91 TII, running terrible!!!! Need Help!!!!
 

Alright guys, I've been searching this forum for the last 2 hours trying to figure this one out, but nothin has really answered my problem. I rebuilt my friends 13B TII back in September with the rotary aviation full rebuild kit . Put the entire car back together, and has had a few very annoying problems since then. First off, it's been streetported, reprogrammed ECU from CorkSport, MSD, electric fan, lightweight flywheel, downpipe, etc. Now, ever since it's first startup, it's been an EXTREMELY hard starter (cold or hot), has had a stumbly and somewhat erratic idle, generally runs rough, seems to rev up much slower than it should, the turbo glows at night, and backfires alot--(the backfiring wasn't nearly as noticeable with the stock exhaust and the downpipe). Now, the car has had roughly 4000 miles put on it, and it does run pretty damn fast, but I know it should be much faster. To give you guys an idea, the car ran almost as if it had a minor vacuum leak---but, I checked for vacuum leaks like 10 times already (I'm talking about having the entire intake and emissions assembly off the car 10 times!!). And yes, I replaced every vacuum line. Now just this past week, we installed another clutch in it, and either a wire got pulled/ disconnected, theres a vacuum leak, or there's a bad solenoid/accessory/ etc.----cause now it's REALLY, REALLY hard to start (takes like 5 mins), it backfires like crazy under acceleration/ deceleration, and refuses to go over 3000 rpm's (cuts out, followed by a backfire) unless I "baby" the throttle to get it to go to 5000 or higher. Overall, it runs terrible at any given rpm.
If anyone knows what the hell is going on, please let me know.
P.S.--I have alot more info that I didn't include, but I'd rather not write a novel!!

Brian

is the timing set right? clogged cats?

car sounds like it's in limp mode...change AFM, check for boost leaks.

Yeah, the timing has been a finicky thing. I was told by the guy at KD Rotary that when a stock ECU is reprogrammed, that I should set my timing at 10 degrees advanced from the original leading timing mark. Thats where it is set. I know he's right, because I tried setting it at the original leading mark and it ran like it had 40 HP and the turbo was glowing bright orange!!---Now it only glows at night with it advanced.
Also, it's definitely not a clogged cat cause we had the exhaust disconnected last night right at the downpipe and it ran the same. (pissed off the neighbor---he came over like 2 mins later to complain!!). Any other suggestions are welcome.

When you took it apart.. did you put that stupid little wagon wheel lookin valve back in the ACV the right way??????

It sounds like the TPS is off. This would cause the idle problem and the heavy backfiring.

yeah, I put the valve in the correct way

All this & no ECU error codes?

Here is a wild guess - Primary & secondary injectors reversed?

Know both Skip and Dave at KD and would be very curious as to why they would recommend advancing the timing 10 degrees because of an upgraded ecu. I have a G Force in my '89TII and right on the stock setting it runs great. Usually a reprogrammed ecu has a very agrressive timing map so you wouldn't want to advance the initial set point.
Sorry this doesn't help, but with the car running so poorly with the stock setting, are you sure the ecu is functioning properly. I say check AFM for proper operation.

Alright, just got back after fiddling with the car for a few hours, and this is only what I came up with: The only code I got left is the one for the throttle sensor. I checked terminals 2F and 2G ,I believe, at the ECU and there's definitely readings there. I can't remember exactly what they were but they responded to throttle input (1- 5 volts). The funny thing is that at first it read 1.40 volts at "closed" throttle, and 4.20 at open throttle. So I fiddled with the TPS sensor a little bit--- (I really didn't do anything except for moving the throttle by hand and pushing in the TPS "trigger/ button" manually all while not touching ANY wires). Then my friend who was in the car said "hey, what'd you do???", I responded saying, "nothing, why??", then he told me that it suddenly changed. It read 1 volt at idle and like 4.9 volts at full throttle. Still, it's giving the same error code.
The BIGGEST thing I noticed was where the wire harness clips into the ECU. There seem to be alot of "splices" that consist of 2 wires going into 1, or vice versa, and wrapped with some kind of shiny blue electrical tape. The one that really had me worried was where 2 gray wires (the kind with the wire braiding around the inside wire) go to the ECU. Near the ECU, the braiding was pulled out of both of these wires, and connected to some black wire that went back towards the firewall. Overall, it looked as if it had been messed with. The wiring is really worrying me because I do NOT feel like messing with that whole area. If anybody is familiar with this, please help.

