1G Weird old Probelm : Crank no start when COLD !

[ali_viento]

Hey, I have this issues from 2 years ago and since i was super busy on my work then i couldn't find time to tackling anymore , but from the last week i starts again and checked many things .

Why i said weird cause its changing its behavior each time we wants to getting starts , it means sometimes the engine crank with no starts then i try to push the gas pedal several times to starts , sometimes its takes more time to starts with 2 cylinder and no injector pulse on random cylinders ( maybe cyl 1 and 2 but the next time its can completely different cylinders ) or even sometimes its get starts with 3 cylinders like one time has no pulse on injector #1 , another time no pulse on injector #3 but when the engine getting warm all the injectors firing without any problem , also you can turning off the car and again starts smoothly , I must mention that today after starts with 3 cylinders with no pulse on injector #1 , its getting fire on cylinder #1 few mins later but engine hesitating when push the gas rapidly and its fine revving if push the gas slowly , you can see on the log i attached .

We have sparks , we have fuel on fuel rail with 37 psi pressure , wiring harness and connectivity between ECU and Injectors are fine , between injector resistor and injector plugs also good , grounds fine , timing belt is correct at time , no sign of blown head gasket with perfect compression on all 4 cylinders , tested all this checklist with 1 or 2 good ones without any success : Coil , ignition wires , fuel filter , power transistor , injector Resistor box , map sensor , CAS , MPI relay, different set of Injectors , Ecu .

I really Confused since im working on dsm’s for many years and this problem is unique but maybe there is something that you can help me or trace it from the logs . Sorry for long story and thank you for your time .

 

[motomattx]

Camshaft position sensor intermittent would be my guess.

 

[1990TSIAWDTALON]

Coolant temp sensor maybe???

 

[ali_viento]

Camshaft position sensor intermittent would be my guess.

I just changed the CAS with good one and care about the match mark on TDC , also there is connectivity between 4 wires of CAS connector and ECU side plug . is there anything else that i need to test for CAS ? thank you for your reply

 

[ali_viento]

Coolant temp sensor maybe???

Thanks for reply,
I just used the DSMlink and if you can access to see my logs that attached to this post then there is no problem to reading the coolant temp and it seems its working fine and also i have question that if we use the DSMlink that we have control everything then still coolant temp is effective ?!

 

[1990TSIAWDTALON]

I will have to look at a log when I get home, I didn't bring Link with me to run at work. The coolant temp is a temperamental little sensor and sometimes effects starting all together but you probably know that since you have been working on them. We don't have "control" of the sensor that talks to the ECU to "trick" it that I have ever seen. I will try to find some time to go over the logs you have posted though and see if anything sticks out to me, not that I am the professional, but I understand and tune my own reasonably well.

 

[tstkl]

On my 89 mirage GT I had a similar issue. It turned out to be the MPI fuse was cracked (not blown) so it would be able to arc the gap in the afternoon when it was warmer and it wouldn't be able to arc the gap when it was colder. Try checking your fuses and inspect them very thoroughly.

 

[ali_viento]

I will have to look at a log when I get home, I didn't bring Link with me to run at work. The coolant temp is a temperamental little sensor and sometimes effects starting all together but you probably know that since you have been working on them. We don't have "control" of the sensor that talks to the ECU to "trick" it that I have ever seen. I will try to find some time to go over the logs you have posted though and see if anything sticks out to me, not that I am the professional, but I understand and tune my own reasonably well.

it will be very helpful Man, Thanks again

 

[ali_viento]

On my 89 mirage GT I had a similar issue. It turned out to be the MPI fuse was cracked (not blown) so it would be able to arc the gap in the afternoon when it was warmer and it wouldn't be able to arc the gap when it was colder. Try checking your fuses and inspect them very thoroughly.

Thanks for reply , you mean the 20 amp blue fuse for MPI that it looks good when i checked but its just visual check and tomorrow i will be remove it and check for connectivity with Ohm meter .

 

[ali_viento]

Thanks for reply , you mean the 20 amp blue fuse for MPI that it looks good when i checked but its just visual check and tomorrow i will be remove it and check for connectivity with Ohm meter .

