hurleysurf24

iTrader: (3)

OK well I finally got around to taking some video and pics .. which makes it a bit easier to describe.

First off: 1988 Convertible- S4 T2 Swap. Engine is street ported, S5 exhaust mani and turbo, racing beat turbo back. Emissions removed and block off plates installed

The main problem is that the car will not hold an idle without me holding down the gas. When I do hold the gas down below 3500 to keep it from stalling, it sounds loopy and it the idle will jump up and down 100-300rpms. I know that it has to either do with not enough fuel .. or too much air. My mind is telling me that the Primaries are sticking or leaking, one of the two.


Also here is a sound clip to more clearly hear whats going on


I checked the engine bay, and all hoses look they are fine. When I initially start the car after it has sat overnight, I can hear a definite audible hissing sound.




I looked around and found some things that I want to double check on .. so I'm including some pictures here to make sure everything is copesthetic (spelling?) and to get a second opinion.


1. THE O2 Sensor is not connected to anything. I just wanted to double check that it shouldnt be as I have all emissions removed (dont mind the crispy connector .. its still fine)


2. There are a bunch of various connectors coming off the engine harness that are not being used .. what are these, and should they be connected?





3. I found to pipes that were uncapped and did not have any lines on them. Should these be capped off, and would this effect the vehicle?



4. Just wanted to double check my BAC is being ran right.





THANKS GUYS !!!!!

neodriftout

I am no expert but you need a boost gauge so you can see if you have a leak, a vacuum leak will cause problems similar to what you have.

Also I believe that tube coming out of your fire wall is A/C related and of no worry but I would cap the inter cooler you might be leaking from there.

Also the BAC you wont need, it only helps you warm up faster I think, regardless if you eliminated emissions that should be gone too.

Its been awhile since I wrenched om my TII do i hope what I am telling you is accurate.

hurleysurf24

iTrader: (3)

yea .. im going to adjust the tps tomorrow and see if it helps at all

WingsofWar

mine does the same thing, except it doesnt jump that much ...it almost sounds like a small misfire..and it bounces from 800-850. and when it warms up it holds idle..but bounces..and the motor kinda shakes.

tell me if you get any progress with yours im stumped myself.

hurleysurf24

iTrader: (3)

wings .... mien doesnt bounce that much. in the video i forgot to mention that because it does not idle and the accelerator pedal is a bit sensitive its hard to hold it in one place (not reaalllllly one place since it fluctuates about 100-300rpm at the point i try to hold it at).

my motor shakes aroudn 700-1000 if i let off the gas and let the idle drop before it dies.

scrip7

iTrader: (6)

I just did a writeup about rough idle/ stalling problems. This should also work for streetported engines:

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/rx7-rough-idle-diagnosis-simplified-645051/

nitronatefc

iTrader: (2)

You definitely need to cap the big nipple on the intercooler you have circled in the pic. Do you have the injector resistor pack installed? Not all 88's were low impedence injectors. Did you do the throttle body mod? When I removed my emissions on my S4 TII, I couldn't get the car to hold an idle. I then realized I needed to adjust the throttle plate to allow more airflow at idle b/c the idle air control thing is no longer there. It would start to hiss like a major vac leak when revs got below 1100 until it clunked out unless you feathered the gas a little. Your doing the same swap I am. Good luck

scrip7

iTrader: (6)

You still have your BAC installed, but it will not control idle speed because you have capped it off. The hose that you removed goes to the air intake duct. The BAC controls how much filtered air enters the engine to control idle speed. I listened to your sound clip and it sounds to me like you have a large vacuum leak. Use propane at the hose connections you have pictured and see if your engine responds to it. Also read my earlier post:


https://www.rx7club.com/showthread.php?t=645051

YaNi

iTrader: (2)

Please stop posting BS info...
The BAC valve has nothing to do with warm up, thats the thermowax on the throttlebody. The BAC valve is used to hold idle when the engine is under load (AC on, Alternator draw, etc). There are no positive results from removing the BAC or thermowax.

hurleysurf24

iTrader: (3)

MY CAR HOLDS IDLE

I adjusted the tps and it seemed just fine. I also played around with the resistor a bit to smooth it out .. so now its holding idle and not bouncing as much as it was previously.

im pretty sure i have a vacuum leak on the manifold gasket though

neodriftout

Hey jerkoff if you are going to quote me do it right!!!

I highlighted some parts that you obviously missed and also in the future try not to jump into a thread spew a bunch of crap then jump out with out even attempting to stay on topic or help in anyway.

kthxbye