I'm pretty pissed at my car right now so bare with me if this doesn't make sense right away. I've never really had my car when it was
OK so a little background info:
Haltech'd 88 TII
720cc/1600cc
No idle control
No OMP, premix

Everthing on the intake manifold has been blocked off except for this air valve (pictured below) I forget the name for it.


All the side vacuum ports (3 on each side of the upper intake) have caps. Except the lower vacuum port on the radiator side of the upper intake. I have a vacuum hose that tee's off to the map sensor and the FPR
The only other vacuum hoses are for the bov and boost gauge.


Got it tuned by gaby skern back in july. Ran good before and after that.
After the last few dyno pulls, it would idle at around 2000 rpm but have the same (sometimes more, -15-20in-hg) vacuum reading on the gauge. After it would cool down, it would idle somewhat normal again. Someone at the shop mentioned it may be some sort of stock emission thing (thermowax?) in the throttle body that would get hot and let air in? Kinda confused on that.

Anywho, fast forward about a month. Its been idling fine around 1000 rpm, just from me adjust the idle screws.

So last week after boosting for a couple seconds it starts to have a slightly higher idle around 1500rpm and then after driving it went up to about 2000 rpm at idle. (Probably unrelated)Later that night, I tried to fix some surge I had and I changed the spring in my Tial bov to a lighter spring.
Driving around, it feels like someones pushing the throttle down making the car always accellerate. I even unhooked the throttle cable, and unscrewed the main idle screw all the way and it would still idle around 2000.


So today I finally decide to go and fix it, I take the intake/TB off and tighten the lower intake just in case something work itself loose(2 months back, I had it ceramic coated and put all new gaskets on the upper and lower intakes)
The lower butterfly idle screw(?) The adjustment screw on the underside of the TB closest to the radiator. I adjusted that since it was all the way in, to see if it would change anything.
I also adjusted the spring loaded screw under neath the main idle screw, again, to see if it would change anything.

So I get it back together, it idles even higher and is running pig rich (10AFR) and I noticed I forgot to hook up the vacuum line that goes to the map sensor and fpr.
Hooked those up and tried again, same result. Idle is now around 2300-2500 rpm and 10 AFR's. It sounded completely different and bogged down, like a lawnmower Now the vacuum/boost gauge is reading -10inhg, less vacuum than before. But for the life of me, I cannot find a vacuum leak.

I give it some gas to check the EGT's (dual egt gauge) to see if my motor blew (I'm paranoid) and although very slow due to the excessive fuel, I do see the Front and Rear exhaust temps rising almost evenly. I guess that would rule out a leaky injector?
At this point the entire shop is full of fuel smoke and I gave up, completely baffled.

Just giving alot of info so you guys know everything
Let me know if you guys have any ideas, I'm all out of them.
I'll try to retrace my steps and include anything I did, I forgot




Thanks!

 

Completely random but is there any way I could have damaged the tb or intakes in any way? I know they are like strong heavy metal but just thought i'd throw that out there.

 

did you pressure test to see if you have a vaccume leak?

 

sounds like classic vacuum leak symptoms, it is getting air somewhere behind the throttle plates. that will cause the map sensor readings to be too low, causing you to run too rich like you say

 

Higher than normal idle can only be due to a sticking TB or vacuum leak.
If you haven't pull all that emissions and cold start crap off the TB, that's a good place to start.

Spray starting fluid or carb clean while the engine is running, and you WILL find the leak.

Blown motor will NOT cause the engine to idle higher.
It will only cause the engine to idle LOWER.


-Ted

 

Thanks for the input guys. About 5 minutes ago I used one of those vacuum leak tester smoke machines on it. Hooked it up to a large vacuum line and pumped up the entire intake system. I didn't see any smoke at all until it started coming out of the air filter. I guess I'm going to try looking at my throttle body again. The plates are closing, when I had the TB off I held it up to a light and could only see a slight sliver of light coming around the butterflys.


