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Trans am no longer starting Good evening, My name is Michael and I live in France. I bought in October 2018 a pontiac Trans Am GTA 1991 TPI. I bought it from an individual (not very honest either by the way) and I drove a week before breaking down. The day after my purchase it was difficult to start between 10 and 15 minutes before that cracks and it every day but once the first start is done it left the quarter turn until the next morning or it started again. And one day while driving, the engine stopped and since then I have not been able to restart it. Looking under the steering wheel the VATS system had already been modified, a resistance to key's place was installed. I have already changed the fuel pump, the spark plug wire, the spark plugs, the distributor rotor; the starter module in the dispenser, the dispenser cap. I just bought a pro module at newrockies but nothing works ... The engine runs, I have ignition, the fuel arrives but the engine does not start. It's been more than 3 months since I broke my head with the technical magazine to try to understand why. My last research is the top dead center sensor but I can not find it on this engine. Is there one? Otherwise if I really can not restart it I plan to put a carbu I see that this solution because I live there is no specialized garage in the American ... If you have any idea they will be welcome ... Thank you. Mike |
Re: Trans am no longer starting Hello,Since 3 months that I seek, I think the injectors are not controlled ... I controlled the voltage across the injectors and I have 12V on the 2 terminals of the connector, is this normal?Apart from the VATS system what can cut the injectors? If anyone has suggestions, thank you in advance for your help Mike |
Re: Trans am no longer starting To check vats you can backprobe the dark blue wire at the ecm pin f10. You will have a hz signal or 2.5v. other things that can shut down injector pulse. Shorted injectors you can ohm them and post the findings. Or bad ignition control module. A bad tps showing 4.5v or higher in idle position will also shut down injector pulse. |
Re: Trans am no longer starting Thank you for your reply. I will control the voltage on the F10 terminal of the ECM but I installed this famous case to short circuit the VATS (normally). I will also look at the ohms at each injectors and give you my results. the control module is the one in the distributor? If so, it is new. Finally the tps, is the connector with 3 wires (gray / blue and black)? I tested and I have 5V between black and gray and 0.68V between blue and black. Thank you Mike |
Re: Trans am no longer starting Your correct the ignition control module is in the distributor. The tps reading is correct. The injectors should be between 15.5-16.5 . |
Re: Trans am no longer starting Here is a pinout for your 1227730 ecm to test f10. sounds like you have a resistor bypassing the key tumbler reader. If that’s the case the passkey module can still fail. http://chevythunder.com/fuel%20injec...20(ecm#1227730) |
Re: Trans am no longer starting Sorry, I noticed you purchased a new Rockies bypass kit. I have never heard of them it must be a module that feeds the ecm a 30 or 50hz signal to f10. https://newrockies.com/frequently-asked-questions/ |
Re: Trans am no longer starting Hello ,I did not have much time today to check everything but I still controlled the resistance of injectors and I between 1 and 1.1 Ohm ... Is this possible? I have checked several times and I am far from the prescribed 15 Ohms ... On the other hand if I put 12V at the terminals the coils are activated ... I hear them snap Thanks Mike |
Re: Trans am no longer starting Are any of the injectors higher than 1 ohm . Maybe your meter is on the wrong scale. |
Re: Trans am no longer starting So they all have the same resistance. And my device automatically calibrates itself normally but I will reverify tomorrow. We have 6 hours of time difference. I will see with another device to be sure Thanks Mike |
Re: Trans am no longer starting Hello, So I tested the injectors with another device and I found between 13.6 and 13.8 ohm. I disassembled them and I put 12V to stick the coil and I sent a light blow of compressed air and no worries it is not clogged. So I have to test the 2.5V at terminal F10 of the ECM. I will do it once the injection ramps and injectors reassembled. If you think about other checks or tests .... Thanks in advance. Mike |
Re: Trans am no longer starting Is the new Rockies device a duel frequency unit ? some volt ohm meters have a hz setting like a fluke one I have. i don’t think the injectors are shutting down the injector driver. You can try to unplug all the injectors and check for pulse with a noid light. |
