Ok i took my car to a friends house today to see what my timing looked like. First my friend took off the little rubber grommet off the block to see with a timing light. He flipped out and told me to have a look at what he was seeing. There was a 0 on my Clutch Masters Flywheel, so he put a mark on it to see it with the timing gun. I cranked it up and i could see the little mark with the timing light for like 2 seconds, it would be in line with the little tooth then it would jump up then down and then back to the center of the tooth! In which when i saw it going up and back down it would SPUTTER. My friend told me there was something making my timing jump around. What could this be? How do if fix this problem?I was running the dayum ECU that was sent to me with my motor which was a AUTO p13 in my 5 speed lude. Now im running a neptune chipped P72 with a h22a base map. And it idled alittle better than the p13 and ran better , but i was having this sputter at idle. It looks like this could be it but what could be making it jump around???
Needs yalls help really bad Maybe someone out theres had this problem.

 

TTT - Has someone ever seen this b4?

 

if your idle is fluctuating then it will look like your timing is changing. just make sure its idling steady as a rock and the timing mark shouldnt jump around like you described.

 

Correctomundo. Looking at your timing at idle is the best way to see how steady your idle is.

 

I didn't completely follow your description, but the timing is not necessarily constant. It is controlled by the ECU, and if you open your ROM with an editor you can see how it changes with manifold pressure and RPM. Now if it's jumping around while the engine is at a constant load and RPM (idle) there is something not right. The problem could be the ROM you are using, or it could be a hardware problem. I've seen some pretty screwed up fleabay "race" type chips, but if the ROM is good it could be a sensor going bad in the distributor (assuming OBD1) . A really loose timing belt could cause some jumping. Another possibility is EMI from the ignition messing with the crank signals going to the ECU. Make sure the valve cover is grounded and your ignition wires are a good EMI suppression type. If you can borrow from someone, you might try swapping out the distributor and wires, and go from there.

 

I don't know how things work with alternate ecu's etc.. but was the service connector jumped? - with a p13 if the service connector isn't jumped the ecu will compensate for any timing changes you make - perhaps something to that effect could have caused your jumping around phenomenon. (?)

 

yes, also what year is this prelude? the jumping could be caused by the idle speed fluctuating. if the idle is rock solid, and the timing is jumping around, then it sounds like the ecu is bad, if this is a 5th gen. the ecu has complete control over timing on the 5th gens.

neil

 

Thanks guys for your replys. (Altilude)i dont think the jumper was ever jumped while doing timing. That was something we didnt do and something i need to try. (flyrod) ill also see if the timing belt is loose or has some slack for some reason. (onefastrx7turbo) My car is a 96 prelude si 5 speed with a 93 JDM H22a swap OBD2-OBD1. While it was sputtering one day i decided to look at my ECU to see if it was making good contact with the Obd2-Obd1 conversion harness. Thats when i realized that my ECU was a Automatic P13 ECU, It had a code then AT at the end of it. I thought that had something to do with some of the jerking and sputtering i was getting. So i decided to call Tony Palo at T1 Race Development and get my 95 gsr P72 chipped with a prelude base map. When i got it back it ran alot better and it even kept an idle but i still had a sputter. Tony does good work from what i know. So i know its not the ECU now. And also my car has a brand new distributor that i got from Yonaka Motorsports so i know its not the distributor going bad.Could the timing be juming up and down do to a vacuum leak also? Thanks again