Bad Idle has me stumped

Dr.Evil

Dr.Evil

Addicted to Boost
Alright I am out of ideas once again as to why my Ty idles really rough at an idle ONLY WHEN HOT. Sometimes its so bad it will almost die and I can feel the whole truck shutter. Most of the time it sounds like a miss and I can feel it every couple of seconds. It idles fine when I first start driving it. If its hot out, it starts to miss pretty quick. If its night or cool out, Its not nearly as bad. Also, when I have the ultimate chip in, it amplifies the problem on any setting. Here is what I have gone through to get rid of it without success:

Replaced:
Plugs w/ OEM's
Wires (black beauties and also tried Summit wires)
Cap (MSD)
Rotor (MSD)
Ignition module (OEM)
Coil (MSD)
Set timing to 0*
Hard lines replaced w/ soft
High-flow intercooler pump, hardwired and always on
New Aluminum CCHE
CCHE electric fan installed, on when the pump is on
Injectors w/ accel 30 LPH
Intake gaskets
Port matched upper/lower intakes
160* theromstat
Cleaned the IAB and TB passageways

I think that is it. I hate driving it around town because at a stop light it sounds like a beater that isn't running right. Crusing it runs great, just a bit of KR that 100 octane fixes. What else is there to try? I realize these trucks don't idle the best from the factory, but this is way worse then the factory idle. Any ideas would be great. let me know what you think this points to:

The hotter it is, the worse it acts up
all the usual suspects have been replaced
Ultimate chip makes it worse

theres got to be something I missed.
 
Don W.

Don W.

Stab it and steer it
Re: Bad Idle has me stumped

2cents.gif
02 sensor? Wide band?

Do you have datamaster?

Let it idle rough for a while then pull the plugs a take a look.

All the above is just
2cents.gif
 
Dr.Evil

Dr.Evil

Addicted to Boost
Re: Bad Idle has me stumped

O2 sensor is a good idea. I remember it started idleing rough after I put a tank or 2 of 110 leaded mixed w/ 91. It ran great, but may have eaten up the O2. It is just a stock relacement O2 I have in there not, I will try putting the old one back in.

I have DM, however the cable I have quit working (it could be the comp though) and I have not been able to get any DM files of it running bad. I broke my laptop screen, so as soon as I get that back up I will find a way to get DM to work.
 
Dr.Evil

Dr.Evil

Addicted to Boost
Re: Bad Idle has me stumped

Boostedpimp said:
clogged fuel filter? or possibly a bad temp sensor?
Click to expand...

Forgot to add I replaced the fuel filter and the temp sensor also.

Could a weak fuel pump cause the problem? I won't think so because it seems to depend on intake temps.

Where is the pickup coil?

Is the IAB and IAC the same thing?

How do you re-set it? I took the idle controller that is on the bottom of the TB off and cleaned it out. The plunger thing inside was rock solid. I did not move at all when I pulled on it. I thought this was strange, so I want to NAPA and checked out a new one and it was the same way. So I just cleaned it w/ some carb cleaner and put it back on. Didn't help.
 
SeattleSy#1255

SeattleSy#1255

Category 5 Conservative
Re: Bad Idle has me stumped

p/u coil is on the dissy shaft. if you are going to do that, mine as well replace the entire dissy with a stock replacement. may want to try that and see if you can find someone that can swap in a MAP sensor as well. if you have local guys, you can try both of theses things before you buy them. dissy is around 110 at autozone. i hate to tell people to start throwing parts at it, but it seems you have tried the free and basic things already.
 
D

denny

Active member
Re: Bad Idle has me stumped

Good luck finding you problem and when you do please let me know.

I have the same issue, I must have spent close to 1k in replacing parts, I even got a new chip.
Now I have no old parts to replace, only replacing replaced parts.

good luck , hope you find a fix, and let me know what it is.!
 
Jimmy

Jimmy

Banned
Re: Bad Idle has me stumped

Dr.Evil said:
Forgot to add I replaced the fuel filter and the temp sensor also.

Could a weak fuel pump cause the problem? I won't think so because it seems to depend on intake temps.

Where is the pickup coil?

Is the IAB and IAC the same thing?

How do you re-set it? I took the idle controller that is on the bottom of the TB off and cleaned it out. The plunger thing inside was rock solid. I did not move at all when I pulled on it. I thought this was strange, so I want to NAPA and checked out a new one and it was the same way. So I just cleaned it w/ some carb cleaner and put it back on. Didn't help.
Click to expand...
IAC is the Idle Air Controller.Never heard of an IAB.
To reset the IAC:
With the engine warmed up and the truck shut off,jumper the 2 top right ports on the ALDL.Turn the key to on (you should hear the IAC spinning.)Wait 30 seconds,then turn the key off.Remove the jumper.Pull the ECMB fuse out then put it back in.Start the truck.It should find it's own idle.
__________________
 
Dr.Evil

Dr.Evil

Addicted to Boost
Re: Bad Idle has me stumped

Jimmy said:
IAC is the Idle Air Controller.Never heard of an IAB.
To reset the IAC:
With the engine warmed up and the truck shut off,jumper the 2 top right ports on the ALDL.Turn the key to on (you should hear the IAC spinning.)Wait 30 seconds,then turn the key off.Remove the jumper.Pull the ECMB fuse out then put it back in.Start the truck.It should find it's own idle.
__________________
Click to expand...


Alright ill try that. Im still learing about these trucks...what is the ALDL and where is it? Also, which is the ECMB fuse?

Thanks
 
QUICK STORM

QUICK STORM

B.A.M.F. BMW Tech
Re: Bad Idle has me stumped

Dr.Evil said:
Alright ill try that. Im still learing about these trucks...what is the ALDL and where is it? Also, which is the ECMB fuse?

Thanks
Click to expand...

ALDL is the connector underneath the steering column dash area. it basically is an interface into the vehicles computer, you can hook a scanner to it and read real time/computed data.
ECMB fuse is in the fuse box labeled ECMB. good luck!
 
Dr.Evil

Dr.Evil

Addicted to Boost
Re: Bad Idle has me stumped

QUICK STORM said:
ALDL is the connector underneath the steering column dash area. it basically is an interface into the vehicles computer, you can hook a scanner to it and read real time/computed data.
ECMB fuse is in the fuse box labeled ECMB. good luck!
Click to expand...


Tried what you suggested and it didn't help. I tried swapping back the old O2, didn't help either.

Any other ideas?
 
S

syco 2

New member
Re: Bad Idle has me stumped

are u throwing a check engine light? did u check the egr? when sitting at idle can u break torque it and the problem go away?
 
Dr.Evil

Dr.Evil

Addicted to Boost
Re: Bad Idle has me stumped

I disconnected the EGR hoping that would help & it didn't. Now it just throws an EGR code.

With the AC on, the problem is not as bad. It seems like it is the worst when there is no load on the motor.

any other ideas?
 
Windedv6

Windedv6

Ty n 10s
Re: Bad Idle has me stumped

Don't take this as we don't think you did the timing right. But, did you set the timing with the brown wire disconnected? Also friend of mine had this happen and I switch out his sy computer for my 93 ty computer and it straightened up. I believe there were upgrades to the computers from 91 through 93...

John
 
berzerker

berzerker

wookie
Re: Bad Idle has me stumped

if i were you i would try to rule out bad cylinder . run the engine from a cold start up .let run for 20 seconds or so . then touch each exhaust mainfold port . CAREFULL !! each port should be pretty warm to the touch . if one is still cold or not as warm as the others thats your culprit for running bad . look into valvetrain or ignition problems on that cylinder.
i
 
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