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xbrdr1
09-28-2009, 09:03 AM
2001 Indmar LTR... is there a 'computer hookup' on this motor similar to a vehicle?
So any autozone/advance can hookup the computer code scanner?

Does anyone know where the hookup might be? :confused:

Thanks

bigmac
09-28-2009, 09:19 AM
The connector will be standard and use OBD I or OBD II, but IIRC will require a code reader with marine-specific software.

You could try calling Indmar, or PM Engine Nut here on Team Talk...he's an Indmar engineer.

xbrdr1
09-28-2009, 09:38 AM
Thanks bigmac. When shifting into forward/reverse... just into gear, not pass where it 'locks' into gear....there's quite a bit of rattle.. and the engine almost dies. Also, for the first half hour of running.... when shifting into gear the engine will rev a bit... about to 1300 or so.

I'm thinking one of the sensors...... ??

bigmac
09-28-2009, 09:53 AM
If the engine throws a code from the ECM, you'll usually some kind of notification...usually the "check engine" light. In the absence of such notification, a code reader probably won't give you much, if any, information. In your case, I'm wondering if you aren't having an issue with the Idle Air Controller.

xbrdr1
09-28-2009, 10:01 AM
Good suggestion, thanks.

Any idea where I might find that on the motor?

Also, can this be a 'chevy' part from napa.. or does it have to be marine?

JimN
09-28-2009, 10:49 AM
Thanks bigmac. When shifting into forward/reverse... just into gear, not pass where it 'locks' into gear....there's quite a bit of rattle.. and the engine almost dies. Also, for the first half hour of running.... when shifting into gear the engine will rev a bit... about to 1300 or so.

I'm thinking one of the sensors...... ??

Look at the throttle lever when you shift- the cable may be binding and opening the throttle. Do you have Perfect Pass or anything like that?

The rattle is coming from the transmission, right? That won't show up in any engine codes because the transmission doesn't have any sensors that report to the ECM.

A cheap code scanner will allow you to see the codes on the check engine light but it won't give any kind of graphical info. AFAIK, most OBD II readers don't read OBD I ECM codes. Some do but you'll have to decide how much you want to spend for one. On a 2001, you can read them with a paper clip and a test light, if you want.

JimN
09-28-2009, 11:00 AM
Good suggestion, thanks.

Any idea where I might find that on the motor?

Also, can this be a 'chevy' part from napa.. or does it have to be marine?

The IAC is on the throttle body but I would make sure the part is actually bad before replacing anything. The part number should be etched into the barrel and it's not marine specific.

If you really want to have an idea of what the motor is about, buy a manual. It'll show what to test, it should have troubleshooting flow charts and diagrams, the parameters for the sensors, info about 'what happens when...' and all of the codes. You can use a GM car manual but it'll have a lot of info that doesn't apply- what does apply is the same for the marine motors.

xbrdr1
09-28-2009, 11:13 AM
Good info.. thanks Jim. Yeah, I have a 97 Z71, and a Haynes Manual that I've spent much time with.. including sensors and the like. Then, when you read what the sensor does... it's always like 'well, I suppose that can be it. But, since I don't have the engine light on... I guess it's not a 'typical' sensor... and that the IAC won't trip the engine light. true?

I know that IAC can be pricey. Do you know which year/vehicle that 01 ltr would match to?

I thought it was something like a 98 Tahoe.


So.. testing the IAC.. take it off, turn key to 'on'... see if it moves.

JimN
09-28-2009, 11:46 AM
Good info.. thanks Jim. Yeah, I have a 97 Z71, and a Haynes Manual that I've spent much time with.. including sensors and the like. Then, when you read what the sensor does... it's always like 'well, I suppose that can be it. But, since I don't have the engine light on... I guess it's not a 'typical' sensor... and that the IAC won't trip the engine light. true?

I know that IAC can be pricey. Do you know which year/vehicle that 01 ltr would match to?

I thought it was something like a 98 Tahoe.


So.. testing the IAC.. take it off, turn key to 'on'... see if it moves.

IAC isn't a sensor. It's what the ECM uses to control the idle speed when the throttle plate is at 0%. Perfect Pass or a throttle cable restriction would cause the same problem if the idle never went below about 700 RPM but since it does, it should be checked. How clean is the flame arrestor? Fuel delivery issues can cause the idle to drop, too.

The motor is very similar if you look at everything other than the intake plenum, assuming the Tahoe has multi-port injection and non-distributor ignition.

xbrdr1
09-30-2009, 09:07 AM
Can anyone confirm the location of the iac and ecm in these pics please?

JimN
09-30-2009, 09:31 AM
The photo on the left is the DLC (Data Link Connector) and the one on hte right looks like the TPS (Throttle Position Sensor), but the resolution isn't good enough to zoom in for a better look. If it has three wires, that's not the IAC, which has four wires but is also mounted on the throttle body. It's usually a dark colored cylinder with a pair of blue wires and a pair of green wires.

Your Haynes manual should have a photo of an IAC. As I posted before, don't just start throwing parts at it- that's a waste of money, adds to the frustration and guessing isn't the best method of troubleshooting when performance issues can be found objectively. Check the fuel pressure first. If you see that dip and it coincides with the RPM fluctuations, you'll know that it's not the IAC or a sensor.