Re: Trans am no longer starting I do not know much about the Rockies module. Apparently, it completely bypasses the immobilizer system. Good idea to see if the injectors are piloted, I will rather plug a bulb ... So I will go back up the TPI system and do this test I will tell you what he has. Thank you very much for your help and your advice, it's really very nice. Because I'm starting to lose hope of seeing my car roll again. It's been 20 years since I dream of an American car but I regret my purchase ... Mike |
Re: Trans am no longer starting Most of those bypass modules can be set to 30 or 50hz make sure you have it set correctly. When you are turning the key to the crank position is your starter engaging? If so does the "Security" light go out on your dash or stay on? Or if you turn your key from off to run (not crank) does the security light come on and then go off? The pickup coil and ignition control module in the distributor could be an issue are you getting spark during crank? |
Re: Trans am no longer starting hello aviator 857. So my ignition module is new in the distributor, yes I spark sparkles. The only thing I have not changed about the ignition system is the pulse generator (coil under the lighter finger) the starter is running well, my security light comes on with the ignition and then goes off. With the rockie module the security light does not come on at all. I configured it as marked on the specific instructions for my vehicle. Thank you Mike |
Re: Trans am no longer starting I forgot, the ignition coil is new too .... Mike |
Re: Trans am no longer starting This is a TPI car correct? What is your fuel pressure during cranking? If any of your injectors are out of range it can cause none of them to fire, low fuel pressure will also. (I know all new parts but new parts can be bad). Fuel pressure regulator? pull the cold start injector and put a little gas in and see if you can get it to fire over, Obvious question do you have at least 1/2 tank of fuel so the fuel pick up can fully prime the system? |
Re: Trans am no longer starting
Originally Posted by Aviator857
(Post 6280505)
This is a TPI car correct? What is your fuel pressure during cranking? If any of your injectors are out of range it can cause none of them to fire, low fuel pressure will also. (I know all new parts but new parts can be bad). Fuel pressure regulator? pull the cold start injector and put a little gas in and see if you can get it to fire over, Obvious question do you have at least 1/2 tank of fuel so the fuel pick up can fully prime the system? |
Re: Trans am no longer starting I already test everything "tuned performance" explained the same things to me. The 8 injectors are ok. I do not have a cold start injector on this engine. Yes useful question but I have gas in the tank. The pressure is 3 bar at the injection rail. Thank you Mike |
Re: Trans am no longer starting Ok... I'm stumped. Can you use starter fluid to start the engine not sure if I would advise spraying it in via throttle body though. I know I've have had and seen injectors stuck with varnish that would not spray enough to start the car but would keep it running once started. 43psi/3bar should be plenty of fuel pressure. Any chance you can get your hands on a injector test light to see the computer is commanding they fire? Something like this? https://www.amazon.com/dp/B01L7ASGIY/ref=cm_sw_r_cp_apa_i_KNkxCbBK24MRT |
Re: Trans am no longer starting Looks like f10 should see a 30hz signal. Regardless if you hook a 50hz signal to f10 you would see 2.5v on it and 30hz signal. Does the directions on the new Rockies module say what wire does what frequency? https://www.thirdgen.org/forums/elec...frequency.html If all that checks out the new icm might be bad or there is a break in the icm wire purple/white stripe. This wire runs from the icm to the ecm pin d8. You could ohm the wire to make sure it has continuity. |
Re: Trans am no longer starting Hi , So I think we advance thanks to the idea of the bulb I found that only 4 injectors were piloted. The 4 on the same side on the cylinders 2 4 6 and 8 on the other 4 cylinders the injectors are not controlled the light does not come on at all ... Where do you think it could come from? Thank you very much for your help I hope again to find the fault ... Thank you Mike |
Re: Trans am no longer starting I'll see at the cable if nothing abnormal ... Mike |
Re: Trans am no longer starting Check the fuse for the injectors there are two one for each side. |
Re: Trans am no longer starting indeed I am stupid I did not think. so I changed the fuse and my injectors are well piloted. but she still does not start. remains the icm to check |
