Flyers311

i am looking for some advice on how I can ensure my ls swap is running safely and not damaging itself.

A year ago I bought a ls1 / t56 to swap into my 87 camaro. The engine was not running when I purchased it so I could not verify its condition very well. After the swap was completed I could never get it running 100%. I bought some really cheap sensors at first which was a mistake. (map, maf, iat, o2) Map didn't work out of the box so that immediately got replaced with a quality sensor. That finally allowed the engine to star for the first time. It had a high idle. I was able to temporarily get the idle down by taping over the small hole on the throttle plate. Then when driving the maf sensor stopped reading and the car wouldn't move. Well waiting for a tow it started reading again so I drove home and the next day I bought a quality maf sensor and o2 sensors. The only cheap sensor left is iat and the temp does read accurately so I haven't replaced it. Next, to try and fix the idle, I tested the iac solenoid and found it to be bad. Once that was replaced, I removed the tape from the throttle plate. The idle was much lower however the car would frequently stall when the clutch was pushed in approaching a stop. At this point the car was clearly burning oil. I tested compression and it was low on all cylinders. This all happened over the course of 1000 miles of driving. The only consistent check engine light code was a Radom misfire on all cylinders. After about 50 miles it would keep coming back. Also if I used 6th gear it would immediately throw that code and flash, but stop as soon as I went to a different gear. (This only happened a few times and as soon as the light started flashing I let of the throttle )

Since all of this I have bought a lq4 and successfully swapped that in place of the ls1. It started up easily idled slightly high but smooth. I drove it very slowly around my neighborhood once and drove great. I am currently waiting to get my computer back from a mail order tune to adjust for the larger displacement.

So so that brings me to my concerns as to how do I ensure I don't ruin another engine. I was just looking at videos I took of the exhaust from the ls1 swap and the video from when I first completed shows no smoke at idle or while reving. A video I took right before pulling the engine shows it smoking at idle and huge puffs when reved. This pretty much confirms that the engine was damaged while I was driving it with the issues I mentioned. The ls1 cylinder walls have vertical marks on the top and bottom of every cylinder.

My my first thought is that driving with the iac solenoid not working caused the issue. The timing was all over the place trying to correct the idle. I would assume that this could have caused detonation at higher rpms.

Does anyone have advice on what I can do to ensure that my lq4 is running safely? I know very little about engines unfortunately. I would really like to avoid this from happening again. The engine is stock other than headers. The tune will be for a stock lq4. Map, maf, o2, iat, and iac are all les than a year old and work properly. The lq4 ran fine on a stand prior to me purchasing. I have a obdII scan gauge that I can read most of the sensors with.

Any help is much appreciated.

SheepDog209

iTrader: (2)

Sensors go bad all the time, but don't cause physical damage to the engine. How many miles were on the first engine? Single or dual exhaust (was it smoking out of 1 tail pipe or both if dual)? Why was it sold in the first place? I'm not convinced you did anything to damage it.

Flyers311

Thanks for the reply. Claimed mileage was 25,000 but I knew that was unrealistic. It was clean looking on the outside when I bought it. It was sitting in a 94 trans am but not hooked up. Seller said he was going a different route. I have just assumed the engine had very high mileage due to how even the wear on the cyclinders was. Compression was between 65-100 psi on all cylinders when I pulled it back out. I was't worried about it till recently watching videos of the exhaust and seeing all that smoke 2 months after the video with no smoke. Maybe it was oil accumulated in the intake by then idk.

exhaust is single so no way of know if it was just smoking from 1 side.

What about if he tune was way off? That's the only other unknown I can think of. If the previous owner had messed with the tune and screwed it up and then I just assumed it was a stock tune.

DT69cam

Based on what you are saying, that Ls1 was shot. A flashing MIL (Check engine light) is telling you you have a severe mis in the engine. You state the compression was low, oil buring, etc, that = motor is done. I would try and find a local tuner so this way he can make adjustments as needed. Mail order tuning can be difficult.

Pop N Wood

iTrader: (1)

I agree.

Usually good practice to pull a head and a couple of rod/main bearing caps when checking out any unknown used motor. You of course did drain and replace the oil and filter before starting the motor? Check the intakes for dirt/debris?

Pretty easy to rebuild the bottom end. All is not lost.

Flyers311

Just so everyone can see what I am referring to I have put links to the videos below. There is about 1000 miles more on the engine in the second video.

First start no smoke:
https://youtu.be/22YstWVn_IU

Last start lots of smoke:
https://youtu.be/wDr7z2b8r1A

And yes the oil and filter were new and intake was debris free.

Flyers311

What about the old injectors leaking fuel after shutting off the engine, then causing washout of the cylinders? Engine had sat for a couple of years prior to me buying it. Several injectors were partially clogged. I ran cleaner through them all prior to starting the engine up and they all looked to be spaying fine but they could still be leaking fuel.