heavy hesitation/possible misfires???

DriftingFC · 08-12-2008, 10:48 PM

ok. I want to give as much info here for all of you to read and possibly help me with. And this just started happenig Saturday during drift practice.

1988 TII
Stock ports
No emissions
fresh rebuild with 2k on it
Stock ECU
Stock fuel system (injectors cleaned before engine was ever started)
Stock turbo
Running premix
3 inch catless exhaust with a silencer to keep her quiet and stop over boost
If you need more info, let me know

Last Friday I adjusted the TPS (via OHMS on a fluke 98, which allows to graph the full range and see any hiccups/dead spots) and adjusted my timing as I had JUST turned 2k miles on my fresh rebuild. Idle great @ 750-800 and timing is perfect. Car is back firing since about 1k on rebuild but I assume it is because there is no cat, no air inection and no afterburn system.

I drive 40 min @ highway speed to the track. No issues, car is running 180-200 depending on load of car. I get to track, and the car sits for about an hour before we get going. I did Idle it for about 10 minutes after getting there. Get in tech line, do my first run, and no issues.

While waiting for my next run, I notice my temp creep to 205. Then to 210, then 215. I shut the car down and I dont hear my cooling fan running. It is a taurus 2 speed wired to run high off a switch in the dash. I pop the hood and the relay is shot. So I wait 10 minutes and limp back to my pit, with 180-190 temp.

Install a new relay, and go rip it up again. No issues, not getting above 200 temp. Get in line, and by this time its a 15 min wait to run because of the ammount of cars. Well, the car is starting to stumble when the gas peddle is pressed. In neutral and in gear.

I get out of line, and back to my pit area again. Temp is holding @ 180-190. I check my timing, and its on. I retard it, probably abour 1-2 degrees to see if it clears, it dont, so I advance the same and it dont clear.

I sit for about 30 min, then start the car again. No issues!!!!!! Im like WTF??? Run again, and the bog/hesitation/stumble happens again. Sit again for 30 min, and all is fine. I did notice after my last run, when I popped the hood to check fluid levels that my filler cap @ the neck by the Thermostat was leaking. Yano like a bad cap does. Once it cooled down, it stopped leaking.

I ran about 10 times in a span of 6 hours there and my last 2 runs were fine. No issues after the runs. I pack up, and drive home. No issues driving home.

Car sat since then. I replace both the rad caps, top off coolant, and go for spin tonite. Car warms up as usual, running 180-190. I get gas, and on the way home, it is sputtering again!!! It was alot worse then what I was getting @ the track. To the point where it felt and sounded like I Was running on one rotor!!! I pull over for about 20 min and let the car sit. It was dark so I couldnt really look around under the hood. I start her up and it seems ok, so I start to drive home again. Im about a mile from home. Well, as soon as I get into 2nd gear, it starts again. Temp is 180.

What, to you rotor gurus, does this sound like? To me, I would assume its something electrical that is killing the signal for ignition or fuel once the car warms up. Tomorrow Im going to look at the wiring for the CAS TPS and the MAF. Make sure the signals are all good once the car gets to temp.I also want to check the spark from my leading coil. With it being progressavely worse today and feeling like it was running on one rotor, leads me to believe its centered around there. I also will do the "poor mans" compression test with a cylinder tester with the valve removed and watch the pulses.

Sorry for the long post, but I wanted to get you as much info as possible. I AM an auto tech, with a heavy background in diag work, but the majority of the shit I work on is ODBII/CAN and this is my first rotary I owned and worked on.

I did put it all back together after the PO totally stripped it to include harnesses, so I know the car but I hope you guys that have been in the rotary game for years can point me in a direction a lil faster then I can get at.

Thax guys.

Phoenix7 · 08-13-2008, 01:12 AM

1. do you have a fuse or a breaker for the efan?
2. Have you messed with the idle speed screw in the past?
3. did you find TDC and then set the timing after the rebuild?

Good luck.

DriftingFC · 08-13-2008, 05:55 AM

1. Yes. The relay was mounted on the strut tower and had no air flow over it. Probably why it popped.
2.Yes. I set IDle speed several times during break in.
3. Yes. Timing was set @ start up and 2 times, checked after.