Re: Trans am no longer starting If your injectors are pulsing and you are getting spark, it should run... Have you pulled a spark plugs and verified they are clean and gapped and you are getting spark. Injectors could be stuck even if they test good with resistance and air tests. Is battery fully charged? Try cranking it 3-4 times for 20 seconds each attempt with your foot on the gas pedal. Is it possible the injectors are leaking into the intake and the engine is flooded. |
Re: Trans am no longer starting I will change the pulse generator and check again the ignition to 8 candles. I would also change the icm and test the continuity of the wire as suggested "tuned". Once done, I will give you the results. Thanks for your help . Mike |
Re: Trans am no longer starting |
Re: Trans am no longer starting
Originally Posted by Mike69
(Post 6280625)
Hi , So I think we advance thanks to the idea of the bulb I found that only 4 injectors were piloted. The 4 on the same side on the cylinders 2 4 6 and 8 on the other 4 cylinders the injectors are not controlled the light does not come on at all ... Where do you think it could come from? Thank you very much for your help I hope again to find the fault ... Thank you Mike |
Re: Trans am no longer starting Hi. So I have good news: the car is going to restart. hooray !!! After checking the ignition, it was good, I decided to change the witness again. So I roll on a new icm that I had in stock and the car must start a quarter turn ... Many thanks to you for your really great help. So for info rockies module works perfectly, I removed my keyboard case and put this module in place and do not worry, it completely bypasses the VATS system. thank you very much again mike |
Re: Trans am no longer starting Great news, Glad you found the problem. |
Re: Trans am no longer starting yes it's really nice to hear again purring the V8 ... On the other hand, a question goes through my head, what can cremate the ICM? a surge? a regulator or other defective? In your opinion ? thanks again to you ... Mike https://cimg1.ibsrv.net/gimg/www.thi...bd6693c443.jpg |
Re: Trans am no longer starting A ignition coil with to high resistance can cause the icm to fail. heat from not having a thermal paste under the icm and just old age. |
Re: Trans am no longer starting Heat is usually what kills them, did you use thermal grease on the first one? Also alot of people have had issues with dead new ones. |
Re: Trans am no longer starting ok the ignition coil is new now and yes I put the thermal grease under the first ... A cremated ICM can stop the engine while driving? I think I'll put an ICM in advance in the glove box in case or with a screwdriver it can be useful .... Where to buy this module to have a quality piece? In general I order on rockauto .... Another big thank you mike |
Re: Trans am no longer starting RockAuto is a great source for parts. Is the one you purchased a acdelco ? Here is a recent thread on icms https://www.thirdgen.org/forums/tech...odule-any.html |
Re: Trans am no longer starting Hi. Thank you for the link . the module that I had nine but hs I do not know the brand. The one I mounted is a Tx I think. I see indeed that even in nine modules are defective .... Good to know. Otherwise a module that burns while driving can stop the car? Thanks again . Mike |
Re: Trans am no longer starting This should be the first part replaced when try to solve a run/start issue. I have been through 2 in the past 4 yrs. The last one took me forever to find. Why, because I had just replaced it a little over a year prior. These things suck! As tunned said the AC delco from rock auto I feel to be the best of the replacements. My mechanic says the same. |
Re: Trans am no longer starting
Originally Posted by Mike69
(Post 6281497)
Hi. Thank you for the link . the module that I had nine but hs I do not know the brand. The one I mounted is a Tx I think. I see indeed that even in nine modules are defective .... Good to know. Otherwise a module that burns while driving can stop the car? Thanks again . Mike You can either loose spark or injector pulse or both at the same time. |
Re: Trans am no longer starting good evening I have some connection problems I thank you again for your help. I'll be back soon as my internet is repaired. Mike |
Re: Trans am no longer starting I ran accross this video on youtube, its a vett but if anyone is having a no start, no start when hot, this is 100% the steps to go through. Obviously you will not have all the high dollar tools but many of the same tests can be done with common multi meter etc. |
Re: Trans am no longer starting Good evening, I found my internet connection ... So for more than 2 weeks my transam starts quarter turn I can enjoy sunny days finally ... It's really fun. I will be able to begin its complete restoration. So I keep an ignition management module in the car. I tested it before of course to be sure that it works ... Thank you all for your help .... Mike |
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