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Unread 07-26-2002, 06:30 PM   #1
CJ8DV8
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Join Date: Mar 2002
Location: LI, NY
Posts: 35
Engine "Hesitates" while accellerating

Here's another one-

If you've been following my line of questioning you know I've had a million problems. I've got most of them sorted out but now...

When I accellerate normally, the auto trans will shift and then the engine will hesitate before it starts pulling rev's again. Both shifts- first to second and second to third. If I get on it, it will either run fine or the hesitation will be so bad it will make me fall forward in my seat. When I accellerate slowly, the hesitation isn't there.

What a PITA. Makes me hate to accellerate. I always cringe when the trans shifts, in anticipation the "pause" in power.

Any thoughts?

I'm in the process of rechecking everything for the 14th time. I have new carb, new tune up, new fuel filter, new fuel pump and have checked for vacuum leaks until I'm stoned on starter fluid.

If you've had this problem, what fixed it? What else should I look at or else what should I look at for the 15th time?

PS My mechanics can't figure it out. My next move is to go into the local Jeep dealer's service department and in a loud voice say "Do you know where I can find a good Jeep mechanic?" so the whole customer lobby can hear me. They can't seem to get anything right lately.

Anyone?

__________________
Black '83 CJ8
258 I-6
Auto
Half hardtop
Rustproof plywood floorboards and bed upgrade.
Lots of work, but working on it.
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Unread 07-27-2002, 08:01 PM   #2
CJ8DV8
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UPDATE

UPDATE-

I'VE FOUND THE SOURCE OF HESITATION!!! ...Or did I?

I spent the day going through the engine- again. I rechecked my mechanics work. Here's what I found:

1. All intake and exhaust manifold bolts were not torqued correctly. Seems he only torqued the easy-to-get-at ones and guessed at the rest. I had a hard time weaseling my torque wrench onto a couple bolts but I got them all.

2. Found a burnt vacuum hose to the EGR valve that was too close to the exhaust manifold. I could see a hole where it was burnt through. Replaced the hose.

3. Replaced one of my pulse air vacuum controlled valves. It was stuck closed. Apparently, these things are supposed to leak a little vacuum in order to bleed down and close the valve when the solenoid cuts the vacuum. I guess I need to replace the other because it holds vacuum solid and the valve stays open.

4. Sealed an exhaust leak where the pipes connect at the front of the cat.

Now, after finding and fixing all these problems, IT RAN WORSE THAN EVER!! It felt like it was running out of gas and it took nearly flooring it to get it to move out of its own way! I relaced the fuel filter and it was still the same.

So, how did I fix the hesitation? I disconnected the EGR VALVE!

It runs like it's brand new now! I'm even beginning to love the BBD carb - it's running that good!!

Problem now is that I don't want to leave it disconnected- It does some good things when it's working correctly- and yes, it's brand new.

So what could be the problem now?? I'm thinking it may be a partially clogged cat and that the exhaust gases are blowing through the EGR valve more than it should because of the increased back pressure. This would also explain why it got worse when I sealed the leaky exhaust pipe connection. Sound right?

How do you check for a clogged cat without taking it out and running straight pipes to see if it gets better? Is there a way to tell or is that why they make "test pipes"? I think there's a way to tell with a vacuum gauge, but I can't remember.

Sorry for the long post. I hope someone can benefit from my grief, even if all you learn is "Don't trust your mechanic to do a thorough job", like I have.

Can someone help me with the EGR problem and how to test a catalytic converter for clogging?
__________________
Black '83 CJ8
258 I-6
Auto
Half hardtop
Rustproof plywood floorboards and bed upgrade.
Lots of work, but working on it.
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Unread 08-03-2005, 11:41 AM   #3
copbait
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Maybe have a shop hook one of those sniffers up to your tailpipe and analyze if your exhaust system is working properly or not...?
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Unread 08-03-2005, 01:23 PM   #4
bcar240
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If the cat is shot, it will have a distinctive smell in the exhuast. Not that you need to be sniffing your exhuast often, but it is something like rotten eggs. But if that is not there, it doesn't mean the cat is not clogged. I assume you checked the accelerator pump already, being you worked on the carb some, but I thought I would mention that just in case. EGR valves can wear out too, you might just need a new one.
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