Cam Timing

miniwhlminiwhl Band Wagon
in Engine & Drivetrain
Just got my new (old) '89 RT4WD going, with a rebuilt d16-z6 engine installed, but using an a6 obd-0 distributor and computer. (vTec will have to wait a while) I am seeing the codes 4 (crank angle) and 9 (no 1 cylinder position) on my obd-0 computer. Could this indicate the cam is still out of time? I've had to retard the ignition timing to reduce detonation jingling, but my so-called mechanic friend keeps trying to convince me the cam's in time. (He timed it) I think the cam is one tooth off, the car runs a little off and starts hard so I don't want to drive it too much to keep from breaking the pistons.

Comments

  • efrue57efrue57 New Wagonist
    crank angle code means a bad distributor. might also be the reason for code 9 but I'm not sure.
  • danzdanz Wagonist
    usually u wont get those codes unless the distributor is broken or wired wrong

    even if its a tooth out, you shouldnt see those codes.
  • Speed PhreakSpeed Phreak New Wagonist
    I'll have to respectfully disagree with the 2 posters above. I've had SOHC engines be 1 or 2 teeth off and they will throw the code 4 or 9. If you're unsure, throw a timing light on it and see how far out of time it is. A tooth off on the cam will throw it about 10~12 degree's on the crank, if it's a tooth advanced it'll make your ignition timing advanced as well.... detonation and such
  • gunsup0331gunsup0331 New Wagonist
    ^^^good posting
  • danzdanz Wagonist
    Speed Phreak wrote:
    I'll have to respectfully disagree with the 2 posters above. I've had SOHC engines be 1 or 2 teeth off and they will throw the code 4 or 9. If you're unsure, throw a timing light on it and see how far out of time it is. A tooth off on the cam will throw it about 10~12 degree's on the crank, if it's a tooth advanced it'll make your ignition timing advanced as well.... detonation and such


    fair enough.. then i will ask you, since the ECU has no other reference, how can it tell that the timing is out?

    let me just be fair and say it wont.

    unless its obd2b.
  • miniwhlminiwhl Band Wagon
    Thanks, Speed Phreak,

    This is exactly what is happening. I have to crank the distributor all the way retarded in its slot to get it to start right, even then it holds back and detonates some. I don't have access to a timing light any more, so I'll have to get one somewhere. When I do manage to get this straight, I'll post up to let everyone know what's actually happening. I respect everyone's advice, but sometimes different experiences lead to different conclusions.

    miniwhl (Jesse)
  • Speed PhreakSpeed Phreak New Wagonist
    danz wrote:
    Speed Phreak wrote:
    I'll have to respectfully disagree with the 2 posters above. I've had SOHC engines be 1 or 2 teeth off and they will throw the code 4 or 9. If you're unsure, throw a timing light on it and see how far out of time it is. A tooth off on the cam will throw it about 10~12 degree's on the crank, if it's a tooth advanced it'll make your ignition timing advanced as well.... detonation and such


    fair enough.. then i will ask you, since the ECU has no other reference, how can it tell that the timing is out?

    let me just be fair and say it wont.

    unless its obd2b.

    Technically you are correct OBD-1 or OBD-0 ECUs don't have a crank based reference point like the OBD-2 cars. However the MPFI/OBD-1 distributer has 3 sensors in it for determining cam to crank positioning and ignition timing. Crankshaft Sensor, Top Dead Center sensor and Cylinder 1 position sensor, all have a different number of "teeth" that generate a distinct signal to the ECU. I've dabbled in tuning and tweaking ECUs on Hondas for a while but not to the depth of going through the factory code. I do know that compared to many other companies Honda/Acura ECUs are very over-engineered when it comes to both their programming and electrical design.

