What causes my car's timing to retard instead of advance?

Question

I have a '95 Honda Civic VX, D15Z1 VTEC-E engine, 174,000 miles. It runs roughly, acceleration and mileage are poor. A timing light shows that when I snap open the throttle, the timing briefly *retards* about 10-15 degrees, then returns to initial (16 deg BTC) as RPM stabilizes.

Testing on another Honda (same year, diff. model) showed the expected advance. Mine retards.

The timing also does not advance as RPM increases gradually. I see slight variation, 1-2 deg, as I slowly increase RPM, but it always stays around the initial setting. Behavior is same in neutral or top gear (front wheels off ground).

MAP and throttle position sensors test 100% normal. TDC, crank angle, and CYP sensors (in distributor) pass resistance tests. Distributor is original but ignitor and coil have been replaced recently. A different ECU did not solve the problem. This engine does not have a knock sensor.

What could cause "backwards timing" that I haven't checked?

Thanks for the help!

I forgot to mention that the CEL is not on, and no codes are set. Plugs are new. Old ones were black w/ carbon in 2000 miles. Oxygen sensor, dist. cap, rotor, all were new 2000 miles ago. About 10k on air filter. Compression is good, checked 2000 miles ago - IIRC, 215-220.

Ignition advance behaves exactly the same when I jumper the ECU test terminals (which is the way you set initial timing), which seems odd. Tried a second ECU - no change.

I thought of a knock sensor freaking out and lying to the ECU, but this engine doesn't have one.

I could be wrong, but I'm pretty sure the driveability problem is 100% caused by the timing not advancing. It NEVER advances under ANY conditions. That can't be right.

Answer 1

Efficient,
So its either a mechanical or electrical problem.
I assume you first eliminated mechanical problems..
It sounds like you eliminated electronics already except distributor.
I have replaced many of those distributors in my career and I probably would have started there.
Basically what you have is the same amount of retard that you should be getting in advance timing and then it drops off.. So somethings backwards...
So ask yourself what controls amount of advance ECU sends out?
ECU gets signal from TPS, the Distributor, and crank angle.... it then sends advance signal to distributor. So if we know its not the ECU, I assume the ECU logic signal is correct. The TPS or CAS. Then what is it??
I assume you have the old rectangle type connector on your distributor.. I am surprised your distributor made it this long. That distributor and the timing belt/water pump are about all that wear out on a well maintained 1.5..
Take the distributor off the compatible honda you have and install in yours or just get new dist..
I bet your ICM is haywire and translating signals incorrect.. I think ICM is same amount $ as distributor.
I saw one post regarding mileage don't worry about that unless its been abused or overheated. Its just breaking in.. Gotta love Mr. Hondas motors
BE SURE AND CHECK/CLEAN ALL GROUNDS!!!

Answer 2

I assume from your post, that most of your engine has had periodic and scheduled maintenance done, which is to say we can rule out stupid things like the air filter, correct?

I'd check for EGR issues, vacuum leaks, possibly an O2 sensor. But before you get into expensive components the fuel filter does come to mind, perhaps a PCV valve or a clogged breather cap.

Answer 3

174,000 and runs roughly? Have you run a compression and leak down test? If the engine is good continue get a asian tester and test for codes. Does that Honda have a Knock sensor? Does the engine rattle to cause it to go to knock retard? Does the distributer have vacuum hoses for advance and retard are they correct?, and check the mechanical advance by twisting the distributor rotor and see if it snaps back it is lubricated under the rotor with thin oil. Machine oil or wd-40.

Answer 4

How about 10 for mr Cristian? That's where I'd start!!!

Answer 5

It sounds like you have the intake valves staying open or closing too late in compression stroke. There must be a timing problem between the crank and the cam shafts. Distributor timing should not have any effect on fuel spillage.

Answer 6

An experienced shop technician on the http://www.IATN.net website would know the answer to your question. The only problem is that you have to pay about $50 per year to access their data base of problems similar to yours. However, that's the level of expertise you need to understand and solve your problem.

Answer 7

I remember a problem with those distributors back when I was a Honda Tech.....I would lean towards this area. its that or the pcm.....

also is the timing belt old ???

Answer 8

SOUNDS LIKE A TIMING BELT LOOSE OR WORN

Answer 9

old age

Answer 10

need a match stick?