My car is a 1988 320i with motronic 1.3 with Getrag 240 tranny. Couple weeks ago, I spotted a 1990 325i car for selling relatively cheap, so I took the whole car and going to drop the m20b25 engine into my car. During the 325i purchase, the owner did tell me he had the a rocker arm, all the valves replaced about 6 month ago.
Last week, my shop was basically removing the engine from the old car and perform some maintaince, items like oil pan, crank, valve cover seals, timing belt, water pump...etc.
Over the weekend, was the main show. We began to pull off my m20b20 out of the car. 1st thing we noticed was the injector harness in th car was wrapped in thick layers of electrical tape. After cutting open the tape, we discovered 3 injector wires were broken off from the connector. Whoever did the repair actually bypassed the connector and twist the wires together. I had no issue with this, except the repair guy used [plastic bag] as insulator to prevent short. My shop then decided to pull off the engine harness from the beatup 325 and used that instead.
When engine/tranny was finally back into the car. It was time to turn on the engine. As soon as we turn the key to position III, we saw smoke coming out from the main relay. Immediately removed the negative battery cable and took a closer look. We found out the red/yellow wire coming out from main relay leg 87 had melted down to bare copper wire.
At this point, we could not figure out why since the shop does not have E30 electrical manual. The shop believed the replacement harness must got twisted and cause a short somewhere. He took out another spare set of M20 engine harness and swapped in.
While my shop was doing another harness swap, I was busy search online for E30 electrical manual. Thanks for the great E30 community, the PDF was downloaded within 15mins. I took about another 10 mins to learned that the fried wire was actually for ABS which my car did not have.
I immediately gone back to garage area to tell the shop owner, but it was 1min too late. The poor guy had finished the swap and decided to try it. Again, smoke came out, and this time even fuse box was smoking pretty good.
The shop guy was speechless. After we took a smoking break and examined what had happened, we finally realized what the problem was. the freaking harness did not match~!! duh~~!
That red/yellow wire is actually an ABS power wire which goes to the pump. The wire itself will go to pin 20 on C101 then route it's way to ABS. Since my car is a 1988 320 w/o ABS, the pin 20 on C101 is actually a brown color ground wire coming out and going into interior. Big Duh~~!!!! No wonder we kept frying that wire.
After we cut that red/yellow wire off from the main relay and turned the key on, thank god there is no smoke. We were ready to crank the engine.
After few cranks, the engine is alive, but raced itself to 2000rpm, then cough itself to death. Checked all wire connections, vacuum hoses and spark plugs, we found out the #6 cylinder was lean while #1~#5 were running way rich. Code shown 1122, and AFR reading shown a very lean condition. Took a closer look and found out intake manifold gasket for #6 cylinder was not installed properly which cause a massive leak. duh~ Took off the intake manifold and reseat the gasket again
While we had the intake manifold off, we also discovered the intake valve for cylinder #1, #3, #4 and #5 were coated with good amount of engine oil. More oil stain was found between cylinder head and block at various spot which lead us to believe the head gasket is not seating properly and cause some oil to come out. We then decided to put everything back and confirm the vacuum leak 1st and deal with the oil leak later.
Everything is back and we were ready to start the engine. This time, the engine would idle itself ok, but still shaked a bit. Idle AFR still shown a very lean condition. Give it some gas, and AFR would dither around 14.7. We believed the engine still had a vacuum leak, but much smaller. We began the hunt for more vacuum leaks.
While we let the engine idle and investgating the vacuum leak, we found more oil leak and some strange rattling sound. We pulled the oil dipstick to verify the amount of oil, only to find out we went from dip stick max to min during 1st engine crank to now.
We had massive oil leak.
The rattling sound were traced to inside the timing covers, but we were not sure what that was. We then pulled apart the timing cover to trace the rattle/rubbing noise.
My shop guy, myself were tired, angry, and speechless. We took out the service record for the previous cylinder head service and studied it. In summary, the previous repair was a piss poor repair job. Head bolts, camshaft seals, valve stem seals, did not get replaced when head was off. Either the guy did not want to spend extra or the pervious guy wanted to save $.
I finally gave in and decided to pull the head off and want to refresh the cylinder head. Right now, the car is still in the shop waiting for cylinder head to come back. I just keep my finger crossed that nothing more will break or gone wrong from this point.
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Update #1
The head gone to machine shop today and came back with horror news.
1. head was wrapped and had to be machine off 0.20mm to be flat. Cylinder #3~#5 area was 0.15mm less. This would explain the oil leak around cylinder #3~#5
2. Camshaft is no good. Several lobes shown good amount of scratch and grooves. Journals also had a lot of marks
3. The area around #6 cylinder intake rocker arm had a hair crack. The machine guy said the previous repair must tried to hammer out the rocker shaft and cracked the head. He said it can be repaired though.?
4. All exhaust valve were not sealing properly and had to be replaced.
5. Few more rocker arms had to be replaced
We conclude the previous repair was probably due to overheating. The oil spray bar was clogged resulting little lubrication for the valvetrain. The repair guy obvious did a piss poor job by not resurfacing the head, cracked the head and lie about replacing all 12 valves.
