Ok, here is the setup.
1990 DX civic. multipoint..
1996 motor, only used the head and the block. Kept the 1990 manifold on. Didnt change a thing. using the stock distributor also. Only wiring that was changed was the fan switch.

Before the swap, the car ran fine, it just smoked really bad so we put a new motor in. After the swap we started the car up and it ran fine for 15 mins, if you didnt touch the gas. It was very hard to start though. It would backfire through the intake manifold. The vehicle will idle fine until you touch the gas, then it starts to die. You have to just feather the gas to get it to stay running. All the time its backfiring through the intake...

So, being the intake manifold was pulled off the old motor and no wiring was changed at all, what could cause this?? My first check is to see if the engine timing is on. Besides that, dont really know what else to check.. Going to make sure the map sensor hose isnt blocked at all.

ANy help?

 

You say the 90 DX has the multi-port swap done on it?

so you have 4 injectors?

what ecu are you using?

 

NO, multipoint is that one injector crap.

The car is a 1990 DX stock... Doesnt have 4 injectors... I didnt change ****.. I just took a 1996 motor, head, block, and put it in. i used EVERY other wiring and manifold off the stock motor....

 

Multipoint is 4 injectors. What you have is dual point, which is throttlebody injection. There is two injectors. one has a brown plug and one is green. I would guess crank and cam timing. Did you take off the timing belt? If it is only one or two teeth off, it will still run. The backfiring through the intake means that it is sparking while the intake valves are open or you have a super-bad valve. Usually you won't see intake valves burn, but it happens. I would try the timing first. Hope this helps.

 

check your firing order.

 

Mike, thanks man.

Ya, its the dual point then.. Only 2 injectors...

Ok, next question for you, we used the 1990 distributor on the 1996 head. It bolted on no problems. Can we use that?? or do we need to rewire the 96 distributor??

thanks for all your info.

 

Here you go......
Do this First http://www.fourthgenhatch.com/mpfi.html


Then do this Second http://www.angelfire.com/ks/crx/pic2.html


That should solve all your problems..........
Good luck....

 

Uh no. The car is stock. There is no need to switch it to fuggin the 4 injector setup. IM using the stock 1990 manifold with the stock dual point setup.

 

Ok then, when you get an intake backfire its usually because your firing order is off. You might have your plug wires on wrong or your distributor on wrong. Also do you have a CEL?

 

Firing order is correct and there are no cels. Distributor is not 180 degrees out otherwise it wouldn't start at all.

 

I don't think you should need to use the 96 distributor but it may be lined up different. When the crank and cam are at TDC, Is the distributor at the same angle as it is on the D15B2/B1 head? Uhm... I have never done that swap. I wish I could help more.

By the way, a lot of these people just write 'BUMP' What does that mean?

 

a thread or topic is moved to the top of the forum when some1 replies. if it's been a day or so a topic will be 4 pages back. people write Bump to, "bump" the thread to the top.

back on topic. you were correct to use the dpfi dist. but I would suggest doing a mpfi swap, it's fairly easy and you should see a good power gain w/ it.