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Egr delete on 89 yj running bad

23K views 16 replies 8 participants last post by  iLuvJeepYJ 
#1 ·
Alright guys, ive got an 89 yj and i just recently completed the 2100MC upgrade. I thought this would fix my problem with my jeep running terrible but it didnt at all. Ive checked timing (8atdc), carb is tuned, high flow cat, did nutter bypass, new spark plugs, ignition coil is only about 8 months old, new distrib cap and rotor, new wires, now what?? Performance has hardly changed :( it started running bad one day when i turned it on about 8 months ago and hasnt been same since.. I revived it after it had been sitting for 3 years because of carb probs and it ran right until then. The gronk guy said something about blocking off egr. Is this a good idea or get a new one? I no longer have the egr tubes and cooler that went to the old setup and the old cat. What should i do? Any solutions to the problem? Any advice is great! Thanks
 
#3 ·
the egr isn't needed, some say it prevents overheating but the aftermarket intakes don't have it and they work great. if its stuck open it could be your problem. also, check for vacuum leaks, the brake booster is one many overlook. to check just pinch the hose closed, vice grips work.
 
#5 ·
Assuming there is nothing else wrong with it, the EGR's natural state should be closed, so you can pull the vacuum line off of it and plug it. Then see if it runs better, if it helps then you can go about capping it off permanently.

Also, I am not sure what altitude you are at, but the higher you are at the more advanced your timing needs to be to run right. I am at 4500 ft above sea level, and used a vacuum gauge to get my timing just right, turns out that up here the timing needed to be at about 13 deg, the default 8 was not even close to enough. Once I got the timing right on mine with the MC carb it came alive.

The other thing is make sure you hit the bottom of your carb with some starter or brake fluid and listen for the idle to change. The MC2100 base gaskets are really easy to end up with a leak between the carb and the spacer, if they are not put in either exactly right or with some silicone(or both).
 
#6 ·
Any vacuum leak would be suspect. Cap off everything except the distributor and see if it runs better. And it could be the dist. vac pot too. My CAD system had a huge leak and I ended up eliminating it. I also eliminated the EGR making a block off plate for the it at the manifold along with a lot of other things.
 
#9 ·
A stuck EGR will ONLY effect the engine at Idle because it creates an internal vacuum leak. Once the engine is off idle, about 1,500rpm the EGR becomes a positive port....
Does it run poorly ALL the time regardless of RPM ?
Pull the plugs and see what the gap is, what color are the porcelins.
Plug gap should be .060".
Porcelins should be a light tan color. If they are white, it's running very lean, vacuum leak/timing or carb jet issue. Dark would indicate a rich condition, carb jetting or weak ignition spark.
 
#10 ·
A stuck EGR will ONLY effect the engine at Idle because it creates an internal vacuum leak. Once the engine is off idle, about 1,500rpm the EGR becomes a positive port....
Does it run poorly ALL the time regardless of RPM ?
Pull the plugs and see what the gap is, what color are the porcelins.
Plug gap should be .060".
Porcelins should be a light tan color. If they are white, it's running very lean, vacuum leak/timing or carb jet issue. Dark would indicate a rich condition, carb jetting or weak ignition spark.
Well whats going on is that a have still an extremely bad idle, terrible accelerations(have to use lots of gas when im releasing the clutch to keep the damn engine on), stalls at red lights, i cant really even get it into 4th gear unless im going downhill(very weak power) i haven't touched 5 gear in months. It was running like this even before the MC2100 upgrade, changing out that stupid carter didnt make much of a difference.
 
