I finished my mpfi swap this morning and am having a few issues, I searched but am not finding anything for my problem. The car started fine and runs with some hesitation, which I believe may need adjustment on timing, but I have a CEL but when I look at the ecu, I have no codes being thrown. On top of that, my fan is now running with the ignition on which it wasn’t before. I’m still looking for answers online but I cannot figure how I managed to screw up my radiator fan wiring. Any tips?

thanks in advance.

 

well lets start with the basics
first
what kind of ef do you have?
second
is it auto or 4-5 speed?
third
did you mess with the fan wiring?
fourth
do you have a stock engine or something else?

 

As Marcos said, we need more info:

1. What is the year, trim level, and transmission of the chassis you did the swap on?
2. Was the chassis wiring harness untouched prior to the swap?
3. Was the engine wiring harness untouched prior to the swap?
4. Did you build your own harness or use a purchased conversion harness?
5. Are you staying OBD0 or did you convert to OBD1, OBD2a, or OBD2b? What ECU are you using?
6. What engine is in the car now?
7. What car/engine did the MPFI swap come from?
8. Which fan is running - radiator or AC?
9. Do you have another MPFI ECU you can swap in to verify you don't have a bad ECU?

 

 

All my DPFI to MPFI knowledge is on a 90 DX Sedan, so keep that in mind. Pin B4 on the PM5 (DPFI) and PM6 (MPFI) OBD0 ECU's goes to the radiator fan switch via a YEL/GRN wire. I'd start looking there for your issue.

 

 

Some folks have had luck with the eBay distributors, but I had 2 bad ones in a row. Mine were from Rock Auto and not eBay, but same thing I think. I ended up spending the $ and getting a Duralast Gold for AutoZone with a lifetime warranty, and it has been good so far (4 months).

Did you run shielded wire for the CYP? The CYP signal is susceptible to noise from other electrical sources and could be causing the CEL. This is why the OEM Si harness has the CYP wires shielded. If you do run a paired shielded wire, make sure you only ground one end of the shielding for each unbroken section of shielded wire. I used a 6-pin connector in the engine compartment for my CYP wires, Injector 3 & 4 wires, and reverse lights (since mine was also an auto originally). Because there are two discrete runs with a connector in the center, I had to ground both runs. For the CYP wiring on the chassis harness side of the connector, I tied the shielding into A2 on the ECU. For the CYP wiring on the engine harness side of the connector, I tied into the BLK/RED on the passenger 14-pin connector, which goes to the G101 ground.

 

 

 

Hi guys need help, I have a 88 ef hatch with a gsr swap and it wont rev high once it reaches 3k rpm to 4k rpm it bogs down....I've had this car for 5yrs it had d16 with a mpfi conversion ran fine then swap a b16a jdm and ran fine then i blow the block so got another block and rebuilded the obd0 b16a and then the problem started when i would give it gas it would bog down and not rev past 3k rpm I have changed the fuel pump, filter, tps was calibrated, iacv, ecu, dizzy, cap, spark plugs n cables....checked compresssion good , injectors good, so then i gave up on the b16a and swapped it out and put in a obd1 gsr engine and coverted to obd1 and have the same issue i check dizzy cables are ok they are connected where they belong i have a cel that is for the 02 sensor.........i dont have cyp sheild ground since the d16 ...... how do i ground it? the only thing i kept was same engine harness.... helpppppp plz and thank you..

 

dude read my build thread Marcos new work car 90 sedan
the answer to your problem is on page 4 and 5