Hello Again, Today i just checked all the main fuses such as MPI , Alternator and all of them fine and had connectivity , then I checked the Coolant Temp sensor and its also doing well , after this tests i cranked the engine but still no luck like before and after few seconds to push the gas pedal several times , it wants to get start with hesitation like always , finally starts with 3 cylinders and this time injector # 3 not firing , turned off the engine and one more time try to check the CAS wiring and it seems all 4 wires had connectivity on right pins and then try to install 1g Green Top CAS over the 2g Black Top CAS ( its working for about 8000 km after rebuilt ) and it seems the car starts better and this time all injectors firing , after that i try to get back PTE 880's instead of OEM 510's injectors and its seems 880's stuck since they didn't use for about 2 years , then i tried to inject the cleaner to feed nozzle and + - battery probs to shocking the injectors , after few clicking , they starts to work then install them on fuel rail and after changed the deadtime and global on Dsmlink , engine starts very smooth , but like you knows , it needs to sit all over the night and tomorrow check that if its fixed or not .

 

[ali_viento]

Thursday , I went to the garage and crank it again without any success like before then i tried to compression test the engine when its cold and there is no good result since cylinder # 2 and cylinder # 3 had ZERO pressure and it seems the car just wants to starts with 2 cylinders ( we know the zero compression is the reason that injectors Not firing on cylinder 2 and cylinder 3 ) and you know its not good news , i just starts the engine with 2 cylinders and after a few mins , cylinder #2 and after that cylinder #3 came alive and i just let the engine fully warmed up , after that i replaced the old old 20w50 engine oil with new 10w40 with filter and went out for some cruising and WOT then get back to the garage.

tomorrow morning ( Friday ), before starting the engine , i tried to check something before crank the engine when the engine still cold , first i removed the MPI fuse and got the compression test and the result is much better since all four cylinders had compression ( 1st : 135 , 2nd: 140 , 3rd: 130 , 4th: 140 ) . then when still no gas pressure on fuel system , removed the fuel rail and test the injectors out of the head to check them for leakage and they are firing nice without any leakage , after that installed the fuel rail and got back everything and try to crank the engine ( when cold ) and its starts very smooth .

Finally i must thank you all mates but Its very hard to say , after all this troubleshooting , the main reason is the very old thick oil that didn't have enough viscosity to made compression on the cylinders and its the reason that the oil burning smell comes out from the oil catch can, also bad news is my leak down test result is not good and engine has about 60% leakage from the rings ( oil dipstik side , valve cover oil filler cap side ) all cylinders and also white/bluish smoke out the exhaust when push the gas pedal rapidly .

by the way , i know this engine needs to rebuild but for now you think any oil additive will helping or they are junk and its useless idea ?!

 

[o0GuitarKid0o]

Thursday , I went to the garage and crank it again without any success like before then i tried to compression test the engine when its cold and there is no good result since cylinder # 2 and cylinder # 3 had ZERO pressure and it seems the car just wants to starts with 2 cylinders ( we know the zero compression is the reason that injectors Not firing on cylinder 2 and cylinder 3 ) and you know its not good news , i just starts the engine with 2 cylinders and after a few mins , cylinder #2 and after that cylinder #3 came alive and i just let the engine fully warmed up , after that i replaced the old old 20w50 engine oil with new 10w40 with filter and went out for some cruising and WOT then get back to the garage.

tomorrow morning ( Friday ), before starting the engine , i tried to check something before crank the engine when the engine still cold , first i removed the MPI fuse and got the compression test and the result is much better since all four cylinders had compression ( 1st : 135 , 2nd: 140 , 3rd: 130 , 4th: 140 ) . then when still no gas pressure on fuel system , removed the fuel rail and test the injectors out of the head to check them for leakage and they are firing nice without any leakage , after that installed the fuel rail and got back everything and try to crank the engine ( when cold ) and its starts very smooth .

Finally i must thank you all mates but Its very hard to say , after all this troubleshooting , the main reason is the very old thick oil that didn't have enough viscosity to made compression on the cylinders and its the reason that the oil burning smell comes out from the oil catch can, also bad news is my leak down test result is not good and engine has about 60% leakage from the rings ( oil dipstik side , valve cover oil filler cap side ) all cylinders and also white/bluish smoke out the exhaust when push the gas pedal rapidly .

by the way , i know this engine needs to rebuild but for now you think any oil additive will helping or they are junk and its useless idea ?!

If anything try STP zinc additive it's super thick but mixes with the oil I dont think it will help you a lot but it's worth a shot . Good for older motors I used it alot on my n/t

 

[motomattx]

Yamaha Ring Free.