Boostmaniac · 08-13-2008, 10:41 AM

Quote:

Originally Posted by DriftingFC

1. Yes. The relay was mounted on the strut tower and had no air flow over it. Probably why it popped.
2.Yes. I set IDle speed several times during break in.
3. Yes. Timing was set @ start up and 2 times, checked after.

Most fuses aren't designed to be air cooled, if it popped it was most likely the result of too much current going through that fuse/relay.

Boostmaniac · 08-13-2008, 10:43 AM

Have you by any chance changed the plugs?

DriftingFC · 08-13-2008, 11:24 AM

The fuse didnt pop, the relay went bad. I have not pulled the plugs. I just got home for the day and will be doing all my testing now.

TehMonkay · 08-13-2008, 01:18 PM

Probably the wiring, my car did the same thing before i tore it apart.

Boostmaniac · 08-14-2008, 11:51 AM

I had a buddy that put about 2k miles on his car after a good rebuild and he had those EXACT same problems, just on the dyno. Turns out his plugs were super shot. They'd heat up and misfire. Changed em out on the dyno and bam, problem solved.

EDIT: I just read that it has 2k miles on it also. Change them out anyway. Rebuilds kinda like to kill their first set of plugs and I have no idea why.

DriftingFC · 08-15-2008, 06:49 PM

Ya, so I pulled the plugs, and they look fine. I ordered a new set anyways. So as Im putting the old ones back in, and got all my handy dandy diagnostic tools ready, I notice that the TPS is frikin unplugged!!!

Explains all the backfiring and my issue I had. Jeezus. Im going for a ride and see if it is cleared. Hopefully it is.

Boostmaniac · 08-18-2008, 09:48 AM

Lol, update?

DriftingFC · 08-18-2008, 06:38 PM

Yup. All cleared up. Guess the ECU was not shutting the injectors down on Decel and that was my backfiring, and flooding issues. All is well with the FC.

YaY lol. I cannot believe I totally missed it. I was kinda in a hurry @ work when I adjusted it so when I finished I either didnt plug it in, or didnt get it all the way in.

08-12-2008, 10:48 PM	#1
DriftingFC Rotary Fan in Training Join Date: Feb 2008 Location: Pittsburgh Posts: 81 Rep Power: 18	heavy hesitation/possible misfires??? ok. I want to give as much info here for all of you to read and possibly help me with. And this just started happenig Saturday during drift practice. 1988 TII Stock ports No emissions fresh rebuild with 2k on it Stock ECU Stock fuel system (injectors cleaned before engine was ever started) Stock turbo Running premix 3 inch catless exhaust with a silencer to keep her quiet and stop over boost If you need more info, let me know Last Friday I adjusted the TPS (via OHMS on a fluke 98, which allows to graph the full range and see any hiccups/dead spots) and adjusted my timing as I had JUST turned 2k miles on my fresh rebuild. Idle great @ 750-800 and timing is perfect. Car is back firing since about 1k on rebuild but I assume it is because there is no cat, no air inection and no afterburn system. I drive 40 min @ highway speed to the track. No issues, car is running 180-200 depending on load of car. I get to track, and the car sits for about an hour before we get going. I did Idle it for about 10 minutes after getting there. Get in tech line, do my first run, and no issues. While waiting for my next run, I notice my temp creep to 205. Then to 210, then 215. I shut the car down and I dont hear my cooling fan running. It is a taurus 2 speed wired to run high off a switch in the dash. I pop the hood and the relay is shot. So I wait 10 minutes and limp back to my pit, with 180-190 temp. Install a new relay, and go rip it up again. No issues, not getting above 200 temp. Get in line, and by this time its a 15 min wait to run because of the ammount of cars. Well, the car is starting to stumble when the gas peddle is pressed. In neutral and in gear. I get out of line, and back to my pit area again. Temp is holding @ 180-190. I check my timing, and its on. I retard it, probably abour 1-2 degrees to see if it clears, it dont, so I advance the same and it dont clear. I sit for about 30 min, then start the car again. No issues!!!!!! Im like WTF??? Run again, and the bog/hesitation/stumble happens again. Sit again for 30 min, and all is fine. I did notice after my last run, when I popped the hood to check fluid levels that my filler cap @ the neck by the Thermostat was leaking. Yano like a bad cap does. Once it cooled down, it stopped leaking. I ran about 10 times in a span of 6 hours there and my last 2 runs were fine. No issues after the runs. I pack up, and drive home. No issues driving home. Car sat since then. I replace both the rad caps, top off coolant, and go for spin tonite. Car warms up as usual, running 180-190. I get gas, and on the way home, it is sputtering again!!! It was alot worse then what I was getting @ the track. To the point where it felt and sounded like I Was running on one rotor!!! I pull over for about 20 min and let the car sit. It was dark so I couldnt really look around under the hood. I start her up and it seems ok, so I start to drive home again. Im about a mile from home. Well, as soon as I get into 2nd gear, it starts again. Temp is 180. What, to you rotor gurus, does this sound like? To me, I would assume its something electrical that is killing the signal for ignition or fuel once the car warms up. Tomorrow Im going to look at the wiring for the CAS TPS and the MAF. Make sure the signals are all good once the car gets to temp.I also want to check the spark from my leading coil. With it being progressavely worse today and feeling like it was running on one rotor, leads me to believe its centered around there. I also will do the "poor mans" compression test with a cylinder tester with the valve removed and watch the pulses. Sorry for the long post, but I wanted to get you as much info as possible. I AM an auto tech, with a heavy background in diag work, but the majority of the shit I work on is ODBII/CAN and this is my first rotary I owned and worked on. I did put it all back together after the PO totally stripped it to include harnesses, so I know the car but I hope you guys that have been in the rotary game for years can point me in a direction a lil faster then I can get at. Thax guys.

