Hello,

Just did the DPFI to MPFI swap this weekend and have some issues:

1) idle is at 2,000 to 2,500 when I first turn it on. Then, after 10 seconds, it goes down to 1,500 and then drops to around 500. Then it surges to 1,000 again. It keeps idle hunting between 500 and 1,000 rpms. When I disconnect the EACV, the car stays around 1,000 rpms, but it is very shaky.

2) I have Cel code 14. At first I had a Cel code 16 and a high idle at 3,000 to 4,000 rpms, but I changed the IAT. Now # 1 is happening and I have Cel 14.

3) Car runs really rich. Lots of black stuff and water shooting out of muffler. Also, car runs in limp mode.

I checked the vacuum lines and they seem to be good. The coolant hoses seem to be ok, but I was a little confused since most write ups and diagrams had a throttle body with the FITV under the throttle body. Mine does not have one and it also only has 1 hole inside the throttle body, not 2.

The wires seem to be good at the ECU. Not sure what else it could be. Any help would be appreciated.

Thanks

 

What setup are you running?

 

I'm using my stock engine that came standard with my 1990 Civic Base model. The only mods that i have done are switched to 5 speed transmission and now this MPFI swap.

Thanks!

 

D15B2 in a 1990 Civic with a 5-speed swap and a DPFI to MPFI conversion.

EDIT: What ECU are you running? OBD0 or OBD1? What distributor?

Alright, could be a misfire.


That should be a step in the right direction (8:00). You can diagnose what cylinder is misfiring, if there is one. If it is, check for compression, fuel, and spark.

 

Thank you for your help. Didn't know a misfire could cause all those issues. I am using a 1990 Civic SI Distributor and a PM6 ECU. They worked fine on the other cars they were on. Also, have new NGK spark plugs and new NGK wires.

 

Okay, that's usually the easiest thing (wrong parts) to fix. Double check your wiring if there isn't a misfire.

 

I'd double check that you didn't accidentally get your tps and map sensor connectors crossed. I speak from experience, the car ran just like you're describing when it happened.

 

Worked on the car today and noticed that a bunch of hoses did not have clamps on them. I went through all the hoses and added clamps and made sure they we're secure. Also noticed that 2 of my injectors were leaking, so I swapped them out. Cleaned my EACV with MAF cleaner and checked the vacuum lines once more. Added a lot more coolant (didn't realize it had leaked so much). Started the car and I do not get a CEL anymore and the car does not run rich. It starts at 3k rpms, but as soon as I started driving it, it drove great. Had lots of power, and there was no hesitation. Drove it for a mile and it felt great. When I stopped, the idle was surging from 500 rpms to 1.5k rpms. I let it idle for awhile and it kept on surging.

Now. I did notice that the PCV valve needs or be put in correctly. I broke the grommet awhile ago, so I just have it plugged into the breather tube directly, but it seems to be in tightly. I did not clamp it since I ordered a new grommet and will be getting it on Tuesday. Could it's be the source of my surging idle? I checked the EACV wires and they look fine. When I unplug the EACV, the idle stays constant, the engine just shakes a lot and doesn't sound good. So, since it is having this affect, I am assuming the EACV is working, or at least wired correctly?

Almost there, just need to correct this surging idle!

 

Drove the car again and noticed that the idle surge goes away if I drive it for a couple of miles, but the idle stays at 2,000 rpms. Also, noticed that my car doesn't start at times unless I step on the gas pedal a couple of times while turning the key. Anyone have any ideas? Checked my oil too and it seemed on the low side. I may change the oil after work.

 

Id suggest looking for any leaks around the intake manifold, also try unplugging the the iacv and resetting the ecu then plug it back in.

 

Thanks for the advice. I sprayed CARB cleaner around the intake manifold and vacuum lines and the idle remained the same. I did unplug the IACV and the idle did drop and the car started running bad. So, it seems like the IACV is working...Maybe I need to get a new IACV gasket?

 

Got everything working well now, it was the intake manifold gasket. I used the previous one since it was only 6 months old. Seems that it wasn't a good idea.

Another problem that I seem to be having is when I start the car. When I first turn the key to try to start it, it does not turn over. But, when I try the second time, it always turns over right away. Not that this is a big problem, but wondering if this could get potentially worse. Sounds like a fuel problem, but I am not sure.