Voodoochiled445

ok so I back tracked everything I did and got it running much better. I had put an aftermarket air filter on at first, ran great. I decided to put the stock set up back on. The vent hose from the crankcase has trace blow by. Inside of my air cleaner was covered in oil and so was the intake hose. I cleaned it, put the aftermarket air filter on and no bogging! I had 2 backfires while shifting but I'm thinking that may be because of the cherry bomb thats on it now. Every car Iv owned with a straight pipe or cherry bomb would pop a little on deceleration or shifting. Also I don't see any gas in the vacuum line, Iv tried running a clear vacuum tube and see no gas but it sure smells like it. Any ideas?

Ok I was thinking fuel pressure also, I checked the fuel pressure regulator for leaks and I can't say I found gas but the vacuum line to it reaks of gas and I swabbed a qtip into the vacuum inlet of the fuel regulator and it smelt of gas. I remember reading somewhere if it smells or has gas in that vacuum line its diaphram is toast. Is that right?

No mice nest, wiring looks good except front blinkers and parking lights not working. I have put many tanks of premium fuel in the tank and 2 cans total of seafoam at different fill ups. Truck is becoming very annoying, I have a '78 cherokee, everything is original and it runs like a dream. Good power, no smoke, all lights and electrical work... WHAT WENT WRONG AMC??? That truck is twice as old and beat up and runs twice as good. Same can be said about any car pre 1980 that I have owned. :wall: I'm going to do that EGR test now and be back with results. Btw plug wires are on correct, I used autolites for spark plugs, nothing fancy.

Well after driving it some more I'm thinking TPS, seems the slower and steady I push the pedal the more fluid the acceleration. If I'm real steady I can bring it over 3000 RPMs and shift with no bogging or backfire. If I mash it or push real fast it will bog and backfire. TPS? to me it really feels like the advance timing is off, what are symptoms of a bad knock sensor? past 3500RPMs the engine isn't so smooth and shakes the truck quite a bit, bad motor mounts? truck gets to point A to point B but just doesn't feel "right". Previous owner said it sat for many years before he owned it and he drove it very little. I don't know if that can help anyone with anything but thought Id mention it. :wall:

Ok got the meter working, still trying to figure out how to read all the numbers and lines but I can say it operates smoothly from close to WOT. Not sure if its the right volts tho. will check the EGR next.

Ok so I have the 5 volts with the ignition on coming from the wiring harness, now how do I check the sensor? The little positive and negative leads don't fit in the tps with the harness connected... I'm kinda confused :huh???:

odometer reads 161,318 I hate cars with computers!!! haha I was thinking timing chain, timing is usually the cause of backfiring so my first guess awhile ago was maybe a bad knock sensor. It feels like it isn't advancing fast enough, almost like when a vacuum advance isn't working properly. Damn sensors! haha :wall:

Well I plugged up my vacuum lines to the EGR and plugged the EGR nipple and I still get a back fire while pushing in the clutch at any RPM higher then 2500rpm. I have no vacuum leaks that I can find, I have sprayed starting fluid everywhere a vacuum is present, in the engine bay and lines connecting to the tranny. I have altered the CAD to stay engaged ala the guide found on this forum, so that vacuum motor is bypassed and lines are capped. Seems this has been happening since the new o2 sensor, brand new bosch. Knowing my luck I bought a bad one...

Also I have no emissions where I live so I'm wondering if I can just delete the EGR for now. I know it can be done on an old school engine by plugging the vacuum lines but this car has a brain (computer), so can I plug them and not make it mad?

Thanks for the info! Ill need to get a multimeter, been needing one a lot but never got around to buying one, I will break down and get one. Iv tried chasing down vacuum leaks by spraying starting fluid around any vacuum source and get no gain in idle speed or rpm so EGR might make sense since its not always getting vacuum if I understand it correctly. Been nose deep in my Chilton but a lot of it is kinda lack luster.

I spent a good amount of time looking through searches but Id like to post a new thread with my exact symptoms. Here is what I have done to my '87 Comanche 4.0 5 speed: New cap and rotor New plugs and plug wires New oil and oil filter New fuel filter New alternator Seafoam in intake and gas and tranny fluid through intake(before putting in new O2) New air filter New O2 sensor OK so the truck is running a lot better then when I first purchased it but I am having some intermittent bogging issues and backfiring. Sometimes the truck runs real smooth and crisp and then sometimes it feels like something is just not all there. Doesn't run bad but just doesn't feel "crisp". Today I was on the highway doing about 2,500-3,000rpms in 4th and then whenever I let off or gave it gas it began to bog and miss real bad and backfire repeatedly. After that episode it backfired a few more times only when letting in the clutch to shift, it then drove fine for the rest of the day. I checked the coil and got a decent spark, wasn't blue but I have cheap wires. That wasn't what concerned me but what did is I noticed it needed to crank a few times before the coil produced a spark, every coil iv seen got a spark instantly the ignition was tapped but those were old school points and condenser style ignition set ups. :wall: :wall: :wall: Last I noticed my throttle response was WAY better if I slowly press the gas, if I just mash it, it takes forever to climb RPMs. Any help and tips would be very appreciated :wall: :wall: :wall: btw I have cleaned many grounds including battery negative to engine (that was scary dirty)

Thanks for the advice! Ill go through all the steps and should have it done in a few hours tomorrow. This is my second jeep, as you can see in my avatar, Iv also been wrenching on a '78 Cherokee. Getting the hang of these AMCs as Iv mostly worked and built old school chevys. :thumbsup:

Yes that's the one weather is crappy right now (live in washington) but I really need my truck so may just be a trooper and do it in the rain tomorrow haha Any other tips?

Ok gotcha, I'm done with this vacuum issue on the CAD, going to follow a guide i found and get that puppy locked in. Thanks for the replys!

After reading I'm thinking of just putting the CAD locked in 4wd, I know people say its ok to drive as a daily like this but I have one concern. wouldn't the front and rear wheels move at the same speed? If so wouldn't it shudder while taking turns as a result of the front end moving faster while turning sharp. Thanks in advance.