#12 ·
I'm writing this on my cell, so I apologize for typos and auto corrects, lol...
Ok, so its prob not fuel then, I wouldn't do anything else related to upgrades until you sort out the mechanical cause. All four stroke engines work exactly the same...
Suck- air/fuel charge is drawn into the cylinder...
Squeeze- charge is compressed...
Bang- ignition/power stroke....
Blow- exhaust is pushed out...
It sounds like the engine has dropped a cylinder(s). The easiest way to check this condition is to disconnect one plug wire at a time and see what happens to the idle. If this is the case, the idle will not change much, if at all, when the wire is removed from that cylinder. I'm going to assume that you have replaced the wires, if not, check the resistance with an ohm meter or switch two wires and plugs and see if the problem moves to the other cylinder with the wire and plug. If it does, replace the plugs, wires, cap and rotor.
There are several options at that point regarding further diagnosis, I prefer doing a cylinder leak-down test, although a compression test is effective as well. The difference being that you can pinpoint exactly where the compression loss is going.with the leak-down option. Most parts stores will rent or lend the testers.
The initial steps for both tests are the same, disable the ignition coil and pull all the plugs....
Compression test- starting with cyl #1, screw the appropriate adapter Jose into the spark plug hole until the o-ring seats, hand tight is sufficient. Crank the engine over for a few seconds, no more 5. Record the results from each cylinder, you should have about 150-ish PSI. If there is more than a 10% difference between cylinders, you found the culprit. The problem is that you still don't know what the cause is. If two adjacent cylinders are low, suspect a blown head gasket...
Leak-down test- You will need an air compressor for this one... Pull the valve cover, insert hose in plug hole, rotate the engine until the test cylinder is at Top Dead Center with the valves closed. Hook up your air supply to the tester, some of these have a regulator, adjust it untold the gauge reads "0" PSI. Connect the hose from the plug port to the tester, record the results. Up to 10-15% is ok in an older engine. Now, here's the cool part. When you isolate the cylinder with the highest leakage, track down where the compressed air is going...
Valve train-cracked head...
Adjacent cylinders- head gasket...
Tail pipe/intake- bent valve...
Radiator- head gasket/cracked head...
Oil return holes in the head- bad rings or scorred cylinder...
This should keep you busy for a bit, but its the only way to really figure this out :)
 
#14 ·
I'm writing this on my cell, so I apologize for typos and auto corrects, lol...
Ok, so its prob not fuel then, I wouldn't do anything else related to upgrades until you sort out the mechanical cause. All four stroke engines work exactly the same...
Suck- air/fuel charge is drawn into the cylinder...
Squeeze- charge is compressed...
Bang- ignition/power stroke....
Blow- exhaust is pushed out...
It sounds like the engine has dropped a cylinder(s). The easiest way to check this condition is to disconnect one plug wire at a time and see what happens to the idle. If this is the case, the idle will not change much, if at all, when the wire is removed from that cylinder. I'm going to assume that you have replaced the wires, if not, check the resistance with an ohm meter or switch two wires and plugs and see if the problem moves to the other cylinder with the wire and plug. If it does, replace the plugs, wires, cap and rotor.
There are several options at that point regarding further diagnosis, I prefer doing a cylinder leak-down test, although a compression test is effective as well. The difference being that you can pinpoint exactly where the compression loss is going.with the leak-down option. Most parts stores will rent or lend the testers.
The initial steps for both tests are the same, disable the ignition coil and pull all the plugs....
Compression test- starting with cyl #1, screw the appropriate adapter Jose into the spark plug hole until the o-ring seats, hand tight is sufficient. Crank the engine over for a few seconds, no more 5. Record the results from each cylinder, you should have about 150-ish PSI. If there is more than a 10% difference between cylinders, you found the culprit. The problem is that you still don't know what the cause is. If two adjacent cylinders are low, suspect a blown head gasket...
Leak-down test- You will need an air compressor for this one... Pull the valve cover, insert hose in plug hole, rotate the engine until the test cylinder is at Top Dead Center with the valves closed. Hook up your air supply to the tester, some of these have a regulator, adjust it untold the gauge reads "0" PSI. Connect the hose from the plug port to the tester, record the results. Up to 10-15% is ok in an older engine. Now, here's the cool part. When you isolate the cylinder with the highest leakage, track down where the compressed air is going...
Valve train-cracked head...
Adjacent cylinders- head gasket...
Tail pipe/intake- bent valve...
Radiator- head gasket/cracked head...
Oil return holes in the head- bad rings or scorred cylinder...
This should keep you busy for a bit, but its the only way to really figure this out :)
Well..i took my jeep out for a drive today and it was still driving the same way..until i entered my neiborhood and the damn thing shut down!! While i was in 2 gear! Thats right! No spark! After i*coasted home* (got LUCKY), i popped the hood and smelt something burning but it wasn't any major need electrical wires..the ignition coil was pretty warm to hot. I have no radio, battery is fully charged, pretty much not electronics work except for my headlights and brake lights. The starter wont even crank! Its like its dead! Please help!
 
#15 ·
There's another thread on here, "my jeep won't crank " , sounds VERY similar to what's going on with yours now, ran like crap then shut off and no restart. There's a jumper harness between the battery tray and the fuse panel that he found deteriorated, see what that thread says, it was just posted tonight You can get there by going into my profile and looking at the all posts by link, I think.
 
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