Block-off Plate Nightmare
 

This is my 3rd t2 and 5th rx7, I'm not an expert but feel I know my way around, any advice is appreciated!

1987 Turbo II with 115K. Rebuilt engine circa 15k miles old(according to former ownership).

I bought the car in fairly stock condition. It ran and would drive okay after start up. However at start up it would miss for like 2 seconds until you applied fuel and then it was happy. All the rubber in the engine bay was about shot...time for new lines...

So, here's where the problems start... I bought a block off plate kit, and all new vacuum lines, and fuel lines. I followed the Rotary Resurrection block off guide... With all that done the car is not happy, its hard to start and backfires etc... I figured it was a vacuum leak. Took it all back off and used silicone rtv to reseal everything. No dice. I have spark from the coils(pulled the boots off at the plugs, and it sparks like hell). Reset TPS and idle to within range. Checked and recheck clamps at the intake etc. Fuses are good.

Compression checks at about 95psi on all rotor.

Sprayed carb cleaner on all lines and plates. No change.

THIS is what I find most interesting: I can pull a vacuum line off and nothing changes. No change in idle...doesnt bog

Any ideas? the car feels like its misfiring. What am I missing here, if I made a gooberhead mistake please inform :)

May be a dumb question,but did you adjust the variable resistor and idle screw after removing everything? Did you check the manifolds for leaks as well?

And tell us what exactly did you block off.

Variable resistor has been adjusted a few times... Idle is set to about 1k.

Pretty much removed everything in this guide:
Rotary Resurrection home of the budget rebuild.

Did you remove the BAC? Also, is the TPS set right (G/R wire measures 1 volt w/key to on and engine completely warmed up)? And has the plug to the water thermosensor come loose or to the AFM as well.

The variable resistor should favor a rich setting (past the half way mark between lean and rich (should be set w/the initial coupler jumpered and engine fully warmed.

After my emissions delete recently,mine had to be set full rich. Or else it would stutter and misfire

BAC has been removed.

TPS was set according to the FC3S Pro guide(FC3S Pro v2.0:&nbsp TPS adjustment for 1986-1988 RX-7 Turbo II models)

Variable resistor is favoring rich. Not turned all the way up, but pretty much pointing to the "R" with the screw head, if that makes sense.

AFM- coupled to aluminum piping with silicone couplers, nice and tight there.

The Water thermo-sensor is pretty shoot. Its pretty much broken. Would this cause a rough and misfire condition?!? The plastic cracked on this and the pins were ripped out.

The water thermosensor helps to dictate how much fuel is injected based on the temp of the engine, so it is quite important. Secondly, the BAC is not an emissions item and is there for idle stability thus it is vital. Focus on these two items and it should rectify most of your problem.

Just popped in a new thermosensor. problems remain. I may try the BAC sometime tomorrow...

Lets talk some grounding points.
My car's main harness ground is at the IC bracket, I cleaned that up and even added a ground to the battery from there. What grounds at the bell housing, that wire is corroded through and I dont know where it went...

You need to make sure the voltage reading at the ECU checks out for the thermosensor (2 to 3 volts w/key to on and not 5 volts). The bell housing ground runs to the fire wall near the wiper motor.

And did the engine have the injector resistor box or not?

Is the resistor box in the passenger headlight area under the air box? If so, yes it has one...
I am going to be doing ECU stuff soon, gonna add some grounds and solder the horrid factory crimps.

Its worth mentioning that before I had sporadic boost gauge activity, now I have nothing...

The fuel resistor relay is under the air box but the injector resistor is against the passenger fender well. I cannot remember if all turbos had the high resistance injectors or not, though. Checking the ohms of the secondary injectors ought to be easy.

Gauge itself might be faulty or the connection to it could be iffy. the gauge has 4 wires. Black is ground. B/W has 12 volts w/key to on. Brown/White wire has 5 volts w/key to on. The Brown/Red wire has 2.3 to 2.7 volts w/key to on.

This means you have a vacuum leak.

As to the original poster, put the BAC back. You gain nothing by removing it.

Are you sure there are no vacuum leaks and the hoses are connected up where they should be?

If you aren't getting boost gauge activity, I'd check that hose and the sensor.

I'm not the op having idle issues.

Back by popular demand is the BAC, but no changes... went ahead and checked timing too. Pulled the CAS and re-stabbed at the mark, it may have been a little out, but the problem persists.

Would it be a big deal if there were no filter on the AFM? I have one on order but nothing on there..:

It's being stated if you have to go full rich it is to compensate for a vacuum leak.

Well I know none of my vaccum lines are leaking nor the block off plates,also resealed both intake manifolds. Noticed an issue with the brakes on a test drive so I guess I'll be looking over the booster for leaks then.

Doesn't matter whether there is an air filter from an operation perspective. Obviously you don't want to drive around like that due to dirt, though.

Is your TPS plugged in and adjusted correctly?

Since you had the intake manifold off, is the ECU ground reinstalled?

I agree with this AND if you noticed your brakes are being funky AFTER you've done alot with vacuum related parts, than i bet you have a vacuum leak where you've worked, OR forgot to hook something up, a brake booster rarely goes bad, especially that quick

Smoke Machine will find the vac leak quick, they are expensive, but there is a diy on the internet somewhere. Just google it.

TPS is adjusted according to FC3Spro website... within spec.

ECU ground- Is that the one grounded at the intercooler bracket, if so, the terminal ring has been cleaned as well as the metal it grounds to. It was reinstalled.



Is there another ground I'm missing?

Will try smoke machine tricks tomorrow, and enjoy smoking a cigar too.

The main engine ground grounds to the engine block. Towards the back of the engine but on top of it and close to the driver's side.

No vacuum leaks! Smoke tested and nothing!! And went ahead and replaced plugs too. I'm scratching my head.

What was the method used for smoke testing? I see you mentioned the cigar earlier. I hope you didn't just try to blow cigar smoke into the system. I don't think that will produce any where near the volume of smoke you need in the time frame you need it in.

Yes, I used a cigar in an enclosed container with about 5psi going to it, then feeding in the braked booster inlet.

However, I may have found my issue: terminal loose in injector connector. I haven't got it back together to test it... found it during my lunch break. To be continued...