FIXED BUT PROBLEM CAME BACK, SEE BELOW

Hi guys....
I'm hoping you could help me with an issue that's popped up in my car.
My car was originally a D15B2 DPFI car, now it's got a D16Z6 in it with a MPFI conversion and a Rywire OBD1 conversion harness.

It's been about 3 months since the swap and it's been perfect, except now I get an odd sorta of lack of power that feels like an ignition cutout. It's got much worse in the past few days. Basically I will be driving and the car will totally lose power, but it wont stall, it just looses power. Normally changing the position of my foot on the throttle (letting off or flooring it) will make it stop, but it will still sometimes take one or two seconds (full 1 Mississippi, 2 Mississippi) before it returns to normal.
Sorta sounds like a rev limiter sometimes, like really fast short bursts of gunfire or something (but not loud).
It has also done this while idling, basically what happens is my idle drops a bit and it runs rough and sort of lopes.

Possibly related, I have got code 9 3-4 times since the swap. Most of those times was in the past few weeks.
Is my distributor bad?
The CYP sensor is the one that used shielded wire, maybe it's getting interference at the ends of the wire where I spliced it into my harness?

tia for any input you might have.


Modified by Run Away at 1:21 PM 3/21/2008

 

Anyone?

 

Bump. So I spun a bearing on that motor and when I pulled the motor I discovered the harness had a few sections where wires were touching (I had soldered my harness together and instead of heat shrink I had used liquid electrical tape, sorta like a rubber coating but I guess with the vibration and heat it worked its way bare where there was contact) so I fixed all of those.

With the harness all re-heat-shrinked, the problem was fixed and all was good.

Now 5 months later I'm getting the exact same problem, except no codes now. I'm pretty sure here are no wires shorting this time (everything was heatshrinked), and I can't get the problem to appear at all by wiggling and pushing and pulling and sqeezing my wirring harness, all around the distributor.

Had anyone experienced this?
Does anyone know if this is my timing jumping around, spark cutting out or what?

Help would be much appreciated.




Modified by Run Away at 2:20 PM 3/20/2008

 

No codes at all? I did have an issue slightly related with my DIY OBD-1 conversion was that the unshielded distributor wiring added from DPFI --> MPFI would pick up interference and throw all sorts of electrical gremlins until I ended up replacing the whole selection with another portion of shielded harness.

 

Thanks for the reply.

Nope none at all. When I jump the two wires provided on the Rywire harness for the CEL, it just turns on steady like it's supposed to, no flashing.

I just went to check the CELs again and found something interesting, when I first start the car (cold, it's around zero here so it idles at 2k when first started) it does the ignition stumble, then levels out. I shut it off and tried it 3 more times and it did it every time.

I re-did the two sheilded wires when I dropped in my current motor, but I'll wrap some more tinfoil (and ground it) around the sensitive wires and see if there's any change.

 

my turbo a6 did the same thing had to finally replace the dizzy housing around 100.00 new from Honda no more cel or other bs

 

i would try replacing ur dizzy with another known good one and check ur plugs and wires. might also be a faulty fuel pump or pgm relay.

 

Thanks for the reply rey...

I added some more tinfoil around the cam/crank sensor wires around the ECU and sorta wedged the foil against the ECU casing so it should have a ground, didn't help....


I'll try to track down a good dizzy to try. Plugs and wires are both new-ish NGK, less than 10,000kms on them. Less than 6 months ago anyways.

Fuel issues is an interesting guess too, I haven't really thought of that because of how the car feels when it acts up. Do fuel pumps fail in a manner where they put out very little, but enough to keep the car running? Because it never ever has actually stalled, just runs rough, it doesn't cause the car to coast when it happens while driving (it just maintains the same speed, won't accelerate).

 

well, if the wires and plugs are good, i would try another dizzy first. i have seen a faulty main relay before where it would cut out fuel momentarily and then kick back on. very hard to tell unless u have a VOM or test light on the wire while driving.

 

i've had a similar problem like that on my grey one as before where it seems to go on limp mode once in awhile... maybe check to make sure all the connections are good at the conversion harness as well.

 

Well I havn't tracked down another dizzy yet but I checked the plugs on the conversion harness, they're all good.

I've found that it consistently happens on cold start ups if I blip the throttle it stumbles and won't rev for a second, then it's fine.

So I'm going to play with the wiring going to the coolant temp sensor and maybe see if there's something going on there.

 

Swapped in a different distributor, fired it up and it did the same stumble/drop in revs when I blip the throttle.

I havn't taken it for a spin to see if it still does it while driving but there's a good chance it will since the ignition cuts out when I blip the throttle when the engine is cold just like before.


Modified by Run Away at 7:09 PM 3/23/2008

 

only happens when it's cold? maybe iacv?

 

When the motor is cold is the only time I can consistently get it to missfire/cutout "on command" I guess I could say.

Otherwise once warm it just cuts out randomly, I can't find a specific condition/temp/speed/throttle position where it will start acting up. If I knew what conditions triggered the cutout that would help because then I could force the car into cutting out and then check what my spark is doing when cutting out.

