Hello All,
I have started a new topic in hopes of getting some eyes on and further help with my issue that happened in July 21'; this update is also posted on old thread.
The previous topic was , 2000 Prostar 190 - Cranks but no start, it can give a history for those who haven't seen this topic yet, but in summary, I have had a marine shop look at it for 3 plus hours and other mechanics , marine and auto and no one has been familiar enough with the setup. We have been using the Diagnosis for Distributorless setups and always leads to ICM(ignition control module ) and I/we have replaced with a cross-referenced auto part which these threads have confirmed do work but have still not made a difference. The easier checks have been doubled checked CPS,TPS,fuel, ignition switch,MAP , fuses etc.
Larry at Indmar has said we have tried everything he can think of.
I am hoping that someone that knows this setup or had similar issue will see this and continue helping as it would be much appreciated.
Update:
1. I sent ECM to OBD for diagnosis; in short, it is all good, Bob doesn't see anything wrong with it. He found "one logged code - M34 MAP low and showed no run cycles without that setting". HE cleared it and ran ECM; " the injectors fired fine, all sensors and relays, IAC, IC and bypass were good.
2. I acquired another set of CPS's as one mechanic suggested possibility that ones from Alibaba may not be good quality; made no difference.
3. All circuit wires coming from ECM terminals have been tested for Continuity and are All Good.
All circuit wires between ICM and ECM have continuity and have been checked that nothing adding or leaking on these wires.
4. Some measured values: Throttle position sensor - 5.2 v key on ; MAP sensor - 5.21 v key on I believe these are correct
Circuit 950 is 4x reference from ICM to ECM - Diagnosis Chart says value for voltage on crank should be 1-2v BUT mechanic measured 4.94v.
5. We have double checked that CPS wires are not reversed and that they are sending spec. value to the ICM.
We have not measured psi of fuel at rails but good pressure was at rails when schrader value depressed judging from spray force coming out.
6. I talked to a Mastercraft dealer and the tech guy was excellent in trying to help and understood how hard these types of issues can be as these setups were not used much and for only a few years, so not many are familiar with them. He could only guesstimate that it might have something to do with a timing issue but he would have to see this setup as it has been so long since he has seen as well.
So, without the ability to bench test the 3 ICM's I have, (including one that was working in a vehicle the week before I hooked it onto my engine) we are having a hard time believing that all three ICM's are not working but the charts still point to this being a possible issue. We have one more used auto ICM on order that we will try but we are unsure if there's still the real problem, if not the ICM, which is blowing this unit up everytime we hook a different one to the engine and crank it.
Others who have had my exact no start issue ( TT thread - 2001 XStar LTR no ignition & $500 tow and no spark LTR 330hp Quick Help! ) have also measured higher voltage on the 4x ref. circuit from ICM to ECM as above stated in # 4. Poster JimM was trying to find a service manual that might shed some light on the meaning of this discrepancy to confirm if the ICM is then at fault, but no threads or Larry at Indmar have been able to supply the answer to this.
Also, from research of many threads here on TT, some of the many wise posters have had good suggestions :
1. Throttle Position sensor is not sensing properly or it is not working - We have resistance on the sensor and moved it around enough that we think we have ruled this out.
2. Brass oil pump wear issue and /or oil pressure sending unit not working - checked for wear ;looks good and new sending unit for oil pressure installed 20-30 hours ago.
3. Fuel pump or wire connector at fault - we haven't checked much on pump as we have pressure at the rails and not just a fuel issue as NO spark either.
4. Engine coolant temp. sensor is faulty - we do have resistance over it but don't really know spec on that or if it would shut engine down without engine light/buzzer occuring as well
5. CPS sensor bottom connection wire is tight and pins could be compromised somewhat - all pins on sensors checked and seem the same without issue.
Another couple of questions I have after review of some previous posters comments:
1. mtajpa - said " You did say you checked the fuses on top of the ECM, there should be 3 of them. This would be a common problem if MEFI main fuse is blown." - at first thought one of the 3 was a MEFI fuse but they are for Fuel pump, ECM/Bat., and Injectors. IS there a separate main fuse for the MEFI as you mentioned? we haven't been able to find any other fuses except the ones under the dash which are all good.
2. Mikeg205 - said " ICM is easy to source" - I don't think this is reference to a new part as I've understood it is discontinued and when checked with Tech Services, theirs was a used part as well. If you happen to have a source for a known good ICM part other than TS, please let me know , but will check again with TS to see if theirs are refurbed or known to be functioning properly.
Still really no further in finding the real issue without known good parts or better insight of how the system works; I'm trying to source a service manual for this engine.
Any further help with this would be awesome as have run out of options.