    My best guess would be the ECU's algorithms for determining the engine's speed, firing order, and position look based off of the aforementioned sensors account for this. Obviously there isn't a "your engine is out of mechanical time" code. Best way the ECU knows to account for the differences in what it expects from the engine and what it's getting would be for it to chalk the problem up to a faulty sensor. Not a strong technical argument I know, but i have seen the same problem a few times on personal vehicles as well as client/friends vehicles.


    I don't mind intellectual debate when it helps out, cheers
  • JakerJaker familEE
    miniwhl wrote:
    I have to crank the distributor all the way retarded in its slot to get it to start right, even then it holds back and detonates some.

    This. Your cam timing (timing belt) is out at least 1 tooth. From the sounds of things, it's more like 2 teeth. Is the distributor cranked back towards the firewall, or forward towards the rad? Firewall - cam timing is retarded, rad - cam timing is advanced. What camshaft gear did you use? This can affect your ability to time the motor correctly. Oh, and how did you attach the OBD0 distributor to the Z6 head? It doesn't bolt up. Maybe you've got the distributor grossly out of phase.
  • danzdanz Wagonist
    Speed Phreak wrote:
    danz wrote:
    Speed Phreak wrote:
    I'll have to respectfully disagree with the 2 posters above. I've had SOHC engines be 1 or 2 teeth off and they will throw the code 4 or 9. If you're unsure, throw a timing light on it and see how far out of time it is. A tooth off on the cam will throw it about 10~12 degree's on the crank, if it's a tooth advanced it'll make your ignition timing advanced as well.... detonation and such


    fair enough.. then i will ask you, since the ECU has no other reference, how can it tell that the timing is out?

    let me just be fair and say it wont.

    unless its obd2b.

    Technically you are correct OBD-1 or OBD-0 ECUs don't have a crank based reference point like the OBD-2 cars. However the MPFI/OBD-1 distributer has 3 sensors in it for determining cam to crank positioning and ignition timing. Crankshaft Sensor, Top Dead Center sensor and Cylinder 1 position sensor, all have a different number of "teeth" that generate a distinct signal to the ECU. I've dabbled in tuning and tweaking ECUs on Hondas for a while but not to the depth of going through the factory code. I do know that compared to many other companies Honda/Acura ECUs are very over-engineered when it comes to both their programming and electrical design.

    My best guess would be the ECU's algorithms for determining the engine's speed, firing order, and position look based off of the aforementioned sensors account for this. Obviously there isn't a "your engine is out of mechanical time" code. Best way the ECU knows to account for the differences in what it expects from the engine and what it's getting would be for it to chalk the problem up to a faulty sensor. Not a strong technical argument I know, but i have seen the same problem a few times on personal vehicles as well as client/friends vehicles.


    I don't mind intellectual debate when it helps out, cheers[/quote:3ixmd3m0]


    i appreciate u replied back with a well thought up response.

    "insert dart in neck line from Old School here"

    haha. cheers
  • miniwhlminiwhl Band Wagon
    Hey Guys,

    Finally got tired of messing with the car myself and got a local professional to tune it right. Turns out the cam was in time, the distributor was bad, Kudos to danz and efrue57 for calling this right to start with. All indications were that the cam or distributor was out of time, but the bad components inside the distributor just made it seem that way. Got the car back, and it runs perfectly, no hard starting or apparent detonation at all. Had to buy a new distributor, but, for all in the area, there is a JDM Motors warehouse which sells new OEM Japanese parts for $110. This beats any eBay price I've found, and they have the right one for my projected DOHC ZC stroker motor, too. The problem occurs when you convert an OBD-1 engine back to OBD-0. The 88-91 distributor doesn't fit the 92-95 head (Honda doesn't want our stuff to get cross-wired, so they make it safe for us) so you have to use the early distributor and slot the ear at the top to be able to bolt it to the head. I've heard you can swap internals out, but Philip Wong at Intercrew just slotted the top ear and timed it right.

    Thanks for all the good advice and patience with me,

    Jesse
  • danzdanz Wagonist
    glad u got it sorted out and updated the thread. the world needs more of that.
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