So it happens anytime it wants to, but consistently happens when I blip the throttle when cold.
I took some video with my phone, I'm going to see if you can hear/see what's happening once I transfer it to the computer.

 

There's a short clip from this afternoon.

The sound and video arn't synched up but you can hear it the best starting at around 0:19 seconds left.
All I'm doing there is starting it up cold, and tapping the throttle quick. Each time I tap the throttle you can also see the tach drop (remember the sound and vid isn't synched).

No comments about the uber shitty exhaust.

 

well, i don't think it's a fuel issue... does the car idle fine when it's warm? pretty stumping; i keep coming back to the fact that it may be wiring related... have u pulled apart ur harness since u fixed it the first time? u may want to redo that just to be sure.

 

Yeah it runs mint like 95% of the time, purrs like a kitten, idles rock steady at 800rpm. Only acts up after it's been sitting cold a few hours and every now and then while driving.

I'm pretty sure it's a wiring issue now too since trying the new dizzy, makes sense because that's what my issue was the first time and the symptoms are exactly the same.

I haven't been able to pull apart the harness, no. I've got the time with the easter weekend but no place to do it, my work is closed so no shop time for me.

I'm not sure if I should go about fixing my harness or re-doing it from an umolested DPFI harness. It would be nice to re-do it properly and not my current one that's full of solder.

Thanks a ton for all your help rey.

 

no problem mang. lemme know if u need any help with the wiring... i work with wiring everyday, all day long lol!

 

Alright well I had a chance to work on the car on monday, I spent a good amount of time on it....
I stripped back the harness for the distributor, all the wiring goes down and loops back to the main connector on the passenger side then through the firewall to the ECU.
There's actually no modified wires there from the conversion, it's all factory. I just added 2 more shielded wires for the cam sensor (which are good, took a close look at them).
The only wire I didn't follow all the way was the white wire which carries the advance spark signal from the ECU. This wire goes under the intake manifold and through the drivers side connector, and from there it must go all the way under the dash. I thought this was odd, but I didn't trace under-dash or under the intake manifold, I just checked to see if the white wire on the main connector (body to engine harness in the engine bay) was the same one at the dizzy, and it was.

I also checked to see if my spark plug wires were arcing, which they arn't.
I tried smacking the dash by the main relay while it was acting up, made no difference. This makes me think it's not that, my experience with temperamental main relays is that a smack will get them going again.

I also laid out my conversion harness and all the ECU wiring in the passenger footwell out, checked all connections and went for a drive with it all laying out to see if maybe separating all the wires and laying them out would maybe prevent some interference, or separate two wires that were crossed or something but it still does it.

My next thing I'm going to check now is MAP sensor....if it's giving false readings it would have an effect on my spark and fuel delivery.
I have two MAP sensors underhood too right now I believe, the stock firewall mounted one and the one that is mounted on the Z6 intake manifold. Just plugging into the other one will be an easy thing to change to see if it makes a difference.

Then I'm going to try to get my hands on an uncut harness and re-do my harness if that fails. I think the section under the intake manifold where that white ignition advance wire runs is where most of the modifications to the harness were.

 

whrn was the last time you chamged the fuel filter? i've had the stumbling rough idle too, and it was the fuel filter.

 

check out ur map sensor and see if that does anything. altho, that white wire going towards the drivers side seems odd... anyway, i hope this helps...

 

Fuel filter was just over a year ago, something like 25,000 kms.

Thanks for the diagram rey, I'll be sure to update after I try switching the MAP sensors.

What's that diagram from? I've been using a combination of '90 DX, '90 Si and '93 Si diagrams off Mitchell on demand and they're decent but some of the wire colours at the A/B/C plugs (stock OBD0 wiring that plugs into the conversion harness) for the ECU are not right.

Yeah the white wire is weird that it takes the long way around, but it was the only white wire on the drivers side connector, and I verified it with a continuity test. Def. the same wire.

 

the diagram is off a 93 si. did u do a continuity test from the dizzy to the pinouts on the ecu?

 

I didn't think to test from the ECU pins to the dizzy plug, I'll try that next time I get a chance to work on it.

I tried plugging in my old MAP sensor quick on my way home from school and it ran like crap, it idled really low and didn't rev smoothly. Using the Z6 MAP sensor on the IM the car runs a whole lot better.
I dunno if that's just because the stock OBD0 MAP isn't compatible with the P28 or what....no CEL though in the 30 seconds I had it running with the OBD0 MAP.

But I'm thinking I'll take off the stock Z6 MAP and make sure the hole it's sitting in is nice and clean and make sure the MAP itself is clean and there's no oil or anything covering the vacuum reference port.

Right now I'm just thinking re-do my harness, I'm ordering some of these ( http://www.rs-autosport.net/ca...d=194 ) as we speak.

 

r u using a converted dpfi harness? why don't u try using an si harness? i know it's tough to find but it's all plug and play from there with the exception of the dizzy wires and the injector clips (if u converted to obd1 injectors).