Page 1 of 3 123 LastLast
Results 1 to 10 of 23
  1. #1

    Default Where is advance on Indmar's HEI distributor?

    While troubleshooting my boat (as written in earlier post), suddenly I lost all mechanical advance in the distributor. In other words, the engine runs at 10 BTDC at 750 RPM just the same as at 3,000 RPM.

    I opened the cap and attempted to diagnose the problem, assuming there was some centrifugal weights or springs (based on what I read on the Internet). However, there doesn't appear to be any sort of advance system implemented.

    Am I missing something, or is this done in the module somehow? I can't understand how it could be done by the module because it isn't specified and it certainly doesn't tie out to a computer as with an EFI engine, etc.

    Thank you in advance for any ideas!
    -Rusten

  2. #2
    Join Date
    Nov 2003
    Location
    Texas
    Posts
    61

    Default Replying to Topic 'Where is advance on Indmar's HEI distribu

    Is it carb, or fuel injection? It should have an HEI distributor anyway. If Its HEI you'll have two connectors at the base of the distributor. Theres a base timing connector that should be unplugged when checking timing. Not too sure where that connector is. maybe its unplugged. If you go to indmar.com you can purchase a shop manual. It should have that kind of info for you.

  3. #3

    Default Replying to Topic 'Where is advance on Indmar's HEI distribu

    Sorry. It's a 350 Vortec, carburated. It has the HEI distributor with the Delco module.

    I'm getting the impression that the module is providing the advance, despite there being no EFI computer.

    If the module does provide the advance.. Does anyone know -- is it only this unique delco module that creates advance on it's own, or is this common with HEI modules?

    Thank you in advance!

  4. #4

    Default Replying to Topic 'Where is advance on Indmar's HEI distribu

    I should also mention, I attempted twice in the past to purchase such as shop manual without luck. Indmar doesn't sell to consumers, it appears. Keaton, do you know of a way around this? As I've mentioned in other posts, I don't have a responsive dealer in my area - which is the reason I need such a manual.

    Brian Raymond has responded to other people on setting base timing by applying positive current to the black wire on the timing shunt; however, there has never been clarification provided as to whether this is relevant for a carburated engine without an ECU. When I applied current to the shunt, it did nothing.

    I'm still without advance and no idea where it's supposed to be coming from. I can only assume the module because I just don't see anything other than the breakleress hall-effect pickup.

    -Rusten

  5. #5
    Join Date
    Nov 2003
    Location
    Texas
    Posts
    61

    Default Replying to Topic 'Where is advance on Indmar's HEI distribu

    There are several types of hei dist. There is the earlier kind with vacuum advace and a module and there is the later kind that uses the knock sensor signal to tell the module to retard. This is called ESC system. (electronic spark control). If its running at 10 degrees BTDC at idle then it doesn't sound like there is anything wrong. The module will pull down the advance based on the signal from the knock sensor. Im a gm tech at a dealership and vehicles use the same system. Sounds like you have another problem.

  6. #6

    Default Replying to Topic 'Where is advance on Indmar's HEI distribu

    This is the more modern style, no vacuum and breakerless. I don't think it uses a knock sensor to retard the timing, but I could be wrong about that -- I thought the only wires with missing ends were the ones going to the ingnition, but it's very likely I'm missing something.

    I was under the impression this was the 1985-1993 distributor for 350's, although this is a 2000 engine.

    From what you're saying, it sounds like the advance is implemented by the module (even without an ECU), is that correct? I'm still not receiving any advance and wondering how it's normally implemented, since there are no springs or weights.

    If there is no advance and it's supposed to be provided by that module, I had assumed I would need a new module, is that fair? Do you know about the shunt and whether applying positive is required for setting "base timing" on this model?

    Thanks again!
    -Rusten

  7. #7
    Join Date
    Nov 2003
    Location
    Texas
    Posts
    61

    Default Replying to Topic 'Where is advance on Indmar's HEI distribu

    With the kind of dist. your talking about you have to have some type of ecm to tell the module how much to advance or retard timing. The ecm needs inputs like throttle position and engine load. Are you sure you don't have a computer controlled carb.(CCC)
    CCC has a throttle position sensor on the side and the ecm uses a MAP sensor to measure engine vacuum to tell the ecm engine load. The distributor you have only works with an ecm to advance. Im not sure about adding power to a shunt. On vehicles we ground or open a pigtail thats usually mounted near the fire wall. This puts the ignition system in base mode to adjust or check timing. If you don't put it in base mode then you'll have a reading that is already been adjusted by the ecm and thats probably why you think its not adjusting when it really is. You wont see much advance with no engine load. On vehicles we set the timing to 0 degress in base timing mode.
    I got my manual from indmar but through my dealer.
    What kind of symtom do you have? Most lack of power concerns are poor fuel quality or fuel starvation

