bucking on anykind of acceleration

[clough1022]

I have a 90' plymouth laser RS completely stock, recently about 2 months ago i replace the engine with a 90 gst motor. Everything was doing find until about a two weeks ago when i started it up one morning and it started bucking and idling at 500 rpm and when i try and drive it down the road the bucking gets worse and the car has no power.(it takes me about 15 minutes to get up to sixty.) So first thing i check after school was the plugs and wires .
The plugs showed me i was running lean which is good, but decided to change them anyway along with the wires. replace the wires now it only bucked when the engine was cold then went back to the bucking when it was warm and cold in about a week. I checked the tps also it turned out fine. also when i replaced the motor i replaced the fuel pump with the one out of the gst.
please help and if u need anymore info please ask!

P.S. Also when standing over the engine and i rev the car up just a tiny bit and let off i hear a metallic rattling sound near the transmission.

 

[BOBS90TURBO]

It may have jumped timing, have you checked, here is info on how to do it
http://www.vfaq.com/mods/timingbelt-1G.html

Are you building any boost, getting a ton of knock???

Is it bucking under throttle, or is it missing at idle also???

Have you checked for a boost leak, a bad leak can cause bucking.

As for the noise from the transmission, are you talking about from inside the car, or standing over the engine. If inside, it could be a throwout bearing. If on the outside, I have no idea.....

 

[Old Mitsu Tech]

I would have said plug wires hands down. Check and make sure you didn't crack a plug porcelain. Recheck the wires as I've had them go bad pretty quickly sometimes. I can't tell you why, but they do. Also, when you replace wires, save the slip as you will be using the warranty on those. I do.

You can also check your wires at night. Using a spray bottle, spray the wires, coils etc and look for arcing. Coil towers can be a source of this also. Just don't get a finger in there and find out what 20,000 volts feels like. I'd give a dollar to see that

The long boot that goes to the plugs is usually the culprit. Look at them closely for little white splotches with a tiny black dot in the center. If not sure, wipe some rtv over it and let it cure. If the miss goes away, you found it.

Good Luck

 

[clough1022]

It may have jumped timing, have you checked, here is info on how to do it
http://www.vfaq.com/mods/timingbelt-1G.html

Are you building any boost, getting a ton of knock???

Is it bucking under throttle, or is it missing at idle also???

Have you checked for a boost leak, a bad leak can cause bucking.

As for the noise from the transmission, are you talking about from inside the car, or standing over the engine. If inside, it could be a throwout bearing. If on the outside, I have no idea.....

(question 1)yes when i do it seems like it goes away a little bit but not much.
(2)both
(3)no
(4) from under the hood
hope this helps on HELPING ME find the problem

 

[BOBS90TURBO]

I would go with the idea of OLDMITSUTECH first, check the wires for arching, but If sure that is not the problem, pull the plugs one at a time while at idle and look to see if you are getting spark on each plug wire, It could be a bad coil pack. BE CAREFULL NOT TO TOUCH THE END PART AND GET SHOCKED, IT REALLY DOES HURT!!!!!!

Have you checked the ECU??? (behind and lower than the radio) Pull it out and take the top off and check for a funky fishy smell, look at the boards for any burn marks, check for any leaking out of the caps, I had one go bad once, and it caused some crazy engine problems, and took weeks to figure out the problem, make sure your mass is good and plugged in.

 

[clough1022]

i check my plugs and all of them were good except for the number 4 plug which was back (not a back soot like carbon) but a black polished look.

also i think my intercooler might have a leak because when the car is idling i can hear a hissing sound somewhere around there.

and the black snorkle looking thing on the air can is that important because one of my friends said u can take it off and i did and when a rev it up under the hood it sounds like it is sucking in to much air.

i will go head and finish trying your ideas.

 

[BOBS90TURBO]

Mkae sure your intercoller pipes clamps are all tight, If you have a boost leak, it WILL cause a car to run like crap, I really think that is your problem, do you have a boost leak tester, if not you should look at the vfaq's and build one, it is very easy to do, and a must for any turbo car owner, I have several people that I have checked and fixed boost leaks, and people were shocked, it is like adding 100HP somtimes.