Thanks
I have started a new topic in hopes of getting some eyes on and further help with my issue that happened in July 21'; this update is also posted on old thread.
The previous topic was , 2000 Prostar 190 - Cranks but no start, it can give a history for those who haven't seen this topic yet, but in summary, I have had a marine shop look at it for 3 plus hours and other mechanics , marine and auto and no one has been familiar enough with the setup. We have been using the Diagnosis for Distributorless setups and always leads to ICM(ignition control module ) and I/we have replaced with a cross-referenced auto part which these threads have confirmed do work but have still not made a difference. The easier checks have been doubled checked CPS,TPS,fuel, ignition switch,MAP , fuses etc.
Larry at Indmar has said we have tried everything he can think of.
I am hoping that someone that knows this setup or had similar issue will see this and continue helping as it would be much appreciated.

Update:
1. I sent ECM to OBD for diagnosis; in short, it is all good, Bob doesn't see anything wrong with it. He found "one logged code - M34 MAP low and showed no run cycles without that setting". HE cleared it and ran ECM; " the injectors fired fine, all sensors and relays, IAC, IC and bypass were good.
2. I acquired another set of CPS's as one mechanic suggested possibility that ones from Alibaba may not be good quality; made no difference.
3. All circuit wires coming from ECM terminals have been tested for Continuity and are All Good.
All circuit wires between ICM and ECM have continuity and have been checked that nothing adding or leaking on these wires.
4. Some measured values: Throttle position sensor - 5.2 v key on ; MAP sensor - 5.21 v key on I believe these are correct
Circuit 950 is 4x reference from ICM to ECM - Diagnosis Chart says value for voltage on crank should be 1-2v BUT mechanic measured 4.94v.
5. We have double checked that CPS wires are not reversed and that they are sending spec. value to the ICM.
We have not measured psi of fuel at rails but good pressure was at rails when schrader value depressed judging from spray force coming out.
6. I talked to a Mastercraft dealer and the tech guy was excellent in trying to help and understood how hard these types of issues can be as these setups were not used much and for only a few years, so not many are familiar with them. He could only guesstimate that it might have something to do with a timing issue but he would have to see this setup as it has been so long since he has seen as well.
So, without the ability to bench test the 3 ICM's I have, (including one that was working in a vehicle the week before I hooked it onto my engine) we are having a hard time believing that all three ICM's are not working but the charts still point to this being a possible issue. We have one more used auto ICM on order that we will try but we are unsure if there's still the real problem, if not the ICM, which is blowing this unit up everytime we hook a different one to the engine and crank it.
Others who have had my exact no start issue ( TT thread - 2001 XStar LTR no ignition & $500 tow and no spark LTR 330hp Quick Help! ) have also measured higher voltage on the 4x ref. circuit from ICM to ECM as above stated in # 4. Poster JimM was trying to find a service manual that might shed some light on the meaning of this discrepancy to confirm if the ICM is then at fault, but no threads or Larry at Indmar have been able to supply the answer to this.
Also, from research of many threads here on TT, some of the many wise posters have had good suggestions :
1. Throttle Position sensor is not sensing properly or it is not working - We have resistance on the sensor and moved it around enough that we think we have ruled this out.
2. Brass oil pump wear issue and /or oil pressure sending unit not working - checked for wear ;looks good and new sending unit for oil pressure installed 20-30 hours ago.
3. Fuel pump or wire connector at fault - we haven't checked much on pump as we have pressure at the rails and not just a fuel issue as NO spark either.
4. Engine coolant temp. sensor is faulty - we do have resistance over it but don't really know spec on that or if it would shut engine down without engine light/buzzer occuring as well
5. CPS sensor bottom connection wire is tight and pins could be compromised somewhat - all pins on sensors checked and seem the same without issue.
Another couple of questions I have after review of some previous posters comments:
1. mtajpa - said " You did say you checked the fuses on top of the ECM, there should be 3 of them. This would be a common problem if MEFI main fuse is blown." - at first thought one of the 3 was a MEFI fuse but they are for Fuel pump, ECM/Bat., and Injectors. IS there a separate main fuse for the MEFI as you mentioned? we haven't been able to find any other fuses except the ones under the dash which are all good.
2. Mikeg205 - said " ICM is easy to source" - I don't think this is reference to a new part as I've understood it is discontinued and when checked with Tech Services, theirs was a used part as well. If you happen to have a source for a known good ICM part other than TS, please let me know , but will check again with TS to see if theirs are refurbed or known to be functioning properly.
Still really no further in finding the real issue without known good parts or better insight of how the system works; I'm trying to source a service manual for this engine.
Any further help with this would be awesome as have run out of options.
Thanks
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