Like I said before, the first thing i did when i got this car was take off all the emissions and stock bs and throw a standalone on there, so I'm a little lost on what things should look and work like.

thanks

 

update:
Ok. I adjusted the bottom butterflys on the tb and backed them way out. They were all the way turned up (they were before I believe). I got it to hold a somewhat steady idle at 1000. but still running pig rich even with my fuel trim control **** turned all the way down (~12% fuel leaned)
The motor still sounds funny. Like a deeper noise and sounds like its struggling or a slight break up.
Its running so rich I can't really get it to heat up well enough to get a egt reading. I got it to move a bit by holding a high rpm and they were not quite equal, but it was running ~10 afr also. So not sure how accurate that would be in diagnosing something else.
Vacuum gauge still reads alot lower than it used to ~10 in/hg.
So now I'm wondering if either I somehow blew a little chunk of seal (checked the turbo, some play as usual but nothing too crazy or different) or whether the plugs are so fouled now that it can't ignite as well.
So I guess tomorrow I'll do the oh so great compression test and depending how that goes I'll either get new plugs again and continue this witch hunt or part the whole car out.

 

Change the plugs and try again. Sounds like it's fouled the plugs.

 

No dice. tried some used plugs I had that I knew to be good.
Sorta thinking this is an ignition problem, I'm going to check ignition stuff.
I'm getting ready to give up and part this thing out if I can't sell it as is.

 

I doubt it is ignition related...


there are a few things that could keep the idle high

1. vacuum leaks
2. not enough slack in the throttle cable
3. The themal wax setting needs adjustment ( I would just remove it)
4. The BAC valve is stuck open or needs adjusting
5. The throttle plate set screw needs adjusting

I would recheck for vacuum leaks... use some brake clean and spray around the usual suspects... vacuum lines, gaskets....etc. if the idle changes when you spray it with brake clean you have found your leak


also... the rotary can be very susceptible to fouled plugs, even if a plug looks clean and dry, it may still not work. best to drop the cash on new plugs


why are you running a fuel trim???

 

Checked all those things. I'm still on the path of an ignition issue.
Today I tested the ignition with my spare cas. Plugged it in and tried to watch the leading coils arc (plugs off). The leading (with the Fc1000 amp) didn't fire. So I wiggled some wires and made sure it was all snug and tried it again. This time the leading coils fired like crazy. Huge arc!

tried starting the car again and still did the same thing. So I now know, its getting fuel and spark (leading and trailing). Maybe the plugs are already fouled?
Going to try a new set of plugs and then I'm giving it up. You guys can have at it if I part it out.

Running a fuel trim on the street to lean out the afr's cruising etc. I get shitty gas mpg

 

If you've flooded it, which it sounds like you have, just pulling the plugs out and blowing them off or even putting another used set in doesn't always solve the problem. Once the engine floods and you don't have spark to start the car then all the time you're cranking it trying to start it you're just dumping even more fuel into the chambers and it's making the problem worse. Now you've washed down the chambers and you have no compression to go along with weak spark.

1) Pull the plugs. If you must reuse them spray them down with carb cleaner and blow them off with compressed air. If they're NGK and you bought them from a chain store there's a good chance they have a lifetime warranty. If so return them for a new set. Seriously, I know Advance does this. Just keep your receipt and never buy plugs again. In the end it's best to start with a NEW set of plugs especially when you're having the kind of problems you are having.

2) Unplug the CAS and with the plugs out turn the engine over with the starter. It's very important to unplug the CAS so you don't have more fuel being injected and the coils are not popping away trying to light the mist of fuel that's going to blow out the spark plug holes. Yes, this step can be very dangerous. Do not do this when there is a handy ignition source in the area. Turn the engine over for 5-10 seconds until there is no more fuel exiting the engine.

