture was off because of the bad connections affecting ECU readings?

 

No the smoking was due to bad oil-control ring seals (inserts) and/or flattened oil-control ring springs. I know this because during the rebuild I installed new Viton inserts and new control-rings springs. I reused the control-rings themselves because they were still quite "sharp" and had no chips, dings or pitting. I also reused the original turbo, so by taking a look at the variables, it was pretty obvious it was my (bad) oil-seals that were causing the smoking. Now everything is smoke-free and glorious.

 

Yes, I saw the part where you mentioned the oil seal o-rings, and got a bit confused. Thanks for the clarification.

 

heye big Favour can you post pics of were the grounds are i just got an 88 FC it needs the grounds to be re-conditioned.

 

Read this: http://www.aaroncake.net/RX-7/grounding.htm

 

Whelp, looks like I know what I'm doing next. I've actually been thinking about this for a while; now I know it's worth it. Thanks. I'd like to get working on my car again anyway while I wait for $ for more expensive things.

 

I have the ECU grounded to the mounting plate and a beefed up firewall ground, and my car runs very smooth, no hesitations at all. I've heard some people add a ground to the alternator casing.... I might do that too after a while.

 

Are you saying that you just have the ECU bolted down like stock, or that you actually added an extra grounding point by the ECU for the four ground wires coming from the ECU? (The latter is what I was referring to).

 

That's completely pointless, since the alternator is bolted to and hence grounded through the block, which is grounded directly to the engine. If adding a wire from the alternator case to the battery makes any difference, it could only be because the engine-battery wire is completely shot.

 

Good ol' grounds. Can't have a circuit without em!

 

man this thread is just in time, my engine is out the car n everything. Cleaning those grounds ASAP.

 

Finaly a cure for the bucking beast that is the N/a

 

I did this just last week while doing my emissions removal. The firewall ground was just laying on the transmission!!! (read: not attached to the firewall in any way)

I ran a new ground wire, properly heat shrinked, and cleaned off the other under UIM ground as well as the one on the driver's side shock tower. The starter ground looked ok, aside from being a little dirty, but since I don't have to remove anything major to get to it, I'll do that and the ECU grounds later when I'm done w/ the gauge install.

The car certainly seems to run smoother.

 

That's a nice looking car...