Off Roading Forums banner
1 - 13 of 13 Posts

·
Registered
Joined
·
368 Posts
Discussion Starter · #1 ·
As a reminder... the YJ7 is an 89 258 with the TF999 auto. I have had the tranny serviced recently as well as the stock carter craporator. I still have minor dieseling when in gear at idle and it frequently kills.

Question... I am thoroughly convinced the problem I've been having all along is the lock-up on the torque converter. I think the lock-up silinoid (correct term?) is sticking and keeping it partially locked when the tranny is engaged at idle. Is this something external to the TC and can it be replaced without tearing down everything. Isn't the TC on the 89 YJ built by GM? Any help or thoughts would be appreciated.
 

·
Registered
Joined
·
13,432 Posts
There is no lock up solenoid. It's lock up is purely driven by hydraulics. Dump the OEM Carb and go with EFI and be done with it!
 

·
Registered
Joined
·
3,501 Posts
Money Money Money Money.... MONEY.

/ubbthreads/images/graemlins/laugh.gif

Dump the stock carter and get a MC2100 /ubbthreads/images/graemlins/wink.gif
 

·
Registered
Joined
·
368 Posts
Discussion Starter · #4 ·
Thanks Larry but I'm 99% sure its not the carb at this point. I noticed my tranny fluid was a little low, I added fluid and it reduced the problem somewhat. When I come to a stop I hear a sound like an electronic whistle coming from underneath but not when moving... like when you get interference over your radio and you end up with an audio tachometer. There has got to be some tie to the tranny/torque converter. We tried to unplug the converter temporarily to see if it stopped the problem but the neutral start switch is tied to the connection.

Is there something to this????? It can't just be the Carter.
 

·
Registered
Joined
·
13,432 Posts
[ QUOTE ]
We tried to unplug the converter temporarily to see if it stopped the problem but the neutral start switch is tied to the connection.

[/ QUOTE ]

That's because the backup/neutral switch IS connected to that connector. There is NOTHING electrical (except the safety neutral switch) located in a TF999/904. Trust me on this one...

That's not to say the TC ain't sucked, or that the transmission doesn't need a rebuild.... What's the ATF Look like? Has the ATF and ATF filter been changed lately?

I still think it's carb related.

LEVE
 

·
Registered
Joined
·
368 Posts
Discussion Starter · #6 ·
Yes, the ATF was just serviced three weeks ago... minor debris but seemed to be okay. It had leaked from the pan slightly for the last several months so I was always topping it off with less than a pint every couple months. Its old and beaten but seems to be in reasonably good working order. The motor purrs like a kitten in park and neutral... it has never run so smooth. Put it into gear and it instantly diesels and will just quit like you turned the key to off. and the whine only occurs in gear at/and approaching idle. I'm obviously out of my league on this one.
 

·
Registered
Joined
·
13,432 Posts
If it dies when in idle, then the idle tubes are still clogged/clogging. The vacuum should go high and if that's dumping you'll have a problem. The evaporation canister can be ruptured and you could be sucking raw fuel up into the carb and that'll kill it when it starts to come to idle.

Try the following. At road speed (30mph, or so) put it in neutral... see what happens.

Then at the same speed, down shift and slow down... and see what happens.

Let us know.

LEVE
 

·
Registered
Joined
·
368 Posts
Discussion Starter · #8 ·
Will do... thanks again Larry, I can always count on you.
 

·
Registered
Joined
·
280 Posts
Have you done the Nutter bypass. If not the computer has a low speed timing retard in it. Idles like crap and takes off at about 1000 rpms.
 

·
Registered
Joined
·
368 Posts
Discussion Starter · #10 ·
No bypass. Idle problem is only when motor is under a load (transmission in gear). Idle in park and nuetral is the best its been in the entire time I've owned the Jeep.

Larry, I took it out of gear at 30-35 and it idled down perfectly... down shifted and it started to miss and cough as I slowed to 10 and below.. it shut off before I come to stop. In fact, I smell gas when it quits like its choked out but I don't think thats whats happening.

 

·
Registered
Joined
·
13,432 Posts
OK, if the motor is warmed up, and in idle everything works fine. However the second you drop it into gear... it struggles and dies. So, the next question is what's happening with the idle Sol-Vac?



Then it's on to the



If it's ruptured, and the CTO is not working then it lets the raw fuel be sucked into the carb and floods the engine.

Check those items out...
 

·
Registered
Joined
·
368 Posts
Discussion Starter · #12 ·
Now that IS a good question. There is no canister anymore since most of the emissions stuff is gone. There is also no vacuum line into the Sol-Vac and if I put a vacuum on it, nothing changes.
 

·
Registered
Joined
·
13,432 Posts
[ QUOTE ]
Now that IS a good question. There is no canister anymore since most of the emissions stuff is gone. There is also no vacuum line into the Sol-Vac and if I put a vacuum on it, nothing changes.

[/ QUOTE ]

OK, since you gutted some of the emissions, what's left?

The best thing you can do is restore the emissions. or set the stepper motor to drill the metering tubes, set the stepper motor to full rich, and then bypass the computer.... and treat the BBD Carb as you would any other carb.

If the MCU is still connected, it's getting little/no/garbage inputs from non existent sensor and still trying to control the mixture with no input.

GIGO....
 
1 - 13 of 13 Posts
Top