So, ouch.... that's more bad news coming. At this moment i am just praying by replacing all these parts would get the car back running properly. Kinda sux so much had to be done on this engine. I know there is always risk involved buying used engine, only this time, I have very little luck on the purchase.
Oh well, will keep you guys updated.
Last week, my shop was basically removing the engine from the old car and perform some maintaince, items like oil pan, crank, valve cover seals, timing belt, water pump...etc.
Over the weekend, was the main show. We began to pull off my m20b20 out of the car. 1st thing we noticed was the injector harness in th car was wrapped in thick layers of electrical tape. After cutting open the tape, we discovered 3 injector wires were broken off from the connector. Whoever did the repair actually bypassed the connector and twist the wires together. I had no issue with this, except the repair guy used [plastic bag] as insulator to prevent short. My shop then decided to pull off the engine harness from the beatup 325 and used that instead.
When engine/tranny was finally back into the car. It was time to turn on the engine. As soon as we turn the key to position III, we saw smoke coming out from the main relay. Immediately removed the negative battery cable and took a closer look. We found out the red/yellow wire coming out from main relay leg 87 had melted down to bare copper wire.
At this point, we could not figure out why since the shop does not have E30 electrical manual. The shop believed the replacement harness must got twisted and cause a short somewhere. He took out another spare set of M20 engine harness and swapped in.
While my shop was doing another harness swap, I was busy search online for E30 electrical manual. Thanks for the great E30 community, the PDF was downloaded within 15mins. I took about another 10 mins to learned that the fried wire was actually for ABS which my car did not have.
I immediately gone back to garage area to tell the shop owner, but it was 1min too late. The poor guy had finished the swap and decided to try it. Again, smoke came out, and this time even fuse box was smoking pretty good.
The shop guy was speechless. After we took a smoking break and examined what had happened, we finally realized what the problem was. the freaking harness did not match~!! duh~~!
That red/yellow wire is actually an ABS power wire which goes to the pump. The wire itself will go to pin 20 on C101 then route it's way to ABS. Since my car is a 1988 320 w/o ABS, the pin 20 on C101 is actually a brown color ground wire coming out and going into interior. Big Duh~~!!!! No wonder we kept frying that wire.
After we cut that red/yellow wire off from the main relay and turned the key on, thank god there is no smoke. We were ready to crank the engine.
After few cranks, the engine is alive, but raced itself to 2000rpm, then cough itself to death. Checked all wire connections, vacuum hoses and spark plugs, we found out the #6 cylinder was lean while #1~#5 were running way rich. Code shown 1122, and AFR reading shown a very lean condition. Took a closer look and found out intake manifold gasket for #6 cylinder was not installed properly which cause a massive leak. duh~ Took off the intake manifold and reseat the gasket again
While we had the intake manifold off, we also discovered the intake valve for cylinder #1, #3, #4 and #5 were coated with good amount of engine oil. More oil stain was found between cylinder head and block at various spot which lead us to believe the head gasket is not seating properly and cause some oil to come out. We then decided to put everything back and confirm the vacuum leak 1st and deal with the oil leak later.
Everything is back and we were ready to start the engine. This time, the engine would idle itself ok, but still shaked a bit. Idle AFR still shown a very lean condition. Give it some gas, and AFR would dither around 14.7. We believed the engine still had a vacuum leak, but much smaller. We began the hunt for more vacuum leaks.
While we let the engine idle and investgating the vacuum leak, we found more oil leak and some strange rattling sound. We pulled the oil dipstick to verify the amount of oil, only to find out we went from dip stick max to min during 1st engine crank to now.
We had massive oil leak.The rattling sound were traced to inside the timing covers, but we were not sure what that was. We then pulled apart the timing cover to trace the rattle/rubbing noise.
My shop guy, myself were tired, angry, and speechless. We took out the service record for the previous cylinder head service and studied it. In summary, the previous repair was a piss poor repair job. Head bolts, camshaft seals, valve stem seals, did not get replaced when head was off. Either the guy did not want to spend extra or the pervious guy wanted to save $.
I finally gave in and decided to pull the head off and want to refresh the cylinder head. Right now, the car is still in the shop waiting for cylinder head to come back. I just keep my finger crossed that nothing more will break or gone wrong from this point.
================================================== ==
Update #1
The head gone to machine shop today and came back with horror news.
1. head was wrapped and had to be machine off 0.20mm to be flat. Cylinder #3~#5 area was 0.15mm less. This would explain the oil leak around cylinder #3~#5
2. Camshaft is no good. Several lobes shown good amount of scratch and grooves. Journals also had a lot of marks
3. The area around #6 cylinder intake rocker arm had a hair crack. The machine guy said the previous repair must tried to hammer out the rocker shaft and cracked the head. He said it can be repaired though.?
4. All exhaust valve were not sealing properly and had to be replaced.
5. Few more rocker arms had to be replaced
We conclude the previous repair was probably due to overheating. The oil spray bar was clogged resulting little lubrication for the valvetrain. The repair guy obvious did a piss poor job by not resurfacing the head, cracked the head and lie about replacing all 12 valves.
So, ouch.... that's more bad news coming. At this moment i am just praying by replacing all these parts would get the car back running properly. Kinda sux so much had to be done on this engine. I know there is always risk involved buying used engine, only this time, I have very little luck on the purchase.
Oh well, will keep you guys updated.
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