Engine Heistating, smooths out after 2k rpm

[sleepy98gsx]

Here's my dilema..I bought this car for $200, the guy was the original owner and said he had the engine replaced due to a timing belt letting go on him. He said he thought the bottom end had an issue and after talking with this guy, he ended up just rambling and had no idea about engines or cars whatsoever. The car is a '90 Laser Turbo, i just put a new t-belt, tensioner, everything on the car, new plugs, wires, and i just put a spair set of factory injectors i had from another talon (injectors worked great when removed from the talon for upgrade).

The car will start up and once running for 30 seconds or so it will idle on its own, but it still seems as though it's misfiring while sitting, it will hesitate slightly with gas applied to 1800 rpm or so, then once above 2k rpm it will smooth out and run as it should.

A few things i notice at idle, i smell a lot of fuel? also every now and then i will hear a slight "gurgle" from the air filter. When i first got the car i took the timing cover off and found the belt was off 1 tooth. Possible it bent any valves being off only one tooth? i Have checked, i am obiously getting fuel and i have spark at all 4 cylinders.

I plan on doing a compression test within the next day or two, when i get a chance to grab my tester. But in the meantime any input would be greatly apprecieated. Thanks a lot guys.

 

[94dsmgsx]

First thing is run a Compression test and report those numbers on here. Have you checked your ignition to make sure your getting spark? Your probably misfiring on one or two cylinder's. I would start the engine and put gloves on and pull a plug wire from each cylinder individually. That way you can isolate which cylinder's aren't running.


You should test the ignition system first. Then if that checks out check your fuel system.

 

[sleepy98gsx]

yeah like i said i'll be doing the compression test tomorow at the latest, i did check to see if i was getting spark at the plugs and i had spark to all 4..

 

[sleepy98gsx]

alright well i think i may have foud the problem..my compression test results are as follows:


Cyl 1=160 Cyl. 2=below 25 Cyl. 3=160 Cyl. 4=below 25

So something is going on internally..i checked again, with car running and found similar results..i pulled the wires and got good spark on all 4, but noticed the engine only ran worse when i pulled cylinders 1 and 3, 2 and 4 made no difference what so ever between getting spark and no spark so i guess my next step is the head is coming off tomorow.

 

[sleepy98gsx]

just a finishing update, i pulled the head off today and found two burnt valves..i guess that's what i get for buying a $200 DSM!!

 

[Fast-Orange]

alright well i think i may have foud the problem..my compression test results are as follows:


Cyl 1=160 Cyl. 2=below 25 Cyl. 3=160 Cyl. 4=below 25

So something is going on internally..i checked again, with car running and found similar results..i pulled the wires and got good spark on all 4, but noticed the engine only ran worse when i pulled cylinders 1 and 3, 2 and 4 made no difference what so ever between getting spark and no spark so i guess my next step is the head is coming off tomorow.

It ran worse when you pulled cylinders 1 and 3 because those were the only cylinders with compression and were doing all the work, also for a future note a leak down test is a good way to determine if you have burnt valves, most likely have to pull the valve cover so you can see when your pushing down on the intake or exahust valves on the bad cylinders then watch to see if you have any other valves pushed down on other cylinders and if there is air comming out of the s/p hole then you know you have burnt vales on the cylinder your leak testing.