Help please!! Tj pops and backfires

[Chupa1]

I just got a 98 tj 4.0 5spd with a blown motor. I replaced the engine with a used one and i got it to turn on, but it is very hard to start when cold. The engine pops from throttle body and i can here a very loud sucking from the air filter. I tried cleaning the IAC sensor which was very dirty but still no help. If i play with the gas for a few minutes it will finally idle smooth but when i put it ingear and try to drive it i have no power at all, it just bogs down. I have 2 trouble codes p0500 (vehicle speed sensor malfunction) and p1594 (charging system voltage too high) i read the p0500 onlys deals with cruise control and speedometer gauge. And my volt gauge does not show high voltage. Any help would be great.
Thanks.

[6spdYJ]

What year is the motor you put in? Did you use the flywheel from your original motor on it? Did you replace the whole motor (manifolds etc) or just the block and head? Lack of power could be a few things - MAP sensor, TPS or distributor position. The distributor is not used to set timing. It sets the start time of the injector pulse. It will run in almost any position, but if they're starting too late or too soon, you may just be getting a dot of fuel into the chamber. Also, a compression test will tell you if the cam timing is off at all. Lots of questions, lots to look into. Be patient, you'll get it. When it actually has your blood in the engine, there's a sick satisfaction.

[NAILER341]

If you put your old distributor in, you may have it a tooth off.

[HB Jeeper]

first pass is to make sure the wires are on right. check your firing order. Also how did the other motor blow? The lack of power could be from a plugged exhaust (catalytic).

[Chupa1]

The new motor basically a longgood block was supposed to also be out of a 98. I used my old intake and exhaust manifolds. I put my old flywheel on the engine . I just purchased the jeep as a little project and it already had holes in the block. (Threw a rod) after i swapped everything over on the motors and installed it, it fired up just runs real bad. Im just not sure if i did somthing wrong or if a have a bad sensor somewhere because the jeep wasnt working when i got it. Thanks for the help guys.

[aw12345]

Start with the simple stuff. Use a vacuum gauge how much vacuum at idle. Check firing order 153624. Make sure you did that right so watch which way the rotor turns when you crank it. If the sparkplug wires are on correct and it still runs like crap, there are a couple of things you want to look for if you rev it up a bit for a while does the exhaust manifold and pipe get red hot?
Also when you crank it does it sound like it cranks at an even speed? If it speeds up and slows down it has a dead hole.
Vacuum at idle should be somewhere around 19-21" of vacuum on a vacuum gauge if it is low there is a good change it has an intake leak. Also you can try to take the exhaust pipes loose off the exhaust manifold and see if it runs noticeably better.
This should get you a lot closer to getting an idea what you need to do to get it running right.

[Chupa1]

When i installed the distributor i had the engine at tdc. Then i pulled the cap checked that the rotor was at number one and pluged in the wires 153624 in a clockwise direction. Would the engine even turn on if i was off 180? When i crank the engine sounds good it spins fast untill it starts. Im not sure what u meant by dead hole? But the exhaust manifold does not glow red. I once let it idel for like 15-20 mins and it was not red hot but when i put it in 1stgear it poped and had no power i had a hard time just moving forward at all. When i swaped motors i drained all fuel out of tank and put 5 gal of fresh gas but my fuel gauge still says empty with the light on. Could u that be a problem?

[HB Jeeper]

It would not start if you were 180 out. since there is no advancement on the distributor, you cannot adjust it to see if it will run any better. You may need to bring it back up to TDC and check the wires again. you may be off by one.
The dead hole is that one cylinder is not firing. to check this, you can have all of the wires lightly in plcae on the plugs and then start the engine...starting from front to back pull the #1 wire off and see if there is any change in how the engine is running. Do this through #6. If it runs rough(er) on each wire then you are most likely fine. if you find 5 cylinders are fine but one is not, then pull the one plug, check if it is fouled with raw fuel or no fuel.
Also, check to see if your injectors are all working. If you have a long screwdriver you can put the tip on the round black portion of the injector just below the electrical connector and put your ear on the other end, like a stethoscope. Listen for fast clicking...that is the injector pulse...if one is not pulsing then replace it.
To be honest, I feel like you are most likely off on your wires. the no power sounds like the timing is retarded and since there is no way to advance it, you need to move the wires back one (counterclockwise)

[Chupa1]

Thanks for the help. I will take a double look at the plug wires when i get home.

[Chupa1]

So i finally got around to working on the jeep. I double checked the wires and i had 3 &4 CROSSED. so i went to start it and nothing. I pulled the distributor cap and. Rotar and the cam sensor. I did not know about the alignment holes on the round plastic and the body of the distributor. So long story short put it all back snd it starts right up. I drove it up and the street and it works great. THANKS FOR ALL THE HELP!! I still have the check engine light on. Any ideas??? Thanks again for the help.

[inVERt'D]

Sure your code scanner doesn't have a clear function? If not, take off the battery leads and hold them together for at least 30 seconds. Supposedly, that will clear the computer.

[aw12345]

You most likely have missfire codes set, drive it for awhile and it should clear the light takes like 30 key cycles or something like that

[HB Jeeper]

aw12345 is exactly right...after so many cycles of the ignition with no triggers, the light will go off. The other option (does not work on all models of cars) is to pull the ECM fuse for 30 seconds.

[inVERt'D]

Without going into a lot of detail, the ECU uses a lot more metrics than key cycles to set and clear codes.

At any rate, disconnecting the battery will clear the ECU and do it much faster. It's not like there would be anything valuable in the memory anyway--he just got it running.

[aw12345]

If there are no active codes the light will go off eventually, most likely it has several misfire codes set because of the crossed wires.
disconnecting the battery cables and holding them together for a minute or so will clear the codes and also forces the ecm to relearn which after an engine swap isn't a bad idea at all