08-13-2008, 01:18 PM	#7
TehMonkay Rotary Fanatic Join Date: Apr 2008 Location: Louisville, KY Posts: 302 Rep Power: 18	Probably the wiring, my car did the same thing before i tore it apart. __________________ My car blows up everytime I start it, it's rotary

08-13-2008, 05:55 AM	#3
DriftingFC Rotary Fan in Training Join Date: Feb 2008 Location: Pittsburgh Posts: 81 Rep Power: 18	1. Yes. The relay was mounted on the strut tower and had no air flow over it. Probably why it popped. 2.Yes. I set IDle speed several times during break in. 3. Yes. Timing was set @ start up and 2 times, checked after.

08-13-2008, 10:43 AM	#5
Boostmaniac Rotary Fanatic Join Date: Apr 2008 Posts: 182 Rep Power: 0	Have you by any chance changed the plugs?

08-13-2008, 11:24 AM	#6
DriftingFC Rotary Fan in Training Join Date: Feb 2008 Location: Pittsburgh Posts: 81 Rep Power: 18	The fuse didnt pop, the relay went bad. I have not pulled the plugs. I just got home for the day and will be doing all my testing now.

08-14-2008, 11:51 AM	#8
Boostmaniac Rotary Fanatic Join Date: Apr 2008 Posts: 182 Rep Power: 0	I had a buddy that put about 2k miles on his car after a good rebuild and he had those EXACT same problems, just on the dyno. Turns out his plugs were super shot. They'd heat up and misfire. Changed em out on the dyno and bam, problem solved. EDIT: I just read that it has 2k miles on it also. Change them out anyway. Rebuilds kinda like to kill their first set of plugs and I have no idea why.

08-15-2008, 06:49 PM	#9
DriftingFC Rotary Fan in Training Join Date: Feb 2008 Location: Pittsburgh Posts: 81 Rep Power: 18	Ya, so I pulled the plugs, and they look fine. I ordered a new set anyways. So as Im putting the old ones back in, and got all my handy dandy diagnostic tools ready, I notice that the TPS is frikin unplugged!!! Explains all the backfiring and my issue I had. Jeezus. Im going for a ride and see if it is cleared. Hopefully it is.

08-18-2008, 09:48 AM	#10
Boostmaniac Rotary Fanatic Join Date: Apr 2008 Posts: 182 Rep Power: 0	Lol, update?

08-18-2008, 06:38 PM	#11
DriftingFC Rotary Fan in Training Join Date: Feb 2008 Location: Pittsburgh Posts: 81 Rep Power: 18	Yup. All cleared up. Guess the ECU was not shutting the injectors down on Decel and that was my backfiring, and flooding issues. All is well with the FC. YaY lol. I cannot believe I totally missed it. I was kinda in a hurry @ work when I adjusted it so when I finished I either didnt plug it in, or didnt get it all the way in.