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wierd mpfi swap problem


verv
01-21-2005, 11:06 PM
here is my story,
i read a lot about the dpfi to mpfi swap here in this forum i even copied the directions and printed them off. the swap had excellent directions to follow. well the swap went ok but the effect sucks totally
When i fired it up it started just fine but as i was revving it up it stuttered all the way through the rpm range and it dies off at 6200 rpm.
there are no codes and the stupid thing runs great at idle. So naturally i decided to take it on the road and it had less power than the dpfi. so much for quick horsepower. I have switched the injectors around and some combinations have made the engine runs worse but that is no suprise to all.

here are the specs: hf-2 manifold
si distributer
obd0 injectors
throttle body
resistor box
pr4 ecu
d15
4spd tranny wwwaaahhhhh

any help would be much appreciatted help please

civickiller
01-22-2005, 09:53 AM
is it running rich ? hows hte timing ?

verv
01-22-2005, 01:09 PM
the timing is fine and it acts like a injector is bad but they all have the same ohms rating, my next step is to rewire it for obd1 injectors, i am going to try that today

civickiller
01-22-2005, 03:29 PM
ok let us know how that works out. it could have been like a clogged injector, or again if its running too rich it could cause that

verv
01-23-2005, 01:41 AM
clogged injectors and the ecu has a large fuel curve, a friend of mine has a pm6 ecu so i tried it and it runs better, the next thing is my compression is a little low so with all of this together it kills the power that this supposed create.
just wating for my next upgrade, well i still have about the same power.

poordudewhowantcar
01-24-2005, 08:42 PM
dude i have the same problem i bought a 90 dx from this 30ish year old white guy (No Offence to Anyone).
The block is a d15 with mpfi.
but i have a pm6 ecu and most likely more si parts.
i checked the ecu cuz it was throwing a code and it was code 10 which is the (AIT) Air Intake Temp sensor.
so im in the same boat as you my car runs hella rich.
Also the guy SPLICED the wiring harness about every 6-8 inches . My plan is to just to get a new harness an do an engine swap:bigthumb:

verv
01-24-2005, 10:05 PM
ok i wasnt able to switch the injectors because upon closer inspection i discovered that my other set was in fact just 1 obdo and 3obd1's. here is an update with the pr4 ecu the idle is erratic at best and wont go above 4200 rpm without some serious backfireing through the intake and with the pm6 it wont go above 3800 rpm because of the backfiring through the intake. and with the pm6 the idle after acceleration drops down to 300 and then recovers. of course it show a eacv code. now with the pr4 it shows a code with 4 long flashes and 3 quick ones. i find it rather funny that with 2 different ecus i can have such a variety of codes. my next step is to strip the electrical tape of and run some shielded wire throughout the hole stupid thing.
Just in case anyone is wondering the injectors are all in their right pins made double sure of that today. one of the things that i am wondering is if the distributor key is reversed. well i will try that later. does any one now of a quick fix besides a good sized hammer, lol And does anyone know how much work it would take to put in a dohc zc 1.6 jdm with 5 spd

civickiller
01-24-2005, 10:17 PM
if the iat is broken, it could cause your car to run rich because it tell the ecu the temp of the air. so if its broekn and reading real cold your ecu is gonan dump more fuel in it. kinda like how when you first start your car in the morning it runs rich.

TuRD86
01-31-2005, 11:28 PM
I have done like 3 dpfi conversions and haven't had these problems, I would go through the wiring. I know that when I first did the conversion the only problem was getting the right clips to the right sensors. Befor I got them all sorted out the car had unusual idle and several codes. As far as the running rich in your case in paticular, you said you have 1 obdo and 3 obd1, if you want to run the obd1 injectors you need to get rid of the injector box.To do that just take all four of the red/black wires that power the injectors and solder the all to the thick yellow/black wire that powered the risistor box. This will change the impeadence from low to high impeadence. If you go with the other injectors and still run real rich i would dig through the wiring. Depending on how many miles you have on the intake manifold (mine has over 200,000) I would take off the EACV and clean it be sure to make it tight when putting it back on or you will have good ol honda up down idle. Hope this helps you a bit, good luck!

civickiller
02-01-2005, 01:02 AM
try and put a timing light on it. make sure the 2 blue wires on the dist are the right way

fast2camciv
02-07-2005, 11:11 AM
It really sounds like you have some wiring issues there. i ran into this a long time ago when i did my dx to zc swap i spliced a harness together and somewhere along the line i had a bad connection and it took forever to diagnos it so i just bought a junk yard harness and took my time soldering all the connections and it fired on the first time and has run smooth for 3 years now. check all your wires and redo the ones that are questionable. if you are getting really weird codes then its prolly the wires.

verv
02-15-2005, 11:57 PM
well many thanks to all th people that have posted and helped me out on this project and here is an update. i did figure out the problem and it wasnt timing or too much fuel but the problem is i have a bad valve. dont that figure. now i am in need of a d16zc engine for the full swap next it will be a turbo. always gotta have more power.

verv
04-25-2005, 01:51 AM
Here is another update when i pulled the head off to check the valves i decided to take some measurements on the valve diameter and the cam specs, along with port and polishing the head and grinding in the valves. Now what i discovered is that the difference between the two cams is quite a lot the first thing is that the cam lobe seperation was .120" . And the cams degree at top lift was 7.5 degrees off from each other. I now have put the whole thing back together and have been very pleased with the results. My 0-60mph time went from 19 seconds to 9 seconds. I also installed a fuel pressure regulator that i modified so i could just the fuel pressure lower that stock. I have adjusted it down to 25 and i still get 32 mg when i keep my led foot out of it. The poor thing still burns oil but at least it has the power too. My next project will be to make 300hp out of a sohc d16.

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