As a side note to this step, you should not crank an engine without the ignition coil leads hooked up with an ability to fire, especially with a CDI box. It's hard on the coils if they cannot discharge when they're supposed to. If you want to check for spark leave the leads hooked up and stick a plug in the boot and lay the plug on the intake or inner fender where it has a good path to ground.

3) Once the engine is cleared of the flood install your new spark plugs. Plug up the CAS and give it a try.

Last note. If you're wiggling wires and things are suddenly working you've got disaster waiting to happen. It only takes one misfire to ruin an engine and the easiest way to do that is with suspect wiring. Fix it and if you're not certain how get it to someone who is.

 

Deflooded the car with the plugs out. Threw the new plugs in and fired it up. It sounded normal for about 3 seconds and then it started having the same struggling noise and it went rich again.
Fun eh?

 

Take fuel out of the map. It's really pretty obvious.

 

I would ditch the fuel trim... work on the fuel maps under cruise conditions (AFR about 12.5) and then as you get into the boost range tune to 11.5:1

if this is a E6X then utilize the closed loop for even leaner cruising AFR's... you can get the closed loop to run around 14

 

You run 12.5:1 cruising? wow.

Should be able to tune the cruise ranges to mid 14's with the map itself and no closed loop, at least thats what I do.

 

+1


And yes ditch the trim ****.

 

i was just being a little conservative since it isnt my car... I run my 20b 14-14.5 at cruise and 12 @ full throttle... my car is not turbo

 

I understand your view on that. I'm just saying I had the car tuned by Gaby Skern and it was running pretty decent until I pulled off the upper intake and had this issue. Something changed it night/day. It used to idle around 12-13 afr and then all of a sudden when I got it back together I've got a 10 afr idle.
Strange question, could my FPR (Aeromotive) have screwed up somehow? For the longest time it was running too high of a fuel pressure until it got tuned and got turned down. They have a couple FPR's at the shop I work at, just wondering if its worth swapping out just to be sure.


Now I have noticed when I changed my TPS sensor (months back) to a GM type instead of the s5 wide range, that I had to readjust the throttle pump settings as it wouldn't rev up right and sounded weird. I'm wondering if I changed something with the tps thats making it do the same thing. I have messed with the throttle pumps just to see if anything made a difference, but couldn't get it to change anything. I may go check that out again with more detail.



I've got another rotary guy thats going to help me out soon, I just need a set of fresh eyes to check everything over since I'm so used to looking at it. I could have missed something.
Thanks for the advice tho. I'll keep you guys updated on this issue

 

Did you hook the vacuum line up for the FPR? Not having it referencing vacuum would lead to high pressure at idle and a rich condition. And yes a bad regulator could cause the same. I had a bad stock regulator on an FD cause a similar issue a while back. What is the fuel pressure doing?

 

Yes, theres vacuum line that T's to both the FPR and Map sensor.

Not sure what the fuel pressure is doing, the gauge is actually broke right now. I'll swap out gauges and figure that out quick.

 

Is the MAP sensor reading correctly? Did you switch vacuum ports when you had the manifold off? What is the MAP on the data page saying when the car is idling? Sounds like you have the vacuum line routed to one of the ports that does not see vacuum.

 

Checked the map sensor, swapped it out for another 3 bar that was known to be working. I'd have to check the idle vacuum again, off the top of my head the vac gauge in the car said ~-10 in/hg (again, normally reads -15) and the Haltech data page said -5-6 psi? Not sure on that, have to check.
All the vac ports on the sides of the intake (front and rear) are unused and capped except for the lowest port on the intake, front side (closest to front of car). This one line T's to the FPR and Map sensor. (heard this was the best vac signal)
I've been using the same vac port routing forever, everything has been the same.

 

Ok. I'm stumped.

FWIW, the Haltech reads vacuum in negative PSI. One PSI is approximately equal to 2 in/hg. So -5 psi would equate to the 10 in/hg you see on your gauge.

 

stupid question, but i have to ask because its been posted before on the forum more then once... did you leave a rag in the intercooler piping?