  8. #8

    Default Replying to Topic 'Where is advance on Indmar's HEI distribu

    Hi Keaton,
    Thanks a lot for the suggestions. You probably don't want to read the long details of the issue I'm having, although it's an interesting thread ( here: http://www.moomba.com/bb/viewtopic.php?t=1213 ). The short version is that I'm not able to get over 3,500 RPM under load. It's not the fuel, everything has been replaced leading up to the engine, just to be sure (new fuel pump, fuel filter, fuel filter assembly, pickup from gas tank, hose cleaned out, etc). The fuel has been entirely drained and replaced with fuel that was checked prior to using. As far as air goes, I've run it w/o the flame arrestor, etc. I've aligned the shaft, replaced all ignition related components other than the distributor/module, just about anything that's ever been suggested since I'm certainly no expert in this area!

    The reason I'm asking about timing separate from the above issue -- is that I know for a fact that it's not performing correctly. I'll explain... I set timing twice during the process of diagnosing/testing this engine. Both times I made sure it was at the recommended timing (8-10 degress BTDC); both times it had 24+ degrees advance at 4,000 w/o being under load. It always ran perfect, was in-time, etc.

    Out of nowhere, the engine wouldn't start. After listening to it, my friend told me the timing was way out. I couldn't believe it, but to appease, I twisted it -- it eventually started/ran when it was severely advanced. In addition to being overly advanced, it had also lost any mechanical advance. The timing stays consistent no matter what the RPM.

    The ignition module with the Indmar/GM HEI looks like this:
    http://www.skidim.com/prodinfo.asp?n...5&mitem=36

    The wire that would typically go to the ECM are *not* connected, as you'll see in the specs for this engine. There is no sort of ECM and the only two wires on the carburator are to engage the choke, from what I've been told. I had once, accidentally, operated it without those wires connected and it still had advance. I simply can't find anything outside the simple ignition module, nothing that would provide advance.

    Keep in mind, this is a separate issue from my performance problem. I haven't even put the boat in the water since this started, I'm definitely not going to get into my original problem until I can figure out why I have to run over 50+ advance and no added advance comes into play any longer.

    If I could start by determining where the advance is coming from, and whether it indicates I need a new module/this would fix the issue, I would do that prior to continuing.

    If there were only a local Indmar mechanic that would return a phone call, I would be set!
    -Rusten

  9. #9
    Join Date
    Sep 2004
    Posts
    14

    Default Replying to Topic 'Where is advance on Indmar's HEI distribu

    Rusten,
    Its been a long time since i have played with inginition systems so take this with a grain of salt. It seems strange that your base timing changed so much. I once had a bayliner that had a distributor problem and shortly after the dealer fixed the problem it would not run. I found that drive gear that contacts the cam gear was worn down and had sliped which caused the timing to be off. Other mechancal issues that could effect base timing might include slipped timing chain (unlikley if this was the same motor problems i recalled from this summers posts on message board) (however a cam that is out of time with the crank could cause loss of power)

    If the control module controls the advance and it not advancing as RPM increases then possibley a knock sensor is picking up an engine noise and limiting the advance. It is almost impossible to efficiently trouble shoot this problem without a manual. With that said one could trace the wires that plug into the module and use logic as for the porpuse of each wire based on where it comes from.

    Good luck and keep us posted as this is an interesting problem.
    Geezer

  10. #10
    Guest

    Default Replying to Topic 'Where is advance on Indmar's HEI distribu

    The ignition control module has a built in "logic." This logic references off of the pick up coil and rpm. This "logic" has a built in timing curve of about 21deg. plus the 10deg. gives you a total advance of 31deg. When at 3000rpm, you should have about 28deg. showing at the crank. I have seen cases where the module has gone bad and not delivered the proper timing. This can happen when the shunt wire is hooked up to positive current to long. Hope this helps, keep us posted. Brian Raymond

Similar Threads

  1. Plug wires and distributor
    By Rugburn in forum Service & Repair
    Replies: 3
    Last Post: 08-24-2006, 07:36 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •