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Cold start and bogging issue
#1
I am new to this forum but have been here before.
I have a 1991 Geo Tracker, soft top, 5speed stick 4x4. Love the rig, made a Toad out of her, added a small winch on a pull out hitch in front and the sweet part, NO Rust !! I have invested over $6500 in her and Love driving it. Just installed a new engine long block with a 7 year, 100,000 mile warranty so I am pretty sure its built right.

The issues.
Before installing the new engine, I had been here and tested just about every module, sensor on her to make her run as well as she could.
One problem has been, you had to feather the throttle for about 15 seconds before she would go into the high idle. After she was on the high idle, she would step herself down to the mid and then low idle and would run as well as she could with on cylinder loosing compression. The head was pulled and taken to a local machine shop that checked for leaks, decked it and replace 4 valves. After about only 2 years, she started loosing compression again, plus always had that piston slap sound that was Really loud when cold. But she would run pretty good with one weak hole. This was the Only issue I had with her.

Now after the new motor, I notice she is bogging when accelerating. Old school V8’s with carbs, its like the timing was off.
I jumped the Dizzy freeze jumper in and timed it like the manual said. But when we were installing the engine, my son-in-law had the carb (I now its not called a carb, but hey, I am a Old (74) mechanic that grew up in my dads auto wrecking yard building hot rods) off the manifold and notice the first start of the engine, we had to monkey with the throttle cable to get her to idle fast without stalling. That is all I have done to her to this point.
Right now, I can feather the throttle to get her to go high idle, she will do mid and then to low idle and then I am ready to head out onto the road. As long as she is up to engine temp, she seems to run ok, But if I not let her get up to operating temp, she will stumble until warm as well as accelerating, start her bogging or hesitating. I only have about 400 miles on this new engine..

Where should I start?? 

I don’t remember all the names of all the modules but I do have the Factory Geo Tracker service manual as well as the Wiring manual for a 1991 Geo Tracker. I can look things up. I also need to figure out how to share pictures here as well as I am not on a iPad Pro tablet as my laptop died.
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#2
(11-08-2021, 05:49 AM)Helmar Wrote: I am new to this forum but have been here before.
I have a 1991 Geo Tracker, soft top, 5speed stick 4x4. Love the rig, made a Toad out of her, added a small winch on a pull out hitch in front and the sweet part, NO Rust !! I have invested over $6500 in her and Love driving it. Just installed a new engine long block with a 7 year, 100,000 mile warranty so I am pretty sure its built right.

The issues.
Before installing the new engine, I had been here and tested just about every module, sensor on her to make her run as well as she could.
One problem has been, you had to feather the throttle for about 15 seconds before she would go into the high idle. After she was on the high idle, she would step herself down to the mid and then low idle and would run as well as she could with on cylinder loosing compression. The head was pulled and taken to a local machine shop that checked for leaks, decked it and replace 4 valves. After about only 2 years, she started loosing compression again, plus always had that piston slap sound that was Really loud when cold. But she would run pretty good with one weak hole. This was the Only issue I had with her.

Now after the new motor, I notice she is bogging when accelerating. Old school V8’s with carbs, its like the timing was off.
I jumped the Dizzy freeze jumper in and timed it like the manual said. But when we were installing the engine, my son-in-law had the carb (I now its not called a carb, but hey, I am a Old (74) mechanic that grew up in my dads auto wrecking yard building hot rods) off the manifold and notice the first start of the engine, we had to monkey with the throttle cable to get her to idle fast without stalling. That is all I have done to her to this point.
Right now, I can feather the throttle to get her to go high idle, she will do mid and then to low idle and then I am ready to head out onto the road. As long as she is up to engine temp, she seems to run ok, But if I not let her get up to operating temp, she will stumble until warm as well as accelerating, start her bogging or hesitating. I only have about 400 miles on this new engine..

Where should I start?? 

I don’t remember all the names of all the modules but I do have the Factory Geo Tracker service manual as well as the Wiring manual for a 1991 Geo Tracker. I can look things up. I also need to figure out how to share pictures here as well as I am not on a iPad Pro tablet as my laptop died.
COLD START, 
when you  key on the DP is fully extended, this sets huge fast idle 2000 RPM  for 5 to 15 seconds, then it closes and IAC in the base of TB (carb) sets the new base RPM 1500 about
and until the IAC closes, at 150F water temp,  and then 800 hot engine RPM kicks in with ECU+ISC hot idle controls.
the MAP runs fuel mix + ECT temps
the RPM is always a based on vacuum or air leaks to the plenum below TB area is that spot, all air lands,
For feathering I think that is 10% foot forced throttle, if yes, the engine  lacks air,  so will want to flood like that,
the DP and he IAC must do there  jobs (DP + dash pot, IAC = idle air control (thermal only)

that is I think is wrong,

nice car good luck on your build, I loved my 91 and zero rust,  so ran great for sure in deep snow.

a friend here. 4wd in deep snow.

https://www.fixkick.com/videos/AVI/kickin.mp4
http://www.fixkick.com
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