so i finally was able to try and crank this long term project of mine (financial troubles dragged it out waaay too long) last night but it wont crank.

its a 89 dx hatch with a B20, converted to mpfi and OBD1. using a junkyard obd1 PR4 ecu. obd0-obd1 conversion harness. original (for motor) obd2 injectors with no resistor box. OBD2 dizzy (original for motor) that has been spliced into harness

it turns over great but just wont catch.

the fuel pump relay was buzzing at first, but i found a loose ground in teh engine bay. After grounding it, the pump comes on fine and the relay isnt buzzing anymore. and if i loosen a fuel line it sprays everywhere so im getting fuel.

getting spark too. when i pull out a plug and boot it will spark against the block just fine.

did the K-test on it and im getting 4.7 volts at the map sensor. so i think the ECU is fine.

i plugged a noid lite into one of the injectors but its not lighting up. so aparently the injectors just arent firing.

what do i check next? or what else can keep the injectors from firing?

 

Do you have a multi-meter? check voltage at the PCM to see if it is trying to fire the injectors. you should see a pulsing signal

 

0.0 v without key in
11.0v when i first put key in position II, then it drops and stays at 6.4v
7v steady when i try and crank it.....now 6v...now 5v....and the engine is dragging. **** gotta go charge my battery.

should i be seeing a steady 12v from the inj1 wire coming from the ECU? or a pulsing signal like odysseus said? once i charge my battery, i mean.

 

i know it sounds kinda irrelevant but are u getting spark?

 

actually it IS quite relevant, BUT was already covered. i said in my first post that i am getting spark.

 

didi you have to convert to mpfi with the swap, sounds like they either 1. dont have any power from the ecu 2. the dizzy's crank angle sensors wiring is screwy, you say you get spark but absolutly no fuel so i would check these 2

 

I'm assuming during your DPFI --> MPFI you added the additional wires needed for the injectors?

 

im pretty sure there is some kinda wiring that has to be done when removing the resistor box, double check wiring there maybe

 

is your map reading 4.7V with the engine running cause that is way too high it should be about .98V at idle. do you have two injectors firing are do you not have any injectors firing. and my understanding is that you can not use a mpfi harness on a dpfi cause the injectors and map receive their signal from a different connector

 

yes. i did the dpfi to mpfi swap first (moved several pins around, added the other 2 injector wires, swapped the outer 2 map sensor wires, spliced the 2 injector yellow/black wires into the new 4 injector yellow/black wires using a junction box, etc). then plugged in the obd0-obd1 harness.

 

The outer 2 throttle position sensor wires get swapped, not the MAP sensor. I dont know if that would cause it not to start, but check to make sure you did the TPS not the MAP sensor.

Maybe the MAP vs. TPS was a typo, but if not, there is a good chance other wires are mixed up too. Double check everything.

 

x2 nothing needs to be done at the MAP. just the outer 2 wires on the TPS, i just completed the mpfi swap on my hatch and it runs perfectly

 

yes, sry. was a typo. Just to make sure tho, i went and looked at my TPS wires, because its been several weeks since i did the actual wire conversion. they are currently the same as the picture below. this is correct for a MPFI engine, right?

im about to check the voltage of my yellow/black injector power wires that i spliced together. see if i messed something up there.

 

no. 4.7v with key in the ignition. and i was checking the supply wire, which should be reading about 5v, NOT the signal wire which changes voltage according to how high the vacuum is(if im understanding how to do the K-test that is. i could be completely wrong).
the engine wont run so i cant check the voltage while its running

ive only checked one

i dont exactly understand what u mean. i swapped several harness pins at the ECU and ran 2 more wires from 2 of the pins i just cut/moved for the other 2 injectors. aka, a DPFI to MPFI conversion

 

If you can't figure it out I would just send the harness to the guys at rywire.com. They did my EF b18b1 obd0 -> obd1 4 years ago and I've never had any problems.