And yes you have to have the snorkel thing connected, if you are talking about the thing that goes from the mass air to the turbo compressor intake, your friend is dead wrong, your car is not set up for that.

 

[pwayzjellyroll]

dunno if this makes much sense but a friend of mine had the same bucking problem a while back, it used to buck very bad in the lower rpm's and took him a while to get to a speed here it stopped, his problem was his motor mount broke but i duno if that helps you much just another thing to check

 

[clough1022]

thanks for the idea but think i found my problem. I was at my auto class and i was going to check my ignition timing and the front wheels were off the ground and i went over to the passenger side and was checking my lugnuts to see if they were tight and just to make the long story short the wheel was moving but the lugnuts were tight so i got a new wheel bearing and going to put in on monday. that could be my problem right please correct me if im wrong.

 

[milz]

I have a 90' plymouth laser RS completely stock, recently about 2 months ago i replace the engine with a 90 gst motor. Everything was doing find until about a two weeks ago when i started it up one morning and it started bucking and idling at 500 rpm and when i try and drive it down the road the bucking gets worse and the car has no power.(it takes me about 15 minutes to get up to sixty.) So first thing i check after school was the plugs and wires .
The plugs showed me i was running lean which is good, but decided to change them anyway along with the wires. replace the wires now it only bucked when the engine was cold then went back to the bucking when it was warm and cold in about a week. I checked the tps also it turned out fine. also when i replaced the motor i replaced the fuel pump with the one out of the gst.
please help and if u need anymore info please ask!

P.S. Also when standing over the engine and i rev the car up just a tiny bit and let off i hear a metallic rattling sound near the transmission.

WTF
1) if the car has no power why are you still driving it every day?? 15 min of bucking is 15 mins to long!!
2) running lean is not good!!!!!
3) check to see if a bolt came lose on your flywheel and is flying around your bell housing (take off the inspector plate and feel around)
could also be a engine bearing. Did you check or replace the main and rod bearing before they installed the motor.
4) have you ever did a compression check? if the number are lower than 100 your going to have to pull the head off the motor or rebuild the motor
5)wheel bearing needs to be fixed... YOUR ENGINE WILL STILL RUN POORLY
6) taking your snorkel off your air can is not bad!!!!!! it will allow the turbo to work more efficient
7) fix the leak!!! hissing sound the 1gen intercooler like to rust out check for rust or pin holes, clamps ic pipes

check all that and tell me what happen!!!
Good luck

 

[clough1022]

yeah i got the wheel bearing fixed monday but the site was down on my end and i couldnt get on to post. Also the rattling i thought it might be a loose or broke off flywheel bolt first when i heard it because i saw it on another post. the hissing im not sure is coming from the ic but im like 75% percent sure it is so ill check it. and finally when i got the wheel bearing fixed the bucking stoped here and there now it bucks every once in awhile but the car still lacks a whole lot of power. Ill get right to the things to check and post back.

thanks

 

[clough1022]

sorry about posting late but my internet was acting up. So i checked for a boost leak none that i could hear so that was good. Checked the compression it was about 160 over all four cylinders. also checked the timing the timing was off about 20 degrees before TDC so i adjusted it and i rev it up a little to see if it was different and when u rev it up the timing mark jumps like 15 to 20 degrees before TDC. its fine when it idles but as soon as u give it a little gas it jumps. So im going to take the timing cover off tommorow and see if my balance shaft belt broke or if the auto tensioner is loosing pressure. So if have ANY more ideas i could surly use them.

thanks

 

[rkarkosh]

I'm confused about the timing advancing like you said, if the ecu is still connected then it is suppose to advance like that. It sounds like you did not ground the wire found near the battery. Did you use a manual?

 

[clough1022]

yeah i grounded the the ignition timing adjustment connector i just didnt know it advances that much when you give it gas.