Brutal stumble

[Tommyquest]

I have had it with this truck. Out of nowhere the tach jumps like mad.
I have done the following already.
Replaced:
plugs
wires
cap
rotor
distributor
coil
reloaded ostrich
swapped ostrich cable
swapped for known good chip
tried different bin
distributor to coil wire
reset IAC

checked grounds

I'm out of ideas. Any help would be great. I have an .avi vid of it but it won't upload. Thanks.

 

[etriebe]

Re: Brutal stumble

Does The truck actually buck around or is it just the tach. I had a broken white wire from the coil to the dist one time and the tach would jump around quite a bit.

 

[WyoSyclone]

Re: Brutal stumble

Can you datalog it and see what happens during the stumble periods??

 

[cloneman315]

Re: Brutal stumble

what does the wbo2 say?

 

[bezerk]

Re: Brutal stumble

Iac?

 

[Tommyquest]

Re: Brutal stumble

Does The truck actually buck around or is it just the tach. I had a broken white wire from the coil to the dist one time and the tach would jump around quite a bit.

Forgot to add. Swapped it too. Only at low speed and barely.

 

[Tommyquest]

Re: Brutal stumble

what does the wbo2 say?

It's on the rich side but not out of the ordinary for cold start. I didn't want to run it too much and foul another set of plugs.

 

[Tommyquest]

Re: Brutal stumble

Can you datalog it and see what happens during the stumble periods??

Haven't yet.

 

[cloneman315]

Re: Brutal stumble

is it showing it on the wbo2?also the distributor that you put in,was it new?is it a stock syty one etc?

 

[Tommyquest]

Re: Brutal stumble

is it showing it on the wbo2?also the distributor that you put in,was it new?is it a stock syty one etc?

I'll have to watch it tomorrow. My hot water heater tank cracked last night so I have my hands full replacing it today. I'll have to log it tomorrow. The disributor is stock. The one it replaced was only 6 months old. I wanted to rule out the pickup and ign. module since it was under warranty anyway.

 

[Tommyquest]

Re: Brutal stumble

Here is the log. I didn't want to run it too long and foul the plugs.
http://tommyquest.com/idle4.uni

 

[bezerk]

Re: Brutal stumble

your iac is way to high. try to check for extreme vacuum leaks. put pressure on you manifold

 

[bezerk]

Re: Brutal stumble

also i would try to swap the ecm, because it looks really weird

 

[Tommyquest]

Re: Brutal stumble

also i would try to swap the ecm, because it looks really weird

Just tried that. Same result.

 

[Tommyquest]

Re: Brutal stumble

Well I went outside today to move this 3600 pound paper weight. Start it up and it purrs like a kitten. Go figure.

 

[turbodig]

Re: Brutal stumble

Well I went outside today to move this 3600 pound paper weight. Start it up and it purrs like a kitten. Go figure.

This screams loose ostrich or ECM connections. A loose socket in a G1/G3 can act like this.