It really really sounds like a timing issue. I know you have it set where you think it should be, but every once in a while you get an engine that cannot be timed per marks on the front pulley, especially if it has ever been swapped with one from another engine, or if the plates were removed and mixed up with others.

IN these cases, I play with teh CAS, skipping it a tooth one way then another, turning it back and forth with the engine running until it smoothes out and drives as if that is where it 'wants" to be. Then I retard it a few degrees for safety (as they will run really strong with advanced timing until they blow) and leave it there.

I would say timing aswell. also if you have the stock downpipe on it there is a baffle in it a big one. they will clog up to. take it off and see if you can shine a lite through it. dont run the car with out it!!!!!!! you can melt stuff behind the turbo.on the fire wall. plus you could over boost bad.

also how much did you port it?

One is for the oxygen sensor and one is for the knock sensor. The wire braiding is a shield to prevent interference from other electrical fields. This shield should be grounded on the ECU end only. Definitely a plus when the wires are both OK but I don't think they are releated to your problem.

Scott

Kevin: I'll definitely take your advice about the timing issue, and I'll see what I can do.-----actually, come to think of it, there is one important thing I forgot to mention: I used series 4 side housing plates, series 5 housings, series 4 rotors, eccentric shaft, front and rear counterbalancers, and I can't remember which front pulley I have (with the timing marks).

rxsevn89: we put on an aftermarket straight through downpipe, and your typical streetport.

REX4LIFE: Here's a funny thing. Out of curiousity, I cut that black wire that connected to the braiding from those 2 wires and I turned the ignition on. I went from having 1 code (Throttle sensor), to having like 10 codes!!! I can't remember them all, but I remember codes for the thermosensor, AFM, throttle sensor, O2 sensor, and a few others as well!!!!

Anybody know what this is all about?!?!?

sounds like you clipped a ground. i would say, whether you want to or not, you should fix the wiring before you do anything else..get the fsm from iluvmyrx7.com and check every splice with the wiring diagram. if one of them is the problem, you dont want to do all kinds of other shit and then have to go back and fix it when you fix the wire.

pat

Well, my find's got the 4 inch thick factory service manual that he bought for like $125. So, I'll try checkin in there.
Any other input??

OK, firt off, the additional engine code we were seeing was the air thermosensor. The next thing I will clarify is that the wires to the ECU that had the odd grounds were a White one (probly O2 as Rex4Life said) and I don't recall the color but the other was the airflow signal (i know because I was hooling up a super AFC on my cousins car while we were going through all this).
Then the AFC would never tell us %100 for the airflow, but as stated before the TPS we fixed that ????:wtf:
any way the whole wiring harness is a mess as i think it is a mutant put together by someone who didn't know what they were doing....

Pat,
funny you should say that, cause we did. The crazy 2 wires at ecu that turns into 3 wires an inch from the ecu. we cut the black wire which may be a ground. We plan to reconnect it tonight.

Like the man said, shield on the shielded wires NEED to be grounded. The black wire is a factory ground. It NEEDS TO be put back like you found it. Splice the black wire back in.

On a series four that bl
k wire that went to the 02 sensor is also the ground for pin 3G and 3A in the computer and also ties into .........the ground for the air flow meter Hell, pin 2R, a ground is also related to that *black wire*.

The other grey wire with a shield is for.....the knock sensor on a series four.

I also have noticed the cas harness seems to have a shield around it also. These items put out pissant small voltages and that signal can be easily iterfered with by outside forces. Like the man said...EMI.

And remember what the mauual says about extended periods of holding the tps plunger in all the way for more than a few moments.

Are there big differences between series 4 and series 5 connections at the ECU??

brian..... i showed you how different they were last night, on my computer! Never mind him he's high on rotary exaust fumes.

But what does the manual say about the TPS?

how many of you guys are working on the fuckin thing? sounds like you might have too many chiefs and not enough indians....lol

how close are y'all to morgantown?

i could come fix it for ya...or at least give you some good input if youre close...(not that you need another hand or anything..lmao)

pat

shoot on down we are right at the downingtown exit of the turnpike. I would literally see you pass my backyard right before you get to the exit!
If you would really like to jump in also come on down, exit t-pike, 100 N, @ wawa light turn left, when road ends turn left, first nieghborhood on right. 4th house on right. PM me to make sure we are there, or call 610 458 0617. ask for John (my cousin....his car), Brian (2lucky), or me Bob. Help is appreciatted. Just don't look at the huge fuckin mess that my garage is!

oops 4th house on left, and we supply the beer!