Matthew Buck

1999 prelude w/jdm h22a 0bd1 engine with rywire dizzy harness adapter. All stock everything

My issue I'm having is Detonation and pinging. I have installed new knock sensor, map sensor and dizzy. Checked timing, leak down tests and compression test, new plugs and wires, new fuel filter, new injector seals, new egr valve, then egr valve delete, fuel pressure checked, tested tps, tested o2sensor.

I hooked up a snap-on solus ultra scanner and was reading values And found my map sensor is reading max vacuum at W.O.T I really don't think this is supposed to do this. I am getting a code for random miss fire on all cylinders, but also getting no knock sensor signal code. But the knock sensor is supposed to pick up ping and knock and it supposedly is but I have a knock sensor code.

any help would be greatly appreciated. I have no idea other than maybe a shot ecu but would like to see other peopleles opin ions before I start spending more money. The ecu I am running is the stock ecu for the 99 lude.

snobordboy

2 questions at the start, what fuel are you using and how old is it, and what gap are your spark plugs at?

Matthew Buck

It's been a couple months since the plugs but I did what specific said on Mitchell's online. The fuel is 91 octane

motoxxxman

if the map sensor was reading max vacuum at WOT it would throw a map sensor code and go into limp mode, but you didn't mention anything about that. my guess is you have either bad grounds, or bad ecu. or some funky wiring issues.

Matthew Buck

No limp mode at all. It's reading via the Snap-on scanner 29inhg on the map sensor readings. And the grounds I just went through and checked and they all good. Clean and tight! I have been assuming bad ecu. But what ecu do I go with is the stock 99 lude sufficient without tuning issues? I have an obd1 jdm h22a ecu will that work on a obd2 car just fine?

Accordian47

So, OBD2 car, OBD1 motor, OBD2-to-OBDI distributor conversion harness and OBD2 engine harness?
You need to run a OBDI ecu as well along with an OBD2-to-OBDI ecu harness adaptor.

This was my reply before I relised your problem:
29inhg is atmospheric so that should be your map reading with key on, engine off.
How are you getting a full vaccum map reading at wot? Engine running? Or key on engine off?
You should check your 02 sensor readings for your afr. Has the car run properly without detonation WITH your dizzy conversion harness? Its either running lean or you have majorly advanced ignition timing.

Matthew Buck

I swapped the injectors obviously to run on the obd2 ecu. Will I need to run the obd1 injectors obviously with the resistor box?

the inhg at wot is around 29 which should be close to zero while driving. This thing has always acted like this since I have had this engine in it BUT I bought the car with a blown engine and did this swap to get it running. And the only way it will run half decent is the ignition timing all the way retarded. It's reading 5°. But it demands 40° advance wot.

Matthew Buck

Just watched o2sensor readings and the reading are perfectly normal at idle just like I have no flashing cel at idle. Under a heavy load the voltage spikes to .94 volts and stays there all the way through the gear. High voltage means it lean. as soon as I get my foot out of it the sensor reading go back to normal except I still have a flashing cel.

snobordboy

Has this engine had the timing belt checked? Sort of sounds like when I had a cam gear skip a tooth on one of my engines, would only run all the way advanced, re-timed the car and it was perfect again.

Matthew Buck

I have check the cam gears to make sure they line up and they do. I was told that if they skip a tooth it's on the cams not the crank. I did find that the exhaust manifold has a very bad leak at the mounting surface to the head. Thanks to doing a carbon blast with seafoam. So changing that gasket out tonight along with the intake manifold and gaskets and maybe a new knock sensor getting its warranty.

Accordian47

OBDI JDM H22 Injectors are 345cc Peak and Hold Injectors that need to be run with a resistor box.
OBDII USDM H22 Injectors are 290cc Saturated Injectors that do not need to be run with a resistor box.

If your running your OBDI JDM H22 with your stock 99 Prelude OBDII engine harness:
Run an OBDI ECU (Requiring the use of an OBDII-to-OBDI conversion harness)
Run a OBDII-to-OBDI Distributor Conversion Harness
Run the OBDI JDM Peak and Hold Injectors with a resistor box

Just keep the car to OBDI, its alot easier.

Matthew Buck

Well I think the problem is solved. Thanks everyone for the help. I installed a jdm p13 ecu and well the problems are solved. No more pinging. I was able to set my ignition timing also and everything seams perfect. I still have no secondary/downstream o2 sensor so I have a code for that and also no egr valve installed on it and a code fore it as well. But runs way stronger and no more miss fire codes or knock sensor codes. My assumption is the original ecu was fried.


thanks guys