I have a 1991 civic dx with about 168k on it.I recently replaced the engine with an engine from Japan,it was a perfect fit 88-91 1.5 liter.The engine runs fine unless I take it on the freeway, then it shows check engine light and loses power.In order to time the engine with a light to timing marks, I had to rotate the distributor clockwise so far that the that the 3 tabs with bolt holes on the distributor for holding it on the head, did not line up with the 3 threaded mounting holes on the head.To remedy this,I made a bracket between one mounting hole and a tab, and used large washers to hold the distributor down in this position on tabs with bolts in the other 2 mounting holes.As specified for timing, I also put a jumper wire in the ECU diagnostic port under the glovebox when I timed the engine.The timing is correct on cam and crank sprockets and the crank pulley with timing marks is identical to the one on my old engine.I think the timing was over 40 degrees advanced and the car did not run well this way with the distributor bolted down normally.After the check engine light comes on when on freeway, and I stop car, then restart, the check engine light goes off and leaves no codes.If I start up and accelerate on freeway, the whole process starts over again.
I am wondering if the japan camshaft is different than the USA camshaft,this engine head also had a place for a mechanical fuel pump and had an eliptical spot on the cam to drive the fuel pump.I took my old engine in as a core return, so I can't compare camshafts.Has anyone run into this problem, I would really appreciate any help here.
Thanks.

 

So much for "perfect fit". Probe in the #1 spark plug hole to make sure you're really setting the crank to TDC. Then the slot in the end of the camshaft that drives the distributor should be vertical with respect to the engine, i.e. perpendicular to the top of the head when set to TDC1. Spark timing should change dramatically (retard) when you have the test jumper in. If it doesn't change you're not jumping the right thing.

While driving with the check engine light on you could have an assistant watch the LED and count out the code. On the OBD0 system it is not necessary to put the jumper in to read codes-- the LED is always active whenever the key is on and the jumper is only necessary to set timing. If the "BACK UP" fuse in the box under the hood is blown or missing, the ECU will not remember codes with the key off.

Rule #1 about core parts is never return them until after the new part is on the car and working.

 

Slot is vertical,piston is at TDC1 so I guess the cam is ok.
When the distributor is bolted up normally and the crank pulley is at the firing mark, I made sure the sensors inside the distributor for the number 1 cylinder are lined up correctly, but when I have the jumper wire installed in the correct place in the port {brown and green white wires} under glovebox, and I time it with a light, it still is advanced too much.The timing doesn't change much with or without the wire in.It doesn't have LED lights, but would flash the check engine light for codes. I drove the car and did not get any codes,but I did not go on freeway as ran out of time.Anyway the car ran crappy like it was out of time and would just die while idling occasionally.It does have a backup fuse.
Maybe something wrong with the computer?

 

update here-the head cam and crank timing with belt and belt (106 teeth)are right, there is no play in cam sprocket and and cam mounting, all stock.The problem is that the car when timed correctly with a light on the red mark, needs to have the distributor cranked clockwise past the mounting tabs just a bit, if I look in the distributor with car stopped, and the crank pointer on the red fire mark on pulley, the prong for firing number 1 cylinder in the distributor, is still about 1/4 inch before the pickup in the distributor. I have tested the stock distributor and a replacement distributor and both need to be cranked past their mounts to time correctly so the car is firing before the prong passes exactly under the pickup sensor.The car will run fine all day unless I go on the freeway and then after about 5 minutes it throws a code 4, crank alignment sensor and goes in limp mode, usually when trying to keep speed up to 65.I assume the clockwise cranked distributor is causing the code, could it be the computer, I don't know what to try next.Has anyone seen this before?